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AIR User Manual - SiTex Graphics

1. 357 AIR User Manual When first invoked the filter should emit a single line containing a list of RIB commands that the filter will process Then the filter should enter a loop that waits on stdin Each RIB command will be sent as a single line of potentially very long ASCII RIB To pass RIB commands back to the renderer send them to stdout When the filter is done processing the current command it should emit a byte value 255 The filter may also need to flush the stdout stream to force all data down the pipe to the renderer Source code for the sample filters included with AIR can be found in SATRHOME procedurals 19 3 Geometry Export Beginning with release 3 0 AIR allows the polygonal meshes used for rendering to be exported to a file allowing the displaced geometry and other complex shapes such as a blobby system to be saved for re use with AIR or for import into a modeling package AIR can typically re render a baked displacement mesh many times faster than the original object with true displacement To export the rendering mesh for an object provide a filename with the following attribute Attribute render string meshfile filename The file format is determined by the file name extension Extension Format Lib RenderMan RIB dra RIB using DelayedReadArchive obj Wavefront OBJ ply PLY polygon format stl STL format RIB export normally uses the binary RIB format If the mesh file name contains the string ascii the R
2. 2001 2014 SiTex Graphics Inc Color 28 3 3 Ct ctransform rgb current Ct When current space is litRGB the color is transformed as per the description above With the default current space of rgb the above transform does not change the input color Care must be taken with metallic shaders that use the standard color attribute value to modulate reflections because the color used to modulate reflections should not include the effects of spectral prefiltering To handle this situation Air provides an option to query the raw SPD value for the standard Color attribute color spdrgb if attribute rawcolorspdrgb spdrgb 1 When an SPD file is used to specify the material color a reflective metal shader should use the raw rgb value to modulate reflections See Also Spectral Color Definition Tone Mapping Air 11 provides a basic tone mapping operator available as a display mode in Air Show and as an imager shader ToneMap A tone mapping operator converts a high dynamic range image into a low dynamic range image for display A tone mapped image should normally be viewed with sRGB or custom gamma correction or an equivalent LUT The tone mapping operator in Air Show and the ToneMap imager shader is based on the global operator described in Photographic Tone Reproduction by Erik Reinhard et al It has three parameters Middle Luminance the input luminance value correspondin
3. 2001 2014 SiTex Graphics Inc 335 AIR User Manual 13 8 The index of refraction would range between 1 2 and 1 8 An example can be found in SAIRHOME examples effects prism rib Subsurface Scattering SSS AIR provides fast simulation of the subsurface scattering effects common in soft or partially translucent materials such as skin and marble Subsurface scattering is implemented as a new shading language function subsurfacescatter and a capability to store and query a collection of points distributed over a group of surfaces Using Subsurface Scattering Enable subsurface scattering for an object as follows 1 Make all primitives that make up the object part of the same point set as defined with Attribute pointset string handle myobject pts The handle name should be a valid file name if you wish to save the point cache to a file 2 Assign a shader that uses the subsurfacescatter function such as the VTranslucent VSkin or VTranslucentMarble shaders included with AIR 3 Set the shader parameters appropriately for your object Scattering Distance The most important parameter to set is the one that controls the scattering distance Most shaders provide one parameter for setting the distance for the red green and blue color components and another parameter to scale the distance Use the ScatterDistance parameter to define the scatter properties for a particular type of mate
4. 203 AIR User Manual The appearance of waves in windy conditions can be improved using the Chop parameter which sharpens wave peaks and stretches troughs by shifting the surface laterally Because the chop displacement shifts the surface in arbitrary directions you ll need to tell Air that the displacement is not strictly in the direction of the surface normal by applying the following attribute Attribute render normaldisplacement 0 Note that too much chop can tear the surface apart Foam The Chop parameter must be greater than 0 in order for foam to be generated You will need to experiment with the FoamRawOffset and FoamRawMultiplier values to obtain a suitable base level of foaminess Animation The waves will be animated based on the current frame number The current time value is the current frame number divided by the FramesPerSecond value For speed the simulation is computed using the seawave dynamic shadeop DSO included with Air See Also OceanWaves displacement shader 10 10 2 paintedplastic HS plastic surface with a single texture map for color IIlumination Model plastic Features texture map Parameter Default Value Range Description Ka 1 0 0 0 1 0 Ambient reflectivity Kd 0 5 0 0 1 0 Diffuse reflectivity Ks 0 5 0 0 1 0 Specular reflectivity roughness 0 1 0 01 1 0 Specular roughness specularcolor 1itl Specular highlight color texturename vo Texture file name repeatx 1 Copies in
5. texturename File name of texture map to project textureblur 0 0 Blur for texture map texturescale 1 0 Scale factor for texture texturerotate 0 Rotation angle in degrees about the cone axis textureonce 1 0 or 1 When set to 1 only one copy of the texture is displayed textureup 010 Vertical axis used to orient the map projection __nondiffuse 0 0 1 If 1 light is excluded from diffuse light _honspecular 0 0 1 If 1 light will not produce highlights foglight 1 0 1 If 1 light illuminates volumes __ channel l 0 9 Output channel Description The spot_projector shader allows a basic spotlight to be used to project a texture map as a light source like a slide projector Like the spotlight shader the spot_projector shader emits a cone of light with apex at the source point from and direction given by the vector to from The coneangle parameter gives the half angle of the cone in radians The texture map given by texturename parameter is mapped to the inside of the spotlight cone The textureup parameter defines a vertical axis used to orient the map The texture scale parameter can be used to resize the map and the texturerotate parameter to rotate the map By default only one copy of the map is displayed You can change that behavior by setting the textureonce parameter to 0 and converting the texture map to an Air texture file using the Air texture conversion tools mktex or mktexui selecting the desired wrap mode in the proc
6. 2001 2014 SiTex Graphics Inc 289 AIR User Manual _ ambient Oi Cs Ka ambient color diffuse_weight Oi Cs Kd __diffuse diffuse_weight diffuse Nf indirect _ indirect unshadowed _ diffuse_unshadowed Shadow _ shadow __indirect diffuse_weight __diffuse_unshadowed diffuse_weight Ci __ambient _ diffuse See Also Multipass rendering Light Channels 10 15 1environment color environment mapname color environment raytrace color environment environment Optional Input Parameters Type and Name Description float bias offset to prevent incorrect self intersections float blur blur factor for fuzzy reflections string label user assigned name for rays cast by this call float maxdist maximum distance to search for intersecting objects float samples number of rays to trace when ray tracing or samples to use for map access string subset restricts intersection tests to members of the specified groups vector majoraxis tangent vector for anisotropic reflections float majorblur blur in majoraxis direction for anisotropic reflections float minorblur blur in minor axis direction for anisotropic reflections color weight weight or importance of this environment call for importance based ray tracing Ray Tracing Reflections If the file name passed to an environment call is raytrace or reflection Air
7. Shader Guide 112 LightCategories parameter will be included By default LightCategories is setto lensflare Use light categories to exclude particular lights from the lens flare effect including those with no physical location like the indirect light shader This effect works most reliably with point lights since the illuminance loop only returns lights that illuminate the current shading location For spotlights the camera location must be within the cone of illumination to generate a lens flare For a spotlight or area light you may wish to add an extra point light that does not illuminate objects in the scene to generate the lens flare for the the light Output only variables color _ bloom Bloom color color __star Star color color __ring Ring color 10 5 3 Paper imager shader simulating the effect of drawing on rough paper Parameter Default Value Range Description PaperColor 0 8 0 7 0 6 paper color BackgroundColor tid color used for uncovered pixels in the image Bias 0 5 0 1 bias for bump effect Start 0 Q L start value for bump effect End ik 0 1 end value for bump effect BumpName noise bump map name or noise for builtin noise function BumpSizeXY 11 bump map size Bumplinvert 0 Oor 1 when set 1 the bump map value is inverted Description The paper imager produces an apperance of drawing or painting on a rough surface using a bump map The paint rendered image sticks to the higher p
8. The minimum number of motion samples is taken from the pixel samples setting AIR selects the number of motion samples for each object based on how far the object blurs on screen The number of samples is calculated based on the maximum allowable distance between motion samples in pixels which can be set with Option render float motionthreshold 0 5 Depth of Field AIR can simulate the limited focal range of a physical camera to produce depth of field effects Physical cameras have a limited range over which objects appear in focus objects that are too close or too far away appear blurred Depth of field is set by 3 parameters DepthOfField f stop focallength focaldistance The parameters are taken from photography f stop the f stop corresponding to the size of the aperture admitting light into the camera Smaller numbers produce more blur Typical values for a 35mm camera range from 2 8 very blurry to 16 focused focallength focal length of the lens This should be in the same units as focaldistance focaldistance distance from the camera at which objects appear sharpest As with motion blur the quality of an image rendered with depth of field depends directly on how many pixel samples are used Blurrier images require more samples and take longer to render 2001 2014 SiTex Graphics Inc Motion Blur DOF amp LOD 346 16 3 Level of Detail AIR supports the RIB level of detail capability Un
9. 2001 2014 SiTex Graphics Inc Shader Guide 170 TrunkWobble adds random variation along the tree trunk TrunkBend gives a range of angles that cause the tree to bend as it grows If the TrunkSurface parameter is not null it defines the surface shader for the trunk The other shading related parameters for the trunk are passed to the surface shader as follows Tree parameter Surface parameter TrunkColorMap ColorMapName TrunkBumpMap BumpMapName TrunkBump BumpMax TrunkTextureSize TextureSizexy If the TrunkSurface parameter is empty the trunk inherits the surface shader assigned to the VTree procedure primitive The trunk geometry is defined using a RIB Curves primitive The curve definition includes values for the second standard texture coordinate t giving the length along the trunk This information allows textures to be applied to trunks of different lengths without unnatural stretching TrunkCurveType gives the curve type to use for rendering defaulting to a tube For trees that are far away the polyline or ribbon curve types may be used If the TrunkCurveType is set to the empty string the trunk will not be rendered Branches Parameter Default Value Range Description Branches 50 Total number of branches BranchLengthRatio 0 3 0 3 Branch length relative to trunk height BranchiTilt 10 110 Branch angle relative to trunk BranchBend 10 90 0 360 Bend angle along branch BranchBendBack 0 0 Optional bend a
10. AIR User Manual set to down each dimension is reduced to the next lower power of 2 When resize mode is set to up the next higher power of 2 is used Here are the corresponding output values for a 640x480 input image nearest 512x512 down 512x256 up 1024x512 On Linux some old code that tracked file descriptors has been removed from the texture routines New mktex option to convert an image to an Air texture map without resizing the image to a power of 2 in each dimension mktex resize none source tif target tx Mktex has a new blur implementation for environment maps The blur value is now an angle in radians and blur is supported for lat long environment maps The blurring process can take a while so mktex issues a progress message every second Mktex blur is now supported for regular textures The blur value is interpreted as a fraction of the total image area Indirect lighting A new option sets the quality of area light sampling for indirect lighting Option indirect arealightquality 0 gives a multiplier applied to the nsamples value for each light Replaces the old behavior of always using only 1 sample for each area light Max indirect samples increased from 1024 to 4096 Indirect irradiance cache samples now have their radius of influence clamped based on the maxpixeldist setting to avoid artifacts with large radii The indirect cache no longer searches higher bounce levels for cache entries when n
11. Options 54 Option indirect integer envsamples 4 Option indirect float envblur 0 0 Option indirect string envspace Option indirect moving 0 Occlusion Option occlusion string savefile Option occlusion string seedfile Option occlusion integer prepass 0 Option occlusion float prepassfactor 0 5 Spectral Prefiltering and Chromatic Adaptation Option render string dominantilluminant_spd Option render string displayilluminant_spd Option render string currentcolorspace rgb Caustics Option caustic string savefile Option caustic string seedfile Subsurface Scattering Option render float subsurfacetolerance 0 005 Option render integer sssmultithread 1 Option render integer sssautocache 0 Option runtime integer sssinfo 0 Textures Option texture boolean automipmap 0 Option texture string autoresize nearest Option texture string wrapx periodic Option texture string wrapy periodic Toon Rendering Option toon float maxinkwidth 0 0 Option toon float fadethreshold 0 0 Option toon float mininkwidth 0 0 Option toon float inkwidthmultiplier 1 0 Option toon string vectorexportfile Option toon float mergetolerance 0 01 Option toon float maxedgelength 0 Network Cache Option netcache string cac
12. 1 4 15 12 8 wee user shadowgroups Range Oor1 1 12 o 0 24 Oor 1 Oori 0 0 0 5 1 256 Description Light intensity Light color whether to use the computed sun color atmospheric turbidity integer 2 9 date month day of month time of day 24 hour clock observer location difference between local time and GMT When non zero the end time for animation Multiplier for the global time value When positive sets sun zenith position Override for sun azimuth position when 1 Y is up otherwise Z is up North direction as an angle in degrees relative to the X axis Set to 1 for a right handed coordinate system Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for traced shadows Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name 2001 2014 SiTex Graphics Inc 161 AIR User Manual window_size_x 10 window_size_y 10 window_center 00 0 window_xdir 10 0 window_ydir 010 window_panes_x T window_panes_y 1 window_gap_x 0 1 window_gap_y 0 1 window_fuzz_x 0 01 window_fuzz_y 0 01 window_space world texture_name wee texture_blur 0 __hnondiffuse 0 __nonspecular 0 __ foglight 1 _ channel 1 Description window width window height center of window horizontal axis for the window vertical axis for the window
13. 2001 2014 SiTex Graphics Inc 343 AIR User Manual 15 3 15 4 for the environment lookup should normally be set to world Sample shader declaration Surface VMetal string ReflectionName blueskygreenground tx String ReflectionSpace world Cube faced Environment Maps A cube faced environment map is generated by rendering 6 orthogonal views of a scene from the point of view of the reflective object The 6 maps are combined into a single reflection map using the mktex facility mktex envcube px nx py ny pz nz envfile tx A plugin may automatically generate cube faced environment maps A cube faced environment map can be used with any shader that supports environment maps The coordinate space parameter if present should normally be set to world Sample shader declaration Surface VMetal string ReflectionName teapotrefl tx String ReflectionSpace world Anisotropic Reflections AIR ships with two shaders for simulating anisotropic reflections such as those seen on brushed metal surfaces The VBrushedMetal shader can be used for brushed metal surfaces and the VBrushedPlastic shader for plastic surfaces with fine grooves Most shaders that compute anisotropic reflections use a tangent vector on the surface to orient the reflections Valid tangent vectors are always available on parametric surfaces such as NURBs or bilinear or bicubic patches For other primitive types such as polyg
14. AIR User Manual The instCarpet instancer shader creates a carpet of fibers on a rectangular base polygon Carpet Shape The carpet is modeled as a grid of carpet fibers The geometric model of the fibers can be tuned using the following parameters StrandCount StrandHeight StrandWidthFraction StrandTaper StrandBaseVary The overall density of the fibers is set with StrandCount which gives the number of fibers per unit length The diameter of a fiber is given by the StrandWidthFraction parameter as a fraction of the fiber length The displacement bound for the base primitive should be set to the same value as StrandLength By default the carpet curves have the same width from root to tip The fibers can be tapered by lowering the StrandTaper parameter which gives the width at the curve tip relative to the width at the curve root StrandBaseVary varies the base position of each strand TiltMaxAngle TiltPower PolarAngle PolarVary PolarFrequency TiltWMaxAngle gives the maximum angle in degrees between the vertical direction and the tip of a fiber TiltPower is an exponent applied to the tilt interpolation along the strand length The direction of tilt can be changed using the StrandPolar parameters which control a rotation in degrees about the vertical axis Stiffness Stiffness Vary StiffnessFrequency StiffnessAtEdge Stiffness controls how each fiber bends or tilts away from the vertical StiffnessVary and Stiffness
15. Default 30 0 2 0 04 Range 1 40 180 20 0 0 or 1 ribbon polyline ribbon tube 1 O or 1 Description Strand count per unit length Strand length Strand width as a fraction of strand length Multiplier for the width of the curve at the curve tip Set to 0 to taper the curve toa point Variation in the base position of each strand Base rotation about the vertical axis Variation in polar angle Frequency of polar variation relative to the carpet rectangle Maximum amount to bend or tilt the fibers as an angle between the fiber tip and the vertical axis Exponent influencing the way fibers bend Measure of fiber material stiffness Variation in stiffness over the carpet How often the stiffness varies relative to the carpet as a whole Stiffness near the edges of the carpet Width of an edge region in strands Variation randomly added to the edge distance for each strand Base fiber color Color variation per strand Optional color map Optional mask used to cut a shape out of the rectangle Threshold for mask visibility Diffuse reflectivity of strands for indirect rays Whether the strands are visible to indirect rays If greater than 0 the number of rays to trace to compute indirect illumination Geometric representation of the strand curves Whether to export a texture coordinate pair for each strand Seed value for random variation 2001 2014 SiTex Graphics Inc 119
16. Description The VLayeredMaterials shader allows multiple materials to be applied to the same surface The shader has a base material and up to 3 layer materials whose coverage can be controlled with a texture mask All textures and masks share the same underlying 2D coordinate system specified with the Projection ProjectionSpace and ProjectionTransform parameters 10 10 5 Leather surface shader for leather with procedural cracks and wrinkles IIlumination model plastic with Blinn specular Features reflections procedural bump pattern 2001 2014 SiTex Graphics Inc 243 AIR User Manual Parameter Default Value Range Description Diffuse 0 6 0 0 1 Diffuse reflectivity Specular 0 4 0 0 1 Specular reflectivity SpecularSize 0 5 0 0 1 Specular size Blinn eccentricity SpecularRolloff 0 4 Blinn rolloff parameter Reflection 0 3 0 0 1 Reflection strength ReflectionSamples 4 1 256 Number of rays when ray tracing ReflectionBlur 0 1 0 0 1 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup BumpMax 0 1 Max bump amplitude BumpSpace shader space for bump amplitude CrackWidth 0 2 Crack width relative to PatternSize CrackDepth 0 05 Crack depth relative to BumpMax CrackDistortion 1 Q 1 Crack pattern deviation from a regular grid CrackCoverage 0 5 0 1 Fraction of surface
17. Option limits integer splitpolyfaces 25 Option limits integer splitmeshfaces 25 Runtime Control Option limits integer nthreads 0 Option runtime integer priority 0 Option render string bucketorder rows Option limits integer 2 bucketsize 32 32 Option runtime string verbosity normal Traced Reflections Option reflection color background 0 0 0 Option reflection string envname Option reflection float envstrength 1 0 Option reflection integer envsamples 8 Option reflection float envblur 0 0 Option reflection string envspace Indirect Illumination Option indirect integer environmentcache 0 Option indirect integer maxbounce 1 Option indirect float arealightquality 0 0 Option indirect reduceradiosityquality 0 Option indirect string radiositysizespace world Option indirect string savefile Option indirect string seedfile Option indirect integer prepass 0 Option indirect float prepassfactor 0 5 Option indirect string prepasschannels __ lights Option indirect string prepassgroup list of groups Option render syncprepass 1 Option indirect color background 0 0 0 Option indirect string background_spd Option indirect string envname Option indirect float envstrength 1 0 2001 2014 SiTex Graphics Inc
18. The Air distribution includes a small collection of SPD reflectance and illumination files in the spectra directory A search path for SPD files can be specified using Option searchpath string spectrum Spectral data is converted to an RGB color for rendering 2001 2014 SiTex Graphics Inc Color 26 3 2 IIluminant Color Temperature Air 11 allows the spectral profile for an illuminant to be specified by entering a color temperature as the SPD file name value E g LightSource distantlight 1 string lightcolor_spd 2400 sunset Solar Spectrum Air 13 introduces a new capability to define a spectrum using a new builtin sun function instead of an SPD file There are two forms The first is sun zenith 45 turbidity 5 zenith is an angle in degrees giving the sun s elevation measured from the vertical turbidity is a the same value passed to the sunlight shader The second form is sun month 4 day 15 hour 12 timezone 8 latitude 47 longitude 122 turbidity 5 The parameters have the same meaning as those in the sunlight light shader This new capability allows spectral prefiltering and chromatic adaptation to work with a sun light See Also Spectral Prefiltering and Chromatic Adaptation Spectral Prefiltering and Chromatic Adaptation Spectral Prefiltering In Picture Perfect RGB Rendering Using Spectral Prefiltering and Sharp Color Primaries Greg Ward and Elena Eyd
19. The base color of the front side is taken from the object s color attribute The base color for the back side is set with the BackColor shader parameter Front and back sides may each have a texture map with completely separate mapping controls 10 10 3 VAnimatedMap surface shader with animated texture map IIlumination model plastic Features reflections animated texture map Parameter Diffuse Specular SpecularRoughness Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace MapBase MapExtension MapCount MapDuration FrameStart FrameEnd TextureSizexY TextureOriginXY TextureAngle Description Default Value 0 5 0 0 raytrace current woe tif Description Diffuse reflectivity Specular reflectivity Specular roughness Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Map base name minus frame number File name extension for maps Number of maps Number of frames to display each map Frame for map number 0 Frame at which to stop animating Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees The VAnimatedMap surface shader allows a sequence of numbered maps to be displayed during an animation The maps should have a common base name followed by a 4 digit index zero padded followed by the
20. When 0 rays emanate from a single point when 1 rays are parallel Shear applied to light cone Width of the light opening at z 1 Height of the light opening at z 1 Width edge fuzz Height edge fuzz Shape of the light cross section O rectangle 1 perfect ellipse Controls falloff in intensity with angle for a spot light Texture map for filtering the light Amplitude for noise applied to the light Frequency for noise Offset for noise useful for animation 2001 2014 SiTex Graphics Inc Shader Guide 166 shadowname ai Shadow map name or raytrace for traced shadows shadowblur 0 01 0 0 1 0 Blur for shadow map shadowbias 0 01 Bias for shadow map shadowsamples 1 1 256 Rays for traced shadows shadowcolor 000 Color for shadows blockercoords mY Coordinate system for blocker blockerwidth 1 0 blockerheight 1 0 Width and height of blocker in x and y of blockercoords blockerwedge O 1 Blocker width edge fuzz blockerhedge 0 1 Blocker height edge fuzz blockerround 1 0 0 0 1 0 Roundedness of blocker __nondiffuse 0 0 1 If 1 light is excluded from diffuse light nonspecular 0 0 1 Set to 1 to exclude from specular calculations ___foglight 1 0 1 If 1 illuminates volumes _ Channel 1 0 9 Output channel Description The uberlight shader is a multipurpose light shader with many parameters The uberlight shader included with AIR is a slightly modified version of the shader discussed by Ronen Barzel in chap
21. air64 options RIBcommand s RIBfile s Air Control AIR Control provides a graphical user interface for setting basic parameters and starting a rendering process with AIR See Also Command Line Rendering of Massive Scenes Command Line Switches Linux Notes 2001 2014 SiTex Graphics Inc Geiting Started 16 1 4 Linux Notes Libraries The user interface tools such as Air Show and Vshade rely on older versions of GTK GDK and related libraries You may need to add the 32 bit version of these libraries to your Linux installation if they are not already present You can see a full list of dependencies with e g ldd SAIRHOME bin airshow The air binaries and other command line tools do not depend on GTK GDK or the related interface libraries 1 5 Command Line Switches You can view an abbreviated list of command line options by starting Air with an argument of air The following command line arguments are recognized by Air anim nframes starttime endtime fractionopen Generates a sequence of nframes frame blocks with shutter times for animating time varying RIB files at name token value Define a custom attribute with a string or float value the equivalent of Attribute name token value bs width height Sets the size in pixels of the buckets or tiles used for rendering columns Use column bucket order crop left right top bottom Restricts rendering to a subr
22. Output 34 5 Output An AIR rendering process produces one or more raster images Each image is passed to a user specified display driver which may save the image to a file or display it in a window AIR comes with display drivers for most common image formats A current list of AIR display drivers can be found here A plugin or host application should provide an interface for specifying the output images rendered by AIR In a RIB file an output image is declared using the Display call which has the following syntax Display filename drivername channels parameter list Here s an example Display test tif file rgba Driver Specification The driver name is used to select the display driver If the driver name is file AIR uses the file name extension to choose a display driver When the driver name is framebuffer the image is sent to the AIR Show framebuffer instead of being saved to a file Channels The RenderMan standard specifies 5 standard output channels r g b a and z corresponding to the red green blue alpha and depth output values AIR also allows any output variable from a surface displacement or atmosphere shader to be saved to a file Most AIR surface shaders provide a standard set of output variables described in more detail in the multipass rendering section Each additional output value must have its type declared either using the Declare RIB statement or an inline type declaration in the
23. Returns the visibility between two points If there are no intervening objects the function returns 1 1 1 If there is a fully opaque object in between returns 0 0 0 Partial occlusion will return a partial transmission value 10 15 3 voronoi 11 void voronoi string type point pos float jitter output float distl output point centerl void voronoi string type point pos float jitter output float distl output point centerl output float dist2 output point center2 The voronoi function computes a 2D or 3D cellular pattern The type parameter should be either grid2d or grid3d The jitter parameter controls deviation from a regular grid and should lie between 0 and 1 The dist1 parameter returns the distance from the query point pos to the nearest cell center centerl Similarly dist2 returns the distance from pos to the second nearest cell center center2 2D Texture Mapping Preparing Texture Maps For the most efficent rendering in terms of soeed and memory use all texture files should first be converted to AIR texture maps AIR texture maps can be created with the mktex command line utility or the mktexui graphical user interface in addition to the RIB MakeTexture command Your plugin may automatically perform this conversion for you Although AIR can directly use textures in a variety of graphics formats creating an AIR texture file has several advantages e The wrapping behavior of the textur
24. Transformation applied prior to projection ProjectionTransform oroo rFOoOOO 1 0 0 1 0 0 0 0 Description The VSkin shader models the apperance of human skin including subsurface scattering with an optional texture map for detail The skin illumination model has three distinct components e A single scattering component due to light that enters the skin and is then reflected e A multiple scattering component simuluating light that enters the skin bounces around and then exits e A sheen component simulating the shininess of the skin All Single scatter Multiple scatter Sheen 2001 2014 SiTex Graphics Inc 261 AIR User Manual Single Scattering The SingleScatter parameter sets the strength of the single scattering component This component is also influenced by the SkinThickness parameter which should be appropriate for the scale of the model Larger values of SkinThickness produce a brighter single scattering component 0 25 1 0 Multiple Scattering The multiple scattering component is computed using AIR s subsurface scattering capability When a subsurface scattering object is first encountered AIR calculates and stores a set of shaded points distributed over the object s surface You may notice a delay as AIR performs these computations After the point cache is generated rendering should proceed relatively quickly To use subsurface scattering assign the same point set hand
25. c sccceeseceeeeneeeeeeeeeeeeeeeeeseeeeneneeeeenes Light Channels csseccssecesesesesseeeeseeeeneeeessaeseseeesnseeeenseeess Stereo and Multicamera Rendering cssscsseeeeeeeees Motion Vector Output cccccesccesseeesseeeeeeeeeseeesesneeenseeeesseeess Deep IMAGO aea EENE Display DriVerS sen2c ccccsscceecececectecsteees ctacdeceeoscecesdeceasessocczersencces bmp Windows Bitmap cccsssesssseeeessteeensseesesseeeeessenensseeeeseeee deeptxt Deep Image Text File ccescesseessseeeeessteeessneeenssneeeeees exr OpenEXR e sce sees eecac ccc bel ses cececcectecces coeiecaeysteuurceecuteccncesneese framebuffer ese teeneseenesscenensnenensceeeensenenensneeenacceesenenenensneesesensenes hdr Radiance Image Format csseccssseessseeeessseeeessnenensnteeeseeeee jpeg JPEG Interchange File Format cescsseseesseeeereneeeeeeee pic Softimage PIC e reiia aaaea araen ana aeara padara ARAE ainean 2001 2014 SiTex Graphics Inc Contents ll png Portable Network Graphics 22050 esse cocccccccctetccssceccds ecole cccussececaucsendestces sane sodergans eceecueeauassedesseusecdusdaarsdcerracren 45 PSC PHOTOSHOP Mer 45 PEK PTEI peneana a AE 46 rpf Rich Pixel Format cccsssseessseeeessseeeesseeenseeesescneeeeseneeesseeesessaeeeaseneeeaseesessaeesesaneeensneeseasaeeseseneeensneeseseneaeas 47 Ta TANGA E e E E sue 48 tiff Tag Image
26. directional light shader Parameter Default Value intensity 1 0 lightcolor 111 from 000 to 001 shadowname m shadowbias 0 01 shadowblur 0 01 shadowsamples shadowcolor 0 0 0 shadowgroups on shadowattribute __nondiffuse 0 ___nonspecular 0 __ foglight 1 _ channel 1 Description user shadowgroups space Range 0 0 0 5 1 256 Bake map file name Bake mode Blur for bake map query Filter width for bake map query bounding box for moving objects coordinate space of motionbound Description Light intensity Light color Source position of light Target of light Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for traced shadows Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel The distantlight shader emits light in a single direction defined by the vector to from The incident light at the point being shaded is simply the product of the intensity and lightcolor parameters 2001 2014 SiTex Graphics Inc 133 AIR User Manual 10 7 7 Traced Shadows If the shadowname parameter is set to the special value rayt race shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number
27. e New method of transferring primitive variable data to shaders allows prim var data to be used with layered and networked shaders The new method is also slightly faster Area lights can now query the total surface area of the area light geo with float surfarea attribute light area surfarea e New function str_replace last number can be used to replace the last number in a string with a new value e The gather function can now be used to query point clouds Instancers and instancing New data structure greatly accelerates sampling a primitive using standard texture coordinates Instancers can now be evaluated by multiple threads simultaneously Instancers can reference the object space coordinate system of the base object Instancers now handle scale for width and constantwidth prim var data Instancers can reference user attributes attached to the base object Objects created by an instancer now inherit any user attributes attached to the instancer s base object Modified instancer bound computation to look for particle curve width data Multiple instancer shaders may now be assigned to an object e Command line switches e The frames command line option no longer uses the frame range to filter rib based on the frame number passed to FrameBegin This change allows a numbered sequence of files to be rendered regardless of the frame numbers set in the rib In particular this feature now works with the shadow map ribs generated by Air S
28. file varying color __specular quantize 0 255 0 255 Option render commands Display The last line is important it tells AIR to ignore subsequent Display calls in the RIB stream Save the above to a text file say displays rib then render with air displays rib massivescene rib You can save 16 bit or floating point data instead of 8 bit data by changing the quantize parameters For 16 bit output quantize 0 65535 0 65535 For floating point output quantize 0 0 0 0 The frame number can be included in a Display call with nf where n is the number of digits E g Display beauty_ 4f tif file rgba would render to beauty_0021 tif for frame 21 Multiple Outputs in a Single Image Instead of generating a separate image for every output variable multiple output values can be saved in a single file to formats such as TIFF OpenEXR and PSD that support more than 4 channels per 2001 2014 SiTex Graphics Inc 379 AIR User Manual image To save more than one value in a single image provide a comma separated list of output variables in the Display call For example Declare __diffuse varying color Declare __ specular varying color Display multi psd file rgba __ diffuse specular Display Templates The AIR distribution includes 3 template files with Display calls for rendering 8 bit 16 bit and floating point output displays8 rib displaysl
29. indirect Range 1 1024 1 00r1 Description Light intensity Light color Number of rays to trace for each sample Max distance to search for nearby surfaces Whether to use adaptive sampling Optional environment map for background Coordinate space for environment map Light categories If 1 light will not produce highlights If 1 light illuminates volumes Flag indicating indirect light status for multipass rendering Output channel 2001 2014 SiTex Graphics Inc Shader Guide 142 The massive_indirect light shader encapsulates Air s indirect diffuse illumination capability sometimes referred to as global illumination The emitted light value is the indirect light incident at the current shading location scaled by the intensity and lightcolor parameters which can be used to tweak the indirect diffuse results This light shader is designed for computing indirect illumination results without using an irradiance cache The samples maxhitdist and adaptivesampling parameters provide basic controls over Gl quality Massive users will also need to assign a custom options rib to the scene with the following attribute to enable object visibility to indirect rays Attribute visibility indirect 1 Users may also wish to set the number of indirect bounces with Option indirect maxbounce n By default only 1 bounce of indirect illumination is computed See Also massive envlight
30. 0 Multiple Output Images Multiple images can be produced from a single rendering by providing additional Display calls with the file name prepended with a For example Display mp_beauty tif file rgba quantize 0 255 0 255 Display mp_diffuse tif file varying color _ diffuse quantize 0 295 0 255 Display mp_specular tif file varying color __specular quantize 0 255 0 255 Selecting Channel Components Sometimes it may be helpful to save only a single channel from a color output variable A single component can be specified by appending an index after the variable name in the Display call For example the following declaration creates a 3 channel file with the first red component of each output variable Declare __specular varying color Declare __diffuse_unshadowed varying color Declare __ shadow varying color Display key tif file diffuse_unshadowed 0 shadow 0 __specular 0 Per Frame Display Names If a display file name contains the special formatting sequence nf AIR will automatically substitute the current frame number for the sequence E g Display test 4f tif file rgb would become Display test0023 tif file rgb for frame 23 The frame number is taken from the FrameBegin statement in the RIB file 2001 2014 SiTex Graphics Inc Output 36 5 1 Multipass Rendering Multipass rendering is a method of improving the e
31. 1 0 0 01 1 0 0 0 0 0 1 0 1 0 e re oo 0 0 0 1 0 1 256 0 0 1 0 S aces Description Diffuse reflectivity Specular reflectivity Specular roughness specular reflectivity for clear finish layer reflection multiplier for clear finish layer surface roughness sharpness of highlight edge Flake intensity Flake frequency Fraction of area covered by flake Specular roughness for flakes Flake color Reflection strength for base Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup The VCarPaint surface shader simulates metallic car paint with a clear finish The base metal color is taken from the object s color attribute The clear finish adds glossy highlights and reflections unmodulated by the base color to the underlying metal Metallic flakes embedded in the paint can be added using the Flake controls The flakes are distributed in texture space using standard texture coordinates They are generated using an antialiased noise pattern so small flakes will fade out with distance 10 10 3 VCeramic 1 glossy reflective surface with optional texture maps for color and shininess IIlumination model ceramic Features reflections texture maps 2001 2014 SiTex Graphics Inc Shader Guide 220 Parameter Diffuse Specular SpecularRoughness SpecularSharpness Reflection Reflec
32. 2001 2014 SiTex Graphics Inc 395 AIR User Manual 23 3 display device for the desired file format By default the rendered image will be saved at 8 bit precision To render at 16 bit precision change the Quantize values to 65535 0 65535 0 5 To render a floating point image set the Quantize values to 000 0 Air can produce an arbitrary number of additional output images from a single rendering Additional images typically save arbitrary output values AOVs computed by a shader Use the AOV tab to add additional output images Reflections Many Air surface shaders can compute reflections using ray tracing For objects to appear in reflections they must be made visible to reflection or trace rays To enable reflection visibility globally go to the Trace sub tab of a RIB operator s Properties tab and check Visibile in Reflections The Max Trace Depth control in the same tab gives the maximum number of bounces to follow reflection or refraction rays A background color or environment map can also be given that provides a color for traced rays that miss all objects in the scene Motion Blur and Depth of Field Motion blur and depth of field can be enabled on the Sampling sub tab under the Properties tab of the RIB output operator Houdini Lights and Air Houdini automatically translates Houdini lights when exporting a scene to Air Ray traced Shadows If a Houdini light s Shadow Type is set to Ray Trace Sh
33. AIR 7 March 2008 AIR 6 July 2007 2001 2014 SiTex Graphics Inc History 426 29 1 AIR 5 December 2006 AIR 4 1 July 2006 AIR 4 November 2005 AIR 3 1 June 2005 AIR 3 February 2005 AIR 2 9 September 2004 AIR 2 8 June 2004 AIR 13 0 New SketchAir plug in for SketchUp available as a separate download from the SiTex Graphics web site Air Stream for Maya 2 0 available as a separate download from the SiTex Graphics web site New Retexture tool for interactive material tweaks Windows only See the separate Retexture User Manual for more information Physically Plausible Shading e New importance based method for sampling reflections based on a specular BRDF allow reflections and specular highlights to be treated in a consistent manner enabling a new set of physically plausible shaders e New physically plausible shaders SimpleMetal SimplePlastic VPhysicalMetal VPhysicalPlastic Color e Anew Color section of this document provides a simple unified discussion of the proper handling of color input and output values when rendering with Air Other topics dealing with color have been grouped under the new Color section A color can be specified as a solar spectrum New option to have Air automatically convert raw texture images from sRGB color space to linear rgb ColorSpace rawtexture sRGB The option to apply the dominant illuminant and chromatic adaptation to rgb colors h
34. AIR uses this option to expand the internal storage for each bucket to prevent lines from being clipped at bucket boundaries The smoothness of the outlines depends on the number of pixel samples used Increase the number of pixel samples for smoother lines AIR provides several methods of generating outlines which can be divided into two broad categories image based methods and object based methods Image based Outlines Region Boundaries Edge lines are drawn between different regions of an image By default each primitive is assigned a distinct region id A region id can be explicitly assigned to a primitive with Attribute toon integer id n 2001 2014 SiTex Graphics Inc 347 AIR User Manual The image background is assigned a region id of 0 The special region id of 2 causes every polygon to receive a distinct id which can be used to outline a rendering mesh for illustration purposes The region id may also be generated in a surface shader by setting a__ toonid output variable of type float This capability allows shader generated patterns to be outlined Depth Differences Another method of identifying different regions or objects is to use depth based detection which can be enabled with Attribute toon float zthreshold depth Where depth gives the minimum depth between distinct surfaces The depth threshold can be set by a surface shader with a__ toonzthreshold output variable of t
35. Description saves images in Radiance hdr high dynamic range format File extension hdr Channels 3 channels rgb Data types floating point File data compressed 5 7 6 jpeg JPEG Interchange File Format Description saves images in JPEG File Interchange Format File extension jpg Channels single channel or 3 channels rgb Data types 8 bit unsigned integer File data compressed lossy Parameters float 2 resolution x y Gives the resolution of the image in x and y in pixels per unit given by resolutionunit string resolutionunit unit Gives the unit of measurement for the resolution of the image Unit must be one of inch meter centimeter or none The default is none integer quality 75 JPEG uses a lossy compression technique the quality parameter determines how much error is allowed in the compressed image The range is 0 to 100 with 100 providing the highest quality and the least compression 5 7 7 pic Softimage PIC Description saves images in Softimage PIC format File extension pic Channels 3 or 4 2001 2014 SiTex Graphics Inc 45 AIR User Manual 5 7 8 5 7 9 Data types 8 bit unsigned integer File data uncompressed png Portable Network Graphics Description saves images in Portable Network Graphics format File extension png Channels single channel single channel plus alpha rgb rgba Data types 8 or 16 bit unsigned integer File data co
36. Display Diffuse tif file varying color __diffuse e The real names of arbitrary output variables are passed to display drivers so that drivers such as OpenEXR can save full channel names New edge mask option when rendering shadow maps may improve shadows cast by small or thin objects Option render integer shadowedgemask 1 PointsGeneralPolygons now detects and handles non planar 4 sided polygons The Progress command line switch now outputs current memory peak memory and elapsed time in addition to a percent complete value E g R90000 55 1334K 2444K 19S New additions to the Plugins and Companions page e XSIMan a new plugin for XSI from Graphic Primitives e Temerity Pipeline a production management application Bug fixes Uniform string primitive variables were not handled properly Attribute comparison bug affecting bakemaps for BakeAIR Subtle noise bug for sample locations close to but less than an integer Subtle bug in normal compression for normals near 0 1 0 Binary rib bug in handling of 16 bit string ids Long shader parameter names are compared properly with truncated names in s1b files The shading compiler accepts a variable string argument to ctransform AIR 3 1 TweakAlR a new product for interactively tweaking shading and lighting in a scene New Photoshop display driver for producing layered Photoshop files New Photoshop image reader 2001 2014 SiTex Graphics Inc History 4
37. Features reflections Parameter Default Value Ka 1 0 Kd 0 0 Ks 1 0 roughness Ord Kr 1 0 texturename raytrace Description Range ooo ooo ae pea ooo 0 01 1 0 0 0 1 0 Description Ambient reflectivity Diffuse reflectivity Specular reflectivity Specular roughness Reflection strength Name of reflection map or raytrace for ray tracing The shinymetal surface shader is included for compabitility with the RenderMan Interface Specification For a more flexible metal shader with reflections use the VMetal shader instead See Also VMetal shader 10 10 2 ShowNormal surface shader for displaying the shading normal at the current location 2001 2014 SiTex Graphics Inc Shader Guide 208 Parameter Default Value Range UseUnitRange 1 0 or 1 FaceForward 1 0 or 1 Normalize 1 0 or 1 ShadingSpace shader space 10 10 2 howPosition Parameter Default Value Range UnitSize 1 Origin 000 Clamp 0 Oor 1 Cyclic 0 O or 1 ShadingSpace world spaces Description Description When enabled the x y and z components of the normal are scaled and offset to lie in the range 0 to 1 When enabled the displayed normal is always facing forward toward the camera When enabled the normal vector is normalized coordinate space of displayed normal surface shader for displaying X Y Z coordinates at each location Description Divisor for emitted position values Center point for p
38. File Format ioc css22c5cceccceaccecencdecedssenentie cae cece ceneccns as siceuteecdegie cobecutecsdexecesczcepesessectbeaduncet Sapa ceiid rasit 49 sgi SGI Image FOnMAt ecb cecescccccelees ces cetcecededececvatesaacecudesacee cetescuds tices vecesandecudesaces seuesdudvducessauesuadeducycacus seuescvesducrstdees 49 Shadow AIR Shadow Map File csi i cccccccesc2csccetecs czegecces desececeseies ssccesccdcctezeneeecuaeseddconerscecesccscatedenceecuaesacechtescnedsieass 50 texture AIR Texture Mapp cssssessssersesenereneneeessccesessenenenaneeessceseasenensnaneesdsecessesenenenaneeedaeceesenenenenaneeenaneeneanes 50 8 Custom Display Drivers cccsccsseessneeeeseeeseeesesneeenseeeeeeesesaaesesneeeneeeessaesaseaesnseaeesseeesnaeseseeeenseaes 51 Part VI Options 52 T Runtime Control sssccniicnnciel caine iin in iain 55 2 Search Pats senaia AaS EAEE etetac ced AAE aie acceded 56 3 Simple RIB FilterinG wccsccc ccicccce ce cetescct cscs ee cece ected aaier renanira ia dande stteaveestvevanesstuevenneeed 57 4 Shadid O rr ra EEn aE e aE aaa eE Eaa aaa r ar Ea aaraa p area aaa S a AAA Eaa EEE DaRi 58 5 Network Cache seanna RNAAR AA REAREA AAA AAEE AARAA AAAA AANE ARANA AA AAAA 59 6 File Manageme nt oss ccceccrenenennnn en es ecueeedetences sesuaensesesenceeeseceeetteseneees 59 7 USe r Detined Opto S i raae a aaa aaa a arara aaa aa araa aaa raaa aeaaaee a aae adaa aiaa aaia 60 Part VII Attributes 60 T ViSibiIY sisena kee ee
39. Fix for TweakAir so that a missing texture file does not disable texture access for other instances of the shader which may share the same code list Fix for ray attenuation based on ray weight to avoid generating inconsistent results in the irradiance cache mostly only a problem when using the cache without a prepass Color Obtaining correct results from any renderer depends on the proper handling of color input and output Lin values This section describes how to properly convert colors when rendering with Air ear and sRGB Color Spaces The computations performed by Air assume that color values are linear so that say doubling the output color for a pixel doubles the intensity value However most monitors and printers display images ina non linear color space that better matches the response characteristics of the human visual system Obtaining linear color values for use with Air will typically require some conversion on the input and the output sides The non linear aspect of the display color space is often represented as a mathematical function with a 2001 2014 SiTex Graphics Inc Color 24 single parameter called gamma Typical gamma values can range from 1 8 to 2 4 or more In recent years most manufacturers of devices that display images such as monitors or printers or that create images such as cameras and scanners have adopted the sRGB color space as a standard for digital images The sR
40. Inc 47 AIR User Manual 5 7 11 enables saving data as 16 bit floating point numbers half precision The display output quantization should also be set for float precision when saving half data float makemipmaps 1 enables mip map generation for the created PTEX file Each face map will be stored at multiple resolutions for faster higher quality rendering See Also PTEX Per Face Texture Mapping Baking PTEX Textures with BakeAir rpf Rich Pixel Format Synopsis saves data in Rich Pixel Format File extension rpf Channels rgba z P dPdtime z s t Data types various Parameters string author name String identifying the author of the image String description text Description of the image float bits 8 By default R G B A values will be saved as 8 bit values To save RGBA data at 16 bit precision pass the bits parameter to the display call with a value of 16 Description RPF files are a useful way to pass extra information about a scene to a compositing package In addition to the color and alpha information stored in most file formats RPF files can also store depth values texture coordinates surface normals motion vectors and object or material identifiers Because of the variety of output options available in the RPF driver it is somewhat more complicated to set up and use than other display drivers Please read the following carefully Every file using RPF output should have th
41. OpacityPerUnit gives the extent to which the smoke obscures objects behind it ReflectancePerUnit gives the extent to which the smoke reflects light toward the viewer StepsPerUnit gives the number of ray marching steps to perform per UnitSize distance More steps take longer to render but produce better results MaxSteps gives the maximum number of steps to march for any one shader call If SnokeVary is greater than 0 the smoke will be modulated by some Brownian noise to produce an non uniform effect This shader is based heavily on the smoke shader in section 12 6 of Advanced RenderMan by Apodaca and Gritz 10 12 DarkTree Shaders DarkTree is a visual shader creation tool from Darkling Simulations DarkTree 2 0 is an advanced procedural shader authoring tool Its visual flow based editor lets you interactively create photo realistic procedural materials surface shaders and animated effects DarkTree 2 0 includes 100 procedural components that can be combined to generate almost any texture or surface effect you need An evaluation version of DarkTree is available from the Darkling Simulations website Using DarkTree Shaders Darkling Simulations has developed a DSO shadeop a plugin for the shading language that allows DarkTree shaders to be used with AIR the shaders created by DarkTree are not directly compatible with with shading language used by AIR 2001 2014 SiTex Graphics Inc Shader Guide 276 To
42. SAIRHOME examples layers Simple Color Layers Here s a simple RIB fragment that assigns multiple surface shaders to an object Surface ColorMap string ColorMapName grid tx Surface VMarble Prepending the shader name with tells the renderer to append the shader to the list of shaders assigned to the object The shaders are executed in the order in which they are assigned Subsequent shaders inherit the current shading state including the values of global variables from shaders previously executed Here s an implementation of the ColorMap shader that uses a texture map to set the object s color value generic ColorMap string ColorMapName float SetColor 1 output varying color _ Color 0 if ColorMapName Color color texture ColorMapName s t if SetColor 1 Cs __Color In the RIB fragment given above the VMarble shader will use the color map result as one of the input colors for the marble pattern No modification of the VMarble shader is required The new generic shader type is compatible with any other shader type Generic shaders can be used to construct re usable components for layered and networked shaders Sample rib colormap rib Decals The layers example directory includes a LayerDecal shader that applies a masked color to a surface Simple sequential shader assignment allows an arbitrary number of decals to be applied to a surface without constructing a complex custom s
43. The Coverage parameter gives the approximate fraction of the surface covered with nicks 2001 2014 SiTex Graphics Inc Shader Guide 96 10 2 12 VNormalMap Apply normal map with normals stored in object space or world space TextureName me Texture name TextureBlur 0 0 0 0 1 0 Texture blur TextureSizexY 1 L Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees See Also VTangentNormalMap for normal maps stored in tangent space 10 2 13 VPillows pillow pattern Parameter Default value Range Description BumpMax 0 05 Maximum height of pillows TextureSizexY 0 1 0 1 Size of pillow in X and Y TextureOriginXY 0 0 Pattern offset in X and Y TextureAngle 0 Rotation in degrees DisplacementSpace shader spaces Coordinate space for displacement Description The VPillows shader produces a pillowed surface The pattern is applied using standard texture coordinates 10 2 14 VRibbed _ beat adds semi circular bumps to a surface 2001 2014 SiTex Graphics Inc 97 AIR User Manual Parameter Default value Range Description Height 0 1 Maximum height of ribs Frequency 10 0 Number of ribs per texture unit RotationAngle 0 0 0 180 Angle in degrees for rotating pattern DisplacementSpac shader spaces Coordinate space for displacement e Description The VRibbed displacement shader adds ribs to a surfa
44. The __diffuse_shadow variable was introduced in Air 13 The above relationship is preserved through the per pixel compositing and filtering performed by Air and it is now the preferred method of breaking down the diffuse component Most Air surface shaders also provide a__ shadow output variable that computes a shadow value based on the ratio between the shadowed and unshadowed direct lighting __ shadow 1 __diffuse __indirect __diffuse_unshadowed and the corresponding equation for compositing is __ diffuse __diffuse_unshadowed 1 __shadow __indirect However the above relationship is not preserved through filtering and compositing because the equation is not linear and it may lead to artifacts along object edges and in regions with partial opacity 2001 2014 SiTex Graphics Inc 37 AIR User Manual Extra passes in a RIB File To save an extra output variable declare the variable and then add an additional Display to the renderer s output For example you could add the following to a scene file to record a diffuse pass Declare __diffuse varying color Display t pic_diffuse tif file rgb quantize 0 255 0 255 By default additional output variables are saved as floating point values The optional quantize parameter to the Display call can be used to save 8 bit or 16 bit data instead The quantize parameter consists of 4 floats zero one min and max The Display call above r
45. The names of AOV output channels have been modified to work better with Nuke ProExr and other plugins and applications The first four channels for each output variable are now appended with R G B and A respectively Curves and Points primitives can be used as area lights Curves now compute an accurate t value along the curve length RIB filters support many more commands Imager shaders e Imager shaders are now executed prior to gamma correction contrary to the RI spec e Using an imager shader no longer forces display gamma to 1 e environment can safely be called from within an imager shader 2001 2014 SiTex Graphics Inc History 446 mktex and mktexui can convert mirror ball images to lat long environment maps for rendering e New Air Control render queue and airq batch render job submission tool Windows only New shading compiler option fover to enable function overloading New sample HDR environment maps from Aversis www aversis be e TweakAir e Relight shade mode now adds __refract ouput if present for better looking glass e Fix to prevent thread clash with communications thread e Fix for internal compositing with subpixel sampling e Air Show e New sRGB option to display an image with sRGB gamma correction e New View menu item to load a background image which can be toggled with the checked bg button in the toolbar e Vshade e Better code generation for arrays for faster rendering e V
46. WeaveWeftWidth WeaveWeftGap WarpColor WarpMapName Warplsotropy WarpShininess WeftColor WeftMapName Weftlsotropy WeftShininess ThreadAngle ThreadAngleMap ThreadAngleMapMultiply TextureSizexY TextureOriginXY TextureAngle Description Default Value 1 0 1 0 wo Range o o oo e re oo 0 0 1 0 0 0 1 0 0 0 1 0 i surface shader for cloth based on a physical model of woven fabric Description Volume scattering multiplier Reflection multiplier Texture map for base color Texture blur Weave pattern as warp run warp skip weft run Warp thread width Gap between warp threads Weft thread width Gap between weft threads Color for warp threads Texture map for warp color Isotropic scattering tendency Shininess Color for weft threads Texture map for weft color Isotropic scattering tendency Shininess Rotation for thread directions in degrees Texture map for rotation angle Multiplier for texture result Copies of texture in X and Y direction Location of left top texture edge Texture rotation angle in degrees 2001 2014 SiTex Graphics Inc 223 AIR User Manual The VCloth surface shader provides a physically based shading model for woven cloth based on the paper A Practical Microcylinder Appearance Model for Cloth Rendering by Sadeghi et al Thread Directions Woven cloth is made by interleaving two perpendicular sets of threads or yarns known as w
47. and areashadow Motion blur will only appear when 2 or more samples or rays are traced for query Use more samples with these functions to increase the quality of the blur Ray tracing with motion blur can be very time consuming and users are advised to selectively enable it only where necessary For curved surfaces use of the following motion factor optimization can considerably improve performance in some cases 2001 2014 SiTex Graphics Inc 345 AIR User Manual 16 2 Motion Factor Optimization AIR provides an attribute to automatically reduce the number of polygons used to represent a curved primitive based on the how blurred the primitive appears This feature can be enabled on a per primitive basis with GeometricApproximation motionfactor 1 Motion factor is a scalar value large numbers will produce an even coarser tessellation smaller numbers produce a finer one A motion factor of 0 disables the optimization Time Shifting Motion Blocks in RIB Archives The following attributes scale and offset the times passed in a motion block Attribute render float shutterscale 1 Attribute render float shutteroffset 0 Time shifting can be useful when re using archives in an animation sequence Adaptive Motion Blur AIR 6 introduces a new adaptive motion blur option To enable adaptive motion blur set the maximum number of motion samples with Option limits integer motionsamples n
48. blobby for which the DBO is being queried typedef struct int Blobbyld int OpId State These values can be used as cache indices if the DBO employs a caching mechanism Using Dynamic Blob Ops in a Blobby A dynamic blob op can be used like any other primitive blob in a Blobby object DBOs have two required parameters and can have an arbitrary number of float string or integer parameters that are passed to the DBO functions 9000 2 nameix transformix 9000 4 nameix transformix nfloat floatix 9000 6 nameix transformix nfloat floatix nstring stringix 9000 7 nint nameix transformix nfloat floatix nstring stringix nint Int 14 2 ne nint nameix is an index into the string array for the name of the DBO AIR will search the procedure search path for a DLL or shared object with the corresponding name transformix is an index into the float array for a matrix giving the blob to object space transformation floatix if present is the index in the float array of the first of the nfloat float parameters stringix if present is the index in the string array of the first of the nstring string parameters Example Blobby 2 1001 0 llips 9000 4 0 16 1 32 plane 020 1 add I 1000 0100 0010 40 84 1 10000 0300 0010 0001 2001 2014 SiTex Graphics Inc Primitives 74 8 7 2 I plane A sample DBO is included in the AIR distribution in AIRHOME examples primitives blob
49. boolean mergeedges 1 Geometry Export Attribute render string meshfile Attribute render integer makePref 0 Attribute render integer makeNref 0 Attribute render string meshspace world Miscellaneous Attribute render string color spd Attribute render integer runprogramthreads 1 Attribute render string ptexcoordinates st Visibility AIR provides several attributes that control where and how an object appears in a rendering Camera Visibility By default all objects are visible from the camera and appear in the final rendered image Attribute visibility integer camera 1 Set the camera visibility attribute to 0 to hide an object in the rendered image Such a hidden object may still appear in reflections or cast shadows AIR s grouping capability can also be used to restrict objects that appear in a rendering to a list of groups Attribute visibility subset list of names Only primitives in the supplied groups will be visible in the rendered image Visibility in Ray Traced Reflections 2001 2014 SiTex Graphics Inc 63 AIR User Manual 7 2 7 3 In order for an object to appear in ray traced reflections it must be tagged with the following attribute Attribute visibility integer trace 1 By default all objects are invisible to reflection trace rays The objects that appear in a particular reflection can be further cus
50. change the Falloff parameter to 0 to disable intensity decay with distance e In the OBJ network create a Light Template On the Shaders page of the light template set the Light Shader value the AIR light shader added above Move the light template position in a model view so the light is in a reasonable position to illuminate the scene e Render To enable ray traced shadows for a custom light set the Shadows parameter to the special value raytrace The Shadow blur parameter determines the blurriness or softness of the shadows The Shadow samples parameter sets the number of rays to trace when computing the shadow result Ambient Occlusion with Air and Houdini Ambient occlusion can be used either as a surface shader or with a light shader Air s envlight shader provides occlusion based shadows with optional image based lighting To use the envlight light shader e In the SHOP network open the Tool menu and under the RenderMan Light category choose the AIR envlight shader e Inthe OBJ network create a Light Template from Render sub menu under the Tool menu On the Render tab of the light template select the Shaders subtab and set the Light Shader value to the AIR envlight shader added above Make all objects in the scene visible to shadow rays In the parameters window for the RIB output operator look under the Properties tab for the Trace sub tab Set Shadow Visibility to Use Os for opacity e Render a test frame Oc
51. float bd int niarg int iarg int nfarg float farg int nsarg char sarg ImplicitRange returns in rng the range of ImplicitValue results for all points in the bounding box bd If the box is completely outside the influence of the blob ImplicitRange should return 1 1 A DBO may optionally have an ImplicitFree function that is called after each blobby has been processed void ImplicitFree State s Note that ImplicitFree may be called for a blobby even if the blobby does not contain references to the DBO Deformation motion blur is supported for DBOs that implement an ImplicitMotion function void ImplicitMotion State s float movec 2001 2014 SiTex Graphics Inc 73 AIR User Manual float pt float times int niarg int iarg int nfarg float farg int nsarg char sarg ImplicitMotion returns a 3 element vector in movec that represents the motion of point pt over the time interval The times parameter points to a 4 element array shutter open time shutter close time interval start time interval end time Deformation motion blur for a DBO must also be enabled in the RIB file with Attribute dbo integer motionsamples 1 If a DBO does not support deformation blur it should not implement the ImplicitMotion function and the above attribute should not be set The State structure contains two fields that uniquely identify the particular Blobby and the op within the
52. float stepsize color lightdensity color opacitydensity output color opacity The foglight function integrates an illuminated uniform fog function between the from and to points Only light shaders with a__ fogl ight output parameter set to 1 or a__ category parameter that includes foglight are considered by this function The stepsize parameter gives the step size for marching along the ray lower step sizes take more time but produce more accurate results The function returns the cumulative illumination and the opacity variable returns the cumulative Opacity along the ray segment 10 15 1 lt fulltrace float fulltrace point pos vector dir output color hitcolor output float hitdist output point Phit output normal Nhit output point Pmiss output vector Rmiss Traces a ray from pos in direction dir If the ray hits any object hitdist is the distance to the closest object and Phit and Nhit contain the position and normal at that point If no object is hit hitdist will be large and hitcolor will be 0 0 0 Ray tracing may spawn rays recursively if a ray hits a reflective or refractive object If any ray fails to hit an object Pmiss and Nmiss will be set to the position and direction of the deepest ray that failed to hit any objects and the function will return the depth of that ray Otherwise the function returns 0 10 15 14gather gather string category point pos vector axis float angle float samples par
53. genTextureUV shader for querying a texture map using u v coordinates genUserAttributes shader for querying user attributes genUV simple shader emitting the global u v coordinates genColor generic shader for specifying a color value 2001 2014 SiTex Graphics Inc Shader Guide 106 10 4 2 10 4 3 Parameter Default Range Description Color 0 5 0 5 0 5 rgb color value Color_spd a optional file name for spectral color profile ColorName ba optional named color in dictionary DictionaryName SATRHOME viztools path for color colors txt dictionary Description The genColor shader allows a color to be specified using rgb values a spectral profile or a named color in a color dictionary Output only parameters color __OutColor output color genOcclusion generic shader for adding an occlusion output value to a render pass Description The genOcclusion shader performs a simple occlusion query using the default occlusion and indirect settings providing output variables with the occlusion value and bent normal vector Use this shader to add an occlusion output value to any rendering by appending the shader to the list of surface shaders E g Surface VPlastic Surface genOcclusion PointsPolygons Output only parameters color __occlusion occlusion value vector __bent_normal average unoccluded direction in world space See Also Lighting gt Ambient Occlusion genQueryBakedMap gene
54. increment to map blur for reflection rays whether the environment is visible to indirect rays intensity multiplier for indirect rays increment to map blur for indirect rays whether the environment is visible to camera rays intensity multiplier for camera rays increment to map blur for camera rays The envMap environment shader uses an environment map to compute the color for a query ray Use the RotateX RotateY and RotateZ parameters to rotate the environment map with respect to the lookup coordinate space MapSpace Output only parameters color _ background envPhysicalSky environment shader color result environment shader with sky color based on position time and atmosphere 2001 2014 SiTex Graphics Inc Shader Guide 104 Skylntensity Turbidity DateMonth DateDay DateHour LatitudeLongitude TimeZone AnimateHour AnimateTimeScale OverrideZenith OverrideAzimuth GroundDiffuse GroundReflection GroundColor GroundBlendAngle CoordSysYisUp CoordSysNorthAngle CoordSysRightHanded 140 5 2 9 4 1 12 15 1 31 12 0 24 47 45 122 3 8 0 0 24 1 ll 0 0 4 0 1 0 0 0 1 0 95 1 0 8 L5 1 0 or 1 0 1 O or 1 overall multiplier for output color fraction of atmospheric scattering due to haze instead of molecules Larger values model atmospheres with more large dust particles month for sun position day of month for sun position 24 hour va
55. mode black clamp periodic smode tmode and mode set the wrapping mode for the s axis t axis and both axes respectively Each is followed by one of the following possible modes black return color 0 0 0 for texture access outside the range 0 1 clamp clamp the coordinate value to the range 0 1 periodic wrap the texture coordinate e g use s s floor s 2001 2014 SiTex Graphics Inc 413 AIR User Manual The default mode is black for both s and t coordinates size width height Resize the output image to width x height When writing an AIR texture map the output width and height should be a power of 2 flipx Flip the image horizontally flipy Flip the image vertically rot angle Rotate the image in 2 dimensions Angle must be a multiple of 90 degrees 8 Output data as 8 bit unsigned integers 16 Force output of data as 16 bit unsigned integers float Output data as floating point numbers tilesize n Use tiles of size n for mip mapped images The default size is 32 for texture maps and 64 for shadow maps The tile size must be a power of 2 between 8 and 128 inclusive u Forces the creation of an uncompressed texture file d Send output to AIR Show On Linux AIR Show must already be running lzw Enable LZW compression for TIFF images inc Convert the image incrementally one row of pixels at a time This option only works with image readers that support reading an ima
56. ooreo OrROO rFoOOO 1 0 0 0 0 0 1 0 0 0 1 0 0 0 1 0 S aces 0 1 Diffuse reflectivity Diffuse roughness Brick width Brick height Per brick color variation Mortar width Mortar color Fraction to offset every other row Unevenness of brick edges Frequency of brick edge unevenness Depth of mortar groove Depth of indentations Average size of pock marks Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection This shader produces a simple brick surface with grooves for the mortar The base brick color is taken from the object s color attribute The BrickColorVary parameter allows the intensity of the brick color to be varied for each brick 2001 2014 SiTex Graphics Inc Shader Guide 216 10 10 3 VBrushedMetal a brushed metal surface with reflections IIlumination model reflective anisotropic metal Features reflections Parameter Default Value Range Description Ambient 0 1 0 0 1 0 Ambient reflectivity Diffuse 0 1 0 0 1 0 Diffuse reflectivity Specular 0 2 0 0 1 0 Specular reflectivity SpecularRoughnessX 0 1 0 01 1 0 Specular roughness in X direction SpecularRoughnessY 0 3 0 01 1 0 Specular roughness in Y direction Reflection 0 95 0 0 1 0 Reflection strength ReflectionSamples 4 1 256 Number of rays when
57. true The compiled shader file includes a boolean flag for parameters which can be used by an application to detect boolean parameters and provide an appropriate user interface Functions 2001 2014 SiTex Graphics Inc Shader Guide 282 Illumination areashadow blinn brushedspecular caustic cooktorrance diffuse foglight indirectdiffuse microcylinder specular Mapping environment shadow texture 3D point sets bake3d collect subsurfacescatter texture3d Ray tracing fulltrace gather isindirectray isphoton isshadowray occlusion rayhittest rayinfo raylevel trace visibility Patterns voronoi Procedure and Instancer shaders meshinfo ribprintf DSO Shading Functions dictionary str_replace _last_ number Deprecated functions irradiancecache 2001 2014 SiTex Graphics Inc 283 AIR User Manual 10 15 1 User Structures AIR 10 introduces user defined data structures for the shading language Custom record types can be created with the new structure keyword Here s a simple example structure Layer string Map float Weight color Tint For the most part user defined types can be used anywhere a simple type is valid Individual fields within a type are accessed using the following notation variablename fieldname For example Layer First First Map grid tx First Weight 1 0 First Tint color 1 1 1 A user type variable m
58. use mktex angular srcimage destimage For image based lighting a small image is usually sufficient The output image size can be set using the size option E g mktex angular size 256 128 myprobe tif myprobe tx mkex also supports 3D rotation for an angular or ball map allowing you to orient the map properly for a given scene rotx angle roty angle rotz angle These options rotate the map in 3D dimensions around the X Y and Z axes respectively The up axis is Z by default For a modeling problem that uses Y as the up direction rotate 90 degrees about the X axis Rotation about the Z axis always rotates the scene about the vertical axis blur amt The blur option blurs the output image which may reduce noise when a map is used for image based lighting Compositing New in AIR 9 mktex allows images to be created using simple but powerful command line compositing equations The source images may differ in size channel depth or data type mktex will automatically perform any necessary conversions Compositing Syntax and Examples Compositing mode is invoked with the comp command line option followed by an equation which can include source image file names numeric constants and operators For example a simple weighted sum of a diffuse and specular pass could be created with mktex comp result tif diffuse tif mul 0 9 specular tif mul 1 1 Multichannel constants can be created as a comma separated list enclosed in br
59. where ngives the maximum radius of each shading point Polygons larger than the specified size store multiple indirect samples for more accurate shading at the expense of greater render time and memory use By default the radiosity size is treated as an absolute measure in world space The size can instead be measured in pixels with the following option Option indirect string radiositysizespace raster To save time and memory Air will reduce the detail in the radiosity cache at higher bounce levels when the following option is enabled Option indirect reduceradiosityquality 1 Caveats The cache won t produce accurate results if both sides of a surface are visible See Also indirect light shader Caustics Ray Tracing gt Optimizing Memory for Ray Traced Objects Ambient Occlusion Ambient occlusion refers to the extent to which a shading location is blocked or occluded by surrounding objects It provides a good estimate of the extent to which an object is shadowed by surrounding objects with respect to an encompassing environment such as the sky in an outdoor scene Ambient occlusion is a faster alternative to computing indirect illumination for scenes where the soft lighting effects of hemispherical or dome lighting are desirable but color bleeding and bounce lighting effects aren t important AIR can compute ambient occlusion using ray tracing depth maps or point clouds Shaders AIR includes four shade
60. which can be larger than 4GB TweakAir e Networked shaders can be tweaked by including a layername parameter in the IrTweak command specifying which shader to tweak Standard texture coordinates s t are initialized for imager shaders The displayed image may be in 16 bit or float precision When the camera changes TweakAir now casts rays of type camera to compute new visible surfaces allowing objects that are invisible to reflection rays to appear in the IPR view e Tweaking an environment shader now forces re evaluation of any light shaders that sample the environment A new per pixel occlusion cache speeds up re rendering with tweaking the envlight shader Now displays a rough view as the initial deep buffer is filled dPdv is generated when needed for polyline and ribbon curves u and v values are now cached when required Fix to correctly save user prim vars when re tracing the camera view TweakAir detects if a tweaked camera position is really different from the current camera transform before re tracing the view port fixes an issue where Rhino now sends a camera change event even when the camera has not moved Air Show e Anew log window displays any error messages generated by Air during a rendering e Image data saved to OpenEXR files is automatically converted to float precision if necessary e Histogram now ignores empty pixels in an rgba image mktex texture conversion tool e Ptex is supported as an output format
61. 1 0 Texture blur TextureSizeXY 11 Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform 100 0 Transformation applied prior to 0100 projection 0010 000 1 Description The VTexturedBump displacement shader uses a texture map to displace a surface The texture map may be placed using standard texture coordinates or any of the standard 3D to2D projections See Also bumpy displacement shader for very simple bump mapping VBumpRegions for multiple bump maps per surface 10 2 19 VThreads 2001 2014 SiTex Graphics Inc Shader Guide 100 Parameter BumpMax DisplacementSpace Frequency Start End FadeZone SwapXY Description Default value 0 05 shader 10 Range spaces Description Maximum thread height or depth Coordinate space for displacement Threads per unit interval Start position of threads along the vertical axis End position along the vertical axis Fade region near start and end If 1 swap X and Y values The VThreads displacement shader generates a pattern of screw threads typically along a cylinder Parameter BumpMax Columns ColumnGap ColumnWave ColumnRoundness Rows RowGap RowWave RowRoundness TextureSizexY TextureOri
62. 11 2 VFog fast volumetric fog Parameter StepSize EPE LightDensity 0 1 FogColor 111 OpacityDensity 0 0 AttenuateShadowR 0 ays LightIndirectRays 0 Description Default Value Description Step size for ray marching Intensity with which fog reflects light Fog color Tendency of fog to block light If 1 fog will attenuate shadow rays If 1 fog contributes to indirect rays The VFog shader produces a volumetric fog effect using AIR s builtin foglight function 10 11 3 VSmoke volumetric smoke shader 2001 2014 SiTex Graphics Inc 275 AIR User Manual Parameter Default Value Range Description UnitSize 5 0 Overall scale of shaded volume OpacityPerUnit 0 5 0 0 1 0 Extent to which smoke obscures objects objects behind ReflectancePerUnit 0 5 0 0 1 0 Extent to which smoke reflects light towards viewer StepsPerUnit O 1 Step size for ray marching MaxSteps 200 1 Maximum number of ray marching steps SmokeVary 0 Strength of smoke variation SmokeOctaves 3 Ley Octaves of noise for smoke variation SmokeFrequencyP 10 0 Smoke frequency per unit erUnit Description Simple volumetric smoke shader using ray marching The UnitSize parameter controls the overall scale of the shaded volume The UnitSize setting should be roughly 10 100 of the overall dimension of the volume in the scene By adjusting the UnitSize parameter the same smoke parameters can used for objects and scenes of different scales
63. 2001 2014 SiTex Graphics Inc Xl AIR User Manual 15 AIR 2 8 Index 2001 2014 SiTex Graphics Inc Geiting Started 12 1 Getting Started Welcome to Air SiTex Graphics advanced 3D rendering software for visual effects design and visualization Air accepts files in RIB RenderMan Interface Bytestream format Many popular modeling and animation programs can generate RIB output either natively or with the aid of a plugin The following plugins are available from the SiTex Graphics web site www sitexgraphics com Air Stream plugin for Maya RhinoAir for Rhino 4 or Rhino 5 SketchAir for SketchUp The following applications support Air natively or via a 3rd party plugin Massive Houdini from Side Effects Software CineMan for Cinema 4D Other compatible products include CityEngine from Procedural Inc The RealFlow Rendering Toolkit for the RealFlow fluid and dynamics software On Windows systems Air ships with Air Space a standalone user interface for Air More information on Air Space can be found in the separate Air Space User Manual Air can also be used to render a scene file from a command prompt or using the Air Control tool included with Air Air Feature Overview Air is an advanced 3D graphics renderer with a unique architecture and extensive features designed for the rapid production of high quality images Air is a hybrid renderer combining the advantages of s
64. AIR recognizes gzipped files without a gz extension Vortex now works with display drivers that expect data in scanline order Configuration instructions for previewing AIR shaders in Houdini e The BMP and TIFF display drivers now accept resolution and resolutionunit parameters e New shaders VSketchOutline VNormalMap VTangentNormalMap Bug fixes e Fix for traced shadow bug causing horizontal line artifacts e Fix to prevent min z depth filtering from trashing AOVs e On Windows AIR no longer tries to open AIR Show locally when launched with the dhost option e On Linux airmt supports the dhost switch 29 10 AIR 4 1 e AIR Space a new interactive shading and lighting interface for AIR and TweakAIR See the separate AIR Space User Manual for more information e New transmission attributes for compatibility with PRMan Attribute visibility integer transmission 1 enables visibility to shadow rays Attribute shade String transmissionhitmode primitive 2001 2014 SiTex Graphics Inc 451 AIR User Manual determines how an opacity value is generated for shadow queries using the primitive opacity or evaluating the surface shader Support for conditional RIB AIR can now parse gzipped RIB files Gzipped files must have a file extension of gz New interpolation option for facevarying subdivision mesh data New option to apply normal filtering to depth values Option ren
65. Default Value Range Description intensity 1 0 Light intensity lightcolor 111 Light color lightcolor_spd ae Light color spectrum file maxemission 0 If greater than 0 the maximum emitted light intensity from 00 0 Source position of light to 001 Target of light shadowname mm Name of shadow map or raytrace for traced shadows shadowbias 0 01 Offset to prevent incorrect self shadowing shadowblur 0 0 0 0 0 5 Blur for shadows shadowsamples 4 1 256 Number of rays for traced shadows shadowcolor 00 0 Color of shadows 2001 2014 SiTex Graphics Inc Shader Guide 158 shadowgroups shadowattribute _ category window _size_x window_size_y window _xdir window _ydir window_panes_x window_panes_y window_gap_x window_gap_y window_fuzz_x window_fuzz_y window_space texture_name texture_blur __nondiffuse __nonspecular _ foglight channel Description The spot_window_light shader emits light through a virtual paned window defined by the window _ we user shadowgroups wee 10 e rere Oo 0 1 0 1 0 01 0 01 world wee 0 FO 2 Optional groups for ray traced shadows Per object shadowgroups override attribute name Light categories window width window height horizontal axis for the window vertical axis for the window horizontal window pane count vertical window pane count horizontal gap between panes vertical gap between panes horizontal blur vertica
66. Display call For example Declare __ diffuse varying color Display diffuse tif file _ diffuse Multiple channels may be specified for a single image with a comma separated list Display all tif file rgba color __diffuse color _ specular The display driver and image format must of course support more than 4 output channels of data The list of display drivers indicates how many channels each driver supports Quantization and Image Data Precision AIR generates all data as 32 bit floating point values Depending on the file format used the image data may need to be converted to 8 bit or 16 bit precision prior to being passed to the display driver The output precision or quantization is set with the RIB Quantize command or by adding a quantize parameter to a Display call Quantize channels one min max dither Display float 4 quantize zero one min max Typical values for 8 bit precision are 2001 2014 SiTex Graphics Inc 35 AIR User Manual Quantize rgba 255 0 255 0 5 Display test tif file rgba float 4 quantize 0 255 0 255 float dither 0 5 Typical values for 16 bit precision are Quantize rgba 65535 0 65535 0 5 Display test tif file rgba float 4 quantize 0 65535 0 65535 float dither 0 5 For floating point precision use the following values Quantize rgba 0 0 0 0 Display test tif file rgba float 4 quantize 0 0 0 0 float dither
67. Manual 10 10 4 VClay a surface shader for rough dusty surfaces such as clay with no specular highlights IIlumination Model clay Features texture map Parameter Default Value Range Description Diffuse 0 7 0 0 1 0 Diffuse reflectivity DiffuseRoughness 0 5 0 0 1 0 Diffuse roughness wo ColorMapName Texture map for base color ColorMapBlur 0 0 0 0 1 0 Texture blur OpacityMapName a Texture map for opacity OpacityMapBlur 0 0 0 0 1 0 Texture blur BumpMax 0 0 Maximum bump height BumpMapName au Texture map for bump mapping BumpMapBlur 0 0 0 0 1 0 Texture blur TextureSizeXY 1 Copies of texture in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform 1000 Transformation applied prior to 0100 projection 0010 000 1 Description The VClay surface shader produces the appearance of rough surfaces such as clay The base output color is taken from the object s color attribute which is multiplied by the color map value if a color map is provided See Also VConcrete shader 2001 2014 SiTex Graphics Inc Shader Guide 222 10 10 4 VCloth Ilumination Model microcylinder Features texture map Parameter Diffuse Specular ColorMapName ColorMapBlur WeavePattern WeaveWarpWidth WeaveWarpGap
68. Output channel The arealight shader can be applied to any geometric primitive to turn it into an area light source The quality of the illumination and shadows is controlled with the light s nsamples attribute Attribute light integer nsamples where n ranges between 1 and 256 A large number of samples produces smoother results For area light primitives that are simple and convex such as a single polygon or a disk the arealight2 shader can produce similar results much more quickly 2001 2014 SiTex Graphics Inc Shader Guide 128 Light Intensity The emitted light value is the product of the intensity and lightcolor parameters and an attenuation factor determined by the falloff parameter The falloff parameter allows the light s intensity to diminish with distance from the light A falloff value of 2 which is physically accurate reduces the incident light value by the square of the distance from the light Cl intensity lightcolor Distance Distance Although a falloff of 2 is physically correct it can produce very large intensity values at locations close to the light source The maxemission parameter can be used to set the maximum emitted intensity regardless of distance from the light source Alternatively a falloff value of 0 produces no attenuation with distance which may be easier to control Shadows The shadowgroups parameter can be used to restrict shadow casting to the specif
69. Shading e Micropolygon shading handles uniform and constant primitive data e Micropolygon shading texture evaluation is now smoother and more consistent e Mesh displacement now works on meshes without vertex normals Lighting e Added adaptivesampling and rotation parameters to massive envlight e Primitive variable data can now write to light shader parameters The target light shader parameter must be class varying and it must not be an output variable e Spectral profiles for light sources may now be specified using a color temperature for the spectral file name value E g LightSource distantlight 1 string lightcolor_spd 2400 sunset Occlusion e New option to automatically sample the environment for unoccluded rays e Modified the error calculation to work better with small max hit distances Textures e New algorithm greatly improves the efficiency of the texture cache in some conditions Geometric Representation e New attribute to control tessellation based on maximum edge length e Changed tessellation of PointsPolygons primitives with more than 4 sides for compatibility with PTEX Shading Language Extensions e New boolean and integer variable types e Additional rayinfo queries e New mode added for blinn rolloff if rolloff lt O it s treated as the index of refraction of the material for compatibility with Softimage e New built in cooktorrance BRDF e New dictionary DSO shadeop Image
70. Shadows AIR includes an extended version of the distantlight shader distantlight_baked with additional parameters for creating 3D shadow textures and using 2D or 3D baked shadows bakemap me Bake map file name bakemode um Bake mode bakemapblur 0 Blur for bake map query bakemapfilterwidth 1 Filter width for bake map query motionbound 000000 bounding box for moving objects motionspace world space coordinate space of motionbound See Baking Shadows and Illumination for more information distant_projector directional light shader that projects a texture map like a slide projector 2001 2014 SiTex Graphics Inc Shader Guide 134 Parameter Default Value Range Description intensity 1 0 Light intensity lightcolor 111 Light color from 000 Source position of light to 001 Target of light shadowname iea Name of shadow map or raytrace for traced shadows shadowbias 0 01 Offset to prevent incorrect self shadowing shadowblur 0 01 0 0 0 5 Blur for shadows shadowsamples 1 1 256 Number of rays for traced shadows shadowcolor 00 0 Color of shadows shadowgroups me Optional groups for ray traced shadows shadowattribute user shadowgroups Per object shadowgroups override attribute name texturename File name of texture map to project textureblur 0 0 Blur for texture map texturescale 1 0 Scale factor for texture texturerotate 0 Rotation angle in degrees about the cone axis textureonce 0 0 or 1 When set
71. Specular roughness Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Plank width Plank height Per plank color variation Color of base wood Color of dark wood vein Color of groove between planks Width of grooves between planks Depth of grooves between planks Number of rings per unit Frequency of the fine grain Filter width multiplier Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection The VPlanks surface shader produces a pattern of wooden planks useful for rendering wood flooring or paneling 2001 2014 SiTex Graphics Inc Shader Guide 252 10 10 6 VPlastic 1 reflective plastic surface with texture maps for color opacity specular and bump IIlumination model plastic Features reflections texture map Parameter Default Value Range Description Diffuse 0 5 0 0 1 0 Diffuse reflectivity Specular 0 5 0 0 1 0 Specular reflectivity SpecularRoughnes 0 2 0 0 1 0 Specular roughness Reflection 1 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing R
72. Tips for Massive Scenes Houdini Configuring Houdini for Air Rendering with Air from Houdini Houdini Lights and Air Ambient Occlusion with Air and Houdini Global Illumination with Air and Houdini Creating Shaders for Air in Houdini Adding New Shaders to Houdini Tools AIR Control AIR Point Tool airpt AIR Show Image Dis play iac sccessccezecc cect vedecrecctescestctdeccerctececteeccvesecctectes View Navigation cssecsscssesseeesseeseeeeseeesseeesseeeeeeeneeetees Depth Map Display cccsesseeesseeseeeseeesseesseeeeeeeeseeenses Rendering to a Remote Machine s csseceseseeeeeseee Framebuffer Parameter s cessseseeesseeseeneseeeeeneenseee Command Line Options ceeecsseeeeeseeeeeeeeeseeeeeeeneeetees 2001 2014 SiTex Graphics Inc Contents X MGMUS E E 406 e E A A eae 406 Edit eena a n e Goa gee neat ate E E eee ee seen as 407 AY LE ame reer eee erereer err re err ree rere Terre cererre errerr er crree ere rier tr rerec errs err Yrrererrerrererrereerrreetrreerr irri rer errecerreretrrrrerrrr ers 407 PAVIUTVALC sdetcsaapucscxataterassrencaseuccndeasts snctcsutsudtcsayanceadecstecactecutuasstsatt E EE T 408 SOUNG WindOWs ONY insiens iferan aeea Sac evanedh E aigat a aieiaa eiaa ea aE anaa riie 408 OPOS a e a e a 408 Keyboard Shortcuts s sisien iea eaea da aaea i a aaaeeeaa ie iPade aaa eaid Rainaa aaRS iaia 409 4 MakeLlF aoran itunen setecaeecedes ves sececcuecd de
73. Value Range Description Ka 1 0 0 0 1 0 Ambient reflectivity Kd 0 0 0 0 1 0 Diffuse reflectivity Ks 1 0 0 0 1 0 Specular reflectivity roughness 0 1 0 01 1 0 Specular roughness Description The very simple metal shader with no reflections is included for compabitility with the RenderMan Interface Specification For metal with reflections use the VMetal shader instead See Also 2001 2014 SiTex Graphics Inc 199 AIR User Manual VMetal shader 10 10 1 MotionPass surface shader for recording a motion vector Parameter Default Value Range Description MotionSpace camera space coordinate space for output vector OpacityMap Hn optional opacity map BinaryTest 0 0 1 whether to convert the opacity map result to binary 0 or 1 based on the Binary Threshold Binary Threshold 0 5 threshold for converting opacity map result to O or 1 Description This shader emits the motion vector at the current shading location in the specified coordinate space 10 10 1 occlusionpass surface shader for rendering an ambient occlusion pass Parameter Default Value Range Description coneangle 1 57 Half angle for cone of directions to sample invert 0 When set to 1 the output value is inverted mapname raytrace raytrace or name of occlusion map mapblur 0 01 0 0 1 0 Blur for occlusion map mapbias 0 01 Bias for occlusion map maxsolidangle 0 05 Max angle in radians for grouping of points in point based occlus
74. a rectangular opening with optional panes and texture map e New microcylinder shading function based on A Practical Microcylinder Appearance Model for Cloth Rendering by Sadeghi et al New VCloth and VClothAdvanced surface shaders using the new microcylinder shading model New VLeather surface shader New shaders for simulating watercolor painting surface VWatercolor imager WatercolorPaper and stroke strokeWatercolorEdge e New sky _portallight area light shader for windows and other openings admitting sky light Using this shader is more efficient than combining the portallight shader with the envPhysicalSky environment shader e New sun window light shader combines the sunlight and distant_windowlight shaders to simulate sunlight through a window New ShowNormal surface shader for viewing the current shading normal New Paper imager shader The envPhysicalSky environment shader now includes a simple ground model illuminated by the average sky color sun position dependent Updated VPhysicalMetal shader with explicit IOR and Absorption parameters for more accurate metal rendering The indirect light shader has a new parameter to provide separate control over the emitted light intensity when queried by indirect rays Updated VBrick2D and VShinyTile2D surface shaders The VTone surface shader has been updated to better match the Gooch paper on which it is based A Non Photorealistic Lighting Model for Automatic Technical Ill
75. along a shared edge can lead to cracks e The default method can be slow if the initial polygon mesh is very dense since each polygon is essentially processed a second time as a separate primitive To overcome these limitations AIR 5 amp 6 introduced a new mesh displacement method that displaces an entire surface at once using a single dense mesh Enable mesh displacement with Attribute render integer meshdisplacement 1 Mesh displacement is supported for subdivision meshes polygon meshes and NURB surfaces Mesh displacement can be slower than the default method and use more temporary storage The final displaced mesh usually consumes less memory than the default displacement method For subdivision surfaces we recommend using the splitmesh attribute to improve the performance of mesh displacement Attributes and Options The following attributes and options apply to true displacement Attribute render integer normaldisplacement 1 2001 2014 SiTex Graphics Inc 85 AIR User Manual This attribute tells the renderer if displacement takes place only in the direction of the surface normal which is usually the case and that information allows the renderer to employ an additional optimization Attribute render integer triangledisplacement 0 When set to 1 this attribute forces the use of triangles instead of quads for displacement meshes which may reduce artifacts at the cost of increased
76. also present eliminating artifacts along edges and in semi transparent areas e Important fix to enable dither Geometry export e OBJ export now handles facevarying normals and texture coordinates e New attribute to select the coordinate space for exported positions and normals Frame number expansion for RIB file names on the command line E g air frames 19 21 scene 4f rib would render scene0019 rib scene0020 rib and scene0021 rib New option to interpolate density in fragment shadow maps 2001 2014 SiTex Graphics Inc History 444 e Shaders e Added ReflectionGroups parameter to surface shaders VMetal VBrushedMetal VGlass e Modified many surface shaders to only reference texture coordinates when needed resulting in faster rendering and lower memory use when these shaders are used without textures New shaders texturedarealight VPhong VGreyscale Shading language option recognizes Clipping Shutter DepthOfField CropWindow FrameAspectRatio e Shading language attribute recognizes ShadingRate Sides Matte e RLM License Server e Update to RLM 5 0 e AIR looks in SITEX_LICENSE and RLM_LICENSE environment variables for the location of the RLM license file or server if an RLM license file is not present in the bin directory of the AIR installation e Massive e New note on using groups to render mattes and layers e New tips for rendering occlusion and how to control occlusion with groups e New Ma
77. an actual parameter of the shader Each connection is defined with an additional string parameter String connect toparametername fromlayer fromparametername The connection transfers the value of fromparametername in layer fromlayer to the target parameter in the current shader The source parameter must be an output variable of the source shader or one of the global shader variables Ci and Oi The target parameter is normally one of the shader s input parameters but it can also be the global input color Cs or input opacity Os The source and target parameters must have the same type Sample usage Surface ColorMap ColorMapName grid tx layername gridlayer SetColor 0 Surface VMarble connect VeinColor gridlayer __Color In this example the marble vein color is taken from the ColorMap shader s __ Color output variable The network shader capability is used by the Air Stream plug in for Maya to translate Maya s shader networks for rendering with Air Sample rib net1 rib Limitations 2001 2014 SiTex Graphics Inc Shader Guide 280 User primitive data is currently not passed to objects with multiple surface shaders 10 14 The Shading Language The shading language used by AIR is a superset of the shading language described in the RenderMan Interface Specification 3 2 The shading language is similar to C with the addition of special types and functions for shading and lighting c
78. and texture quality 5 Enable mesh data simplification with Attribute render integer simplifyfacedata 1 This will normally result in lower memory use for Massive agents 6 Use multiple instances of the Massive procedural primitive Air 10 and later Massive uses a RunProgram procedural primitive to generate agents at render time That procedural can often become a bottleneck in multithreaded rendering You can allow multiple instances of the RunProgram to run concurrently by increasing the maximum number of instances allowed with Option limits runprogramthreads nmax Air will automatically send the scene options string to each instance of the Massive procedural primitive 2001 2014 SiTex Graphics Inc 391 AIR User Manual 22 14 Rendering a Depth Pass 22 15 There are several ways to render a depth pass with Air Here are two that work with an existing set of rib files so you do not need to set up a separate render pass in Massive or export an additional set of files Method 1 Save the standard depth buffer z as the output image First create a small text file with the following commands Display depth 4f tif file z Option render commands Display Option render zrange 1000 10000 The zrange option sets the minimum and maximum depth values which correspond to 0 and 1 respectively in the exported z value If you wish to save raw depth values omit the line that set
79. and warm colors allowing objects to retain some of their original color in the technical illustration 10 10 8 VToon cartoon shader Illumination model custom Features reflections texture map 2001 2014 SiTex Graphics Inc Shader Guide 266 Parameter Default Value Range Description Ambient 1 0 0 0 1 0 Ambient reflectivity Diffuse lel 0 0 1 0 Diffuse reflectivity DiffuseThreshold 0 1 0 to 1 0 Cosine of angle for transition from lit to unlit DiffuseSharpness 0 9 0 0 1 0 Sharpness of transition from lit to unlit DiffuseLevels 2 1 9 Number of diffuse shading regions Specular 0 5 0 0 1 0 Specular reflectivity SpecularSharpnes 0 9 0 0 1 0 Sharpness of highlight edge s SpecularRoughnes 0 1 0 0 1 0 Specular roughness s Reflection 0 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup wee ColorMapName Texture map for base color ColorMapBlur 0 0 0 0 1 0 Texture blur OpacityMapName pa Texture map for opacity OpacityMapBlur 0 0 0 0 1 0 Texture blur TextureSizeXY 11 Copies of texture in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinate
80. archives at point locations in a particle system Optimization Here are some tips for reducing the memory requirements and complexity of the trees generated by the VTree shader For trees that are far from the camera omit rendering the twigs or branches by setting TwigCurveType Or BranchCurveType to the empty string For nearer trees that are still somewhat far away set the BranchCurveType to ribbon or polyline instead of tube Setting the LeafColorVaryHSL values to all 0 allows all leaves to share the same color saving the storage used by a per leaf color value Setting the LeafSize min and max to the same value saves a per leaf width value when leaves are rendered as points primitives the lowest level of detail representation For distant trees using fewer leaves that are larger may produce a similar appearance at lower memory cost han many smaller leaves References The VTree shader was inspired by Creation and Rendering of Realistic Trees by Jason Weber and Joseph Penn The shader lacks many features mentioned in the article including e Trunk splits e Branch splitting e More than 3 levels of branches leaves e Automatic detail reduction See Also ViInstanceTree instancer shader Strokes Air 14 introduces a new stroke shader type for shading vector based outlines The current stroke shader is declared as a RIB option with Stroke shadername lt parameter list gt Strokes are rendered using vector based outline
81. as well as the plugin The DarkTree plugin will search for DarkTree shaders in the path defined by the SHADERS and or SIMBIONT_RM_SHADERS environment variables Add the directory containing the DarkTree shaders to one of these variables If you have the DarkTree application installed add the DarkTree directory to the SIMBIONT_RM_SHADERS variable as well 10 13 Layered Shaders and Shader Networks Air 11 introduces the ability to use multiple shaders to compute the shading for surfaces displacements imagers and environments This new capability provides a simple solution to several common shading tasks that would otherwise require complex custom shaders Decaling apply an arbitrary number of texture maps to an object s color and feed the result into any surface shader Extra output variables add an arbitrary number of additional shaders to an object to produce extra output values without affecting the normal shading of the object Assign different different shaders to different sections of an object simple shader compositing 2001 2014 SiTex Graphics Inc 277 AIR User Manual allows existing surface shaders to be selectively applied to sections of a surface Replicate application shader networks create arbitrary shader networks by connecting pre compiled components See below for a description of how to use multiple shaders to address each of these tasks Sample shaders and rib files can be found in
82. automatically exports a scene and starts an Air rendering process Alternatively the Air Space user interface included with the Windows version of Air can be used to add materials and lights to a model for rendering with Air See the separate Air Space User Manual for more information Command Line Rendering A RIB scene file can be rendered by starting a standalone Air process from an MS DOS prompt on Windows or a command shell on Linux The general syntax for invoking Air from the command line is air options RIBcommand s RIBfile s Options if present must appear before any commands or filenames Depending on the display settings in the file AIR will either generate an image file or open a window on the screen Any RIB command may be passed as an argument by enclosing it in braces For example air Format 320 240 1 myscene rib Air accepts multiple commands and or RIB files They are processed in order from left to right To abort rendering press Control C in the console window or click the close button on the framebuffer window if displayed If no file name is included in the command line Air attempts to read input from stdin The Reference section contains a list of command line options You can view a short list of command line options with air The user note for Massive on command line rendering introduces several commonly used command line switches Under Windows the 64 bit version of Air can be invoked with
83. by 0 error in occlusion e e e e e e DelayedReadArchives failed to inherit the current true displacement attribute 2001 2014 SiTex Graphics Inc 457 AIR User Manual 29 14 AIR 2 9 Multithreading on Linux in addition to existing support for multithreading on Windows Importance based rendering for faster rendering Texture readers for additional image input formats Faster raw ray tracing performance Ambient occlusion improvements faster rendering better quality less memory Scene storage optimization for memory reduction of 10 20 for typical scenes Additional optimization for polygon meshes Houdini users in particular should see a dramatic decrease in memory use for polygonal objects Support for SideFx s Houdini New parameters for environment and trace to support anisotropic reflection Modified VBrushedMetal shader and a new VBrushedPlastic shader with anisotropic reflections Interior and Exterior volume shaders New VSmoke volume shader see the example in SATRHOME examples effects New pixel filters disk mitchell and lanczos Faster true displacement New attribute to indicate whether displacement takes place only in the direction of the surface normal Attribute render integer normaldisplacement 1 New attribute to select triangles instead of quads for displacement meshes Attribute render integer triangledisplacement 1 Using triangles may reduce artifacts at th
84. by setting the TextureSizexy parameter to 1 1 and the TextureAngle to 90 See Also Baking PTEX Textures with BakeAir PTEX web site http ptex us 12 3D Textures amp Point Sets 3D textures store 3D point based information Typically 3D textures are used to record time consuming shading computations for accelerated re rendering Because 3D textures are accessed using a location in a 3D coordinate system they do not require surfaces to have the well defined set of texture coordinates required for 2D textures Many of AIR s advanced features allow expensive shading results to be saved to a file for later reuse including e Indirect diffuse illumination e Occlusion e Caustics e Subsurface scattering AIR also provides a general mechanism for creating and accessing 3D textures with the bake3d and texture3d shading language functions 3D Point File Formats With version 8 AIR introduces a common set of file formats for all 3D point based data AIR uses the file name extension to determine the point file type 2001 2014 SiTex Graphics Inc 311 AIR User Manual Air Point Cloud apc Unstructured point collection The basic format for storing 3D point based information The entire point set will be loaded at once when accessed Air Point Map apm Point set organized into spacially continguous clusters that can be loaded independently allowing cached access to the point data AIR can efficiently sa
85. call is removed from the RIB stream Sample Usage for Massive scenes The surftoprim filter allows the agent surface shader to be changed in another program such as Maya or Houdini while retaining the per agent parameter values generated by Massive For example say agents have the VPlastic surface shader assigned in Massive and with a different color map for each agent The RIB stream produced by the Massive procedural might look something like Surface VPlastic string ColorMapName shirtl tif PointsPolygons Surface VPlastic string ColorMapName Sshirt2 tif PointsPolygons Applying the following filter Attribute render rifilter surftoprim ColorMapName produces PointsPolygons constant string ColorMapName shirtl tif PointsPolygons constant string ColorMapName shirt2 tif One can then assign the VPlastic shader to a RIB box referencing the filtered agents and manipulate other shader parameters while retaining the color map values generated by Massive Naturally one can use a different surface shader as well and any matching primitive variable data will be used E g AttributeBegin Surface VClay Attribute render rifilter surftoprim ColorMapName ReadArchive agents rib AttributeEnd Writing RI Filters An RI filter is structured similarly to a procedural runprogram The sample filters are written in C but any programming language may be used 2001 2014 SiTex Graphics Inc
86. complex transparency should have the shadow ray transmission type set to shader Attribute visibility string transmission shader By default all volume primitives will cast shadows upon themselves Simple primitives that do not require self shadowing can be accelerated by disabling self shadowing with Attribute visibility integer selfshadow 0 Volume primitives do not cast colored shadows by default To enable colored shadows set Attribute volume integer coloredopacity 1 Rendering with colored shadows is slower but it does not use more memory that rendering with grey scale shadows The look of volumetric primitives can often be improved by using separate opacity values for shadow rays and camera rays AIR provides separate attributes to tint the opacity computed by the surface shader differently for shadow rays and camera rays Attribute volume color shadowdensity 1 1 1 Attribute volume color viewdensity 1 1 1 Motion Blur Volume primitives support internal motion blur if additional motion data is provided in the primitive definition Transformation motion blur is currently applied to volume primitives as internal motion blur Volume primitives boundaries will not blur Regular motion blurred primitives may appear within and pass through volume primitives Tips e The time required to render a volume primitive and the memory consumed is heavily influenced by 2001 2014 SiTex Graphi
87. depending on how the source image was generated Image based lighting usually only rquires a small environment map You can set the output size to reduce a large source image e Set the Output Size to 256 128 The texture converter also allows the orientation of the environment map relative to the scene to be altered using the Rotate 3D controls e Set the Output Directory and click the Make Map button IBL with Indirect Diffuse Illumination If indirect diffuse illumination is being used in a scene the IBL environment map can be added as the background map for the indirect diffuse lighting calculations with Option indirect string envname Option indirect float envstrength 1 0 Option indirect float envblur 0 0 Indirect rays that miss all objects in the scene will take their color from the environment map The envstrength option can be used to scale the environment map intensity while the envblur parameter adds blur to the environment map lookup IBL with Ambient Occlusion Image based lighting can also be accomplished using ambient occlusion with the envlight or massive_envlight light shaders Add a light source with the envlight shader to your scene and set the envname parameter to the name of the environment map Example an example can be found in SATRHOME examples hdribl 2001 2014 SiTex Graphics Inc Lighting 332 13 6 Photometric Lights and IES Profiles AIR 10 and later ca
88. deviation of the true surface from the polygon mesh using GeometricApproximation flatness flatness Flatness is given in units of pixels The default value is 0 5 Air 11 adds a new criterion for tessellation density GeometricApproximation edgelength 0 which gives the maximum length in object space for any edge in the resulting mesh The default value of 0 disables this test which is currently only supported for polygon meshes This control may be useful for increasing mesh density when baking a mesh with BakeAir The automatic meshing routine for NURB surfaces repeatedly subdivides a surface until a surface fragment is flat or a maximum division level is reached Attribute limits integer divisionlevel 16 The default value is adequate for most surfaces A long or complex curved surface may require a higher value indicated by sharp corners or gaps in the polygon mesh Static Meshing Air 9 and later allow the flatness tolerance to be applied as an absolute tolerance in object space instead Attribute render string flatnessspace object The default flatness space is raster the only other supported coordinate system Using object space for flatness produces a tessellation for non deforming objects that does not change with object or camera position A constant tessellation may be useful for cases where changes in tessellation between frames cause unwanted visual artifacts Explicit Meshing The subdivision of par
89. distances in the shaders provided with AIR are all in units of millimeters Use the ScatterDistanceScale parameter to adjust the distance to the scale of your object Larger distances produce more blur and generally take less time to render The SubsurfReflectance parameter sets the nominal reflectance for subsurface scattering Real world values can be found in Jensen et al Although it is possible to control the color of an object by changing this parameter the net effect in interaction with the scattering distance parameter can be difficult to predict Instead use the primitive s color attribute or a texture map to set the base color with the SubsurfReflectance value set for a particular material type Base Color The base color is taken from the object s color attribute multiplied by the texture map color if any See Also Subsurface scattering VSkin shader 10 10 8 VTranslucentMarble a marble with subsurface scattering IIlumination model custom Features subsurface scattering reflections 2001 2014 SiTex Graphics Inc 269 AIR User Manual Parameter Default Value Range Description Ambient 1 0 0 0 1 0 Ambient reflectivity Diffuse 0 5 0 0 1 0 Diffuse reflectivity Specular 0 5 0 0 1 0 Specular reflectivity Roughness 0 2 0 0 1 0 Specular roughness Reflection 1 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections R
90. file name extension The first map should be numbered 0 Animation begins at the frame given in FrameStart with map number 0 which is also displayed for any 2001 2014 SiTex Graphics Inc 213 AIR User Manual earlier frames Every MapDuration frames the current map number is incremented When the current map number reaches MapCount the current map number is reset to 0 If the texture map has an alpha channel the alpha channel result is applied as the surface opacity 10 10 34VBlinn 4 plastic shader with Blinn specular model reflections and texture maps Illumination model plastic with Blinn specular Features reflections texture map Parameter Diffuse Specular SpecularSize SpecularRolloff Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace ColorMapName ColorMapBlur SpecularMapName SpecularMapBlur OpacityMapName OpacityMapBlur BumpMax BumpMapName BumpMapBlur 0 0 raytrace cur 0 0 0 Default Value 0L 5 5 3 7 0 1 0 rent wee Range 0 0 1 0 0 1 OO As Description Diffuse reflectivity Specular reflectivity Specular size Blinn eccentricity Blinn rolloff parameter Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Texture map for base color Texture blur Texture map for specular co
91. for regular textures and all environment texture modes e New incremental conversion mode inc converts an image one row at a time to reduce memory used when converting large images e New stitching option to create a single large image from a grid of sub images e New lzw option to enable LZW compression for TIFF images 2001 2014 SiTex Graphics Inc History 432 e Miscellaneous e Increased max threads allowed to 64 e Under Windows the default shader search path now includes SHOMEPATH SiTex shaders e Deprecated features e 32 bit Linux version of Air e The parallel shading attribute is no longer supported e Fixes e Shading compiler fix to handle undef preprocessor directive e Bug in ptex coordinate generation for polygon meshes that are not all triangles or all quads mangled normals Sub pixel edge mask handling of exactly horizontal edge Bug that prevented light output variables from being correctly initialized when queried from a networked surface shader Modified handling of traced reflections with only 1 sample and some blur to produce smoother non noisy results for first reflections Occlusion and indirect prepasses now work with fragment shading Display driver open and close calls are now single threaded to work properly with libpng and libjpeg Fix for subtle bug in surface shader handling when rendering a shadow map surface shader is no longer optimized away when creating an inline archive with
92. geometry to represent an agent light which is converted to an actual RIB light source by the malt utility prior to final rendering The workflow in detail 1 Create and position standin geometry for each light associated with an agent The shape should be a pyramid or triangle By default malt uses the first vertex as the light position and the average of the other vertices as a target point for the light If the last command line option is passed to malt it will use the last vertex as the light position 2 In Massive assign a special surface shader to the standin geometry with the light shader properties The AIR distribution includes two proxy surface shaders proxy_spotlight for the standard spotlight shader and proxy_pointlight for the standard pointlight shader Most parameters of the proxy shaders mirror those of the corresponding light shader There are a few special parameters Light Shader the name of the light shader to use Due to a bug in Massive 3 0 that initializes all string parameters to the empty string the parameter must be set to spotlight for the proxy_spotlight shader or pointlight for the proxy_pointlight shader ShowProxyGeomet ry set the value to 1 to make the proxy geometry visible in the rendering LightMaxDistance sets the light maxdist attribute defining the range of influence of the light as a distance from the light source position Setting this value appropriately can help reduce render times For ini
93. highlight in the X and Y directions respectively Using a different value for X and Y roughness generates oblong highlights Similarly the ReflectionBlurX and ReflectionBlurY parameters control the shape of blurry reflections using a different value for each parameter produces anisotropic reflections Normally the ReflectionBlurX and ReflectionBlurY values should be proportional to the RoughnessX and Roughness Y parameters respectively to produce a consistent appearance However the RoughnessX value does not have to be exactly the same as the ReflectionBlurX parameter and the RoughnessyY value need not match the ReflectionBlurY value The illumination model is based on Measuring and Modeling Anisotropic Reflection by Greg Ward published in SIGGRAPH 92 See Also VBrushedMetal shader 10 10 3 amp CarPaint 4 car paint simulated as a base metal layer with clear overcoat IIlumination Model metal and ceramic 2001 2014 SiTex Graphics Inc 219 AIR User Manual Features reflections Parameter Diffuse Specular SpecularRoughness FinishSpecular FinishReflection FinishSpecularRoughnes s FinishSpecularSharpness Flake FlakeFrequency FlakeDensity FlakeRoughness FlakeColor Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace Description Default Value 0 3 0 7 0 1 0 0 raytrace NGurrent Range a 001 1 0 0 0 0 O O 1 0
94. horizontal window pane count vertical window pane count horizontal gap between panes vertical gap between panes horizontal blur vertical blur coordinate space for window directions optional texture map texture blur If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel The sun_window_light shader computes the position and color for a sun like light source based on the observer s position the local data amp time and the atmospheric turbidity The turbidity parameter sets the relative portion of atmospheric scattering due to haze instead of molecules Larger values model atmospheres with more large dust particles Output only variables col col See Also envPhysicalSky environment shader 10 7 23 sunlight sun color and position based on observer location date time and atmospheric conditions or _ shadow Shadow value or __unshadowed_Cl Emitted illumination without shadows 2001 2014 SiTex Graphics Inc Shader Guide 162 Parameter Default Value intensity 1 0 lightcolor 111 use_sun_color 1 turbidity date_month 4 date_day 15 date_hour 12 latitude_longitude 47 45 122 3 time_zone 8 animate_hour 0 animate_time_scale 1 override_zenith 1 override_azimuth 0 coord_sys y_is_up 1 coord_sys_north_angle 0 coord_sys_right_handed 1 shadowname Tom shadowbias 0 01 shadowblur 0 01 shadowsamples shadowcolor 00 0 shad
95. if the surface s opacity parameter Os indicates it is transparent Some shaders modify the surface transparency in complex ways not tied to the opacity surface attribute To force the renderer to generate samples behind those objects set the surface Opacity to a non opaque value even though it is isn t used by the surface shader Prepass and Reflections Some surfaces have crisp reflections that may clearly reflect indirect illumination in other parts of the scene To obtain the best results you may also need to precompute indirect values at those reflected locations by tagging a reflective object with the following attribute Attribute indirect integer reflective 1 Prepass Groups The objects that will contribute indirect illumination can be restricted to members of a list of groups by providing the following option Option indirect string prepassgroup list of groups Shading for Indirect Illumination AIR calculates the incoming indirect light at a point by sampling the hemisphere of directions around the surface normal using ray tracing Each ray contributes illumination from the surface it strikes AIR provides custom attributes for simplifying and thereby accelerating the shading performed to determine a primitive s contribution to indirect illumination 2001 2014 SiTex Graphics Inc Lighting 324 Attribute indirect string shading type Attribute indirect float strength 1 Attribu
96. integer transmission 0 2001 2014 SiTex Graphics Inc 61 AIR User Manual Attribute shade string transmissionhitmode primitive Attribute visibility integer trace 0 Attribute visibility integer indirect 0 Attribute visibility subset Motion Blur GeometricApproximation motionfactor 0 Attribute dbo integer motionsamples 0 Attribute render float shutterscale 1 Attribute render float shutteroffset 0 Attribute render integer adaptivemotionblur 1 Ray Tracing Attribute trace float bias 0 01 Attribute trace integer motionblur 0 Attribute trace integer displacements 1 Displacement Attribute render integer truedisplacement 0 Attribute displacementbound float sphere 0 0 Attribute render integer normaldisplacement 1 Attribute render integer triangledisplacement 0 Attribute render integer smoothlevel 1 Attribute render integer meshdisplacement 1 Attribute render fastdisplacement 1 Indirect Illumination Attribute indirect float maxerror 0 0 Attribute indirect float maxpixeldist 20 Attribute indirect integer nsamples 256 Attribute indirect string shading shade Attribute indirect float strength 1 Attribute indirect color averagecolor 1 1 1 Attribute indirect string averagecolor_ spd Attribute indirect float maxhitdist 1000000000 0 Attribute ind
97. is based solely on the direction of the indirect rays If an environment shader varies its computations based on position that behavior cannot be accurately captured by the cache and the cache should not be used in that case Past and Future 2001 2014 SiTex Graphics Inc Shader Guide 102 In older versions of Air the color returned by a reflection or indirect ray that exited the scene was determined by a set of custom options that provided a limited range of options basically a fixed color or an environment map query The new environment shader type provides more flexibility in defining the color returned by exiting rays as well as a unified interface for all ray types If no environment shader is defined Air 11 reverts to the old custom options for indirect and reflection rays In the future it is likely that these old options will be deprecated entirely 10 3 1 envColor simple environment shader returning a constant color Parameter Default Value Range Description Color 1 1 base color Intensity 1 0 intensity multiplier for all rays Reflection Visibility 1 Oor 1 whether the environment is visible to reflection rays ReflectionIntensity 1 0 intensity multiplier for reflection rays ReflectionTint 111 color multiplier for reflection rays IndirectVisibility 1 Oor 1 whether the environment is visible to indirect rays IndirectIntensity 1 0 intensity multiplier for indirect rays IndirectTint L color mult
98. it may inherit whatever color has already been assigned to an object The Surface materials in the standard library for example simply assign a diffferent surface shader for an object and do not specify a particular color 2001 2014 SiTex Graphics Inc Materials 78 SketchAir further extends this color inheritance so that any material that does not define a color will also inherit any color map assigned to a material in SketchUp This allows you to assign a custom surface shader while preserving any texture mapping you may already have performed in SketchUp Material Editor The Windows version of Air includes a stand alone material editor for creating and editing material files The material editor can be accessed from the Tools menu of any of the other Air tools such as Air Show See the separate Air Material Editor User Manual for more information 10 Shader Guide AIR uses small programs called shaders to perform shading and lighting calculations This programmable shading capability is one of AIR s most powerful features by using a suitable shader almost any type of light or surface can be simulated Shader Types AIR supports the following types of shaders surface calculates the color and opacity at a point on a surface displacement moves or displaces a surface to simulate topographical features such as bumps wrinkles or grooves volume modifies the light reflected by a surface to account fo
99. light shader indirect light shader Indirect Lighting 10 7 14 photometric_pointlight point light source with support for IES light profiles and physically based illumination values 2001 2014 SiTex Graphics Inc 143 AIR User Manual Parameter intensity intensityunit lightcolor lightcolor_spd from falloff sceneunitsize illuminanceunity lumensperwatt iesname iesspace iesrotatex iesrotatey iesrotatez shadowname shadowbias shadowblur shadowsamples shadowcolor shadowgroups shadowattribute __nondiffuse __nonspecular ___foglight _ channel Description Default Value 1 0 none Range none candela lum en watt 1 1 1 n 500 17 n shader we user shadowgroups H D O Spaces 0 0 0 5 1 256 Description Light intensity Units for light intensity Light color Spectral power distribution for light color Source position of light Exponent for falloff in light intensity with distance Size of one unit in world space Divisor for emitted light intensity Lumens per watt for watt intensity unit file name for IES light profile coordinate space for IES profile environment map lookup ies rotation about X axis in degrees ies rotation about Y axis in degrees ies rotation about Z axis in degrees Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for tra
100. mapname occlusion apc float mapbias 0 1 float maxsolidangle 0 05 Option render commands Surface Save the above as occpass rib then render with air occpass rib myscene rib Point based occlusion may be faster than traced occlusion for very complex scenes For simpler scenes point based occlusion may be slower than simple ray traced occlusion 2001 2014 SiTex Graphics Inc 331 AIR User Manual 13 5 Image Based Lighting An environment map can be used to illuminate a scene with either indirect diffuse illumination or ambient occlusion In either case the source image should first be converted to an AIR environment map with AIR s texture conversion tools Converting a Light Probe Image A light probe is a popular method of recording the lighting in an environment by photographing a reflective ball placed in the environment By using the light information contained in a light probe image one can make a computer generated object look like it is being lit in that environment For best results the light probe image should be a high dynamic range image which captures the full range of the light in the environment Light probe images are often stored in an angular format or a mirrored ball format Images in these formats can be converted for use with AIR by the mktex or mktexui utilities For mktexui e Start mktexui e Select the source image e Set the Map Type to Angular Map or Mirror Ball
101. memory Concurrent processes can write to different images in AIR Show Rendering processes can write to AIR Show running on any machine on a network Multiple processes can write to different sections of the same image permitting a single frame to be rendered over multiple machines e A sequence of frames can be played as a simple flipbook animation 2001 2014 SiTex Graphics Inc Tools 402 24 3 1 e AIR Show can display 16 bit and floating point image data as well as the usual 8 bit data with an unlimited number of channels per image e Gammaz correction for display without altering the raw image data that is saved to a file e Image navigation including pan and zoom toggle between images wipe between images and view individual pixel values e Special depth map display for previewing shadow maps e Viewing of stereo images as color anaglyphs version 5 0 and later Image Display Gamma Correction AIR Show can gamma correct an image for display purposes without altering the raw image data This capability allows you to view an image properly on your monitor and still save it without gamma correction as a linear image suitable for post processing Gamma correction applied in AIR Show is independent of any correction applied by the renderer based on the Exposure settings in a scene file Naturally you should avoid gamma correcting an image in both the renderer and AIR Show If an image is gamma corr
102. mesh in object space GeometricApproximation edgelength Shader Support for Baked Meshes The following Air shaders can take advantage of baked mesh data The occlusionpass massive occlusionpass envlight amp massive envlight shaders use occlusion values stored ona mesh ina float prim_occ variable The indirect light shader and IndirectPass surface shader to use baked mesh color prim_indirect data for indirect light if available The VTranslucent and VTranslucentMarble surface shaders to use a diffuse result baked to color prim_diffuse if available Examples Sample scene files can be found in SATRHOME examples bakeexamples bakemesh Massive Massive is the premier 3D animation system for generating crowd related visual effects for film and television This section describes tips and tools for rendering Massive scenes with Air More information about Massive can be found on the Massive Software web site www massivesoftware com Tips for using Massive with Air Rendering with Air from Massive Command Line Rendering of Massive Scenes Display Customization and Multipass Rendering massrib Shading and Lighting in Air Space Ambient Occlusion in Massive Mattes Layers and Groups Eliminating Shadow Artifacts on Terrain Automatic Level of Detail Massive Agent Light Tool malt Optimization Tips for Massive Scenes Rendering a Depth Pass Adding a background image Rendering Massive Agents with
103. name ArchivelsSimple 1 Oor 1 When non zero archive is retained as an inline archive to accelerate instancing Scale 1 Uniform scale applied to archive instances MotionBlur 0 Oor 1 When non zero translation motion blur is applied ApplyWidth 1 Oor 1 When non zero scale archive by point width ApplyColor 1 Oor 1 When non zero apply vertex color to archive XAngle 0 Rotation about X axis in degrees XAnglePrimVar a Primitive variable to query for rotation angle YAngle 0 Rotation about Y axis in degrees YAnglePrimVar a Primitive variable to query for rotation angle ZAngle 0 Rotation about Z axis in degrees ZAnglePrimVar a Primitive variable to query for rotation angle PrimVarToAttribute 1 si Primitive variable to convert to user attribute PrimVarToAttribute2 Primitive variable to convert to user attribute PrimVarToAttribute3 me Primitive variable to convert to user attribute PrimVarToAttribute4 ve Primitive variable to convert to user attribute PrimVarToAttribute5 om Primitive variable to convert to user attribute PrimVarToAttribute6 mu Primitive variable to convert to user attribute This simple shader creates a copy of the specifed RIB archive at every vertex position of the instancer base primitive In common usage the base primitive will be a points primitive in which case the point cluster attribute can be used to force a large set of points to be subdivided into smaller sets before the instancer is executed For example tagging the base
104. now be dynamically changed with new IrTweakCamera command Faster IPR display refresh New IrTweakCoordinateSystem command for updating coordinate spaces New IrWriteImage command writes the image buffer to a file TweakAlR can now be run in batch mode with no default display driver and commands piped from a text file Faster storage to deep framebuffer Support for standard Cs color data attached to a primitive Documentation moved out of the Tools chapter to its own topic in the user manual TweakAlR API is now included with the AIR distribution Documentation for the TweakAIR API e BakeAIR Multithreading support Updated legacy code to allow baking larger maps up to 8K x 8K at PixelSamples 1 1 New option to have border filling wrap around in texture space Option bake integer borderwrap 1 This option may be useful when baking Rhino polymeshes e AIR Show 4 Simple render commands added to Tools menu 3D LUT support Drag and drop support from Windows Explorer images and rib files Histogram displays min and max values Image border color is now dark grey instead of black AIR Show now attempts to organize a multichannel file loaded from disk into layers assuming 3 channels per layer with rgb or rgba as first layer e AIR Space Instancer shader support support for IPR view updates faster IPR display refresh new option to import some RIB options support for dropped files apj rib obj the Bake channels paramet
105. objects Attribute indirect maxhitdist 500 Display occlusion 4f png file rgb Option render commands Display Phil s Tips for Occlusion Veteran AIR and Massive user Phil Hartmann offers the following tips on rendering occlusion 1 In Massive set the shading rate to 0 25 or 0 5 Set Pixel Samples to 8x8 Set the trace bias in the range 1 to 10 2 In the massive_envlight or massive_occlusionpass shaders set samples to 32 or 64 Set maxhitdist to 200 to 500 cm 3 If memory use is an issue render the occlusion pass separately from other passes with the massive_occlusionpass shader 4 To maximize processor usage on a multicore machine run multiple processes with 1 thread each rather than a single process with multiple threads Selective Occlusion Testing with Groups Problem A user wishes to render an occlusion pass with agents and terrain in the same image Agents should be rendered with normal occlusion from all geometry The terrain should show occlusion from agents but not from the terrain itself Solution Grouping can be used to restrict the objects tested for occlusion as follows 1 The first step is to assign a group name to the agents by creating a small text file with the following Attribute grouping string membership t agents Assign that text file as a custom rib to the agents in Massive 2 Assign the new massive_occlusionpass shader to the terrain Set the new shadowgroups parameter to a
106. of some watercolor paper due to high frequency variation in how the paint is absorbed The Texture parameter should point to a bump map file or have the special value noise to use Air s builtin noise function The Intensity parameter can be used to adjust the strength of this effect Rough Border When the BorderMin parameter is greater than 0 the imager produces a rough edge around the rendered image The general shape of the visible region can vary smoothly between a rectangle BorderRound 0 and an ellipse BorderRound 1 BorderVary and BorderFrequency control the noise function used to produce the uneven boundary See Also strokeWatercolorEdge stroke shader VWatercolor surface shader 2001 2014 SiTex Graphics Inc 117 AIR User Manual 10 6 10 6 1 Instancers AIR 8 introduces a new instancer shader type for creating new geometry at render time based on properties of an existing primitive As the name instancer implies one motivation for the new shader type is the common need to convert a set of particles into a set of instances of some other geometry type Instancer shaders make particle instancing easy see the VinstanceArchive shader for an example Because an instancer can be applied to any primitive type an instancer can also be used to create primitives along a curve or grow primitives out of a surface An instancer shader is attached to a primitive just like a surface or displacement shade
107. of the selected primitives 20 3 13 IrRefreshWindow C int IrRefreshWindow IPR ipr float left float right float top float bottom Text IrRefreshWindow left right top bottom Use this command to restrict refreshing of the IPR window to a subrectangle The parameters have the same interpretation as the RI CropWindow call Examples Restricting refresh to the upper right hand quarter of the image IrRefreshWindow 0 5 1 0 0 0 0 5 Restoring refresh for the entire image IrRefreshWindow 0 0 1 0 0 0 1 0 20 3 14 IrSelect C int IrSelect IPR ipr char type char handle Text IrSelect type handle Use this call to select primitives for tweaking Primitives can be selected by name or by shading group A primitive s name should be set in the scene file with Attribute identifier string name teapot This object could be selected with IrSelect ipr name teapot A shading group is meant to correspond to the concept of a material in a modeling program The shading group for a primitive is set with Attribute identifier string shadinggroup redbrick All primitives in a given shading group can be selected with IrSelect ipr shadinggroup redbrick By default the new selection set replaces the old list of selected primitives If the handle is preceded by a new primitives will instead be added to the selection set If the handle is preceded by a matching primitives are
108. or 16 bit unsigned integer float File data compressed Parameters float tilesize size Size for image tiles The default size is 32 string wrapmodes Xwrap Ywrap Sets the wrap modes in the X and Y directions which determines how the renderer handles texture access outside the unit square Xwrap and Ywrap should be one of black clamp Of periodic The default value is clamp clamp which clamps texture values at the boundary float 2 size width height Explicitly specifies the size of the largest mip map in the texture file Width and height should be a power of 2 and will be rounded up to a power of 2 if they are not float incremental 1 When this parameter value is included in the Display call the driver expects data in scanline order 2001 2014 SiTex Graphics Inc 51 AIR User Manual 5 8 and writes out each tile as it is completed This option minimizes the amount of temporary memory required when writing large images Custom Display Drivers Display drivers for AIR are written as dynamically linked libraries on Windows or shared objects on Linux AIR can use display drivers written for PRman and AIR also has it s own display driver architecture documented below AIR Display Driver Structure An AIR display driver must implement three functions defined in the SID h header file in SAIRHOME include Required Functions SID_OpenDisplay __declspec dllexport int SID_
109. or a wildcard pattern for pictures to load when started from the command line Menus File Open Cirl O Open a TIFF file saved by AIR AIR Show can only read uncompressed TIFF files Open Sequence Open a numbered sequence of image files Save Ctrl S Displays a file dialog for choosing a file name and saves the current image The file name extension determines the file format Save All Allows all images to be saved at once A dialog is displayed for choosing an output directory and display driver All images are saved to the same directory with the same driver Each image should have a different base name Save Sequence Saves all images as a numbered sequence Close Ctrl W Closes the current image window Close Previous Closes all images prior to the current image in the image list Close All Closes all image windows 2001 2014 SiTex Graphics Inc 407 AIR User Manual 24 3 7 2 24 3 7 3 Edit Copy Crop Coordinates Copies the crop coordinates for the current selection rectangle as a string The string is formated as xmin xmax ymin ymax Copy Decal Projection Copies the transformation matrix that will place a decal within the selection rectangle from the view of the image as a text string of 16 numbers This allows the viewport to be used to position decals on an object Annotate Add a descriptioin to an image which is stored by some file formats such as TIFF Copy
110. or automap shadows with a leaf mask Level of Detail The VTree shader incorporates a simple level of detail feature for leaves Leaves closest to the camera are represented as a six sided polygonal shape Leaves around 1 pixel in size are rendered with as 4 sided polygons Leaves smaller than a fraction of a pixel are represented as oriented point primitives Each coarser level of detail uses approximately half the memory of the previous level The TreeQuality parameter can be used to shift the transition points for the different levels of detail A large TreeQuality value will force the more detailed representation to be used a smaller value causes coarser levels of detail to be used at larger leaf sizes on screen Creating a Tree Archive The VTree shader was created in the Vshade shader creation tool included with AIR Vshade can also be used as a simple interface for creating a tree type as a rib archive Here s how e Start Vshade e Open the VTree shader located in the vshaders Procedures directory of your AIR installation e Save a second copy of the VTree shader to a different directory so the original shader is not overwritten keep the VTree name just save to a different directory You can now experiment with changing parameters under the Parms tab in the Vshade window e By previewing in AIR Show you can easily compare the effects of different parameter changes To render previews to AIR Show instead of the small window in Vsh
111. other scene elements will be affected by the filter To help with debugging filter plugins AIR 8 includes a new echorif command line option that echoes the output from a RIB filter to the standard output stream Sample Filters The AIR distribution includes several sample filters along with their source code in SATRHOME procedurals echorib list of RIB commands The echorib filter accepts a one or more RIB commands as arguments Any matching commands found in the RIB stream are printed to the terminal on stderr and passed back to the renderer for normal processing 2001 2014 SiTex Graphics Inc Pipeline Workflow and Optimization 356 Echorib is useful for seeing exactly what commands are included in a scene AIR has a rif command line switch for applying a filter to the whole rib stream E g to see all attributes in a scene use air rif echorib Attribute myscene rib cullrib list of RIB commands The cullrib filter removes the specifed commands from the command stream before they are processed For example to disable all displacements in a scene air rif cullrib Displacement myscene rib surftoprim list of parameters The surftoprim filter takes one or more surface shader parameters as arguments When the filter encounters a Surface call it stores any parameters that match the argument list and adds those parameters and values to subsequent primitives as primitive variable data The Surface
112. panes and texture map Parameter Default Value Range Description intensity 1 0 Light intensity lightcolor 1 11 Light color from 000 Source position of light to 001 Target of light shadowname ue Name of shadow map or raytrace for traced shadows shadowbias 0 01 Offset to prevent incorrect self shadowing shadowblur 0 01 0 0 0 5 Blur for shadows shadowsamples 1 1 256 Number of rays for traced shadows shadowcolor 000 Color of shadows shadowgroups ia Optional groups for ray traced shadows shadowattribute user shadowgroups Per object shadowgroups override attribute name 2001 2014 SiTex Graphics Inc Shader Guide 136 window_size_x 10 window width window_size_y 10 window height window_xdir 100 horizontal axis for the window window_ydir 010 vertical axis for the window window_panes_x 1 horizontal window pane count window_panes_y 1 vertical window pane count window_gap_x 0 1 horizontal gap between panes window_gap_y 0 1 vertical gap between panes window_fuzz_x 0 01 horizontal blur window_fuzz_y 0 01 vertical blur window_space world coordinate space for window directions texture_name a optional texture map texture_blur 0 texture blur __nondiffuse 0 0 1 If 1 light is excluded from diffuse light __nonspecular 0 0 1 If 1 light will not produce highlights foglight 1 0 1 If 1 light illuminates volumes __ channel 1 0 9 Output channel Description The distant_window_light shader emits ligh
113. primitive with Attribute point integer clustermax 10 would cause the instancer to be run on groups of at most 10 points The shader can optionally convert primitive variables to user attributes assigned to the archives where they can be queried by other shaders The prim vars can have either 1 value converted to a float user attribute or 3 values converted to a color user attribute See Also instMultipleArchives instancer shader 10 6 9 VinstanceTree companion instancer shader for the VTree procedure shader 2001 2014 SiTex Graphics Inc 125 AIR User Manual Parameter Default Value Range TreeArchive ue TreeScale 1 TreeSeed 124 TreeQuality 1 TreeHeightOverrid 0 e TreeRotateX 0 LeafColorOverride 0 Oori LeafColor 0 29 0 LeafVaryHSL 0 1 0 1 0 1 Description RIB archive file name with VTree definition Uniform scale applied to archive instances Base tree seed for random numbers Tree quality override when not 1 Tree height override if non zero Angle to rotate each tree about X axis Set to 1 to override average leaf color Average leaf color Per tree variation in average leaf color The VinstanceTree instancer shader creates copies or instances of a VTree procedure shader definition at vertex locations of the base primitive usually a collection of points Each tree instance receives a unique random seed based on the TreeSeed value and the vertex index so every tree will be uniq
114. primitives into a high resolution buffer one row at a time Note that this algorithm is not the REYES algorithm used by some other renderers The scanline algorithm employs a raster based shading cache to avoid re shading at every pixel sample This method also supports a sub pixel edge mask for capturing sharp edges and small or thin objects Ray Tracing Hider raytrace Air 12 introduces a new primary hider using ray tracing The ray tracing hider ignores the shading rate setting each pixel sample is shaded separately which will in general take more time than scanline rendering with the shading cache For scenes using ray tracing heavily anyway the performance penalty may be modest Some new effects are possible with the trace hider such as shading at different time values for motion blur Jittered sampling for motion blur and dof can be enabled with the following extra parameter Hider raytrace jitter 1 Deep Image Hider deepimage The deep image hider can store more than one depth sample at each pixel which is useful for rendering deep shadow maps or deep images for compositing By default the deep image hider stores all surface samples at each pixel When rendering deep images the hider will remove samples that are occluded by samples closer to the camera when the following option is enabled Hider deepimage culloccluded 1 See Also Deep shadow maps Deep images 2001 2014 SiTex Graphics Inc
115. procedural s bounding box on screen in pixels This detail measure can be used to adapt the level of detail generated by the procedural to the size of the objects in the rendered image The renderer then waits for RIB commands to be sent to the helper program s standard output The helper program must write a byte 255 to stdout when it is done processing the current instance On some systems the helper program may need to flush the output stream to force the final byte to be sent to the renderer The Air distribution includes source code for sample RunProgram procedurals in C and Python in SAIRHOME examples primitives procedurals Air 10 and later can execute multiple copies of a RunProgram procedural to accelerate multithreaded rendering The maximum number of RunProgram instances is set with Attribute render runprogramthreads 1 For the Massive RunProgram procedural Air will automatically send the scene options string to multiple instances The rpp switch can be used to set the attribute value on the command line air p 2 rpp 2 myscene rib In Air 11 and later the RunProgram procedural declaration may omit the bounding box in which case the procedural is evaluated immediately Procedural DynamicLoad A DynamicLoad procedural allows a shared object or dynamic link library to directly add objects to the scene by calling standard RI functions A DynamicLoad procedural call is very similar to a RunProgram call Procedura
116. query function used by subsurfacescatter in the form ofa new collect shading language statement collect executes the body statements once for each point in the object s point set within maxsearchdist of P Like the subsurfacescatter function collect generates a point set the first time it is called if a point set cache file is not used The parameter list can contain one or more of the following output parameters similar to the usage for gather 2001 2014 SiTex Graphics Inc 287 AIR User Manual Type and Name Description color surface Ci sample irradiance point primitive P sample position normal primitive N sample normal float area area represented by the sample float attenuation attenuation function to prevent incorrect scattering for non convex shapes float distance distance to sample point 10 15 8 cooktorrance Color cooktorrance normal N vector V float roughness color ior color absorption If a positive absorption value is provided the material is assumed to be metallic and the corresponding fresnel equation is used For non metals use an absorption value of 0 10 15 9 dictionary float dictionary string dictname string keyname float fvalue float dictionary string dictname string keyname color cvalue float dictionary string dictname string keyname string svalue The dictionary function alllows one to look up a set of values based on a name like lo
117. ray tracing ReflectionBlurX 0 1 01 1 0 Reflection blur in X direction ReflectionBlurY 0 3 0 01 1 0 Reflection blur in Y direction ReflectionName raytrace Name for reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup ReflectionGroups an Groups to test for traced reflections Description This surface shader simulates brushed or rolled metal The shader uses an anisotropic reflection model in which specular reflectivity depends on the orientation of the surface with respect to the incoming light The surface orientation is determined by the primitive s tangent vectors The X direction corresponds to the tangent vector in the u direction the Y direction corresponds to the tangent vector in the v direction Only parametric surfaces such as NURBs bicubic patches and bilinear patches have well defined tangent vectors This shader may not produce reasonable results when applied to subdivision surfaces or polygon meshes The SpecularRoughnessX and SpecularRoughnessY parameters control the size of the specular highlight in the X and Y directions respectively Using a different value for X and Y roughness generates oblong highlights Similarly the ReflectionBlurX and ReflectionBlurY parameters control the shape of blurry reflections using a different value for each parameter produces anisotropic reflections Normally the ReflectionBlurX and ReflectionBlurY values should be propor
118. regions adjoin should slightly overlap to prevent gaps Multiple depth maps can be used to make a cube faced shadow map for a point light Latitude Longitude Environment Maps Create a lat long environment map from an uncompressed TIFF file with mktex envlatl TIFFfile envfile If no output file is given the name of the output file is derived from the input filename by changing the filename extension to env Cube Face Environment Maps Create a cube face environment map from 6 image files with mktex fov angle envcube px nx py ny pz nz envfile Each image contains the environment viewed from a point in one of the 6 orthogonal directions The optional fov argument gives the angle in degrees of the perspective projection used to generate each face of the cube Using an angle slightly larger than 90 degrees can help avoid artifacts along cube edges If the fov option is not present the default angle is 90 degrees 2001 2014 SiTex Graphics Inc 415 AIR User Manual 24 7 5 24 7 6 Mirror Balls and Angular Maps Environment map images are often generated by photographing a reflective sohere Such a mirror ball format image can be converted for rendering with mktex ball srcimage destimage Another common format for probe images is the angular map in which distance from the center is linearly related to angle unlike a mirror ball image To convert an angular map to a lat long map for rendering with Air
119. removed from the selection set wee The special handle can be used to select all primitives IrSelect ipr name 2001 2014 SiTex Graphics Inc 365 AIR User Manual 20 3 15 IrTtweakAttribute C int IrTweakAttributeV IPR ipr char name int ntk char tk void v Text IrTweakAttribute name parameter list Use this function to modify attributes for the selected primitives Tokens in the parameter list must have full inline type definitions The following attributes are tweakable Attribute ipr string shading type Attribute ipr integer displacement n Attribute identifier string shadinggroup name 20 3 16 IrTweakCamera C int IrTweakCamera IPR ipr char name float transform float fov Text IrTweakCamera name matrix fov Use this command to update the camera position used for the interactive viewport The transform parameter is a matrix giving the new world to camera space transform For perspective views the fov parameter gives the new field of view in degrees The name parameter is currently ignored TweakAIR traces reflection rays to update the deep framebuffer when the camera changes Objects must be visible to reflection rays in order to appear in the viewport after a camera move 20 3 17 IrTweakCoordinateSystem C int IrTweakCoordinateSystem IPR ipr char name float transform Text IrTweakCoordinateSystem name matrix This function sets the
120. rendered in the final pass Enabling this option will in general increase rendering time since it forces all threads to wait until the last thread finishes the prepass The option is enabled by default Screen Space Cache By default Air stores the cache as a set of 3D point samples AIR 6 introduces a new screen space cache mode that can be enabled by setting the maxpixeldist attribute to 0 and maxerror gt 0 In this mode Air will store one occlusion sample per pixel for possible re use This produces an appearance similar to rendering without a cache in less time It also decouples the frequency of occlusion sampling from the shading rate Sampling the Environment Air 11 introduces a new option to sample the current scene environment for unoccluded rays The envlight shader provides a sampleenvironment parameter that enables this new mode When the occlusion prepass is enabled you should also enable environment sampling during the prepass with Option occlusion prepasssampleenvironment 1 When used with the occlusion cache environment sampling can be noticably faster and more accurate than the old method of querying an environment map based on the average unoccluded direction vector See Also Ray Tracing gt Optimizing Memory for Ray Traced Objects Lighting gt Indirect Lighting 13 4 2 Depth Mapped Occlusion Occlusion maps offer an alternative to ray tracing for producing ambient occlusion estimates and dome lighting ef
121. renderer because it disables some of the optimizations normally used by AIR Shader Sampling The frequency with which an object s shading is computed is determined by the shading rate attribute ShadingRate 1 The shading rate gives the area in pixels covered by a shading sample If the shading rate is R the renderer will compute 1 R shading samples per pixel When R gt 1 shading samples are shared between adjacent pixels When R lt 1 more than one sample is taken for each pixel The following images illustrate the effect of varying the shading rate 2001 2014 SiTex Graphics Inc Image Quality 30 ShadingRate 4 0 25 shading samples per pixel ShadingRate 1 1 shading sample per pixel ShadingRate 0 25 4 shading samples per pixel When the shading rate is large and the number of samples is low as in the top picture the image appears blocky since neighboring pixels share shading samples 2001 2014 SiTex Graphics Inc 31 AIR User Manual 4 3 When the shading rate less than 1 bottom image more than one shading sample is taken per pixel smoothing the shading The bottom two images in the picture look similar but close examination reveals that the shadow edges and reflections are smoothed in the image on the right The pictures also demonstrate that the rate at which shading is sampled is independent of the rate at which geometry is sampled PixelSamples is 4 4
122. rendering times Option limits integer displacement grid 8 Sets the maximum size of the grid of micropolygons for displacement Attribute render integer smoothlevel 1 Enables additional smoothing of the normals computed for displaced surfaces when the argument value is greater than the default of 1 The range of valid levels is 1 to 6 Attribute render fastdisplacement 1 With the default value of 1 AIR uses a faster displacement method that does not retain the normal values computed in the shader When set to 0 a slower displacement method is used that also allows bump mapping to be applied after the displacement Ray Tracing Displacements Ray tracing truely displaced surfaces can use a lot of memory because AIR must retain all displaced geometry for the duration of the render To save memory a surface can be made to displace when it is rendered from the camera but not when it is ray traced To disable displacement for a surface when itis ray traced use Attribute trace integer displacements 0 True Displacement Tips True displacement can be expensive in terms of memory and rendering times Here are some suggestions for making it somewhat less costly e If you do not need to ray trace a displaced surface make it invisible to shadow reflection and indirect rays AIR can then discard the surface as soon as it has been rendered by the scanline renderer This can have a large effect on memory usage If you
123. ribbon curve orientation problem with right hand coordinate system Fix for linear curves and uniform data Curve width is scaled by a scaling transform Volume primitives e New Dw x shading language function gives the derivative in the 3rd dimension for a voxel e Fix for calculatenormal e Ray marching works with point based data Procedurals e Under Windows AIR now recognizes RunProgram procedurals written in Python or Perl and automatically provides the necessary call to python exe or perl exe respectively e New documentation in this manual e New examples in SATRHOME examples primitives procedurals Subdivision mesh e New interpolateboundary tag option when the single integer argument is 2 boundary edges are treated as sharp creases but boundary vertices with 2 incident edges are not treated as sharp corners RIB Filters e Added Display PointsGeneralPolygons Shutter MotionBegin MotionEnd Clipping Volume e New echorif command line option echoes RI filter output to stdout Displays e Individual components of a color output variable can now be saved using array subscript notation E g Display grey ight tif file _ diffuse_unshadowed 0 __shadow 0 specular 0 would create a 3 channel file with the first red channel of each output variable AIR will automatically recompute a __shadow output value in a rendered image if the corresponding __diffuse and __diffuse_unshadowed outputs are
124. rotation angle in degress about the y axis map rotation angle in degress about the z axis Shadow color Light categories 2001 2014 SiTex Graphics Inc 141 AIR User Manual __nonspecular _ foglight __indirectlight __ channel Description If 1 light will not produce highlights If 1 light illuminates volumes Flag indicating indirect light status for multipass rendering Output channel The massive_envlight shader simulates light incident from a surrounding environment with ambient occlusion The incoming light can be a constant color or taken from an environment map specified with the envmap parameter This shader differs from the envlight shader in providing additional parameters for explicitly specifying the number of occlusion samples and maximum hit distance Shadows are computed by tracing rays at each point using AIR s occlusion function Output only variables color _ shadow color __unshadowed_Cl See Also Ambient occlusion envlight Shadow value Ambient occlusion in Massive 10 7 13 massive_indirect Emitted illumination without shadows light source emitting indirect diffuse illumination with extra controls for use with Massive Parameter intensity lightcolor samples maxhitdist adaptivesampling environmentmap environmentspace _ category __nonspecular ___foglight __indirectlight __ channel Description Default Value 1 0 Ltl 256 wee world
125. shaded grows large Lower FilterWidth values will allow more detail to appear up to the limit set by LevelsOfDetail but the additional detail may cause aliasing in animation 10 2 16 VStuccoed T a stucco Parameter Default value Range Description BumpMax 0 04 Maximum height of bumps Power 5 1 8 Exponent for sharpening bumps PatternSize 0 05 Overall scale of pattern PatternOrigin 000 Pattern offset PatternSpace shader spaces Coordinate space for shading calculations Description The VStuccoed displacement shader produces a stucco like pattern using a single noise function raised to a power The Power parameter sharpens the pattern 10 2 17 VITangentNormalMap Apply normal map in tangent space TextureName ve Texture name TextureBlur 0 0 0 0 1 0 Texture blur 2001 2014 SiTex Graphics Inc 99 AIR User Manual TextureSizeXxY L Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees See Also VNormalMap displacement shader for normals in object or world space 10 2 18 VTexturedBump displacement using a texture map Parameter Default value Range Description BumpMax 0 1 Maximum displacement amount BumpMin 0 0 Minimum displacement amount BumpSharpness 0 5 0 0 1 0 Angle in degrees for rotating pattern BumpBias 0 5 0 0 1 0 Coordinate space for displacement TextureName me Texture name TextureBlur 0 0 0 0
126. subset agents quantize 0 255 0 255 Display terrain_beauty 4f tif file rgba string subset terrain quantize 0 255 0 255 See Also Rendering in Layers 22 8 Eliminating Shadow Artifacts on Terrain Problem When rendering with ray traced shadows terrain geometry may exhibit artifacts in the form of incorrect shadows along the boundaries between polygons Solution In most cases the shadow artifacts are caused by incorrect traced ray intersections There are two solutions 1 The best solution is to increase the shadow blur setting in the light to at least 0 005 In most cases that will completely eliminate the problem See below for why this works 2 Increase the shadow bias either in the light shader or using the trace bias attribute Attribute trace bias 2 For Massive scenes start with a bias of around 2 and keep increasing until the lines disappear Why Increasing Blur Eliminates Artifacts When shadow blur is less than 0 005 AIR antialiases shadows by distributing shadow sample positions over the area being shaded Near polygon edges some of those positions can wind up behind neighboring polygons with respect to the light source This is more likely to happen with a coarse polygon representation When shadow blur is 0 005 or greater AIR antialiases shadows by varying the ray direction from the sample position over the cone angle defined by the blur value only The sample position is fixed at the current shadi
127. syntax for a NuCurves primitive is NuCurves nvertices order knot min max parameterlist nvertices i gives the number of vertices in the i th curve order i is the order of the i th curve Each curve has order i nvertices i knots and all the knot vectors are concatenated into the knots array min i and max i define the range of evaluation of the i th curve The parameterlist must contain at least position data P or Pw If a normal N is supplied the orientation of the curve will adjust to remain perpendicular to the provided normal Otherwise the curve will be oriented to face the incoming ray direction Curve width is specified by either supplying a single constantwidth value or a varying width parameter with values for each curve Like other primitives arbitrary user defined values can be attached to a NuCurves The number of values for each class of variable is constant 1 uniform number of curves varying sum nvertices i order i 2 vertex total number of vertices Blobbies and Dynamic Blob Ops AIR supports all features of the Blobby implicit surface primitive except the repelling ground plane blob op Rendering of blobby primitives can be optimized by using a higher flatness criterion to reduce the density of the polygon mesh produced for rendering Flatness is set with GeometricApproximation flatness 0 5 2001 2014 SiTex Graphics Inc Primitives 72 The defau
128. than the surface normal when computing occlusion Useful when sampling occlusion at positions other than the current shading location float 1 enables sampling of the scene sampleenvironment environment for unoccluded rays 2001 2014 SiTex Graphics Inc Shader Guide 300 Optional Output Parameters Type and Name Description color environment result of sampling the scene environment when the sampleenvironment mode is enabled See Also Ambient Occlusion 10 15 2 rayhittest float rayhittest point from vector dir output point Phit output normal Nhit Tests for an object in direction dir from position from If an object is encountered Phit and Nhit contain the position and normal of the object and the function returns the distance to the object otherwise the function returns a large number 1 0E15 10 15 2 rayinfo float rayinfo string name variable Returns information about the ray that caused the shader to be run rayinfo returns 1 if the query succeeds and 0 otherwise Supported keywords are depth float returns the current ray level where level 0 is a camera ray type string returns the type of ray camera trace transmission photon or collector label string returns the label associated with the current ray by a label parameter to the calling ray tracing function weight color returns the weight or importance of the current ray See Importanc
129. the X direction repeaty 1 Copies in the X direction originx 0 0 Location of left edge of texture map originy 0 0 Location of top edge of texture map Description The shader simulates a colored plastic surface with a usually white shiny specular highlight The 2001 2014 SiTex Graphics Inc Shader Guide 204 base surface color is taken from the primitive s color attribute or from the optional texture map The texture map is placed using the object s standard texture coordinates The roughness parameter controls the size of the specular highlight larger roughness values produce larger highlights See Also VPlastic shader 10 10 2 particle surface shader for volume and point primitives Illumination Model custom Parameter Default Value Range Description Diffuse 1 0 Diffuse reflectivity Incandescence 0 0 Self illumination value Ambient 0 0 0 0 1 0 Ambient reflectivity OpacityMultiplier 1 0 Opacity multiplier PrimaryScatter 0 0 1 to 1 Primary scattering direction PrimaryScatterWeight 1 0 0 0 1 0 Relative weight of primary scattering PrimaryScatterColor 1 0 1 0 1 0 color Per channel scattering multiplier SecondScatter 0 0 b to 1 second scattering direction SecondScatterColor 1 0 1 0 1 0 color Per channel scattering multiplier AngleFalloff 0 0 Exponent for angle based opacity falloff for spherical particles Description The particle shader implements a single scattering illumination
130. the length of du or dv also will not work properly An exception is made for the global variables dPdu and dPdv which are always smooth estimates of the change in P along the u and v axes respectively Derivatives and Varying Conditionals Like other renderers AIR interprets derivatives as differences between adjacent shading samples When evaluating derivatives AIR executes shading language instructions on a virtual SIMD single instruction multiple data machine there is one path of execution and each instruction is executed at multiple shading locations This implementation ensures that derivative values are always available However it imposes two restrictions 1 Derivatives must not be taken within varying conditionals 2 Derivatives must not depend on values that are calculated using varying conditionals Functions that take derivatives either explicitly or implicitly are Du Dv area calculatenormal 2001 2014 SiTex Graphics Inc 281 AIR User Manual and Deriv Dynamic Shadeops DSOs The shading language can be extended by writing custom functions in a programming language such as C which can be called from a shader A DSO must be compiled to a DLL on Windows or a shared object under Linux and the resulting file placed in the shader search path The DSO location should also be included in the search path for header files given to the shading compiler AIR will look for a DSO function in
131. the tip of each tube The direction of tilt can be changed using the StrandPolar parameters which control a rotation in degrees about the vertical axis 2001 2014 SiTex Graphics Inc 195 AIR User Manual StrandSegments TraceTip TraceJoint Each fiber is represented as a chain of tubular line segments StrandSegments gives the number of segments per fiber Each segment can be capped with a sphere TraceTip controls whether a sphere is traced at the tip of each fiber TraceJoints controls whether spheres are traced at the joints between segments in a fiber Carpet Shading The carpet is shaded using an empirical model that assumes some light is reflected from the front of each fiber and some is transmitted FrontScatter BackScatter ScatterPower FrontScatter gives the fraction of light reflected from the front of a fiber BackScatter gives the amount transmitted from behind Both are modulated based on the angle between the shading normal and the view direction such that more light is transmitted along the fiber edges and less in the middle The ScatterPower parameter is an exponent applied to the angle cosine used for this edge based variation SelfShadowMax ColorMapName BaseColor IndirectDiffuse SelfShadowMax gives the maximum self shadowing of the carpet the shadowing effect of neighboring fibers Self shadowing is greatest at the base of each fiber and smoothly attenuates to zero at the tip ColorMapNa
132. time and 2001 2014 SiTex Graphics Inc Shader Guide 196 potentially avoid some artifacts The TraceBias parameter gives an offset used to avoid incorrect intersections in this test Final Remarks The FakeCarpet surface is a fairly complicated shader and you will likely need to experiment with the parameters to reproduce the appearance of a particular type of carpet An IPR session utilizing TweakAir can be used to interactively view the effects of parameter changes See Also instCarpet instancer shader 10 10 1 Glow surface shader with constant color and opacity falloff based on facing ratio angle between viewer and surface normal Parameter Default Value Range Description Intensity 1 0 Overall emitted intensity multiplier AlphaFalloff 4 0 Exponent applied to facing ratio for alpha opacity interpolation ColorFalloff 1 0 Exponent applied to facing ratio for color interpolation EdgeAlpha 0 Alpha opacity value at edges EdgeColor 1411 Color at edge if EdgeColorEnable is 1 EdgeColorEnable 0 Oor 1 When 1 interpolate color using ColorFalloff and EdgeColor Description The Glow surface shader can be used to simulate illumination emitted from a glowing object The Glow shader is assigned to an object modeled to represent the extent of glow emitted by the glowing object Typically the Glow object will encompass the glowing object E g in the thumbnail image above the Glow shader is assigned to a second t
133. time by reducing the number of objects tested for intersection with each indirect ray The following option limits the maximum number of bounces light can take from a light source to a point and appear in the global illumination calculations Option indirect integer maxbounce 1 Lower values take less time and use less memory Since most of the indirect illumination is usually the result of the first bounce a value of 1 is usually sufficient to produce a noticable effect Air 14 introduces a new option to set the quality of area light sampling for indirect light Option indirect arealightquality 0 gives a multiplier applied to the nsamples value for each light This option replaces the old behavior of always using only 1 sample for each area light Adaptive Sampling Adaptive sampling is a method of accelerating indirect illumination When adaptive sampling is enabled AIR casts fewer rays initially and then additional rays only in regions where the initial ray casts indicate high variation Adaptive sampling can be enabled with Attribute indirect integer adaptivesampling 1 The maximum variance allowed before additional rays are cast can be set with Option indirect float maxvariance 0 1 Indirect Cache Because calculating indirect light at every shading location can be prohibitively slow AIR provides an efficient caching mechanism that stores previous computation results and allows them to be re used at new loc
134. to 1 only one copy of the texture is displayed textureup 010 Vertical axis used to orient the map projection __nondiffuse 0 0 1 If 1 light is excluded from diffuse light __nonspecular 0 0 1 If 1 light will not produce highlights foglight 1 0 1 If 1 light illuminates volumes _ channel 1 0 9 Output channel Description The distant_projector shader projects a texture map in the direction defined by the vector to f rom The incident light at the point being shaded is the product of the intensity and lightcolor parameters and the texture lookup result The texture map given by texturename parameter is mapped inside a square given by the texturescale parameter The textureup parameter defines a vertical axis used to orient the map The texturerotate parameter can be used to rotate the map By default only one copy of the map is displayed You can change that behavior by setting the textureonce parameter to 0 and converting the texture map to an Air texture file using the Air texture conversion tools mktex or mktexui selecting the desired wrap mode in the process Traced Shadows If the shadowname parameter is set to the special value rayt race shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace 2001 2014 SiTex Graphics Inc 135 AIR User Manual 10 7 8 The shadowblur parameter gives an angle in radians to distribute the rays around
135. to T If the optional vectors parameter is provided the result is the length weighted average of all microcylinders in the vector list Each vector direction is defined in a local coordinate system in which T is the X axis and Nf is the Y axis Output variables The microcylinder function provides the following optional color output variables specular unshadowed shadow indirect channels specularchannels col nchannels Examples col col col col col or or OF or or Or float array array specular reflection result volume scattering without shadows for all direct lights shadow value complementing the unshadowed output value indirect lighting per light volume scattering values indexed by a light s ___channel output variable per light specular values indexed by a light s __ channel output variable number of valid channels For sample usage see the source code for the VCloth and VClothAdvanced shaders in SAIRHOME vshaders Surfaces 10 15 2 occlusion color occlusion string mapname point P normal N varying output normal Nunoccl parameterlist float angle Returns the extent to which the current location is blocked or occluded by surrounding objects The 2001 2014 SiTex Graphics Inc 299 AIR User Manual direction in which the location is least obscured in Nunoccl The angle parameter gives the half ang
136. to be visualized even in scenes without lights 10 10 9 depthpass orm ia simple surface shader for rendering a depth pass Parameter Default Value Range Description mindistance 0 0 Start distance for interpolation maxdistance t0 End distance for interpolation invert 0 0 or 1 Invert output color Description This shader emits a grey scale color whose intensity corresponds to the distance of the shading 2001 2014 SiTex Graphics Inc Shader Guide 192 location to the camera Points closer than mindistance to the camera are colored black Points farther away than maxdistance are colored white Points that lie between mindistance and maxdistance are assigned a grey color by linearly interpolating based on the position between mindistance and maxdistance If the invert parameter is set to 1 the output color is inverted i e white becomes black and black becomes white 10 10 1 Emitter surface shader for treating an object as a light emitter Parameter Default Value Range Description IndirectIntensity i intensity for indirect rays Cameralntensity 1 intensity for camera rays ReflectionIntensity 1 intensity for reflection rays Width 1 nominal width of surface Length 1 nominal height of surface TextureName nu Color map name Description The Emitter surface shader emulates an area light by adjusting the intensity of the emitted incandescent color based on the size of the surface The Width and Length parameter
137. to compile a RenderMan shader for Air If you are using a version of Houdini prior to 9 1 169 the compile may fail because older version of the hrmanshader utility included with Houdini are not compatible with Air You will need to update the hrmanshader binary or hrmanshader exe in your Houdini installation with a more recent build in order to compile shaders for Air Adding New Shaders to Houdini New shaders that you create can be added to Houdini with the aid of the MakeLIF utility Tools The following programs are included in the bin directory of the Air distribution 2001 2014 SiTex Graphics Inc 399 AIR User Manual 24 1 Tool Air renderer Air Control Air Point Tool Air Show Air Space BakeAir Make LIF Material Editor Retexture Shading Compiler Shader Info Texture Converter Texture Converter Ul TweakAir Vortex Vshade AIR Control Windows only Command air air64 aircontrol airpt airshow airspace bakeair bakeair64 makelif airmated retexture shaded sibtell mktex mktexui tweakair vortex vshade Description 32 bit air binary under Windows 64 bit air binary under Linux 64 bit air binary under Windows User interface for starting and managing Air render jobs Command line tool for manipulating 3D point files Standalone framebuffer for displaying rendered images Standalone interface for adding materials and li
138. transmissionhitmode other than shader Fix for bug in prim var handling in ray tracer for constant and uniform data Fixed bug in instancer handling of normals Fixed bug in display subset mask computation for multilayer images with elements of arrays Tube curve generation when both s t and u v prim vars requested Fix for shading language spline b spline function 29 3 AIR 11 0 e Layered Shaders and Shader Networks e New generic shader type Environment shaders for shading rays that miss all objects in the scene Physical sun and sky shaders Per Face Texture Mapping support for the open source PTEX library e Deep image hider Ray Tracing e New option to optimize memory for ray traced objects Indirect diffuse lighting e Much more efficient handling of indirectdiffuse evaluation with no caching in reflections the number of indirect samples is now reduced based on the number of reflection samples e indirectdiffuse accepts maxerror maxhitdist adaptive and maxpixeldist parameters e New massive indirect light shader e Indirect shading modes constant and diffuse now use prim var Cs data of any class if it is present This allows a mesh with diffuse illumination baked as Cs to be used for fast indirect 2001 2014 SiTex Graphics Inc 433 AIR User Manual illumination with the constant indirect shade mode Subsurface Scattering e New option to automatically generate point set handles
139. type 2 The code does not rely on complicated preprocessor definitions It uses only one simple define for the default values 3 The main source code is independent of the exact defintion of the Layer type and the operations of the AddLayer function Adding a new field to the Layer type requires no modification to the main code Limitations Arrays of user defined type variables are not supported 10 15 2 areashadow color areashadow point P normal N float angle output varying point Psource falloff falloff samples samples shadow traceshadows The areashadow function is valid only within a light source and is only useful in a light source attached to an area light The function samples the geometry attached to an area light using ray tracing for shadows The function returns a color giving the fraction of the sample location defined by P N and angle that is in shadow Psource returns a carefully calculated virtual light origin usable in an illuminate statement A typical usage would be light myarealight float intensity 1 color lightcolor color 1 1 1 float falloff 2 float samples 64 point Psource float inshadow areashadow Ps Ns angles Psource falloff falloff samples samples illuminate Psource Cl intensity pow length L falloff lightcolor 1 inshadow In order to calculate an appropriate Psource areashadow requires in
140. use DarkTree shaders with AIR you need to have the DarkTree DSO called a simbiont by Darkling Simulations installed AIR version 4 1 and later includes the DarkTree DSO on Windows If you are using an earlier version of AIR you will need to install the DSO AIR comes with two special shaders for use with DarkTree shaders The DarkTreeSurface shader allows any DarkTree shader to be used as a surface shader for AIR The DarkTreeDisplacement shader allows any DarkTree shader with bump features to be used as a displacement shader for AIR The Air distribution includes several sample DarkTree shaders in the subdirectory viztools darktree Installing the DarkTree DSO The installer for Air on Windows should automatically install the DarkTree simbiont If that appears to have failed follow the manual installation instructions below The simbiont files are part of the Air distribution The only other step required is to define a SIMBIONT_RM_COMPONENTS environment variable to point to the location of the components used by the simbiont Those components are located in the shaders simbiontrm subdirectory of your Air installation To create an environment variable on Windows 2000 NT XP e Right click the My Computer icon and choose Properties e Select the Advanced tab and click Environment Variables e Click New to create a new environment variable and enter the variable name and value The RMSimbiont archive includes many sample shaders
141. use the depth information to determine if a point is in shadow Shadow mapped shadows are usually faster than ray traced shadows and have smoother soft edges Using Shadow Maps Support for a shadow map must be coded in a light shader If your plugin supports shadow maps it will likely include an appropriate shader and use it automatically Of the shaders included with AIR the pointlight spotlight distantlight and uberlight shaders support a shadow map Soft Shadows Most lights that support shadow maps provide a shadowblur parameter that can be used to blur the shadow map lookup to produce softer shadow edges Shadow blur for shadow maps is specified as a fraction of the total area of the shadow map Shadow Acne and Shadow Bias Occasionally some objects may exhibit incorrect self shadowing from a shadow map especially when using large shadow blur values A light shader typically provides a shadowbias parameter to help prevent incorrect shadows by providing a small offset for the depth information in the shadow map Transparency and Motion Blur AIR shadow maps work with transparent and motion blurred objects For higher quality shadows for transparent objects consider using fragment shadow maps Creating Shadow Maps Your plugin should have an option to automatically create shadow maps for a light A shadow map is created by rendering a scene from the point of view of the light source and recording depth information in an output fi
142. variation Stroke shaders should set output color Ci and output alpha like an imager shader strokePencil stroke shader emulating pencil sketching 2001 2014 SiTex Graphics Inc 175 AIR User Manual Parameter Default Value Range Description ScaleWidth 0 25 0 1 Stroke width as a fraction of the outline width MinWidth 0 02 0 1 Absolute minimum width Wobble 1 0 1 Stroke angle variation Fade 0 25 0 1 Stroke fade out at each end Bias 0 25 0 1 Offset center of stroke toward one end RandomizeDirection 1 0 or 1 Randomly reverse the direction of some strokes ReverseDirection 0 0 or 1 Reverse the direction of every stroke MaxOverdraw 0 4 Maximum amount to extend a stroke at the ends as a fraction of the stroke length Bend 0 25 0 1 Curved vs straight stroke Alpha 1 0 1 Opacity of the stroke Seed 941 Seed for random effects ColorEnabled 0 0 or 1 When enabled use the following color for the stroke Color 00 0 Override stroke color DensityMap a Optional density map file name DensityMapBlur 0 002 0 1 Density map blur DensityMaplnvert 1 0 or 1 When enabled invert the map value use 1 value DensityMin 0 4 0 1 Threshold for low density area DensityMax 0 7 0 1 Threshold for high density area DensityPower 8 Exponent applied to density value Description The strokePencil shader emulates a pencil sketch Stroke width is given as a fraction of the outline thickness defined by the object By using a sm
143. various Turbulence parameters The overall size of the pattern is determined by the PatternSize parameter Both the PatternSize and OpacityMultiplier parameters should be adjusted based on the scale of volume primitive See Also particle shader VSmokeSurface shader 2001 2014 SiTex Graphics Inc Shader Guide 228 10 10 4 VConcrete 4 concrete with grooves and color variation IIlumination Model clay Parameter Default Value Diffuse 0 8 DiffuseRoughness 0 8 GrooveDepth 0 01 GrooveWidth 0 05 GrooveAxis 100 Splotchiness 1 0 SplotchSize 0 2 SplotchColor 0 89 0 89 0 86 ShadingSpace shader Description Ooo oo re oo Description Diffuse reflectivity Diffuse roughness depth of grooves Width of grooves in the shading space axis perpendicular to grooves how much color variation to add size of color varying splotches color of splotches coordinate space for shading calculations The VConcrete surface shader produces the appearance of weathered concrete with grooves The base surface color is taken from the object s color attribute to which splotches are applied according to the Splotch parameters The grooves are oriented perpendicular to the axis defined by GrooveAxis in the ShadingSpace coordinate system For concrete without grooves set the GrooveDepth parameter to 0 See Also VClay shader 10 10 4 VDashes 2a be dashes for curves 2001 2014 SiTex Graphics In
144. want to use the same quality settings on both passes the behavior of AIR prior to release 2 7 set this option value to 1 Increasing the prepassfactor will save rendering time Objects that are not illuminated by the indirect light source do not need to be evaluated during the prepass Such objects should be tagged with the following attribute Attribute indirect integer prepass 0 AIR s indirectchannels light shader can track light channels through indirect bounces In order for the prepass to work properly with channel tracking AIR must be told to record the per channel indirect information with the following option Option indirect string prepasschannels __ lights Synchronization Air 13 introduces a new option to force Air to wait until an indirect or occlusion prepass has finished before rendering the final pass Option render syncprepass 1 This option provides a solution in cases where a bucket has not finished computing in the prepass when it is rendered in the final pass Enabling this option will in general increase rendering time since it forces all threads to wait until the last thread finishes the prepass The option is enabled by default Prepass and Transparency During the prepass the renderer only generates indirect illumination saving time by not running the full set of shaders at each pixel The renderer will calculate indirect light on the frontmost surface at each point and for points behind that
145. when ray tracing Blur for reflections Max level of interreflection Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Groups to test for traced reflections Index of refraction Multiplier for transmitted refracted light Color for transmitted rays Number of rays for refraction Blur for transmission Max level for refracted rays The VGlass surface shader simulates thick transparent glass including the effects of refraction By altering the IndexOfRefraction this shader can also be used simulate other transparent refractive materials such as water or diamond For thin glass objects modeled as a single surface such as a window modeled as a single polygon use the VThinGlass shader instead 10 10 5 VGradient surface shader with color gradient IIlumination model general Features reflections 2001 2014 SiTex Graphics Inc 237 AIR User Manual Parameter Diffuse DiffuseRoughness Specular SpecularRoughness SpecularSharpness Metallic Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace Incandescence StartColor StartColorBlend StartAlpha StartXY EndColor EndColorBlend EndAlpha EndXY Projection ProjectionSpace ProjectionTransform Description Default Value 0 5 0 0 04 5 0 0 1 0 0 raytrace ourrent st shader GOGH oor oS OrFOO Poo 2 0 or 1 0 0 1 0 1
146. will use ray 2001 2014 SiTex Graphics Inc Shader Guide 290 tracing to return an environment value The standard blur and bias parameters to environment have approximately the same meaning when ray tracing is used Sampling the Scene Environment If the file name is the special value environment Air will sample the current environment shader The blur parameter is interpreted as the half angle in radians of a cone of directions over which to sample the environment and the samples parameter can be used to super sample the region Optional Output Parameters The environment function accepts an optional alpha output parameter that returns the next channel after the channels returned by the environment call when an environment map is used When ray tracing is used to compute the returned value the alpha value returns the fraction of the sampled environment cone occluded by reflected objects The alpha value returned by the ray tracer can be used to composite tracing results with a background environment map In AIR 9 and later environment provides a background output parameter of type color that stores the contribution of the background environment map or color for reflection rays Beginning with AIR 9 environment can return arbitrary output variables from the surface shaders of ray traced primitives in the same manner as the gather construct For example color renv color Crefl envir
147. with shader computed transmission New envlight parameter samplelikediffuse to enable sampling the environment using a cosine distribution When the envlight envname parameter is set to environment the environment will be sampled using a lambert brdf producing a result that is much closer to the result from indirect lighting and the result from using the envlight s sampleenvironment switch e Added a shadowgroups parameter to the environment shader to restrict occlusion testing to the members of the specified groups Indirect lighting e New option to automatically build an in memory cache for environment queries from indirect rays Option indirect environmentcache 1 Using the cache produces much smoother results and is usually at least 2X faster for environment queries than rendering without Highly recommended e Indirect diffuse environment sampling is now much cleaner e Indirect diffuse results are less noisy at higher bounce levels Ptex per face texture mapping e New attribute to set the name of the Ptex texture coordinates generated by Air Attribute render string ptexcoordinates st Shaders e New cardlight area light shader emulates the effect of using a constant shaded card to add light with indirect diffuse illumination New OceanWaves displacement shader New Emitter surface shader can be used to create the effect of an area light with indirect diffuse illumination New surface shader ShowPosition N
148. you may need to increase the texture cache size for good performance E g Option limits texturememory 30000 will increase the cache size from the default of 10MB to 30MB Point based Occlusion Air 10 introduces point based ambient occlusion which computes occlusion using a 3D texture file or point cloud Step 1 Baking a 3D point file The first step to utilizing point based occlusion is to generate a suitable 3D point file The 3D point file should be saved as an Air Point Cloud apc file It is very important that the 3D point file include all occluding surfaces in the scene not just those that are visible to the camera The simplest way to produce such a point set is to use the bake3d surface shader included with Air in collect mode which uses the same surface sampling capability employed by Air s SSS feature To do that set the BakeRadius parameter to the maximum radius or size for any point in the cloud Smaller values produce a more accurate but larger point set Set the BakeMap parameter to the name of the 3D texture file with a apc extension The point cloud only needs basic position normal and width information for each point To minimize 2001 2014 SiTex Graphics Inc Lighting 330 the size of the point data set the BakeChannels parameter to the empty string to avoid writing any additional channels To use the collect mode all surfaces also need to be tagged members of the s
149. 0 000 1 Description This surface shader provides a physically plausible plastic or dielectric material The base color is taken from the standard color attribute The Specular parameter scales the result for both specular highlights and reflections Roughness controls the blurriness of reflections and the size of specular highlights larger values produce blurrier reflections and larger highlights Samples gives the number of rays to trace for reflections For larger Roughness values more samples may be needed to produce a smooth result See Also SimplePlastic surface shader VPlastic surface shader 10 10 6 VPlanks wooden planks 2001 2014 SiTex Graphics Inc 251 AIR User Manual Illumination model plastic Features reflections Parameter Diffuse Specular SpecularRoughness Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace PlankWidth PlankHeight PlankVaryColor WoodColor VeinColor GrooveColor GrooveWidth GrooveHeight RingScale GrainFrequency GrainFilterWidth TextureSizexY TextureOriginXY TextureAngle Projection ProjectionSpace ProjectionTransform Description Default Value 0 8 0 2 0 05 0 4 1 0 0 raytrace current 0 68 0 32 0 12 0 08 0 05 0 01 0 03 0 01 0 01 0 001 0 001 22 44 0 25 st shader OOOH oo reo OrROO rFOoOOO S aces Description Diffuse reflectivity Specular reflectivity
150. 0 Option reflection integer envsamples 8 Option reflection float envblur 0 0 Option reflection string envspace Motion Blur in Reflections AIR will blur motion for reflected objects with the following attribute set Attribute trace integer motionblur 1 2001 2014 SiTex Graphics Inc Reflections 342 Valid parameter values are 0 disabled and 1 traced blur enabled For motion blur to appear in reflections the reflecting surface shader must use more than 1 ray sample or at least some reflection blur Traced motion blur will only display the first motion segment of multisegment motion blur ReflectionGroups Reflection Groups AIR can optionally restrict objects appearing in reflections to members of specific groups AIR shaders that allow reflection groups will have a ReflectionGroups parameter accepting a space or comma separated list of groups Only members of the specified list of groups will appear in ray traced reflections 15 2 Reflections using Environment Maps Environment mapping is a fast alternative to ray traced reflections Environment maps store a view of the environment surrounding an object Reflections are simulated by simply looking up a color in the environment map saving the time and memory used when reflections are ray traced There are three main types of environment maps distinguished by the method of projection mirror reflection maps spherical maps and
151. 001 2014 SiTex Graphics Inc Shader Guide 232 TopDecalName _ TopDecalSpace world TopDecalTransform 1000 010 0 0010 000 1 TopDecalFrontOnly 0 SecondDecalName mm SecondDecalSpace world SecondDecalTransfor 100 0 m 0100 0010 000 1 SecondDecalFrontOnly 0 ThirdDecalName um ThirdDecalSpace world ThirdDecalTransform 100 0 010 0 0010 000 1 ThirdDecalFrontOnly 0 Description Decal file name Coordinate space for projection Projective transformation 1 front only 1 back only 0 both sides Decal file name Coordinate space for projection Projective transformation 1 front only 1 back only 0 both sides Decal file name Coordinate space for projection Projective transformation 1 front only 1 back only 0 both sides This plastic shader provides a base texture map with up to 3 projected decals on top 10 10 4Velvet velvet surface shader Illumination Model custom Features texture map Parameter Default Value Diffuse 1 0 BackScatter 0 5 Edginess 10 0 Roughness 0 1 SheenColor 111 ColorMapName me ColorMapBlur 0 0 Range o o oo e re oo 0 01 1 0 0 0 1 0 Description Diffuse reflectivity Strength of reflection toward the viewer Strength of scattering at the horizon Specular roughness Shiny color Texture map for base color Texture blur 2001 2014 SiTex Graphics Inc 233 AIR User Manual SpecularMapName SpecularMapBlur 0 0 Op
152. 001 2014 SiTex Graphics Inc Shader Guide 296 Meshinfo is typically used in a two stage process first meshinfo is called to establish a sampling method and location Then meshinfo is called to query primitive variable values at the current sample location Sample Methods The following sampling methods are supported Sample by vertex float vix 0 if meshinfo sample vertex vix 1 valid vertex index This sample method allows vertex varying and facevarying data to be queried For facevarying data Air picks one face s vertex value for the query result Sample at vertex on face float facevx 2 facevx 0 faceix facevx 1 vxindexonthisface if meshinfo sample facevertex facevx 1 valid vertex on this face This sample method allows access to varying vertex and facevarying data Sample at standard texture coordinates float xy 2 xy 0 scoord xy 1 tcoord if meshinfo sample st xy 1 valid s t texture position on surface This method provides access to varying vertex and facevarying data The base primitive must of course have a well defined set of standard texture coordinates If two locations on the surface share the same texture coordinates the sample result is not well defined Sample curve float cv 2 cv 0 curveindex cv 1 positionalongcurve if meshinfo sample curve cv 1 valid position along specified curve This method samples
153. 014 SiTex Graphics Inc 129 AIR User Manual area lights arealight2 shader Baking Shadows and Illumination 10 7 3 arealight2 arealight2_baked fast area light shader using AIR s areashadow function Parameter Default Value Range Description intensity 1 0 Light intensity lightcolor 1 1 1 Light color lightcolor_spd a Light color spectrum file maxemission 0 If greater than 0 the maximum emitted intensity including falloff samples 1 1 256 Samples for area light falloff 2 0 1 Exponent for falloff in light intensity with distance shadowbias 0 01 Offset to prevent incorrect self shadowing shadowcolor 000 Color of shadows shadowgroups shadowattribute __nondiffuse __nonspecular ___foglight _ channel Description wee user shadowgroups HoD O Optional groups for ray traced shadows Per object shadowgroups override attribute name If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel The arealight2 shader provides fast rendering for area lights with simple convex geometry such as a single polygon or disk The quality of the area light illumination is determined by the shader samples parameter The light s nsamples attribute should be set to 1 when the arealight2 shader is used Attribute light integer nsamples For complex area light geometry use the arealight shader instead Light Intensity
154. 122 3 8 E O e 0 95 1 0 8 15 10000 we Range 1 12 1 31 0 24 Oori Oori 0O or 1 0 0 0 5 1 256 Description Light intensity Light color When greater than 0 the maximum emitted intensity exponent for intensity falloff with distance atmospheric turbidity integer 2 9 date month day of month time of day 24 hour clock observer location difference between local time and GMT When non zero the end time for animation Multiplier for the global time value When positive sets sun zenith position Override for sun azimuth position Ground diffuse reflectance Ground reflections Ground color Angle in degress over which sky and ground transition at the horizon Ground self illumination when 1 Y is up otherwise Z is up North direction as an angle in degrees relative to the X axis Set to 1 for a right handed coordinate system Global divisor for computed intensity When set to 1 the computed intensity at the current location is divided by the average color of the entire sky Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for traced shadows Color of shadows 2001 2014 SiTex Graphics Inc 149 AIR User Manual shadowgroups shadowattribute user shadowgroups __nondiffuse 0 __nonspecular 0 _ foglight 1 _ channel 1 Description Optional groups for
155. 256 0 0 1 0 spaces spaces Description Diffuse reflectivity Diffuse roughness Specular reflectivity Specular roughness Specular sharpness When 1 use metallic illumination model Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup constant emitted intensity Color at start location Mix ratio with color attribute Alpha at start location Texture coordinates for start location Color at end location Mix ratio with color attribute Alpha at end location Texture coordinates of end location Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection The VGradient surface shader computes a gradient color pattern using 2D coordinates 10 10 5 VGranite 4 granite IIlumination model plastic 2001 2014 SiTex Graphics Inc Shader Guide 238 Features reflections Parameter Diffuse Specular SpecularRoughness Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace PatternSize PatternOrigin PatternSpace VeinFraction VeinFuzz VeinColor VeinLevelsOfDetail VeinRoughness VeinFilterWidth Description Default Value 0 8 0 2 0 1 0 0 1 0 0 raytrace current 0 05 0 0 0 shader spaces 0 0 1 0 0 0 1 0 Description Diffuse reflectivity Specular reflec
156. 2D VHair VHexTile VLayeredMaterialS jas ia cciscccvictscecs sestecoc cc secs sepecetecsscc cece dectvected seus a akaa Eana aia aia aranna cage canecstcceuecezenfeeceeccuesseeectuecens 241 DAE i Te E EEE E A cand E state ndcdsebencucuetesd E E EE E E 242 VLines VMarble VMetal VPhong VPhysicalMetal isccscccssscscsicseasessarssavesasadenscsencavasabesencoaiecovacapesavesabeoesedeancandvabasssecanedsvabapenavasabancusesuacandcabaseneazesnsve 248 VPhySsicalPlasti ccccsticcscscsescctcssesecrssescscscsensesasscessatcsescncusenctecedsavesavebcnsansacerssubdsenncisenuanap satcsevdncusentubanssabcseveasestses 249 VPIANKS acssscssnccsescnicsanesssicenecedscetesscsvvesesscvasestcdunecadneanicrsstenssutesesausosdvueceixstiecescsevscriscencssbedevacedseriecendsunecencetvecess VPIASHC seencesdsniesdsleicsnscdescscvecsassceccntcnsicusvsndastercsutcossudecdsdeneicenbencectesverssteacsdeccesenctsesucncecniceescusterdactenseatcecsendecises VRUDDEr gectscscsctcecsscecsccccheceneccccceaccseececansceezecscSceeieas iecheccctedwtcessccpneccbecsncsocadbaeastedenans ceuensscedcetoesagevecccnacsudessecsuanete VRustyMetal VSCREOM e E E E E E E E E E E E E E E E A 2001 2014 SiTex Graphics Inc Contents Vi VShadeCarpet se0e VShadowedConstant VShadowed Transparent s20e 0c2sfesccdccdececceecateecece cided na aeaaaee aaa Aaaa naaa Aaea vedenabdecueveccte EAE anaa aaa aAa niaaa kaaria nana
157. 327 AIR User Manual Attribute indirect float maxhitdist 100000 Using as low a max hit distance value as possible can greatly accelerate occlusion estimation by limiting the number of potentially occluding objects Using an appropriately low hit distance can also allow occlusion to be useful in interior scenes Adaptive Sampling Adaptive sampling is another method of accelerating ambient occlusion When adaptive sampling is enabled Air casts fewer rays initially and then additional rays only in regions where the initial ray casts indicate high variation Adaptive sampling can be enabled with Attribute indirect integer adaptivesampling 1 The maximum variance allowed before additional rays are cast can be set with Option occlusion float maxvariance 0 1 Occlusion Caching Because tracing shadow rays to estimate occlusion is an expensive operation Air allows occlusion values to be saved and re used just as indirect illumination samples can be Caching of occlusion values is controlled with the optional maxerror and maxpixeldist parameters passed to the occlusion function or if those are not provided by the corresponding indirect attributes Attribute indirect float maxerror 0 2 Attribute indirect float maxpixeldist 20 If maxerror is 0 Air will not cache occlusion values and occlusion will be recalculated at every shading location Rendering without a cache is obviously slower but it can produc
158. 4 The Shading Language csseccsseeeeescesteeseseeeenseeeeeaeeesaaeseseeeeneeeessaesaseeesaseaeesseassnaesaseenenseaeees 280 15 Shading Language Extensions cccscccseesseeeeseeeeeeesesnaeeneeeeeeeeeeseaeseseaeenseaeeeeeeeseaeseneenenseeeees 281 User StrUCtUneS misisse aiias tase caccacsdet detessacecteadet fe aaea aaie eaaa ie iadaaa aaae iada ai aaia daara ii 283 areashadow ws 284 Bakes cerieceiesectcdidcses ninaapa aana nai aeradenn 285 eain O E a E E A E E E E E 285 brushedspecullar seccccisiscccscsssscssccsscsssecascsssseasarssasanssancsateanuatssaoanesabaceassnuaranacapavatcdeveebuarsbanendvabcceasenuarsvasubsvabect esaze 286 CAUSTIC O ccc T E E E E E E 286 ol eea O A E E E 286 COOKTOMANCE e EEE E E 287 dictionary diffuse abrial alna aO m 289 lee ECelai G Ae a EEE A E E E E E E A 291 fulltrace cissveccscicascrscrssarcsesascceastaeesssatunsnancdsdeccuatavdoanesanaasdsiauassvabubesensdsearaudsasancdesensesentabassvddunasansdsiecaodisedoanddeeoaare 291 gather wassssecncccestecssasencacucesessarssatcseoacensavacbarsnavcsencucnsencababssutdsessbensenectaresabcsensncisenuanapssaudscosucmsenvusasarababdvencesiies 291 indirectdiffUSe sseciscceccsaserescsevocnsarsvassndsacseascnuarssacabanbessveabuarsvacapesabancaseniarssaoanesabdcedeebuarssaoandsabcersnaniarsvesabesanddedeuaei 293 itradiancecache erosicrnde nandaan aaa inakaa aaaea Ea aaea sdevectetaterdedeyeoudsaveunces sfuvsctesate deceyeaadvenctenere
159. 5 0 5 Color at base of curve TipColor 1 0 1 0 1 0 Color at tip of curve ColorBias 0 5 0 0 1 0 Bias for color interpolation along curve N_Srf 000 Surface normal at base of curve provided per curve in Curves primitive definition Description This shader is designed to shade fur generated with Joe Alter s Shave and a Haircut The diffuse color is based on the RootColor and TipColor which are linearly interpolated along the curve s length The result of that interpolation is then multiplied by the curve s color attribute See Also VHair shader 10 10 5 VGlass n glass shader for thick solid glass with refraction effects lllumination model custom Features reflections 2001 2014 SiTex Graphics Inc Shader Guide 236 Parameter Specular SpecularRoughness SpecularSharpness SpecularColor Reflection ReflectionSamples ReflectionBlur ReflectionMaxLevel ReflectionName ReflectionSpace ReflectionGroups IndexOfRefraction Transmission TransmissionColor TransmissionSample s TransmissionBlur TransmissionMaxLev el Description Default Value 1 0 0 1 0 8 1 0 1 0 1 0 raytrace current we Range 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 1 256 0 0 1 0 1 20 spaces 0 1 10 0 0 0 1 0 1 256 0 0 1 0 1 20 Description Specular reflectivity Specular roughness Sharpness of highlight edge Color of specular highlight Reflection strength Number of rays
160. 54 Shading language extensions e New shading language voronoi function that is 4 times faster than the equivalent shading language code e diffuse phong and specular accept an optional initial light category e Extended diffuse function with output variables to facilitate multipass rendering e More efficient rendering of Point sGeneralPolygons and polygons with texture data Additional attributes for geometry export e Export to ASCII RIB e Export to RIB using DelayedReadArchive e Automatic generation of _ Pref data e Automatic generation of _ Nref data e The gather function has anew othreshold parameter to control ray continuation Faster lighting calculations in MayaMan especially global illumination with maxerror 0 e New toon option to set a minimum ink width when the fade with distance option is enabled Option toon float mininkwidth 0 0 e More accurate ray tracing with better detection of degenerate triangles e New option to set the maximum grid size for displacement Option limits integer displacementgrid 8 e More efficient handling of uniform data Optimized shading structure storage for BakeAIR especially for primitives that are not baked Inline archive support for Procedural RunPrograms Changes to the AIR shader library e Most surface shaders have additional output variables for multipass rendering __diffuse_unshadowed shadow and__ indirect e Parameter name
161. 6 rib displaysfloat rib These templates can be found in AIRHOME archives They can be customized by adding or removing symbols at the beginning of Display lines to enable or disable the corresponding output image As is the templates render TIFF files Change the extension of the image file name to select a different image format To render to AIR Show change the output driver name from file to framebuffer See Also Output 22 4 massrib Massrib is a command line tool for manipulating the rib files produced by Massive Note Massrib is no longer needed to render Massive scenes with Air on Windows now that Massive and the Massive procedural primitive run under Windows Massive uses a procedural primitive to generate the members of a crowd at render time which is very efficient but not easy to customize The main function of massrib is to convert the Massive procedural calls to a plain binary or text rib file The resulting flat rib file can be rendered without access to the Massive scene files or Massive procedural A flat rib is also amenable to further postprocessing since it is just a plain rib file There are several disadvantages to using a flat rib First the flat rib files themselves can be rather large Second the procedural method of crowd generation employed by Massive allows AIR to render huge scenes very efficiently since each agent is generated only as and if it is needed If an agent does not need to be ray traced AIR c
162. A E E A E Con aa CI EEEE EN E EAEE E EE EE E E E EE E E E E AE E EE EEEE c nstant ezecceceeetecsecececdeeediece secede cessed cesta deca eda cecece dh cence detecteeet canbe seeceeedeeuebeddet echended whedche deeaheuesdecsevekendscacke Dark TREE SU Ma Ce A EE E E E E N E E E E E E defaultsurface Celt oiua o7 CT Ean EES ES EESE S S EE E A E P E E E A E EEE EE gain A n E E E A A E T E AE E EE AEE LO T o E EEEE E E E A E E E E E A E E E EE E GOV e O O a a a a R a a ea eara e E o PEE Aaaa rE eae a paa aaea Aa eraai INGIFECIPASS EEEE E EPEN S E E EEE E E EA E BEE E EEEE E E EN Massive occl sioNpaSS sse erreper eo aar raae ap Saare Sero te arar s aaee daare dencucesssiccesteccerszecssteesesesenerecces matte ecccece cecerecc accents disnas Secccene ceccbenedecceene ddce bene Seccewat adecbecedeccceue Sddcbeueteccenecdecbebedeucvenedddebeueicssceuesdbcbesctensvenase 2001 2014 SiTex Graphics Inc AIR User Manual metal MotionPass OCCIUSIONPASS E E EE 199 OCCANSUMAGCE ve seiicssesceressecsesecevccsasssiesetctcdccecstvuscetstubecesseevees etenisuccsvveccessvuseetesutesededevscrseceoesntusstacedscviesetessbivevcetiersye 200 OceanSurface With Foam ivesccccescsccecssccscscsctcesasoecscnceescocecesascencentcsescoseserasecacsuncosscncesessesencssteseesceesessceeadencessensecters 201 PAINted PlASHIC isiccsscisacsscsasarcscssvocnsarssassvesascsesneasarseasabavabessseanudrasacapesabcnsusenuarssacane
163. AA EEEa iaa na aniani aaa Aaina Eanan 325 Ray Traced OcCIUSION siciiiicccssteissescscscscscestsscecsescsencsetersestersestcosscoceddceseetscutendesscserststeiesecesscscncestescesetenersnsterdestene 326 Depth Mapped Occlusion iz zecccccecssccssceecass nrnna cectaecsceeccesscatpescussenesacersuecseee cast apna aaaea Saa ra Aa eiie 328 Point based Occlusion viisciccccscssccescecscscecesssacicesscencesncsessentersasscncscceeesactcessunencsanceeesebiceshdocacsencerssanbcrssdbessestesevessue 329 Image Based Lighting i iinccsciccts cece ceccectceds ced cone eecetede pct EE 331 Photometric Lights and IES Profiles csssecceseeeeseeeseeeeeeeeeneneeseaeseseeeenseeeseeeseseaesnsenenenees 332 GAUSUICS samenee iea a aa ea ae aaeoa E i aTa a aa oaea ata enasi Daea a aaa 333 Subsurface Scattering SSS si ciciscsccevescse eves teasceeeseccvedoastevesunsevestoascrvesaceuet soaseevesnasevveluaweveesnuceve 335 Baking Shadows and Illumination cceeceeeeeeeeeeeeene ee seeeeneneeeeeeeesaeseneeeenseeeeeeeseseaesnsenenenees 337 Ray Tracing 338 IMportance Based Rendering ceseecccceeeeeeeeneeeeeeenseeeeeenseeneeenseeeeeaseeeeeenseeeaeenseeeeeseseeneneeseeenens 339 Optimizing Memory for Ray Traced Objects cccscccsecesseeceseeeeenesesnaeeeseeeeeeeeesseesaseeeenseeeeeaes 340 Reflections 340 Ray Traced Reflections nec sivcteen cee ceed cecenectececeue cavesencconecuncccerenscueteesctccsersdnaueuerepccueeencusdeexeucnesses 340 Reflections u
164. Beginning with version 4 AIR can render Points primitives as bilinear patches which can be textured and used as sprites Patch sprite mode is enabled with 2001 2014 SiTex Graphics Inc 69 AIR User Manual 8 5 Attribute point string type patch Patches are oriented perpendicular to the camera unless a per particle normal N is provided in which case each point is oriented perpendicular to its normal vector If normal vectors are provided the primitive may also optionally contain a per particle vector xaxis defining the horizontal orientation of the patch When present the normal N and horizontal direction xaxis together precisely define the orientation of each patch The size of each patch is taken from the primitives varying width or constantwidth data For non square patches a Points primitive can include a constant or varying pat chaspect ratio parameter giving the width to height ratio for each patch If the aspect ratio is less than 1 the patch width is scaled by the aspect ratio If the aspect ratio is greater than 1 the patch height is divided by the aspect ratio Patches can be rotated by including a pat changle parameter giving the rotation angle in degrees Any varying parameters attached to the Points primitive are converted to uniform parameters for the bilinear patches Points as Spheres AIR 5 and later will render points as true spheres with Attribute point string type sphere Points as
165. Blur 0 0 OpacityMapName Ai OpacityMapBlur 0 0 BumpMax 0 0 BumpMapName um BumpMapBlur 0 0 ap 0 Range O 1 O 1 1 1 Description Diffuse reflectivity Diffuse roughness Specular reflectivity Specular roughness Texture map for base color Texture blur Texture map for specular color Texture blur Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur 2001 2014 SiTex Graphics Inc Shader Guide 254 TextureSizexY 11 TextureOriginXY 0 0 TextureAngle 0 Projection Met ProjectionSpace shader ProjectionTransform OHOO rFoOoOOO 1 0 O 1 0 0 0 0 Description S aces Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection Rubber appearance as a rough matte surface with soft specular highlights 10 10 6 VRustyMetal 4 metal with rust spots Illumination model metal Features reflections Parameter Default Value Diffuse 0 Specular 0 98 SpecularRoughness 0 2 Reflection 1 0 ReflectionSamples 1 ReflectionBlur 0 0 ReflectionName raytrace ReflectionSpace current Rustiness 0 5 RustColor 0 27 0 05 0 03 RustColorVaryHSV 0 15 0 1 0 1 PatternSize 0 2 PatternOrigin 00 0 PatternSpace shader S S aces aces Description Diffuse ref
166. C1 output variable All AIR light shaders as well as the light shaders included with MayaMan and RhinoMan provide this variable 10 10 7 VShadowedTransparent renders a shadow value into the alpha channel for compositing over a background image Parameter ShadowiIntensity 10 10 7VShinyTile2D Default Value 1 0 ceramic tile with reflections Range 0 0 1 Description 0 Shadow multiplier 2001 2014 SiTex Graphics Inc Shader Guide 258 IIlumination model ceramic Features reflections Parameter Default Value Diffuse 0 6 DiffuseRoughness 0 3 Specular 0 4 SpecularRoughnes 0 1 s SpecularSharpnes 0 8 s Reflection 0 8 ReflectionSamples 1 ReflectionBlur 0 0 ReflectionName raytrace ReflectionSpace current TileSize 0 1 0 1 TileStagger 0 0 TileColorVary 0 1 GrooveWidth 0 005 GrooveDepth 0 01 GrooveColor 0 91 0 91 0 91 BumpHeight 0 0 BumpWidth 0 01 TextureSizexY 11 TextureOriginXY 0 0 TextureAngle 0 Projection st ProjectionSpace shader ProjectionTransform 1000 0100 0010 000 1 Description 020 150 S aces Description Diffuse reflectivity Diffuse roughness Specular reflectivity Specular roughness Sharpness of highlight edge Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Width of tile Fraction to offset every other row of t
167. Disks AIR 8 and later can render points as disks with Attribute point string type disk If a per point normal N is provided in the point data the disk will be oriented perpendicular to the normal vector Otherwise disks will be oriented perpendicular to the camera for scanline rendering and perpendicular to the incoming ray direction when ray tracing Point Clusters To make rendering more efficient AIR 8 and later can divide a large point primitive into smaller reas coherent groups called clusters The maximum number of points in a single cluster can be set Attribute point integer clustermax 5000 If the custermax attribute is set to 0 the point primitive will not be subdivided into clusters Shading Points AIR includes a special particle surface shader for shading points that represent small particles for simulating phenomena like smoke or dust Curves AIR supports the standard Curves primitive which can be used to define linear or cubic curves as well as NuCurves primitive described below for rendering NURB curves Cubic and NURB curves are converted to a view dependent linear curve at render time based on the 2001 2014 SiTex Graphics Inc Primitives 70 flatness attribute GeometricApproximation flatness 0 5 which gives the maximum deviation in pixels allowed in the linear approximation Lower flatness values will produce more accurate curves which use more memory Curve Types AIR suppor
168. Fraction of layer that is vein color VeinTurbulence 1 0 0 0 3 0 Amount of turbulence to apply VeinFllterWidth 1 Filter width multiplier for antialiasing PatternSize 0 4 Width of one layer of marble PatternOrigin 000 Pattern position PatternAxis 100 Axis perpendicular to marble layers PatternSpace shader spaces Coordinate space for shading calculations Description The VMarble shader simulates a marble pattern material with reflections The size or scale of the marble pattern is set with the PatternSize parameter The marble is modeled as alternating layers of a base substrate whose color is taken from the primitive s color attribute and a vein layer whose color is set by the VeinColor parameter VeinFraction gives the fraction of each pair of layers that is the vein color The layers are oriented perpendicular to the PatternAxis VeinSharpness determines the sharpness of the edge between the colored vein and the base material r VeinTurbulence controls the how much the marble is distorted by a simulated turbulent flow 2001 2014 SiTex Graphics Inc Shader Guide 246 0 5 i rf i This shader performs anti aliasing by fading out the marble pattern as the region being shaded grows large Lower VeinFilterWidth values allow more detail to appear but the additional detail may cause aliasing in animation 10 10 6 VMetal 4 metal shader with reflections and color texture map Illuminati
169. Frequency control the variation in stiffness across the carpet StiffnessAtEdge gives the stiffness value near the edges of the carpet EdgeWidth EdgeVary EdgeWidth defines a region near each edge as a strand count If this value is greater than 0 the shader automatically bends the strands close to an edge so they tilt perpendicular to the edge and away from the carpet EdgeVary varies the calculated distance edge value to prevent artifacts from a regular pattern Color ColorVary ColorMapName Color gives the base color for the carpet which can be randomly varied for each strand using ColorVary If a ColorMapName is supplied the color of each strand is taken from the color map indexed using the texture coordinates of the base polygon If the color varies per strand the instancer attaches a separate color value to each strand MaskName MaskThreshold MaskName is an optional mask texture map which can be used to cut irregular shapes out of the base polygon MaskThreshold gives a minimum value used to determine where the mask is opaque Carpet Shading This instancer shader is designed to work with the companion VShadeCarpet surface shader which 2001 2014 SiTex Graphics Inc Shader Guide 120 10 6 2 should be assigned to the base polygon IndirectStrength IndirectVisibility IndirectSamples By default the carpet fibers are not visible to indirect rays set IndirectVisibility to 1 to enable visibility T
170. GB color space is approximately equivalent to a gamma value of 2 2 though that approximation is not very close at the low end of the intensity range Input Color Conversion In order to provide Air with linear color values color properties selected in a user interface may need to be converted from the display color space to a linear space Your plugin or application should do this automatically or have an option to do so Texture maps also need to be converted from a display color space if the images are not already linear Here is a comparison of an image in a linear rgb space left and SRGB space right Linear images will often appear too dark when viewed on a normal monitor without gamma correction The Air texture conversion tools mktex and mktexui can be used to convert an image from sRGB color space to linear rgb space They can also be used to convert the image to an Air texture file that is more efficient for rendering Air 13 introduces a new option to automatically convert source texture files from SRGB color space This option can be enabled by adding the following to a RIB file ColorSpace rawtexture sRGB when enabled Air will automatically perform an sRGB to linear conversion for images used as texture maps that have not been converted to an Air texture file already This option does not apply to images used as environment maps Output Color Conversion The output colors computed by Air are in a linear color sp
171. Graphics Inc Plugins and Companions 422 Temerity Pipeline is the industry s first complete production control application designed for the film television and game industries Pipeline increases productivity and studio profitability by providing seamless control over distributed processing of jobs revisions and storage management Studio pipelines are managed through one environment allowing artists to spend more being creative instead of dealing with production issues Temerity believes that the development of in house production solutions and pipeline methodologies can be more costly difficult to maintain and less efficient than an integrated solution like Pipeline The tight integration of Pipeline s asset management revision control and distributed execution queue provides both efficiency and new functionality which cannot be achieved through gluing ad hoc combinations of existing production tools Pipeline offers a solid yet highly flexible infrastructure suitable for any studio size or type of production Temerity Pipeline has full support for Air BakeAir and their associated texture and shader utilities DarkTree DarkTree is a visual shader creation tool from Darkling Simulations DarkTree 2 0 is an advanced procedural shader authoring tool Its visual flow based editor lets you interactively create photo realistic procedural materials surface shaders and animated effects DarkTree 2 0 includes 100 procedural compo
172. Highly recommended Newsgroup comp graphics rendering renderman Newsgroup FAQ comp graphics rendering renderman FAQ Creating Computer Graphics Imagery Digital Lighting amp Rendering by Jeremy Birn Good general discussion of techniques for composing lighting and shading 3D scenes Not application specific License Agreement AIR Advanced Image Rendering Software and the Visual Shading and Lighting Toolkit SOFTWARE PRODUCT is owned by SiTex Graphics and is protected by United States copyright laws and international treaty provisions Therefore you must treat the SOFTWARE PRODUCT like any other copyrighted material e g book or musical recording You may make one copy of the SOFTWARE PRODUCT for archival purposes You may not redistribute the SOFTWARE PRODUCT or any of its accompanying materials You may not reverse engineer decompile or disassemble the SOFTWARE PRODUCT SiTex Graphics grants you the non exclusive right to use one copy of the SOFTWARE PRODUCT per license as long as you comply with this agreement Each license of the SOFTWARE PRODUCT may be used on only one computer at one time The SOFTWARE PRODUCT and accompanying materials are provided on an as is basis SiTex Graphics makes no warranty either expressed or implied including but not limited to warranties of merchantability or fitness for a particular purpose with regard to the SOFTWARE PRODUCT and the accompanying materials In no event shall SiTex Grap
173. IB e New Echo RIB command prints a message to stdout e New Camera RIB command for defining additional cameras for stereo and multicamera rendering e MakeTexture MakeShadow and MakeCubeFaceEnvironment now issue INFO messages with the name of the created map e BakeAir e Support for baking multiple outputs to a single map e Individual elements of array output variables can be saved e Map name display reports 16 bit and float precision e Fixed printing of display modes for rendered maps Air Show 5 0 e Stereo view mode e Interactive gain control e New option to disable detection of shadow maps which allows single channel floating point images to be displayed as normal images e Histogram and min max computed only for valid region of a cropped image e Fixes for 3dl LUT loader Air Control e Bug fix for incorrect detection of task completion resulting in orphaned air processes in the task manager 2001 2014 SiTex Graphics Inc 439 AIR User Manual 29 5 mktex Texture Conversion Tool e Added byte word float data conversion and abs composite ops airpt Air Point Tool e New range option shows the min and max value of each stored channel e Support for reading Maya PDC files makelif e New option to create SPDL files for Softimage Bug fixes Important fix for motion blur combined with depth of field bounding box for a facet Problem with SSS cache evaluation when triggered from a refle
174. IB file will be in ASCII format instead of binary Additional Attributes for Geometry Export Attribute render integer makePref 0 Set this attribute to 1 to generate __ Pref point data for the exported mesh containing the undisplaced vertex positions Attribute render integer makeNref 0 Set this attribute to 1 to generate __Nref normal data for the exported mesh containing the vertex normals prior to displacement Attribute render string meshspace world Specifes the coordinate space for exported point and normal data The only support spaces are world and object 19 4 General Optimization Tips Tips on optimizing rendering to reduce speed and or memory used e Ray trace only when necessary to save time and memory 2001 2014 SiTex Graphics Inc Pipeline Workflow and Optimization 358 Objects that do not need to be ray traced should be made invisible to all ray types shadow rays reflection rays and indirect rays AIR can discard such objects as soon as they have been rendered The AIR Show framebuffer can be used to see if any objects are retained for ray tracing in a scene The second box from the right in the status bar displays one or more letters if any objects are visible to shadow rays S reflection rays R or indirect rays I If you are not using ray tracing in a scene make sure that box is empty For motion blurred curved or displaced primitives enable the motion factor optimizat
175. Image Windows only Copies the current image as displayed to the Windows clipboard View Refresh Redraws the display window Zoom In Zoom in on an image Zoom Out Zoom out of an image Zoom Normal Restore image view to the default in which one pixel on screen represents one pixel of the image Gain Displays a dialog for setting the gain or intensity multiplier for an image Gamma Displays a dialog for setting the gamma correction factor for the current image Pixel Zoom Opens a separate window that displays the numeric values of the pixel under the mouse pointer Fit Window to Image Resizes the AIR Show window to display the current image without scroll bars or margins 2001 2014 SiTex Graphics Inc Tools 408 24 3 7 4 24 3 7 5 24 3 7 6 Animate Frame Rate Displays a dialog for setting the playback rate for animation in frames per second Play Forward 3 Play images as an animation once Play Backward Show images in reverse order as an animation once Cycle Forward 4 Cycle images in forward order until stopped by the space bar or stop button CycleBackward Cycle images in backward order until stopped by the space bar or stop button Pong 5 Show images in forward and reverse order alternately until stopped by the space bar or stop button Sort Frames Puts images in alphabetical order based on image name Move Frame Use the subitems to change the position of the current image
176. Maya amp MayaMan 2001 2014 SiTex Graphics Inc Massive 374 22 1 Rendering with AIR from Massive Rendering a Massive scene with AIR requires several steps Create one or more render passes Create one or more renders Each render is associated with a render pass Assign shaders to agents terrain and lights for each pass Export files used for rendering with the Sim dialog Render using the resulting exported files Creating a Render Pass e In the Options menu select Render to display the Render dialog e Choose the renderpasses tab and click add to create a new pass e Change the renderpass name to beaut yAir by typing in the top text box e Change the renderer for the pass to Air using the selection list next to the render caption Creating a Render The next step is to create a render with which to associate the render pass e Select the render tab and click add to create a new render e With the new render selected click on the parameters page e Change the associated render pass for the new render to beaut yAir e Use the output ribs entry to enter the path and file name specification for the exported rib file that will be used for rendering Important the export directory must exist for the scene export to succeed If the directory does not exist you ll need to create it outside of Massive The remainder of the parameters dialog allows you to customize other aspects of the rendering s
177. OpenDisplay SID_Info di int n SID_Parameter p This function is called when the display is opened usually at WorldBegin The SID_Info structure provides the following information typedef struct void globaldata void localdata char errmsg int width height image width and height float par pixelaspectratio float gamma gamma applied prior to final quantization int nch number of output channels int chtype channel type char filename filename passed to RiDisplay char modes modes passed to RiDisplay char software string describing software amp version e g AIR LOON SID_Info A display driver will normally allocate a structure to store its internal data and save a pointer to that structure in Llocaldata p points to an array of n parameters passed to RiDisplay SIDUtil h contains a few helper functions for processing parameters Any non zero return value indicates failure You can optionally return a pointer to an error message in errmsg SID_WriteRect __declspec dllexport int SID_WriteRect SID_Info di int xmin int xmaxplusl int ymin int ymaxplusl void data j The write function is called repeatedly to pass image data to the display routine di points to the same structure passed to the open display routine xmin xmaxplus1 1 ymin and ymaxplus1 1 define the rectangle of image data Currently image data is always passed as complete sca
178. Reflectance parameter scales the result for both specular highlights and reflections Roughness controls the blurriness of reflections and the size of specular highlights larger values produce blurrier reflections and larger highlights Samples gives the number of rays to trace for reflections For larger Roughness values more samples may be needed to produce a smooth result See Also SimpleMetal surface shader VMetal surface shader 10 10 6 VPhysicalPlastic tphysically plausible plastic with texture maps IIlumination model plastic 2001 2014 SiTex Graphics Inc Shader Guide 250 Features reflections texture map Parameter Default Value Range Description Diffuse 1 0 0 1 0 Diffuse reflectivity Specular 1 0 0 0 1 0 Specular and reflection multiplier Roughness 0 03 0 0 1 0 Specular roughness ReflectionSamples 4 1 256 Number of rays when ray tracing TextureSizexY l1 Size of texture map in X and Y TextureOriginXY 0 0 Position of left top corner TextureAngle 0 0 Rotation angle in degrees ColorMapName a Color map name SpecularMapName me Specular map name OpacityMapName Opacity map name BumpMax 0 0 Bump amplitude multiplier BumpSpace shader space in which to measure displacement BumpMapName id Bump map name Projection st projections Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection Transform 1000 Transformation applied prior to 0100 projection 001
179. SiTex Graphics AIR User Manual 2001 2014 SiTex Graphics Inc by Scott Iverson AIR User Manual Table of Contents Part I 1 2 3 4 5 Part Il Part Ill 1 2 3 Part IV 1 2 3 4 5 6 7 Part V 1 2 3 4 5 6 7 Foreword Getting Started INS TAM ATION eaaa aa ana araar aeaa aaa Aaaa a aeann aaa aLa Gaa dia Gamma Correction sasssssssessnnnnnnnnennnnnn nunne nnnm nunne nnmnnn mnane Rendering sessionis aE ESA Linux Notes aeeoea ann aa eaaa ea A aaa E E E Ea Kaa n AAEE Saaai Command Line Switches cccssseceeeseeeeeeeseeeeeeneeeeeeenss What s New Color Spectral Color Definition ssssssssuunnennnnnnnnnnnennnnnn nunne ennnen Spectral Prefiltering and Chromatic Adaptation Tone Mapping sssssssnsesnnnnnnnunnennnnnnnnnnnnnnnnnnnnnnnn ununun nnmnnn nnmnnn na Image Quality Geometry Sampling cccesccesseeeeseeeeeeeeeeeneeeseeesesneeeeseeeeeeees Shader Sampling ccssecceseeeceseeeeseeseseeeeeeeeeseeesesseeenseeeeeeees AIti ALIASIING eariranneisnsniran Pixel Ba se ee ee Clamp to Alpha ai ee eneee aoaeiaa narena seapea eare uaaa Eunana Field Rendering ssssunsssuunnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnmnnn nnmn na Hidden Surface Methods ss nsssnnsunnuunneunnnunnnunnnunnnnnnnnnnnnnnnnn Output Multipass Rendering ccccesseeceseeeeeeeeeeeeeeeeesneeseeesneeeeeeene Rendering in Layers
180. SiTex Graphics Inc Lighting 338 Per object maps may be useful when using maps with baked shadows generated by BakeAIR Baked Shadows for Area Lights The new arealight_baked and arealight2_baked shaders work similarly to the bake shaders mentioned above with the following differences The arealight_baked shader cannot create a 3D texture file bake modes write and append are not supported The arealight_baked shader can read a 3D shadow file generated by the arealight2_baked shader The arealight2_baked shader stores only shadow information in a 3D texture file It does not store the virtual light location returned by the fast areashadow function As a consequence rendering using a 3D texture file will look somewhat different than a normal render with the arealight2 shader Baked Indirect Illumination and Caustics The new indirect_baked and caustic_baked shaders allow baking of indirect diffuse and caustics respectively These shaders support the same modes described above for standard shaders with the natural difference that the light s emitted illumination is stored instead of a shadow value Note that for caustics rendering with AIR s builtin photon cache may be faster than using a baked 3D point file To facilitate the use of the readNDC mode for these shaders the AIR 9 distribution includes new IndirectPass and CausticPass surface shaders for rendering an image with just the indirect diffuse or caustic illuminati
181. Specular color map Reflection 1 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup BumpMax 0 0 Maximum bump height BumpMap Texture map for bump mapping Projection tote type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform 1000 Transformation applied prior to 0100 projection 0010 000 1 aMask Texture map for layer mask aMaskSizeXY LT Size of mask in X and Y aMaskOriginXY 0 0 Position of top left corner of mask 2001 2014 SiTex Graphics Inc Shader Guide 242 aDiffuse aDiffuseColor aDiffuseColorMap aDiffuseSizexY aDiffuseOriginXY aSpecular aSpecularRoughness aSpecularSharpness aSpecularMetallic aSpecularMap aReflection aReflectionBlur aBumpMax aBumpMap we 0 0 1 0 0 0 1 0 0 0 10 Diffuse reflectivity Diffuse color Diffuse color map Size of texture map in X and Y Map position of left top corner Specular reflectivity Specular roughness size Sharpness of highlight edge Whether surface is metallic Specular color map Reflection strength Blur for reflections Maximum bump height Texture map for bump mapping Two more layers b and c with parameters identical to layer a parameters
182. Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur 2001 2014 SiTex Graphics Inc Shader Guide 218 TextureSizeXxY L Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection Transformation applied prior to projection ProjectionTransform OHOO rFoOoOOO 1 0 O 1 0 0 0 0 Description This surface shader simulates the appearance of anisotropic surfaces with a plastic finish such as painted wood The default parameters are based on physical measurements for a semi gloss latex paint applied to wood The shader uses an anisotropic reflection model in which specular reflectivity depends on the orientation of the surface with respect to the incoming light The surface orientation is determined by the primitive s tangent vectors The X direction corresponds to the tangent vector in the u direction the Y direction corresponds to the tangent vector in the v direction Only parametric surfaces such as NURBs bicubic patches and bilinear patches have well defined tangent vectors This shader may not produce reasonable results when applied to subdivision surfaces or polygon meshes The SpecularRoughnessX and SpecularRoughnessY parameters control the size of the specular
183. TextureOriginXY 0 0 TextureAngle 0 Projection Met ProjectionSpace shader ProjectionTransform OHOO rFoOoOOO 1 0 O 1 0 0 0 0 Description This surface shader produces a woven pattern See Also VWeaveDisplacement displacement shader 10 10 8 VWood solid wood shader Illumination model plastic S aces Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection 2001 2014 SiTex Graphics Inc 273 AIR User Manual Parameter Default value Range Description Diffuse 0 7 0 0 1 0 Diffuse coefficient Specular 0 3 0 0 1 0 Specular coefficient SpecularRoughness 0 1 0 0 1 0 Specular roughness WoodColor 0 98 0 63 0 43 Wood color WoodGrain 0 3 Graininess of base wood VeinColor 0 23 0 10 0 05 Wood vein color VeinGrain 1 0 0 0 1 0 Graininess of the vein VeinWidth 0 8 Fraction of each ring in vein VeinFuzz 0 8 Fraction of vein for transition VeinBias 0 8 Relative sharpness of in and out transitions GrainFrequency 200 Frequency of fine grain GrainDepth 0 001 Depth of grain RingFrequency 15 Frequency of wood rings RingVary 1 Variation in ring width TrunkVary 0 1 Deviation of trunk from a straight line TrunkVaryFrequency 2 0 Frequency of trunk deviation AngleVary 0 3 Variation in rings around the central axis AngleVaryFrequency 2 0 Fre
184. The emitted light value is the product of the intensity and lightcolor parameters and an attenuation factor determined by the falloff parameter The falloff parameter allows the light s intensity to diminish with distance from the light A falloff value of 2 which is physically accurate reduces the incident light value by the square of the distance from the light Cl intensity lightcolor Distance Distance 2001 2014 SiTex Graphics Inc Shader Guide 130 Although a falloff of 2 is physically correct it can produce very large intensity values at locations close to the light source The maxemission parameter can be used to set the maximum emitted intensity regardless of distance from the light source Alternatively a falloff value of 0 produces no attenuation with distance which may be easier to control Shadows The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow g
185. Transform Description Default Value 0 5 0 5 0 5 1 0 0 raytrace current st W shader oOo oor OrROO FOr ere W st shader OOOH OQQA OrROO POOQ 0 0 1 0 projections spaces 0 0 1 0 projections spaces Description Diffuse reflectivity of front side Diffuse reflectivity of back side Specular reflectivity of front side Specular reflectivity of back side Specular roughness of front side Specular roughness of back side Reflection strength of front side Reflection strength of back side Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Base color for back side Texture name for front side Texture blur for front side Texture size in X and Y directions Location of left top texture edge Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection Texture name for back side Texture blur for back side Texture size in X and Y directions Location of left top texture edge Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection The V2SidedPlastic surface shader provides a basic reflective textured plastic shader with separate 2001 2014 SiTex Graphics Inc Shader Guide 212 controls for the front and back sides of a surface
186. Tweak4 Description 0 0 or 1 1 0 1 0 0 0 0 0 0 0 1 0 0 0 0 shader space Set to 1 for a 2D pattern using an object s standard texture coordinates Texture width and height for 2D pattern Location of top left corner of texture Rotation angle in degrees for 2D pattern Size of 3D pattern Offset for 3D pattern Coordinate space for pattern Multiplier for bump effect Multiplier for global time value Tweak name Tweak value Tweak name Tweak value Tweak name Tweak value Tweak name Tweak value Tweak name Tweak value Tweak name Tweak value Tweak name Tweak value This shader allows any DarkTree shader to be used as a surface shader for AIR To use DarkTree shaders you must have the RMSimbiont from Darkling Simulations installed The simbiont is available at www darksim com The RMSimbiont file should be placed in a directory that is in your shader search path The shaders directory of the AIR home directory is a good place To use a DarkTree shader enter the name of the DarkTree shader in the DarkTreeShader parameter The DarkTree simbiont will look for the DarkTree shader in the search pathes defined with the SHADERS and SIMBIONT_RM_SHADI ERS environment variables The DarkTreeSurface shader provides a number of tweak parameters that can be used to alter the tweaks defined for a particular shader Some user interfaces such as MatEd will automatically fill in the list of tweaks for a parti
187. Varying data is interpolated and supplied to the surface shader at each shading location This allows a surface shader to modify the base output from a fluild simulation for example to add additional fine detail Particle based User Data Particle data can be rendered as a volume primitive by defining a null grid 0 0 0 and providing P position data with varying data associated with each point The size of each particle can be set with a single constantwidth parameter or a varying width parameter The particles are blended together like blobby primitives to obtain the base opacity value for each shading location accounting for any varying Os or floatOs data supplied Other user data is blended in the normal way Particle based data is evaluated using a fast space subdivision structure which makes it feasible to render large numbers of particles Motion Blur Intravolume motion blur is support for grid based user data by providing varying vector dPdt ime data A constant __motionoffset variable can be used to shift the motion vector relative to a given point 2001 2014 SiTex Graphics Inc Volume Rendering 354 The actual motion vector at point P extends from P motionoffset dPdtime to P 1 motionoffset dPdtime The default motion offset is 0 Transformation motion blur is currently applied as intravolume blur Boundaries of a volume primitive will not blur Procedural Primitives Procedural primitives that gen
188. Volume Primitives Like other primitive types the color and opacity for a volume primitive is computed by a surface shader not a volume shader The surface shader need only compute the shading and lighting at the current shading location P AIR takes care of storing and using the results of individual surface evaluations to compute the visibility and color for individual ray queries for a given volume The following AIR 2001 2014 SiTex Graphics Inc 351 AIR User Manual shaders are designed to shade volume primitives particle VCumulusCloud VSmokeSurface Shading Rate and Volume Quality To accelerate rendering of volumetric effects volume primitives use a dynamically created 3D shading cache which decouples shader evaluation from visibility determination The resolution of the shading cache and hence the quality of the volume approximation is based on the shading rate attribute A larger shading rate will produce a faster coarser image and consume less memory Some common volume patterns do not require fine resolution to produce acceptable results Many of the sample volume scenes included with AIR use a shading rate of 4 and that is recommended as a starting point for volume rendering Volume Visibility and Shadows Volume primitives respect the normal attributes for visiblity to camera reflection and shadow rays Volume primitives are not currently visible to indirect rays Volume primitives with
189. a 3rd party rendering option Version Requirements The information in this section covers Air 7 0 and later and Houdini 9 1 and later Configuring Houdini for Air Set Air as the default RIB Renderer Create a HOUDINI_DEFAULT_RIB_RENDERER environment variable with the value air6o 0 Add Air Shaders to Houdini Air ships with a set of dialog scripts that make it easier to use Air shaders with Houdini To add the 2001 2014 SiTex Graphics Inc 393 AIR User Manual 23 2 dialog scripts to your Houdini installation copy the contents of the directory SATRHOME houdini shop to the shop directory in your Houdini installation If the shop directory already contains files named SHOPsurface SHOPdisplace SHOPfog or SHOPlight append the Air versions of these files to the existing files When you re start Houdini the AIR shaders should appear in the list of generators Each Air shader will have a prefix of air_ Preview Air Shaders in Houdini Air shaders to be previewed in Houdini by defining a HOUDINI_VIEW_RMAN environment variable with the value air Air 7 0 and later for Windows ship with a custom display driver used to send the preview image to Houdini With earlier versions of Air or Linux you will need to run the proto_install utility included with Houdini and install the renderman display driver Remember the installation location you select Then copy the display dri
190. a a pipe 2001 2014 SiTex Graphics Inc Houdini 394 Alternatively you can have Houdini create a RIB file that can then be edited and rendered outside Houdini To enable RIB file generation check the box next to Disk File on the Main page in the rib1 properties dialog and provide a valid file name Applying Air Surface Shaders To produce usable output you will need to assign an Air surface shader to each object The surface can be a shader that has been written in the RenderMan shading language and compiled for Air or a RenderMan shader that has been built in Houdini Air comes with dozens of pre built surface shaders that are ready to use In the configuration section you made those shaders available to Houdini by adding a set of dialog scripts To apply an Air surface shader to an object in Houdini e Display the Shop network and bring up the Tool menu Under RenderMan Surfaces you should find many shops with the prefix AIR Choose one of these surface shaders to apply to your object If you do not see any Air shops return to the Configuration section for instructions on installing the AIR dialog scripts Assign the new AIR shop to your object s using any of the standard methods of material assignment in Houdini When an AIR shop is selected you will a list of shader parameters that can be used to modify the appearance of the shader See the Shader Guide section of this manual for more information about the
191. a file with the same name or an abbreviated version of the function name A sample DSO with source code can be found in SATRHOME examples shadeop 10 15 Shading Language Extensions This section documents additional shading language functionality supported by Air as well as Air specific extensions to some of the standard shading language functions Variables The following additional variables are available inside light shaders Ns and angles are read only variables holding the normal and angle parameters of the calling illuminance loop ss and tt are read only variables containing the standard texture coordinate values s t at the current shading location Structures Air 10 and later support user defined data structures as described here Types Air 11 adds new standard data types integer and boolean integer An integer variable stores whole signed or unsigned integers For backwards compatibility integer parameters are 100 compatible with floats The compiled shader file includes an integer flag for parameters that an application can use to detect integer parameters and provide an appropriate user interface boolean The boolean variable type stores a true or false value Air 11 also adds reserved words true and false that are the only valid constants that may be assigned to a boolean variable A boolean variable may be used anywhere a boolean value is expected Boolean parameter values in a RIB file should be either 0 false or 1
192. aa 109 DACK QMOUNIG MANE EENES E E EEE E E EESE EEEE E E A E E E 110 L ns FlarelMagEr sionin a oeae arsada ae re aen p aia aaraa eri iaeia aaea P aah Sraa ap ie Taaa SEa o piian e aaa a Eai ari 111 Paper sRGB ToneMap VBackDrop VBQGENVIrOnMentt gann EEEN AE EE E EE P E E A EE E EE EE DAET to ET e E A AE E E A EA KAEKA e E E E E E E E E E E E AE E E WatercolorPaper 6 InSTancorS pocotan nA EEA RSNA AEAEE AE EAS EAEE AELE g o1 AEREE EEE E E E A E E E E E 117 instMultipl Archives ccccseserensneeenscenenseneneneneeensceesensenenenaneeedacceseasenensnaneeedsceseasenensnaneesdaecessanenenenaneeataceeesanens 120 MassiveAgentS iissecsceiccsancscccscescssarsecsancscscsessaneirscsnanesabcsadsentarsodsanencbcucesanidrssscapdsatcnessebuarapubandscscaessenbirsedbebdeabaesassaes 121 VArrayOnGUrVe isa cies cc acces cps cdiicess unaenea sacs nanaon aaaea AEE Anaa araka aa Eada sees sesteecs ezcuct ae pdp EEEa Uaua EREA KERA dE aa 121 VA Tay ONSUMACE iiiaae eaen adaa coca aaeeea a a Aaa aAa EA Aara aAa DA cauesdcerdecnctcuezaacecdevencuseutesdcavens 122 2001 2014 SiTex Graphics Inc Contents IV VExtrude VGrowFur VINSTANCOAICHIVE ssc siccsincccscscvecsasececcntcecscusnsesascercsatcostcncecdsdenetcentencectesieststvacsdncceseectsesucnesvsntdsascusteesactesdeaicessancecisie MINSTANGE Wit CG as cs 2cteis cececsscozccbecccecsuccchatetees coenecscedetesceechucscbodviesssscaueecoecebesscassucacbedetaeccceteesceddebeccezeveccctoce
193. ace and they will need to be converted to the display color space at some point in your pipeline When that conversion takes place depends on the target device and purpose Rendering to Air Show 2001 2014 SiTex Graphics Inc 25 AIR User Manual 3 1 If you are rendering to Air Show for previewing or final rendering you can use the sRGB display button in the Air Show toolbar to view a linear image in SRGB color space If possible select an option to render 16 bit or floating point data to avoid banding artifacts that can appear when sRGB conversion is applied to an 8 bit image This may be the only display correction you ll need If you wish to save the image as it is displayed in sRGB space use the Save as Displayed item in the File menu To save the raw linear image use the normal Save command Rendering to a file for later processing When rendering to a file for later processing in an image editor or compositor render linear images at 16 bit or float precision and apply sRGB conversion after any post processing This case includes any type of multipass rendering for later compositing Rendering a final image A rendered image that is to be viewed or printed directly should have appropriate display conversion applied prior to being saved Air provides two main ways to do that The RIB standard defines an exposure setting that can be employed to apply a simple gamma factor typically 2 2 for an sRGB display
194. aces mktex comp greenish png 0 8 1 0 8 mul source png Equations can reference a subrange of channels in a multichannel image using brackets with a channel range after the image name mktex comp result tif m tif 4 6 0 9 mul m tif 7 9 1 1 2001 2014 SiTex Graphics Inc Tools 416 m tif 10 12 Braces can also be used to add channels to an image E g to add an alpha channel to a composite of two 3 channel images mktex comp result tif lightO tif lightl tif beauty tif 3 or merge separate images into a single multichannel image mktex comp multi tif diffuse tif specular tif reflect tif A numbered sequence of images may be processed using the frames option to specify a range of frames mktex recognizes the same frame number expansion syntax as AIR nf where n is the minimum number of digits in the frame number zero padded E g the following command mktex frames 9 11 result 4f tif diffuse 4f tif specular 4f tif would produce 3 images result0009 tif result0010 tif and result0011 tif Compositing operators A B A add B addition A B A sub B subtraction A B A mul B multiplication A B AdivB division A min B minimum of A and B A max B maximum of A and B A dot B dot product of A and B byte A convert A to unsigned 8 bit data word A convert A to unsigned 16 bit data float A convert A to float data abs A take absolute value of A min max extract channe
195. acityMapName mn OpacityMapBlur 0 0 BumpMax 0 0 BumpMapName Le BumpMapBlur 0 0 TextureSizexY 11 TextureOriginXY 0 0 TextureAngle Projection stn ProjectionSpace shader ProjectionTransform 100 0 0100 0010 000 1 Description 0 0 1 0 0 0 1 0 0 0 1 0 S aces Texture map for specular color Texture blur Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection The Velvet surface shader provides a basic velvet appearance with optional texture map for color 10 10 4 VFabric a surface shader for cloth with blinn specular and velvet sheen controls Illumination Model custom Features texture map Parameter Diffuse 0 DiffuseRoughness 0 Specular 0 SpecularSize 0 SpecularRolloff 0 SpecularColor 1 6 8 5 Default Value O O 0 0 Range 1 1 O CO Description Diffuse reflectivity Diffuse roughness Specular reflectivity Specular highlight size Falloff of highlight edge Specular color 2001 2014 SiTex Graphics Inc Shader Guide 234 Sheen SheenBackscatter SheenEdginess SheenRoughness SheenMapName SheenMapBlur ColorMapName ColorMapBlur SpecularMapName SpecularMapBlur OpacityMapName Opacit
196. ade check the Use Air Show item in the Run menu AIR includes a few sample trees in the archives directory To load a tree archive which is just a shader definition with a set of parameter values choose Import Parameter Values from the File menu and pick one of the Tree rib files in the archives directory of the AIR installation To save a tree for future use select Export Parameter Values in the File menu to create a RIB archive with a complete shader definition Be sure to set the Procedure bound appropriately on the View page before exporting Using a Tree Archive A tree archive created with Vshade can be included in a scene using the standard ReadArchive command E g Translate 101 translate the tree into position ReadArchive Tree_Quaking_Aspen rib The following user attributes can be used to customize the tree s appearance without modifying the tree archive Attribute user float treeseed 123 Sets the tree Seed parameter used for generating random numbers Attribute user float treeheight 6 Sets the tree height to a specific value The height should be in the same units as the tree archive 2001 2014 SiTex Graphics Inc 173 AIR User Manual 10 9 Attribute user float treequality 1 Sets the TreeQuality parameter Attribute user color leafcolor 0 2 0 3 0 1 Sets the average leaf color AIR also includes a VinstanceTree instancer shader that creates instances of tree
197. ading for motion blurred unbeveled curves TweakAlR e Support for moving area lights e Fix for black dots in indirect and envlight light caches with multiple threads AIR Show e AIR Show can read AIR shadow maps with a smor sha extension e Fix for refresh bug with small or rapidly rendered buckets e Fix for bug on Linux that prevented AIR Show from restarting immediately e When saving images AIR Show automatically converts data to the proper number of channels and 2001 2014 SiTex Graphics Inc History 450 data type for the selected image format e AIR Space e Cameras can be viewed and positioned in OpenGL views e Per light output channels e New introductory tutorial in the AIR Space user manual e New option to control shading cache memory e New Optimization section in the AIR user manual Optimization to eliminate unnecessary primitive data for MayaMan shaders The Linux distribution is now built on Red Hat 9 instead of Red Hat 7 2 e On Windows AIR and other programs have the argeaddressaware flag set allowing them to access up to 4 GB of memory on 64 bit versions of Windows e The maximum number of Pixel Samples has increased to 32 x 32 New ReelSmartMotion shader computes motion vectors for the Reel Smart Motion Blur plugin from RE Vision Effects Inc www revisionfx com Motion blurred primitives with time intervals that are a subrange of the Shutter time interval are properly dimmed
198. adingmultiplier 1 Values below one reduce the effective shading rate increasing the number of shading samples per pixel for higher image quality at the expense of longer rendering time The sm command line option is shortcut for this option Shading Cache Size To accelerate rendering AIR stores and reuses shading samples when possible The maximum number of shading samples stored for a single polygon is given by Option limits integer shadingcache 1024 Normally the default works just fine For scenes with many output variables and many objects blurred over large distances onscreen the memory used by the shading cache can become a significant factor The maximum memory used by the shading cache is reported in AIR s rendering statistics Using a lower cache limit will reduce peak memory use at the expense of slower rendering Specular Highlight Algorithm The following attribute can be used to select whether the standard shading language specular function uses the algorithm defined in the RenderMan Interface specification or an alternate algorithm that better matches the results of other renderers Option render integer prmanspecular 1 Noise Algorithm 2001 2014 SiTex Graphics Inc 59 AIR User Manual 6 5 6 6 AIR 7 includes a new alternative noise algorithm Option noise string algorithm perlin2 The perlin algorithm uses higher order interpolation for better results with displace
199. adows Houdini will enable ray traced shadows for the light when exporting for Air One other attribute needs to be set to make objects visible to shadow rays e Display the Rib output operator in a panel and select the Properties tab e Look in the Attributes tab for a property named Transmission Visibility If the attribute is not present you can add it by editing the operator type and finding the attribute in the rendering section under AIR 6 0 Attributes e Set the value to Use Os for opacity or Opaque to shadows Note that as of Houdini 9 1 160 native Houdini lights do not provide much control over ray traced shadows In particular there is no control over shadow blur or sampling For more control use a custom AIR light shader instead see below for instructions Shadow Mapped Shadows e Set the light s Shadow Type to Shadow Mapped Shadows e Uncheck Transparent Shadows 2001 2014 SiTex Graphics Inc Houdini 396 23 4 e Make sure the Shadow Softness is set to at least 1 Using Custom Light Shaders AIR light shaders can be used in Houdini with the aid of a Light template Make sure you have already installed the AIR shaders for Houdini as described here To use a custom light shader e In the SHOP network open the Tool menu and under the RenderMan Light category choose an AIR light shader For an initial test try the AIR point light shader e Inthe parameter list for the point light shader
200. aeaee ee ae aaae a ia pae EA Edera Sea ea E aE EN aa arepas EE Naa aida erea AaS Espai 99 VThreads iesiri irissevoss saneras aada haer aesan as enaA aeiaai Varase a Esaera Saen daai Eesaun aeaaea Erara aeara 99 VWeaveDisplaceme nt s cccs2ccccc scnctinnecscesssceset csteecatepecndssenecsees feuvecndesueedatessazcecepecceed snuecetdestcecatdecedseuerceecssaesedwececs 100 D gt EMVIFOMIMEMIUS sonnan EEA AEE EAEE ENE E AEE ANEA AEE ANERER 101 CU 0 o ee 102 AAA T a a e E E EE E E ous seuczccecsucudsetesetcedcceccces EE EE E E 102 envPhysicalS Ky ccc2cc cs cccacectseciccin csces sec iara aosi a dara peiden naaa oosina i idara p araa Edera souecauastueeescdeccereueed daaa ridia 103 4 Generis conre a a E aAa AEA a e AA E Aa Eend A AAE Aaa Eana ELAES 105 eaa E E A a A A A E ea 105 GOEMOCCIUSIOM Teee EE T E E E E ene raeteces 106 genQueryBakedMap sizcesscessecccccs cece recess cenccccececershace vase sectpaccbeteecscceceies stceesaes aaea aia Eienaar ai 106 genTextureUV iscicccestivessecsencscucesesarssatescoccaneasstearssascsencscnsencnnarssutdsessbsnsansctaresabcsensncusensanasssabcscocucusensusasarabcsdvencesiies 107 GENUSErATIDURES we cciesscs scicescnsarsssscsesesenecsancerasabesesescuecnsacapesabesavensuscsdacapesubesandcuuedevacaperaudsabencusshvansbdsabasebeabesnana 107 g nUV vasdniscncanestevescsdsdsdectccsetnctssavassseccisasesidrssadsevendnsdsvucsbecabascnsddusensntavansed cvensusesuanssdsabdssbduciseruatdvesatdvedensesieve 108 5 Images ecien a
201. akemapfilterwidth motionbound motionspace See Baking Shadows and Illumination for more information 10 7 20 spot_projector wee wo 0 1 000000 world space Bake map file name Bake mode Blur for bake map query Filter width for bake map query bounding box for moving objects coordinate space of motionbound spotlight shader that projects a texture map like a slide projector Parameter intensity lightcolor lightcolor_spd maxemission from to coneangle conedeltaangle beamdistribution falloff shadowname shadowbias shadowblur shadowsamples shadowcolor shadowgroups shadowattribute _ Category Default Value 1 0 L u O O oo rR Oo oOo 4 wee we user shadowgroups lensflare Range o o ooo O hoh ao 00 045 1 256 Description Light intensity Light color Light color spectrum file If greater than 0 the maximum emitted light intensity Source position of light Target of light Cone angle Angle for cone edge blur Exponent for cross beam falloff Exponent for falloff in light intensity with distance Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for traced shadows Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name Light categories 2001 2014 SiTex Graphics Inc Shader Guide 156
202. al Workers To start an instance of AIR as a worker for Vortex manually use air vhost ip port where ip is the IP address of the machine running vortex The port is optional unless the port option was used with Vortex By default Vortex will launch a single instance of AIR on the local machine That behavior can be overridden with the local command line option vortex local 2 myscene rib An argument of 0 will prevent any local workers from being started The default number of workers can be set with a VORTEX_NLOCAL environment variable The exact command executed can be customized with a VORTEX_LOCALCMD environment variable The default command is air vhost HOSTS Vortex replaces SHOSTS in the command string with the IP address and port of the Vortex instance VoluntAIR Windows only VoluntAIR is a small program that enables an idle machine to provide workers for Vortex instances on demand To start VoluntAIR on a machine simply enter voluntair at a command prompt VoluntAIR waits for a message from a Vortex instance and starts an instance of AIR when it receives a request The exact command executed can be customized with a VOLUNTAIR_CMD environment variable The default command is air vhost HOSTS Batch Command f a VORTEX_BATCH environment variable is defined Vortex will execute the command given in the environment variable as a separate process The command can be used to submit a batch job to a render farm or to
203. alculations You can find out more about the RenderMan shading language in the following sources The RenderMan Interface Specification 3 2 The RenderMan Companion A Programmer s Guide to Realistic Computer Graphics by Steve Upstill Advanced RenderMan Creating CGI for Motion Pictures by Anthony A Apodaca and Larry Gritz Derivatives in AIR Several functions in the shading language rely on the ability to take derivatives of arbitrary expressions over a surface element The built in functions Du and Dv are supposed to give the change in an expression across a surface element in the u and v parametric directions respectively They are also supposed to give the change between shading samples Because AIR does not shade along the u and v axes it interprets derivatives differently for efficiency Shading is performed at samples which are distributed equally in screen space Du e returns the change in e between adjacent samples in the horizontal direction and Dv e returns the change between samples vertically du and dv are always 1 For the common use of derivatives to generate filter widths for anti aliasing this gives the desired result E g fwidth abs Du e du tabs Dv e dv is a good estimate of how much e changes between shading samples This implementation of derivatives obviously causes problems for shaders that expect Du or Dv to be aligned with their respective parametric axes Shaders that rely on
204. ality of the illumination and shadows is controlled with the light s nsamples attribute Attribute light integer nsamples n 2001 2014 SiTex Graphics Inc Shader Guide 164 A large number of samples produces smoother results When tweaking the number of samples it usually makes sense to increase or decrease the amount by a factor of 2 Light Intensity The emitted light value is the product of the intensity and lightcolor parameters and an attenuation factor determined by the falloff parameter The falloff parameter allows the light s intensity to diminish with distance from the light A falloff value of 2 which is physically accurate reduces the incident light value by the square of the distance from the light Cl intensity lightcolor Distance Distance Although a falloff of 2 is physically correct it can produce very large intensity values at locations close to the light source The maxemission parameter can be used to set the maximum emitted intensity regardless of distance from the light source Alternatively a falloff value of 0 produces no attenuation with distance which may be easier to control Shadows The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute paramete
205. aller ScaleWidth value and increasing the outline width for an edge drawn strokes can be made to overlap at their ends Strokes are drawn thicker in the middle fading out at each end The Fade parameter controls the fade at each end and the Bias value determines where the center or thickest part of the stroke lies along the drawing vector Wobble allows the direction of the stroke to vary from the underlying stroke vector The Bend parameter can be used to draw curved lines instead of straight lines Note that ScaleWidth must by less than 1 for Bend to have any effect Density Map Sometimes areas of an image with many edges may appear to dark when rendered with a stroke shader A density map can be used to selectively thin out lines in dense areas The density map itself can be generated by rendering the scene with all objects white and normal outlines enabled with a black outline color The map file name should be supplied as the DensityMap value and Densitylnvert should be set to 1 2001 2014 SiTex Graphics Inc Shader Guide 176 in this case DensityMin and DensityMax can be used to control the density range over which strokes are gradually faded out 10 9 2 strokeWatercolorEdge stroke shader for simulating unpainted edges for watercolor effect Parameter Default Value Range Description Wobble 1 How much the edge outline varies Fade 0 1 Fading of edge strokes near the end Frequency 25 Frequency of e
206. ame point set with the following attribute Attribute pointset handle occluders Here is a complete rib snippit that can be used to bake an exported rib file Surface bake3d string BakeMap occlusion apc String BakeChannels float BakeRadius 0 1 Attribute pointset handle occluders Option render commands Surface The last line overrides all other surface shaders in the rib file Save the above to a texture file called say bakeocc rib then pass that file to Air prior to the main scene file air bakeocc rib myscene rib Step 2 Rendering with point based occlusion The 3D point file representing occluding surfaces in the scene can be used to produce occlusion with the occlusionpass surface shader or the envlight light shader Set the mapname parameter to the file name of the 3D texture Adjust the mapbias parameter to prevent incorrect self occlusion Control quality vs speed with the maxsolidangle parameter To accelerate the occlusion estimate Air groups points that are far away from the current shading location and treats them as a single occluder The maxsolidangle parameter gives the maximum solid angle in radians that an approximate occluder may occupy before Air substitutes a more detailed representation Larger values produce a coarser occlusion result with lower render times Here s a complete rib snippit for rendering an occlusion pass using a 3D point file Surface occlusionpass string
207. ameter Default Value Range Description UseLuminance 1 whether to use luminance or HSV value Description The VGreyscale imager shader converts the output rgb color to grey scale If UseLuminance is non zero the grey level is based on the color s luminance otherwise the grey level is taken from the HSV value component 10 5 10 WatercolorPaper amp imager for watercolor paper effects 2001 2014 SiTex Graphics Inc Shader Guide 116 Parameter Intensity Texture TextureSizexY Background BorderMin BorderFuzz BorderVary BorderRound BorderColor BorderFrequency Apply_sRGB ClampToAlpha Seed Description Default Value 1 0 noise Ll 99 98 90 33 71 Range 0 1 Oor 1 Oor 1 Description multiplier for texture effect texture file name or noise texture size scaling factors color to apply to non opaque parts of the image minimum border width blurriness of border boundary amplitude of border variation whether the visible region is rectangular 0 or elliptical 1 or some shape in between border color frequency for border variation whether to apply sRGB gamma correction whether to clamp output color to alpha random number seed The WatercolorPaper imager shader adds two effects to make the image look more like a watercolor a rough paper effect and a rough edge effect Rough Paper The rough paper effect simulates the grainy appearance
208. ameters color OutputColorl output color 1 color OutputColor2 output color 2 color OutputColor3 output color 3 float OutputFloatl output float 1 float OutputFloat2 output float 2 float OutputFloat3 output float 3 10 4 6 genUV generic shader that exports the standard u v coordinates of a surface Parameter Default Range RepeatU 1 RepeatV 1 Description Description User attribute to query Default value User attribute to query Default value User attribute to query Default value User attribute to query Default value User attribute to query Default value User attribute to query Default value Description multiplier for U value multiplier for V value The genUV shader exports the standard u v coordinates assigned to an object Output only parameters 2001 2014 SiTex Graphics Inc 109 AIR User Manual Hh loat 2 OutUV u v coordinates as an array of two floats Hh loat OutUVCoverage fraction covered always 1 10 5 Imagers Imager shaders modify the the final rendered image prior to output An imager shader is specified in a RIB file with the Imager statement Imager background color background 1 1 1 The current imager shader is an option i e there is one imager shader or shader network for the entire scene The Imager statement must appear before worldBegin in the RIB stream In Air 11 and later multiple imagers can be specified by pre pending the s
209. ameters statements else statements Ray Tracing 2001 2014 SiTex Graphics Inc Shader Guide 292 gather Is a looping construct for sampling a cone of directions using ray tracing Rays are fired from pos with the ray direction randomly distributed within angle radians of the axis direction If a ray hits an object the optional output variables are updated and the first set of statements is executed If a ray misses all objects the optional else block is executed if present Samples is the requested number of rays to trace The actual number of rays traced may be less because AIR automatically reduces the number of rays cast at deeper levels of recursion There may even be zero rays traced and a shader should handle that case properly The category parameter is a hint to the renderer about the purpose of the gather query The following categories are recognized illuminance sample the incoming indirect light with indirect rays environment sample the surrounding environment with reflection rays occlusion sample with shadow rays gather accepts a number of optional input and output parameters Optional Input Parameters Type and Name Description float bias offset to prevent incorrect self intersections string distribution sample distribution uniform or cosine string label user assigned name for rays cast by this call a shader can query the label with rayinfo float maxdist maximum d
210. ametric curved surfaces such as NURBs quadrics and bicubic patches can be set explicitly using the following attribute Attribute divisions integer udivisions udivisions integer vdivisions vdivisions udivisions and vdivisions are the number of segments used to represent the object in the u 2001 2014 SiTex Graphics Inc Primitives 66 8 2 and v parametric directions respectively Curved primitives will be rendered using udivisions x vdivisions polygons For example Attribute divisions udivisions 12 vdivisions 6 Sphere 1 1 1 360 produces a sphere made of 72 polygons Curved primitives that share an edge should have the same number of divisions along the shared edge to prevent cracks from appearing Set udivisions to 1 to restore automatic subdivision Polygons There are 4 RIB commands for defining polygonal geometry Polygon PointsPolygons GeneralPolygon GeneralPointsPolygons The first two commands should be used only for polygons that are convex and planar The second two commands support concave polygons and polygons with holes at the expense of longer rendering times since every polygon is checked for concavity Non planar Quads Many modeling packages allow the creation of nonplanar 4 sided polygons as part of a polygon mesh Such geometry should be passed to AIR using the GeneralPointsPolygons command so that AIR can properly detect nonplanar quads and convert them to tr
211. an also dispose of an agent as soon as it has been rasterized by the scanline renderer When rendering a flat rib AIR will load all agents which will consume more memory Even with a flat RIB AIR should be able to render many hundreds to thousands of agents before running out of memory Usage massrib render 0000 rib Given a source rib name massrib produces a flat rib with the same name in an output directory By 2001 2014 SiTex Graphics Inc Massive 380 default the output directory is a massrib subdirectory of the current directory which massrib will create if necessary An alternate output directory can be specified using the outdir option massrib outdir usr local tmp flat render 0000 rib The simplest way to use massrib is to convert the main scene rib generated by Massive The resulting flat rib will include the agents and terrain in a single file You can also convert only the agent archive producing an archive with just the agents for inclusion in a scene generated in another application Multiple files can be processed using simple wildcards E g massrib render rib Setting Massive Procedural Options The Massive scene file includes an additional call to the procedural primitive that sets certain options such as motion blur and pass type for subsequent agent calls to the procedural primitive In the current Massive version the call to set procedural options appears after the calls to create the ag
212. an be produced using ray tracing The arealight shader included with Air can be used for brute force simulation of an area light Simulating Area Lights with areashadow Brute force simulation of area lights can be quite slow because it requires executing the light source shader multiple times Air provides a shading language function called areashadow that samples the area light in a single function call The arealight2 shader included with Air uses the areashadow function to provide faster area light simulation When using the arealight2 shader the light nsamples attribute is not used Instead the number of samples is set by a parameter in the shader The areashadow function is an approximation and it only works well for simple geometry such as a disk square or other convex polygon 2001 2014 SiTex Graphics Inc Lighting 314 Area Lights and Indirect Illumination If indirect illumination is employed area light geometry should be made invisible to indirect rays with Attribute visibility integer indirect 0 so that the area light is not included twice in the illumination calculations 13 2 Shadows Air provides three ways to produce shadows ray tracing shadow maps and automaps Each method has advantages and disadvantages in terms of ease of use speed memory usage and quality Ray Traced Shadows Ray tracing is one popular method for simulating shadows A ray is traced from the shading l
213. ance Make an object one sided with Sides 1 Grouping AIR 2 3 and later supports grouping of objects for controlling visibility Group membership is defined with Attribute grouping string membership list of names The list is a comma or space separated list of names Membership can be defined relative to the current setting by prepending the list with a to add groups or a to subtract groups 2001 2014 SiTex Graphics Inc Attributes 64 Groups provide a powerful mechanism for controlling object visbility in a scene including e The visibility subset attribute can be used to define which objects are visible from the camera e Shadow casting groups can be used to precisely control which objects casts shadows from a particular light e Reflection groups restrict objects visible in traced reflections from a primitive e A Display subset selects which objects appear in a particular output image facilitating multilayer rendering and rendering of multiple mattes in a single render pass Shading Language Support for Groups Certain ray tracing functions allow ray hit tests to be restricted to objects in a set of groups The trace shadow environment occlusion and areashadow shading language functions accept an optional subset parameter that contains a list of groups Only primitives in the subset will be tested for ray intersections 7 4 User Defined Attributes Any variable can be de
214. ap In other words a surface should not overlap itself or other surfaces in texture space Assigning Maps to Primitives There are two methods for assigning bake maps to a primitive The first method is to provide extra parameters in the primitive s variable list of the form Constant string bakemap_data mapname where data and mapname match one of the Display calls previously defined The second method is to provide a list of bake maps in the following attribute Attribute bake string bakemaps list of maps where each map name corresponds to one of the Display calls in the scene Baking Once the scene has been configured for baking start BakeAir with the scene name bakeair myscene rib Beginning with Air 14 BakeAir renders baked maps in tiles just like a regular image is rendered with Air The tile or bucket size can be set with Option bake bucketsize 64 64 Tiled rendering is not supported if the wrap border option is enabled or when writing to a PTEX file Tiled rendering should in general improve performance and reduce memory requirements when baking large maps Baked Texture Padding In some cases a baked texture map may contain unrendered pixels Unrendered pixels that border rendered pixels may need to be filled in to avoid rendering artifacts when using the maps BakeAIR can automatically fill in the border around rendered regions in the texture map by replicating pixels The width of this border can be set with Op
215. aps Press this button to create the texture map or maps Standard texture maps and environment maps will have an extension of tx Shadow maps will have an extension of shd Vortex Vortex is a distributed rendering manager for AIR Vortex allows multiple instances of AIR running on different machines to all work on the same image Vortex has a couple basic requirements and restrictions e All files used in a scene should reside on a networked drive visible to all worker machines e The scene file should have only one pass i e one world block which may produce multiple output images Usage Vortex is designed to be a transparent substitute for AIR you can use Vortex to render just as you do AIR vortex myscene rib Vortex manages the rendering process by requesting pieces of the image from each worker task and merging the output from all workers to produces the final image s 2001 2014 SiTex Graphics Inc 419 AIR User Manual Vortex requires one or more instances of AIR running as workers connect to the Vortex host Vortex provides 3 mechanisms for launching worker tasks 1 Automatic launch of workers on the local machine 2 Broadcast message requesting workers from machines running VoluntAIR 3 Execution of a user defined command that e g starts a batch job on a render farm or communicates with a centralized render manager These mechanisms may be used in any combination that is convenient Loc
216. arameter supported in a 3D engine Per vertex data can be obtained by rendering low res maps and extracting vertex data based on the texture coordinates used for baking Examples The sphere and head directories contain examples of baking information for use with VRML files Geometric Manipulation In addition to color and lighting information BakeAIR can record geometric information like surface positions normals and tangents opening up another range of applications For example position normal and tangent maps can be used to place detail objects on surfaces Think of adding fur or horns to a monster or placing grass or trees on rugged terrain Because BakeAIR supports true displacement objects can be positioned correctly on displaced geometry As another example an object whose texture coordinates map into the unit square can be stored in a texture position map and reconstructed using displacement with a renderer such as AIR Two objects stored in texture maps can be morphed by simply interpolating the texture lookup and using displacement Examples The fuzz directory contains simple examples of positioning curves on surfaces used baked geometric information 21 2 Baking Textures with BakeAir This section describes the technical details of configuring a scene for baking textures with BakeAir Your plug in or application may provide a simpler interface for creating and utilizing baked textures To prepare a scene for baking e D
217. arge dust particles 2001 2014 SiTex Graphics Inc 163 AIR User Manual Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows See Also envPhysicalSky environment shader 10 7 24 texturedarealight area light shader with texture map control over emitted light Parameter Default Value Range Description intensity 1 0 Light intensity lightcolor 1 id Light color lightcolor_spd ae Light color spectrum file maxemission 0 If greater than 0 the maximum emitted intensity including falloff coneangle 1 57 0 0 1 5 Angle for emitted light range falloff 2 0 1 2 Exponent for falloff in light intensity with distance texturename iii Texture map file name sizexy Texture map size originxy Texture map origin shadowname raytrace Name of shadow map or raytrace for traced shadows shadowbias 0 01 Offset to prevent incorrect self shadowing shadowcolor 000 Color of shadows shadowgroups i Optional groups for ray traced shadows shadowattribute user shadowgroups Per object shadowgroups override attribute name __nondiffuse 0 0 1 If 1 light is excluded from diffuse light __nonspecular 0 0 1 If 1 light will not produce highlights foglight 1 0 1 If 1 light illuminates volumes __ channel 1 0 9 Output channel Description The texturedarealight shader allows the emitted illumination from an area light to be controlled with a texture map The qu
218. arkened values greater than 0 5 2001 2014 SiTex Graphics Inc 271 AIR User Manual This shader is part of a suite of shaders designed to produce a watercolor image See Also strokeWatercolorEdge stroke shader WatercolorPaper imager shader 10 10 8 VWeave a woven pattern Ilumination model plastic or metal Features reflections Parameter Default Value Diffuse 0 5 Specular 0 5 SpecularRoughnes 0 2 s Reflection 1 0 ReflectionSamples 1 ReflectionBlur 0 0 ReflectionName raytrace ReflectionSpace current Metallic 0 BumpStrength 0 5 Columns 15 ColumnGap 0 5 ColumnWave 0 15 ColumnRoundness 0 0 ColumnColor 18 08 02 Rows 10 RowGap ope RowWave 0 2 RowRoundness 0 1 RowColor 1 00 1 00 0 41 Range 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 Description Diffuse reflectivity Specular reflectivity Specular roughness Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup 0 for plastic 1 for metal Multiplier for displacement values Copies in X direction Fractional gap between each column Amplitude for wavy pattern Cross sectional rounding Color of columns Copies in Y direction Fractional gap between rows Amplitude for wavy pattern Cross sectional rounding Color of rows 2001 2014 SiTex Graphics Inc Shader Guide 272 TextureSizexY 11
219. arp and weft VCloth uses the tangent vectors for a surface which are usually based on the texture coordinates as the basis for the thread directions By default warp threads follow the tangent in the direction of the second texture coordinate Y weft threads follow the X tangent The thread directions can be rotated using the ThreadAngle parameters By setting the ThreadAngle to 90 you can effectively swap the warp and weft directions Rotating the thread directions does not affect the coordinates used for any texture maps Cloth appearance is affected by the type of weave pattern that is used and by the physical properties of the threads This shader allows both sets of properties to be controlled Weave Pattern The weave pattern is taken from the smallest rectangular piece of the cloth that could be tiled to reproduce the entire cloth The shader assumes that this smallest area is much smaller than a pixel and the shader returns the average reflectance over that patch Individual threads will not be visible The WeavePattern parameter gives the pattern as 3 values e The length of the visible warp thread given as the number of weft threads crossed over e The number of weft threads to skip before the next warp thread is visible e The length of the visible weft thread given as the number of warp threads crossed over The rest of the weave definition gives the thread width and the gap between threads in each direction Because the exact
220. arts of the bump and the paper is somewhat or mostly visible in areas where the bump is lower 10 5 4 sRGB applies sRGB gamma correction to the output image Parameter Default Value Range Description ClampToAlpha 1 Oor 1 if 1 output r g b components are clamped to the alpha value 2001 2014 SiTex Graphics Inc 113 AIR User Manual 10 5 5 Description The sRGB imager shader applies sRGB gamma correction to the output r g b channels When ClampToAlpha is 1 each component is clamped to the alpha value ToneMap tone mapping for high dynamic range images Parameter Default Value Range Description MaxLuminance 11 5 luminance corresponding to display value of 1 MiddleLuminance 0 18 luminance mapped to display middle grey MiddleGrey 0 18 display middle grey value PremultipliedAlpha 1 O or 1 when not 0 input color is treated as pre multiplied alpha Apply_sRGB 0 Oor 1 whether to apply sRGB gamma correction to the final color ClampToAlpha 1 Oor1 whether to clamp the final r g b values to alpha ModifyOutputColor 1 Oor1 when zero the imager output color is not modified the tone map value is available in the __ tonemap output variable Description The ToneMap imager provides a simple tone mapping operator for converting high dynamic range HDR images to low dynamic range for display The conversion is based on the global operator described in Photographic Tone Reproduction by Erik Reinha
221. as a new syntax Instead of the old Option render string currentcolorspace litRGB use ColorSpace current litRGB Indirect Lighting e New radiosity cache can greatly accelerate indirect lighting e New option to force Air to wait until an indirect or occlusion prepass has finished rendering before rendering the final pass Option render syncprepass 1 This option provides a solution in cases where a bucket has not finished computing in the prepass 2001 2014 SiTex Graphics Inc 427 AIR User Manual when it is rendered in the final pass Enabling this option will in general increase rendering time since it forces all threads to wait until the last thread finishes the prepass The option is enabled by default e Occlusion e New optimizations improve performance when using a cache for complex scenes with many threads e Output e Most Air surface shaders have a new __diffuse_shadow output value that contains a shadow value based on a linear relationship between the shadowed and unshadowed diffuse values This relationship is preserved through Air s filtering and compositing unlike the old __ shadow output variable which could exhibit artifacts along object edges and in regions of partial transparency __diffuse_shadow is now the recommended shadow value to use in multipass rendering e When the prefilterclamptoalpha option is enabled output from any environment or imager shader is also clam
222. at image These capabilities can be utilized to produce an arbitrary set of mattes for different scene elements in a single render invocation Example say one wanted to render a matte for agents and a matte for terrain Start by creating two small text files agents rib with Attribute grouping string membership tagents and terrain rib with Attribute grouping string membership terrain In Massive assign agents rib as a custom rib archive to each agent Assign terrain rib as the custom rib archive for the terrain Sim and generate the usual set of exported rib files The final piece is another small text file defining the matte images for agents and terrain mattes rib Display tagent_matte 4f tif file a string subset agents quantize 0 255 0 255 Display tterrain_matte 4f tif file a string subset terrain quantize 0 255 0 255 Include mattes rib as the options rib in the massive render dialog or pass it on the command line prior to the main scene file 2001 2014 SiTex Graphics Inc Massive 386 air mattes rib render0001 rib This method can be used to render a matte for any desired grouping of scene elements Rendering Separate Output Images by Group The above technique easily generalizes to separating any output variable by group For example to render separate beauty images for agents and terrain use Display tagent_beauty 4f tif file rgba string
223. at reflectlights 1 e Light channels can be tracked throught indirect diffuse bounces GI with the new indirectchannels light shader With this new shader each light channel includes not only direct lighting but indirect illumination due to the corresponding light source Indirect diffuse Gl 2001 2014 SiTex Graphics Inc History 440 Much faster rendering with bg environment map Much more efficient rendering of multiple bounces without a cache Fix for overblown results with non normalized normals new option to enable light channel recording during an indirect prepass Option indirect string prepasschannels __ lights Shading language environment and trace calls provide a background output value of type color that stores the contribution of the bg environment map or color environment and trace can return arbitrary output variables from ray traced primitives in a manner similar to the gather construct texture3d accepts a fill argument specifying the default value for channels if no points are in range or the channel is missing bake3d accepts an append parameter with a float value If the append value is 1 points are added to an existing file Shaders may query the current frame number with option FrameNumber frame Light shaders can access standard texture coordinates at the current shading location using the new global variables ss and ts e Improved environment ma
224. ata Point Sets as Geometry Air Point Clouds and Air Point Maps can be rendered as geometric primitives using the RIB Geometry call Geometry mycloud apc A point set is represented converted into a RIB Points primitive with file data attached as per point primitive data The normal point attributes such as point type are applicable When rendering an Air Point Cloud file AIR will load the entire point set the first time the set bounding box is encountered When rendering an Air Point Map subsets of the point map are loaded on demand Examples The Bake3d surface shader shows how to bake general data to a 3D texture Source code for the shader is located in SATRHOME shaders src surface Sample RIB files can be found in SATRHOME examples bake3d 2001 2014 SiTex Graphics Inc 3D Textures amp Point Sets 312 See Also Bake3d surface shader 13 Lighting Lighting in AIR is accomplished with the use of light shaders Every light is produced with a light shader Your plugin may include a special set of light shaders that mimic the behavior of the lights in your modeling or animation program Most plugins also allow custom light shaders to be assigned to a light Standard Lights AIR comes with extended versions of the standard pointlight spotlight and distantlight shaders These shaders have been extended in the following ways e All support shadow casting using ray tracing shadow maps or
225. aterial page for the object Assign the MassiveAgents shader as the instancer shader 2 Set the instancer Extent to a value such that the terrain object bounding box incremented by the Extent would encompass all the Massive agents in the scene 3 Set the Agent archive prefix parameter to the file name of the agent archives exported from Massive minus the frame number and rib extension 4 Set the RenderPass parameter to the name of the render pass you set up for Air in Massive 5 Set the Rotate x value to 90 to compensate for the different up directions in Rhino and Massive the Y axis is up in Massive the Z axis is up in Rhino 6 Use the Frame offset value to pick the Massive agent frame that should correspond to the first Rhino frame in an animation 7 Use the Scale parameter to uniformly scale the agents to match the scale of your model By default agents in Massive are assumed to be modeled in units of centimeters 8 To render an animated sequence you must enable one of the animation modes in RhinoAir on the Air Animation page of the Rhino options dialog If your scene does not employ any other animation set the Animation mode to Turntable with a Max angle of 0 9 Render to see your Rhino model with Massive agents generated at render time See Also MassiveAgents instancer shader 2001 2014 SiTex Graphics Inc Massive 390 22 13 Optimization Tips for Massive Scenes 1 Make agents and terrain invi
226. atically compile shaders for you Otherwise you can use shaded from a command prompt The command syntax is shaded lt options gt filename where filename is the name of the shader source file The shading compiler accepts the following options Dsym define preprocessor symbol sym Dsym val define preprocessor symbol sym as val Ipath specify a path to search for included files line print the source code line when an error occurs 2001 2014 SiTex Graphics Inc 411 AIR User Manual 24 6 o filename specify an alternate output file name The default name for the compiled shader is the name of the shader in the source code with the extension slb noopt No compile time optimization norto No run time optimization Air normally optimizes shader code for each instance of a shader cpp Use an external pre processor instead of the built in one The pre processor must reside somewhere in the search path for executables fover Enable support for function overloading multiple functions with the same name but different arguments and or return type Note that nested functions are not currently supported when function overloading is enabled Default Search Path for Include Files A default search path for include files can be specified in a SHADECH environment variable Pre processor Definitions AIR pre defines two identifiers AIR and RAYTRACE RAYTRACE is intended for conditionally compilin
227. ation Shaders may also accept a transformation matrix to be applied to the point prior to projection The transformation matrix can be used to scale translate rotate or shear the texture pattern Coordinate Spaces AIR supports hierarchical modeling in which objects are positioned by applying a series of translation rotation scaling and arbitrary 3D transformation operations Each transformation defines a new coordinate system AIR provides names for those systems or spaces that are commonly used for shading calculations 2001 2014 SiTex Graphics Inc 83 AIR User Manual 10 2 object Coordinate system in which a geometric primitive is defined shader Coordinate system in which a shader is declared world Coordinate system at WorldBegin after the camera has been positioned and before any transformations for objects have been declared The base coordinate system for a scene camera Coordinate system of the camera The camera is assumed to be at the origin with the y axis pointing up the z axis pointing in and the x axis increasing to the right current The space in which calculations are performed within shaders For AIR current space is camera space but current space may be different for other renderers screen Coordinate space after perspective projection with z coordinates scaled and offset to 0 at the near clipping plane and 1 at the far clipping plane NDC Normalized device coord
228. ations Two attributes affect the quality of indirect illumination results using the cache Attribute indirect float maxerror 0 0 Attribute indirect float maxpixeldist 20 The maxerror attribute sets the maximum error that is allowed in any one estimate of the local indirect illumination when reusing samples from the cache Lowering the maximum error causes the 2001 2014 SiTex Graphics Inc Lighting 322 renderer to take new samples more often Setting maxerror to 0 disables the indirect cache forcing AIR to compute a new indirect value at every shading location A reasonable starting value for using the occlusion cache is 0 2 The maxpixeldist attribute gives the maximum distance in pixels over which AIR will re use a given sample Lower values cause more samples to be taken more frequently The indirect illumination cache AIR calculates can be saved to a file and re used when a scene is re rendered As long as no object or light moves the same values will still be valid If the camera position changes AIR may need to calculate some new samples but you can still save a lot of time by giving it an initial set of samples To enable cache writing use Option indirect string savefile filename Load a cache file for re use with Option indirect string seedfile filename Although AIR uses ray tracing to generate new illumination samples it does not need to trace rays to calculate indirect il
229. ault Value Range Description Ambient 1 0 0 0 1 0 Ambient reflectivity Diffuse 0 5 0 0 1 0 Diffuse reflectivity Specular 0 5 0 0 1 0 Specular reflectivity Roughness 0 1 0 01 1 0 Specular roughness SpecularColor 1 l Highlight color RootColor 0 5 0 5 0 5 Color at base of curve TipColor 1 0 1 0 1 0 Color at tip of curve ColorBias 0 5 0 0 1 0 Bias for color interpolation along curve Description This shader makes a flat curve look like hair by illuminating it as though it were a cylinder The diffuse color is based on the Root Color and TipColor which are linearly interpolated along the curve s length The result of that interpolation is then multiplied by the curve s color attribute See Also VFur shader 10 10 5 VHexTile hexagonal ceramic tile with reflections 2001 2014 SiTex Graphics Inc Shader Guide 240 IIlumination model ceramic Features reflections Parameter Default Value Diffuse 0 5 Specular 0 5 SpecularRoughnes 0 1 s SpecularSharpnes 0 8 S Reflection 0 5 ReflectionSamples 1 ReflectionBlur 0 0 ReflectionName raytrace ReflectionSpace current TileWidth 0 1 TileBlur 0 04 TileColorVary 0 3 MortarWidthFractio 0 1 n MortarColor el sd 2 MortarDepth el TextureSizeXY 11 TextureOriginXY 0 0 TextureAngle 0 Projection st ProjectionSpace shader ProjectionTransform 1000 010 0 001 0 0001 Description S 0 0 1 0 S aces aces Description Diffuse reflectivity Specu
230. automaps Non specular and non diffuse behavior e Extra output variables containing shadow values and unshadowed light colors for use in special applications such as computing a shadow pass e Fine control of shadow casting objects with shadow casting groups for ray traced shadows e Per light channel numbers facilitating per light output channels in surface shaders e Most lights have an extended version that allows baking shadows and illumination with 2D or 3D texture maps Special Lights AIR includes additional light shaders for other purposes Area Lights arealight arealight2 portallight and texturedarealight shaders that can be attached to geometric primitives to produce area lights Indirect Diffuse Illumination indirect shader for simulating indirect diffuse illumination Dome Lighting and Image Based Lighting envlight and occlusionpass shaders for ambient occlusion and image based lighting Caustics The caustic shader is used with photon mapping to produce caustic effects Photometric lighting The photometric pointlight shader allows illumination to be defined using physical units or an IES light profile Sunlight 2001 2014 SiTex Graphics Inc 313 AIR User Manual 13 1 The sunlight shader computes the color and direction for a sun like light source based on observer position date amp time and atmospheric conditions Diffuse Only and Specular Only Lights Most non ambient light
231. axis in degrees Primitive variable with rotation angle for X axis Rotation about Y axis in degrees Primitive variable with rotation angle for Y axis Rotation about Z axis in degrees Primitive variable with rotation angle for Z axis prim var to convert to user attribute prim var to convert to user attribute prim var to convert to user attribute prim var to convert to user attribute prim var to convert to user attribute prim var to convert to user attribute Use the instMultipleArchives instancer to create instances of a numbered sequence of archive files 2001 2014 SiTex Graphics Inc 121 AIR User Manual 10 6 3 10 6 4 based on a particle system The archives should be numbered sequentially with no zero padding The archive to use for each particle should be stored as a primitive variable and that variable s name provided in the ArchiveIndexPrimVar parameter The shader can also optionally convert other primitive variables to user attributes assigned to the archives where they can be queried by other shaders The prim vars can have either 1 value converted to a float user attribute or 3 values converted to a color user attribute See Also ViInstanceArchive instancer shader MassiveAgents adds Massive agents to a scene at render time Parameter Default Value Range AgentArchivePrefix mn RenderPass renderpass_ Air MotionBlur 0 Oori RotateX 0 Scale 1 FrameOffset 0 InheritTransform 1 Gro
232. ay also be initialized using a list of values The above assignments could also be made using First qrvd tx 1 0 lt color 1 1 1 User types may be passed as function parameters but may not be used as function return types Variables of the same user type are assignment compatible void CopyLayer Layer from Layer to i to from A user type variable can be part of the shader parameter list in which case each field of the user type is exported as a separate parameter For example given the following shader declaration surface Layers Layer First 1 0 color 1 1 1 E the slbtell utility would return Surface Layers string First Map float First Weight 1 color First Tint 1 1 1 A complete sample shader with source code can be found in SATRHOME examples userstruct This excerpt from the main shader code illustrates some of the advantages of user defined structures surface DiffuseLayers 2001 2014 SiTex Graphics Inc Shader Guide 284 Layer First LAYER_DEFAULT_VALUES Layer Second LAYER_DEFAULT_VALUES Layer Third LAYER_DEFAULT_VALUES color C 0 C ApplyLayer First C C ApplyLayer Second C C ApplyLayer Third C 1 The code is short and easy to understand the higher level functionality of adding layers stands out while the low level details are encapsulated by the Layer
233. ber of shading samples by lowering the shading rate For example a shading rate of 0 5 will result in two shading samples per pixel while a rate of 0 25 will yield 4 shading samples per pixel It is more efficient however to address the specific source of aliasing if possible For example if shadow edges are jagged increasing the number of shadow samples will smooth out the shadows without requiring the entire shading computation to be performed multiple times Shadows 2001 2014 SiTex Graphics Inc Image Quality 32 4 4 4 5 4 6 Both ray traced and shadow mapped shadows can exhibit shading artifacts in the form of jagged edges or for blurry shadows excessive noise In both cases increasing the number of shadow samples will improve shadow quality Most light shaders provide parameter to set the number of shadow samples Reflections Ray traced reflections may exhibit artifacts in the form of jagged edges or excessive noise As with shadows increasing the number of samples or rays used will improve image quality Most shaders with reflections include a parameter to setting the number of reflection rays Pixel Filters Air supports all 5 pixel filters listed in the RenderMan Interface specification box catmull rom gaussian triangle sinc Air provides 3 additional filters disk mitchell lanczos Mitchell Filter The mitchell filter is similar to the catmull rom filter except that the mitche
234. bies Procedurals Air supports the RunProgram DelayedReadArchive and DynamicLoad procedural primitives defined in the RenderMan standard These procedural primitives allow Air to generate or load objects as they are needed during rendering instead of requiring all objects to be loaded before rendering begins A procedural primitive is created with the Procedural RIB call Procedural proctype arguments xmin xmax ymin ymax zmin zmax The last argument is an array of 6 floats defining a bounding box for all objects that will be created by the procedural primitive When the renderer encounters the bounding volume of a procedural primitive Air calls the corresponding procedural function to obtain the contents of the box If the bounding volume is never encountered during rendering the procedural primitive will never be called There are three standard Procedural primitives Procedural DelayedReadArchive The DelayedReadArchive procedural often abbreviated DRA is the simplest procedural to use because it does not require any programming A DRA takes the name of a RIB archive as its only argument For example Procedural DynamicLoad teapot rib 3 3 2 2 3 3 When the procedural is called it simply loads the contents of the specified archive Some plugins have a special RIB export mode that creates a separate archive for each object and main RIB file that references the object archives using DelayedReadArchive procedurals Proce
235. bprintf shading language command Source code for the procedure shaders included with AIR can be found in SATRHOME vshaders Procedures V3DArray creates a 3D rectilinear array of archive instances Parameter Default Value Range Description Archive oe RIB archive file name Scale 1 Uniform scale applied to archive instances CountXYZ 44 4 Array size in each dimension OffsetX 10 0 Translation per increment in X index OffsetY 010 Translation per increment in Y index OffsetZ 001 Translation per increment in Z index Origin 00 0 Offset for entire array VTree procedural tree generator Introduction The VTree procedure shader grows a tree at render time Many variations of the same basic tree look can be generated simply by changing the Seed value used to for generating random numbers during construction of the tree The tree model has four components a trunk major branches emanating from the trunk twigs growing out of the branches and leaves attached to the twigs Tree Shape and Size 2001 2014 SiTex Graphics Inc 169 AIR User Manual Parameter Default Value Range TreeShape 0 0 7 TreeUpAttraction 0 5 TreeScale TreeRotate 0 360 TreeOffset 00 0 TreeUp 010 Seed 123 integer Description Index into tree shape table see below Tendency of twigs and leaves to point up or down Uniform scale applied to tree Rotation in degrees about vertical axis Center of trunk base Up direction for tr
236. c 229 AIR User Manual Parameter Frequency FirstDash FirstGap SecondDash SecondGap ThirdDash Description Default Value 10 0 O O OO O OrRON b Range Description Dashes per unit length in texture space Length of first dash Length of first gap Length of second dash Length of second gap Length of third dash The VDashes surface shader makes a curve primitive into a dashed line using the curve s texture coordinates The color of the dashes is taken from the object s color attribute Frequency sets the number of dashes per texture coordinate unit Other parameters are given as a fraction of the unit interval The pattern can have up to 3 dashes 10 10 4tVDecal2D reflective plastic shader with base texture map and up to 3 decals IIlumination model plastic Features reflections texture map Parameter Diffuse Specular SpecularRoughness SpecularSharpness Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace ColorMapName ColorMapBlur SpecularMapName SpecularMapBlur Default Value 0 5 0 5 0 2 0 8 1 0 1 0 0 raytrace current wee 0 0 1 0 0 0 1 0 Description Diffuse reflectivity Specular reflectivity Specular roughness Sharpness of highlight edge Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup T
237. cally set the displacement bounds for true displacement This parameter should be set to the maximum of all the BumpScale parameters assuming no texture regions overlap VCracks cracked surface Parameter Default value Range Description BumpMax O 1 Maximum depth of cracks CrackWidth 0 2 Crack width Jitter 1 0 0 0 1 0 Deviation from a regular grid PositionVary 1 0 Variation in initial shading position PatternSize 0 2 PatternOrigin 000 PatternSpace shader spaces Coordinate space for shading calculations Description The VCracks displacement shader uses a cellular pattern to generate cracks in a surface VDents gt lt 2001 2014 SiTex Graphics Inc Shader Guide 94 10 2 9 Parameter Default value Range Description BumpMax 0 02 Maximum depth of dents Power 3 1 8 Exponent for sharpening bumps LevelsOfDetail 6 1 8 Levels of detail in dents PatternSize 0 3 Overall scale of pattern PatternSpace shader spaces Coordinate space for shading calculations Description The VDents displacement shader generates a pattern of dents using a turbulence function VDimples pattern of rounded cells Parameter Default value Range Description BumpMax Oel Maximum height of cells Jitter 1 0 0 0 1 0 Deviation from a regular grid pattern Power 2 1 5 Power for cell shape PatternSize 0 2 Pattern size PatternOrigin 00 0 Pattern origin PatternSpace shader spaces Coordinate space for shading calcu
238. canline rendering fast rendering of complex scenes motion blur and depth of field with the flexibility of on demand ray tracing for accurate reflections soft shadows global illumination and caustics Air supports a broad range of geometric primitives including polygon meshes trimmed NURBs subdivision meshes curves particles and implicit surfaces All primitives are supported in their natural form no pre meshing is required Air provides both bump mapping and true sub pixel displacement 8 bit 16 bit and floating point texture maps and environment maps are supported High dynamic range HDR images can be used to perform image based lighting Air offers the flexibility of fully programmable shading using the industry standard RenderMan shading language Air comes with a collection of shaders and hundreds more are freely available The Air distribution also includes Vshade a Visual Tool for constructing shaders without programming Images rendered with Air may be displayed on the screen using the companion Air Show tool or written to a file in a variety of graphics file formats Air can output multiple images from a single rendering for efficient multipass rendering Air is capable of producing high quality contours for cartoon rendering and illustration 2001 2014 SiTex Graphics Inc 13 AIR User Manual 1 1 Installation Installing Air under Windows Run the installer to install Air on yo
239. cattering direction PrimaryScatterWeight 1 0 0 0 1 0 Relative weight of primary scattering PrimaryScatterColor 1 0 1 0 1 0 color Per channel scattering multiplier SecondScatter 0 0 1 t 1 second scattering direction SecondScatterColor 1 0 1 0 1 0 color Per channel scattering multiplier PatternSize 0 5 size of cloud pattern SphereRadius 0 8 radius of soft sphere shape Turbulence 0 1 turbulence strength TurbulenceExponent 0 5 exponent for turbulence sharpness TurbulenceLevels 4 1 9 octaves of fractal noise TurbulenceRoughness 0 5 relative strength of successive noise levels Distortion 0 5 distortion of basic shape Distortion Vector 1 1 1 distortion direction ShadingSpace shader space space for shading computations Description This is a basic cloud shader for cumulus clouds The illumination model is the same as that of the particle shader The cloud pattern is based on David Ebert s cumulus cloud model in Chapter 8 of Texturing and Modeling The SphereRadius parameter gives the radius for a soft sphere shape within the volume primitive If SohereRadius is 0 the soft sphere shape is not used and the entire volume primitive is filled with the turbulent cloud pattern The basic sphere shape can be modified to look less like a sphere by distorting it along the DistortionVector using the turbulence result multiplied by the Distortion parameter The pattern within the cloud is generated using a turbulence function controlled by the
240. ccc icc a a 418 Part XXV Plugins and Companions 420 Part XXVI Resources 422 Part XXVII License Agreement 423 Part XXVIII Copyrights Trademarks and Credits 424 Part XXIX History 425 We AUR e a a iced oe EEE TTT saat Suamaeitmap one E E cutnensaamapencetseesaate 426 i UPR a a a aceihe ceed hee tetbedec enna A E fants 429 3 AIRTIO Ca rra aaa a sees aaa aaa aa aa aE aaar ckevetuaaduccwidvess xadues aceuasueus ndnadvcduadvave ausaeacevacanses 432 AAIR TOO aeree aa a aae e ae eE e E r e eE aE aea a a a ae eS 436 5 AIR9 0 ecestesecceewe evens se cecacetacescasvecscanend codes tncececeusdeuscakecsccewts caus eacecscecetedexsdacucnsceetscevadesuceccessatetes 439 6 AUR BO wcceccseetdsereeeevecacnectinteesvesseceueceevceedennansencierdeedeeneeaeedieedesvsetuensndeeedveddenctnstederdeedveudananelsedsces 442 AUD Or ea pa Era a ar r onavansbensndecyenuveeapeuanstan daaxenupennesedssaniaeipennnctensdmnacapenansaswenadd 444 8 AIRO sungin a a ee aeae E aaea aaa aa Aa a a a a a aE a aa a aE a E 447 UR O E E E AE A E E E E A E T A E A A EE 448 T0 ARA O a a aaa a rea situs ae Aaaa ae aa Eaa aee aE a aaaea aa 450 11 AIR4O0 cetetiveccdintenenntiecsasentenseeeuecesndenussenes sevesndeatceuueetiessndeee aeaaea ENa rE i aeaiia aida au TAa 452 WA Ee a E E E E 453 WS AIR3 0 oria aeaa ances ce aeaa a aa A a ensues sete oss aa ar Eaa aa eaaa aAa a aa aAa a ae aa 455 T4 AIR 2 9 oa eea aea eaaa Eaa ae aaa aa eaaa aea e vs aa aea a aeaaeae aaa aea aaa 457
241. ce by displacing it using sem circles The pattern is applied using the object s standard texture coordinates By default the pattern runs along the first texture coordinate The RotationAngle parameter can be used to rotate the pattern on the surface 10 2 15 VRipples ripple like bumps Parameter Default value Range Description BumpMax 0 1 Maximum ripple height Roughness 0 5 0 01 1 0 Gain LevelsOfDetail 2 1 7 Number of octaves of noise FilterWidth Ou5 Filter width multiplier PatternSize 0 2 Overall scale of pattern PatternOrigin 00 0 Pattern offset PatternSpace shader spaces Coordinate space for shading calculations Description The VRipples displacement shader produces ripple like bumps using several levels of noise patterns The ripples are computed as a 3D pattern with PatternSize determining the overall size of the ripples LevelsOfDetail sets the number of octaves or levels of noise that are combined to produce the ripples The added detail provided by additional levels can be seen in the following examples NS The Roughness parameter controls how much each level of noise contibutes to the final result Lower roughness values produce a smoother final appearance Higher numbers produce a noisier result 2001 2014 SiTex Graphics Inc Shader Guide 98 Some examples with LevelsOfDetail s 0 3 0 5 0 7 This shader performs anti aliasing by fading out the ripples as the region being
242. ce soft shadows by expanding the region sampled by the shadow rays Shadow blur for ray traced shadows is given as an angle in radians for the range of directions in which to cast rays 2001 2014 SiTex Graphics Inc Lighting 316 Ray Traced Shadow Attributes The following attributes can be set for each object Attribute visibility integer transmission 0 When set to 1 an object will cast ray traced shadows Making objects that do not cast shadows invisible to shadow rays speeds up rendering Good candidates are objects functioning as a ground plane or a surrounding volume Attribute shade string transmissionhitmode type Tells the renderer how to treat an object when it is queried by shadow rays Possible types are primitive the primitive blocks shadow rays in proportion to its Opacity attribute setting shader the renderer should execute the surface shader attached to the primitive to estimate the opacity For an object with a surface shader that computes a complicated opacity e g a screen shader you will need to set the shadow type to shader to force evaluation of the shader Your plugin should provide a control for this setting Attribute trace integer motionblur 1 Moving objects with this attribute set will cast motion blurred shadows Motion blurred traced shadows require 2 or more shadow samples or rays Use more rays for smoother blur Shadow Casting Groups Many AIR light
243. ced shadows Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel The photometric_pointlight shader is a point light source with support for physically based illumination values A description of the physically based parameters can be found in the section Photometric Lights and IES Profiles The shadow controls in the shader behave exactly like those in the standard pointlight shader 10 7 15 pointlight pointlight_baked point light source shader 2001 2014 SiTex Graphics Inc Shader Guide 144 Parameter Default Value Range Description intensity 1 0 Light intensity lightcolor 11 1 Light color lightcolor_spd mi Light color spectrum file maxemission 0 If greater than 0 the maximum emitted intensity including falloff from 00 0 Source position of light falloff 2 0 1 2 Exponent for falloff in light intensity with distance shadowname me Name of shadow map or raytrace for traced shadows shadowbias 0 01 Offset to prevent incorrect self shadowing shadowblur 0 01 0 0 0 5 Blur for shadows shadowsamples 1 1 256 Number of rays for traced shadows shadowcolor 000 Color of shadows shadowgroups Optional groups for ray traced shadows shadowattribute user shadowgroups Per object shadowgroups override attribute name _ cat
244. cer shader now reference the instancer shader name The old cilver license system has been de supported e Linux a single set of multithreaded binaries is now distributed for air and bakeair Separate airmt airst and bakeairmt binaries are no longer included Air Demo the number of rendering threads is no longer restricted to 2 2001 2014 SiTex Graphics Inc 435 AIR User Manual Shading compiler shaded e New line command line option will print the line of code where an error occurs e Support for prman style struct field reference eg a gt x instead of a x Fix for dot product and color values Missing quote error message reports the line with the unmatched quote Fix for handling of undeclared identifier in setxcomp etc The option to compile a shader to a DLL or shared object has been de supported Support for longer parameter names up to 63 characters e Fix for ctransform code generation BakeAir e New mode for baking meshes instead of texture maps TweakAir e IrNewRnvironment and IrTweakEnvironment commands for updating environment shaders Air Show 6 e New tone mapping display option e Fix for gain control applied to 16 bit image with sRGB e SRGB display mode is now enabled by default Vshade 4 0 see the separate Vshade user manual for what s new Vortex e New mode for distributed rendering of a sequence uses the same syntax as Air s sequence rendering vortex frames sta
245. cing Shadow map access has a fixed time cost independent of scene complexity Air can usually render shadow maps very quickly since shadow maps do not require as much shading computation as a color image e Reusability Once rendered shadow maps can be re used as long as the relative positions of lights and objects remain the same e Quality Shadow mapped shadows have nice anti aliased fuzzy edges Automaps Automaps are a hybrid method of producing shadows combining the ease of use of ray traced 2001 2014 SiTex Graphics Inc 315 AIR User Manual 13 2 1 shadows with the quality of shadow mapped shadows For automapped shadows Air dynamically creates tiles of a shadow map on demand and then uses those just as a normal shadow map to compute shadow values Automaps require objects to be retained in memory just like ray tracing so they use more memory than ordinary shadow maps Automaps are also typically slower to generate than shadow maps created with a separate rendering pass Occlusion Ambient occlusion can be used to simulate soft shadows Air provides a special envlight light shader that uses occlusion shadows with illumination from a surrounding environment Occlusion can also be used for shadows with any standard light by supplying the special shadow name occlusion Ray Traced Shadows AIR supports the use of ray tracing to produce shadows One or more rays are traced from the light source to th
246. clare __lights varying color 10 Each channel can then be referenced using an index into the __lights array ina Display call E g Display reference tif file rgba Display tlight_O tif file __lights 0 Display tlight_1 tif file __lights 1 Display tlight_2 tif file __lights 2 Per light values should normally be saved with gamma correction disabled gamma 1 Detailed Per Light Channels Some shaders allow per light output to be further broken down into diffuse unshadowed shadow and specular components by providing additional output variables Declare __lights_diffuse varying color 10 Declare __lights_unshadowed varying color 10 Declare __lights_shadow varying color 10 Declare __lights_specular varying color 10 Display diffuse_0 tif file __lights_diffuse 0 Display tunshadowed_0O tif file _ lights_unshadowed 0 Display shadow_0 tif file __lights_shadow 0 Display specular_O tif file __ lights_specular 0 The VBlinn surface shader provides these additional output variables Tracking Light Channels through Reflections Beginning with AIR 9 most AIR surface shaders with reflections allow light channels to include the effects of reflection and refraction The AIR shaders look for the following user option to enable light tracking through reflections Option user float reflectlights 1 Note that light channel tracking must be explicitly supp
247. clared and associated with a primitive as a user attribute Declare fadecolor color Attribute user fadecolor 1 1 1 User attributes can be queried in a shader with the attribute function E g color fadecolor 0 attribute user fadecolor fadecolor 8 Primitives Air supports all primitives defined in the RI Spec 3 2 Supported primitives include Polygons convex and concave polygons with holes single polygon or indexed meshes Bilinear patches and patch meshes Bicubic patches and patch meshes with arbitrary basis functions NURB patches with trim curves Catmull Clark subdivision surfaces Quadrics spheres tori cones cylinders disks hyperboloids paraboloids Points point collections may be rendered as disks spheres patches or particles Curves linear cubic and NURB curves can be rendered as polylines ribbons or tubes Blobby blobby implicit surfaces Procedurals generate or load other primitives on demand at render time Additional Air specific primitives 2001 2014 SiTex Graphics Inc 65 AIR User Manual 8 1 Implicit surfaces based on grid data Volume primitives Procedure shader primitives Approximation of Curved Surfaces Adaptive Meshing Air renders objects by converting them to polygons By default Air automatically subdivides curved surfaces based on how they appear on the screen The accuracy of the polygonal approximation can be controlled by giving a maximum
248. clusion Cache Acceleration The default settings for ambient occlusion can be slow as Air computes a new occlusion sample at every shading location Using an occlusion cache can greatly accelerate occlusion rendering by allowing Air to re use occlusion samples To enable occlusion caching e In the parameters window for the RIB output operator look under the Properties tab for the GI sub tab e Change the Max Cache Error value from the default of 0 to 0 25 e For best results also enable the Occlusion prepass e Render another test frame Occlusion Pass Surface Shader 2001 2014 SiTex Graphics Inc 397 AIR User Manual 23 5 As an alternative to the envlight you can use Air s occlusionpass surface shader to render an occlusion pass See Also Ambient occlusion Global Illumination with Air and Houdini Global illumination in the form of indirect diffuse illumination can be added to a Houdni scene by adding an AIR indirect light and enabling controls in the GI section of the rib output operator Step 1 Adding an indirect light e In the SHOP network open the Tool menu and under the RenderMan Light category choose the AIR Indirect light shader e Inthe OBJ network create a Light Template from the Render sub menu under the Tool menu e On the Render tab of the light template select the Shaders subtab and set the Light Shader value to the AIR indirect shader added above Step 2 Configure globa
249. covered by cracks CrackCoverageFreq 0 2 Coverage variation frequency relative uency to PatternSize CrackColor 000 Crack color CrackColorBlend 0 2 0 1 Amount of crack color to blend into base color in cracks WrinkleFrequency 0 05 Wrinkle frequency relative to PatternSize WrinkleDepth 0 9 Wrinkle depth relative to BumpMax PatternSize 0 05 Overall pattern size PatternOrigin 000 Pattern offset PatternSpace shader spaces Coordinate space for shading calculations Description The VLeather surface shader simulates the appearance of leather using a fine grain pattern of cracks combined with a larger patterns of wrinkles The overall size of the patterns is set by PatternSize and the depths of cracks and wrinkles can both be scaled using BumpMax 10 10 5 VLines line drawing surface shader 2001 2014 SiTex Graphics Inc Shader Guide 244 Parameter BlackThreshold WhiteThreshold Background BackgroundBlend FirstFrequency FirstFraction FirstAlpha FirstAngle FirstColor FirstColorBlend SecondFrequency SecondFraction SecondAlpha SecondAngle SecondColor SecondColorBlend Description Default value 0 0 1idl 400 0 3 Range 0 0 1 0 0 0 1 0 0 360 0 0 1 0 0 0 1 0 0 360 0 0 1 0 Description Diffuse level below which surfaces are shaded with full line coverage Diffuse level above which lines are invisible Explicit background color Blend between exp
250. crease and 1 an infinitely sharp crease AIR automatically translates crease tags into linearcrease tags that produce approximately the same appearance so AIR will work with existing plugins that export semi sharp creases using the crease tag But because AIR uses a different algorithm than Pixar s PRMan the two renderers will not in general produce exactly the same results though the general look should be similar Facevarying Mesh Data 2001 2014 SiTex Graphics Inc Primitives 68 AIR provides two methods of interpolating mesh data assigned as facevarying i e one value per vertex per face By default AIR will interpolate facevarying data linearly across the face of subdivision mesh This linear interpolation can distort texture coordinates because the position vertices move in accordance with the subdivision rules while the texture coordinates move respond linearly AIR provides an alternative interpolation that uses vertex interpolation for facevarying data whereever possible whereever mesh data is continuous with varying interpolation used only along seams between regions Attribute render integer facevertex 1 Tessellation By default AIR converts an entire subdivision surface to a polygon mesh for rendering in one step AIR 5 and later can optionally split a subdivision surface into subregions for tessellation Attribute render integer splitmesh 1 Tessellating by regions may
251. cs Inc Volume Rendering 352 the shading rate and the relative size of the primitive For fast render times use as high a shading rate as possible for the required image quality e When a volume primitive with a high shading rate is viewed face on that is from a direction that is nearly perpendicular to one of the faces of the bounding box artifacts of the 3D shading cache may become visible Such artifacts can be reduced by changing the point of view to a more oblique angle lowering the shading rate reducing the contrast of the shading results or eliminating small pattern details 18 1 Writing Shaders for Volume Primitives Shading for a volume primitive is performed by its assigned surface shader The surface shader need only calculate the color and opacity at P AIR takes care of integrating shading information along query rays through the primitive Surface shader variables are initialized so that sqrt area P gives a good filter width estimate for anti aliasing procedural patterns When applying the shader results to a ray through the volume medium AIR treats the opacity result as the optical thickness of the material over the unit interval in object space The actual attenuation applied for a distance D is 1 exp Oi D Output opacity values greater than 1 are permitted A shader for a volume primitive should normally provide a parameter for scaling the output opacity as the proper value is dependent on th
252. ct ARs ee AAEE 62 2 SIGCUNESS operai EE e ENEE a TEES 63 eeo lU olino En E E E E E E E E E 63 4 User Detined Attributes si si aeaaea na aae amaaa aaa aAa a Aaa ar a a apana aaa cxidcetapansnneas cxueets 64 Part VIII Primitives 64 1 Approximation of Curved Surfaces s sssssssusssuununnnunnnunnnuunnunnnnunnnunnnunnuunnnunnnnnnnnnnnnnnnnnnnnnnn annen 65 2 POIVGONS sineuna A cevecteetsecuectensecetts 66 3 Subdivision Surfaces s es ence ceciekc eck act ceaehsc ccd Saceced cade deci sdathce cadences Saaticesiekenccs aaticees 67 A P ints sereasenscbeceiweverenecncdcceeneverecestdaeteestecraceuatenuceneenredeesddeueenvesnadeaetuerdendeabedseesdertee ensansendierdenvens 68 Be CURVES E E E A E E T E E E A E NE E E 69 6 Blobbies and Dynamic Blob OPS sss sssnsuunnsunnnunnnunnnunnnnnnnnnnnnnnnnnnnnunnnnnnnnnnnnnnnnnnnnnn annn nnnn nnmnnn nnna 71 7 Proc d ralS s i aaee aa aeaa a aa a a eaa ea eaaa aE aaa 74 8 Mpici SU A O S ra a a aa e r ra A aa Arae r aaaea ae eaa aai 76 DTM CUES orason E RER 76 10 Instancing with Inline Archives sssssssenunnennunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnmnnn nnmnnn nnmnnn nnn 76 Part IX Materials 77 Part X Shader Guide 78 1 Common Shader Features scsccescseesssesessseseseseesssaesecnssesaesesnenesaesesasseeaesesaesneaesesaeeananees 79 M minaton Models cc 255 vce cs ves ccc csnecces sccec vecsseccsscocesdctersecesesssezeessesctertsncusdetcesevcoedsscesutcvveterseauent cass
253. ction ray Increased thread stack size for Linux air to prevent overflow Polygon auto LOD properly handles the case where an entire primitive is removed Initialize description string to null in image reader Inline archives fixed to prevent prim lock corruption String to real conversion now properly handles excess zeroes after the decimal point Real to string conversion handles small numbers better Adjusted minimum flatness to allow lower flatness values that may be appropriate when flatness space is not raster space Network cache copy for air on Linux environment fill Custom clipping planes Fix for Display mode to allow inline declaration of output arrays E g Display channell tif file varying color 10 __lights 1 should work now AIR 9 0 New common product licensing TweakAIR and BakeAIR can now use an AIR license A separate TweakAlR or BakeAlR license is no longer required New light shaders for baking shadows and illumination to 3D texture files Important fixes for deep fragment shadow maps e Much better behavior on scenes with high depth complexity e Bug fix for the default shadow mode to correct a case where a nearly transparent fragment was recorded as fully opaque Light channel tracing e AlR surface shaders with reflections now allow light channels to include the effects of reflection and refraction Light channel tracking through reflections is enabled with the following user option Option user flo
254. cube faced maps Mirror Reflection Maps Mirror or planar reflection maps are used to simulate reflections from flat surfaces such as a tabletop floor or wall mirror Reflection maps rely on the fact that the image seen in a planar mirror can be generated by reflecting the camera about the mirror plane That relation implies that a mirror reflection map is only valid for a given camera position A reflection map should have the same resolution and aspect ratio as the final image Your plugin may provide a facility for automatically generating mirror reflection maps A mirror reflection map can be used with any shader that provides an environment map parameter and means of setting the coordinate space used for indexing the environment map The coordinate space should be set to NDC Normalized Device Coordinates Sample shader declaration Surface VMetal String ReflectionName floor tx string ReflectionSpace NDC Spherical Environment Maps Spherical or latitude longitude environment maps store the surrounding environment using a spherical projection Spherical maps are often generated by hand with a paint program A raw spherical texture map should be converted to a latitude longitude environment map using the mktexui or mktex conversion utilties Here s a sample command line for mktex mktex envlatl mymap tif mymap tx A spherical map can be used with any shader that supports environment maps The coordinate space
255. cular shader For those that do not the tweak names and values can be entered by hand 2D or 3D Shading 2001 2014 SiTex Graphics Inc 191 AIR User Manual The DarkTree shading pattern can be calculated in 2D or 3D If the Use2DCoordinates parameter is set to 1 the base shading location will be s t 0 where s and t are the standard 2D texture coordinates for a primitive Optimization If you know that a particular parameter is not used by a given DarkTree shader setting that parameter to 0 will speed up rendering For example if a shader does not perform bump mapping setting the BumpScale parameter to 0 will avoid an unnecessary call to the RMSimbiont Set any of the following parameters that are not used to 0 to accelerate rendering Reflection Incandescence BumpScale Animation DarkTreeSurface uses the shading language time value set with the Shutter RIB call multiplied by the TimeScale parameter as the frame number input for DarkTree shaders By varying the time value in the Shutter call animated DarkTree shaders can be queried at different times See Also DarkTree overview DarkTreeDisplacement shader 10 10 8 defaultsurface a default surface shader Description The defaultsurface shader is used whenever no surface shader is assigned to an object The default implementation colors the surface as though it were lit by a distant light shining from the view direction This shading allows objects
256. cy of brick edge unevenness y Projection st projections Projection type ProjectionSpace world spaces Coordinate space for 3D to 2D projections Transformation 16 1000 Transformation matrix 010 0 0010 000 1 DisplacementSpac shader spaces Coordinate space for displacement e Description The VBrickGrooves displacement shader provides a basic grooved brick pattern See Also VBrick2D surface shader 10 2 6 VBumpRegions multiple regions with different bump maps Parameter Default value Range Description BumpMax 1 Set this to the max of all displacements DisplacementSpace shader spaces Coordinate space for displacement 2001 2014 SiTex Graphics Inc 93 AIR User Manual 10 2 7 10 2 8 FirstBumpMap iii Bump map file name FirstBumpScale 1 Bump height multiplier FirstBumpSizeXY 11 Width and height of bump map in texture coords FirstBumpOriginXY 0 0 Position of top left texture corner FirstRegionSizexY 1 1 Width and height of textured region FirstRegionOriginXY 0 0 Top left corner of textured region The shader includes 5 more texture regions with analogous parameters Description The VBumpRegions displacement shaders allows up to six different regions on a surface to each receive a different bump mapped displacement Where regions overlap the displace offsets are added together The BumpMax parameter does not affect the result of the shader but some plugins may use it to automati
257. data on the curve given by the first index and the position specifed by the second array parameter The second parameter should lie between 0 the start of the curve and 1 the curve end Sample time float mytime time meshinfo sample time mytime This method sets the time at which to query a base mesh with vertex motion blur This method is currently only supported for vertex queries and only vertex position data P is blurred In typical usage a shader will sample at the global time value and at time dtime 2001 2014 SiTex Graphics Inc 297 AIR User Manual Querying Primitive Variables Once the sample method and location have been set subsequent calls to meshinfo can query any standard or user defined primitive variable at the current sample location For example point pos if meshinfo P pos 1 got position data normal nrm if meshinfo N nrm 1 got normal data Point normal and vector values are returned in object space coordinates for the base primitive Standard texture coordinates are always stored as an array of 2 floats float st 2 if meshinfo st st 1 got standard texture coordinates The underlying primitive representation will be a polygon mesh for all surface primitives a list of line segments for curves and a set of vertices for point primitives Information Functions Meshinfo supports the following information functions for querying the bas
258. dchannelcolor array per light unshadowed diffuse values indexed by a light s s channel output variable nchannels float number of valid channels The unshadowed output value can only be computed correctly for lights that export a color __unshadowed_C1 output variable containing the light intensity without shadows The shaders for AIR MayaMan and RhinoMan all provide this variable The indirect lighting output is computed by summing the diffuse contributions from lights that export a float_ indirectlight variable set to 1 The indirect shader for indirect diffuse illumination and the envlight shader for ambient occlusion are both categorized as indirect lights The shadow output value is computed so that the following relation holds diffuse unshadowed l1 shadow indirect Shaders can test a DIFFUSEEXT symbol to see if the shading compiler supports these extensions The extra output variables from diffuse are typically used to provide extra output variables to a shader for multipass rendering The expanded matte shader included with AIR illustrates typical shading language usage surface matte float Ka 1 Kd 1 output varying color __ambient color 0 output varying color __diffuse color 0 output varying color __diffuse_unshadowed color 0 output varying color __shadow color 0 output varying color __indirect color 0 normal Nf Nf faceforward normalize N I Oi Os
259. der string zfilter normal Automap improvements e Much better cache performance e Now work with point lights in addition to spotlights and distant lights TweakAIR improvements e Better handling of displacement shader tweaking e New reflection cache improves refresh performance for objects with traced reflections e New option to automatically update an object when a reflected object changes Option ipr integer retrace 1 e Many bugs fixed on Linux New much improved environment map filtering AIR will automatically generate tangent vectors for polygon meshes based on the assigned texture coordinates Light shaders can query surface output parameters AIR Show can display AIR texture maps Support for texture mapped area lights New surf command line option to override the surface shaders in a RIB file Many surface and displacement shaders have been modified to employ new conventions for 2D and 3D patterns recognized by AIR Space New shaders VRubber VDecal2D replacing VDecal2DPlastic VDecal3D replacing VDecal3DPlastic Vshade now accepts varying input parameters Bug fixes e Failure to free automaps at end of frame e Facevarying interpolation on subdivision meshes e diffuse handling __indirectlight vars Fix for subsurface scattering shaders included with AIR to use all 3 scatter distances Random crash with outlining and multithreading rayhittest now performs a self intersection check if the ray origin
260. determines the shading quality of an image Shading rate is defined as the area in pixels covered by a single shading sample A lower shading rate produces a higher quality image For example a shading rate of 0 25 will produce 4 shading samples per pixel The sm command line option is a multiplier for the shading rate setting in the rib file air sm 0 25 scene rib Bucket Size and Bucket Order By default AIR renders an image in 32x32 pixel tiles or buckets one row at a time top to bottom Using a smaller bucket size may reduce peak memory use and provide better load balancing with multiple threads Set the bucket size with bs air bs 32 scene rib Rendering by column instead of by row can also help minimze memory use for crowd scenes Use ltor of columns to render in columns left to right air ltor scene rib Surface Shader Override The surf switch overrides all Surface shaders declared in the rib file with the alternate shader provided Alternative surface shaders can be used for rendering multiple output passes from a single scene file E g air surf occlusionpass file occlusion tif scene rib A related option nosurf suppresses all Surface shaders in the scene file rendering the scene with the defaultsurface shader which provides simple shading based on the surface normal The nosurf option is useful for quick tests and for debugging For example if your scene is rendering black rendering with nosurf will indicate wheth
261. device Your plugin or user interface should provide an option to set the gamma value for the rendered image For more accurate conversion to SRGB color space the sRGB imager shader can be used to convert the computed rgb values to SRGB color space Your user interface may or may not provide an option for using an imager shader High Dynamice Range HDR Images The output values computed by Air may include values that outside the unit interval The visual appearance of such high dynamice range images can be improved by rendering at float precision and applying a tone mapping operator Spectral Color Definition Air 10 introduces the ability to specify colors as a spectrum using spectral power distribution SPD files SPD files define wave length dependent reflectance or emission values as piece wise linear curve connecting pairs of wavelength and intensity reflectance values Use the following attribute to set the standard Color property with an SPD file Attribute render string color_spd filename spd A color parameter for a shader can be set via SPD by including a string parameter whose name is the same as the color parameter with a _spd suffix For example LightSource distantlight 2 string lightcolor_spd light_CIE_D65_noon_daylight spd The shader doesn t need to do anything with the lightcolor_spd parameter Indeed the parameter doesn t even have to be part of the shader just included in the RIB shader declaration
262. dge variation relative to the entire image Seed 941 Random number seed EdgeColor L Edge color Description This stroke shader is designed to produce the effect of unpainted edges between areas of an image It is part of a suite of shaders written to produce a watercolor appearance See Also VWatercolor surface shader WatercolorPaper imager shader 10 10 Surfaces Surface shaders compute the opacity and color of a surface Plastics 2001 2014 SiTex Graphics Inc 177 AIR User Manual SimplePlastic VPlastic V2SidedPlastic VAnimatedMap VBrushedPlastic VBlinn VDecal2D VDecal38D paintedplastic plastic Bac a 1 Metals physically plaustible plastic material general plastic with reflections and texture maps for color specular opacity and bump reflective textured plastic with separate settings for the front and back side of a surface plastic shader with animated texture map brushed or anisotropic plastic plastic with Blinn specular model reflective textured plastic with decals positioned using standard texture coordinates reflective textured plastic with projected decals simple plastic with texture map no reflections basic plastic without reflections or texture maps 2001 2014 SiTex Graphics Inc Shader Guide 178 SimpleMetal simple physically plausible metal shader metal with reflections and optional colo
263. driver and its append parameter to build a map Render the first sub map to the output file and then append each additional submap Sample files for creating and rendering with a cube faced shadow map can be found in SATRHOME examples cfshadow 13 2 3 Fragment Shadow Maps AIR 5 introduces fragment shadow maps that store additional coverage information and multiple depth samples The additional information allows fragment maps to produce a better shadow estimate for semi transparent objects and objects that are thin or small such as hair or particles Fragment maps are enabled during the shadow map generation phase by giving the maximum number of depth samples to store in each pixel of the shadow map Option limits integer shadowmapdepth n AIR creates a fragment map instead of a normal shadow map when the shadowmapdepth is greater than 1 If a given pixel in the shadow map is covered by more fragments than allowed in the depth map AIR will remove and merge fragments until they fit in the map The minimum fragment map depth of 2 works well in many cases For scenes with complex visibility 2001 2014 SiTex Graphics Inc 319 AIR User Manual 13 2 4 many small or thin objects or many layers of transparency a larger depth value of 4 to 8 may produce better results Another option provides a quality storage tradeoff Option render integer shadowmapformat 0 A format value of 0 will generate s
264. duce the number of polygons in a polygon mesh based on an object s on screen size and other factors Automatic LOD applies only to polygon mesh primitives 2001 2014 SiTex Graphics Inc Massive 388 Enable automatic level of detail for an object with the following custom attribute Attribute render float autolod n where n gives an error tolerance when simplifying a model Reasonable values to try are 0 1 to 0 3 A level of 0 disables automatic LOD Automatic LOD is also influenced by the flatness attribute GeometricApproximation flatness 0 5 which gives the maximum difference in pixels between the original surface and the simplified surface The default flatness value is 0 5 A value of 1 or 2 will produce smaller final meshes Tips A reasonable set of values to start with are Attribute render float autolod 0 2 GeometricApproximation flatness 1 When applied to cloth auto LOD may result in clothing that does not cover the underlying limbs Using a smaller autolod tolerance may help prevent this condition Another solution is to use an opacity map to hide parts of a limb that would be hidden by clothing anyway 22 11 Massive Agent Light Tool malt AIR 8 includes a new Massive agent light tool malt to enable rendering Massive agents with per agent lights Possible applications include vehicle headlights or crowds carrying torches or flashlights The basic idea is to use a piece of standin
265. dural RunProgram A RunProgram procedural allows an external helper program to be used to generate new objects during rendering A sample RunProgram call looks like Procedural RunProgram maketree height 10 width 2 branches 5 2 2 2 2 0 10 The first argument is the name of the helper program Air automatically adds the exe extension for programs under Windows Air 8 and later recognize Python and Perl programs by their corresponding file name extensions and will automatically call the appropriate frontend program to execute those scripts AIR searches the procedural search path for valid RunProgram procedurals The second argument is an arbitrary string that is meaningful to the helper program The helper program can be written in any programming language that can read from the standard input stream and write to the standard output stream The helper program should be structured as a loop that waits for a line of input from the standard input stream The first time a RunProgram procedural is encountered Air starts the help program as an external 2001 2014 SiTex Graphics Inc 75 AIR User Manual process connected to the rendering process using pipes Each time an instance of the procedural is encountered Air sends the argument string from the instance to the helper program via the helper s standard input stream Each argument string is preceded by a single number representing the approximate area of the
266. e Based Rendering for more information indirectdepth float indirect trace depth for current ray samplecount float total sample count for rays spawned from trace etc as set by the samples parameter sampleindex float index of current ray in the range 0 samplecount 1 10 15 2traylevel float raylevel Returns the level of reflection refraction at which the shader is being executed with a value of 0 indicating the shader is being executed from the camera 2001 2014 SiTex Graphics Inc 301 AIR User Manual 10 15 2 ribprintf ribprintf patternstring arglist AIR 8 introduces the ribprintf statement to allow instancer and procedure shaders to send RIB commands to the renderer Ribprintf works the same as printf except that the output is sent to AIR s RIB parser instead of the console See Also Instancer shaders Procedure shaders 10 15 2 shadow color shadow raytrace If the file name passed to shadow is raytrace or shadow AIR will use ray tracing for shadows instead of a shadow map The standard shadow function accepts several optional input parameters Type and Name Description string subset restricts ray traced intersection tests to members of the specified groups string label user assigned name for rays cast by this call float maxdist max distance to trace for shadows measured from the current shading location color weight weight
267. e light float 4 automapscreenwindow left right top bottom where the 4 parameters define the screen window that would be used to generate a shadow map for the light Automap Quality and Appearance Automaps use the same high quality filtering as shadow maps producing smooth soft shadows The 2001 2014 SiTex Graphics Inc Lighting 320 shadow blur and shadow bias parameters are interpreted as they are for shadow maps Automap Cache Automaps are stored in a special cache that limits the total amount of memory consumed by all automaps The cache size can be set with Option limits integer automapmemory 10000 which sets the maximum cache size in kilobytes 13 3 Indirect Lighting Topics Introduction Adding Indirect Light Quality Adaptive Sampling Indirect Cache Prepass Shading Environment Radiosity Cache Introduction Indirect illumination is light that strikes a surface after being reflected refracted or scattered by a surface in contrast to direct illumination that strikes a surface directly from a light source For efficient rendering AIR provides separate mechanisms for simulating indirect diffuse illumination light which is scattered towards a surface by other surfaces and caustics light that is reflected or refracted in a focused manner by other surfaces This section describes how to render indirect diffuse illumination effects with AIR AIR uses a variation of the
268. e queried during the same render pass This mode works well if the 3D point map will be used from approximately the same camera position For greater coverage of a scene and better sample distribution 3D point clouds can be generated from multiple points of view and combined with the AIR Point Tool airpt 2001 2014 SiTex Graphics Inc Shader Guide 186 Sampling using collect If a positive BakeRadius value is provided the Bake3d shader uses the collect function to sample the surface uniformly using BakeRadius as the maximum distance between samples The call to collect samples all objects in the same point set as defined by Attribute pointset string handle name This attribute must be set when using this bake mode Only 1 thread will be used when sampling the surface The baked map can be queried during the same render pass in which it is created The BakeChannels parameter determines which of the supported bake channels are actually written to 3D point cloud any or all may be baked Cs diffuse illumination multipled by object color diffuse_shadowed diffuse illumination with shadows diffuse_unshadowed diffuse illumination without shadows Reading a baked map When the Bake parameter is 0 the shader uses the baked map to provide illumination values during rendering instead of calling the diffuse illumination function Sampling of the map is controlled by the QueryBlur and QueryFilterWidth paramete
269. e cost of increased rendering times Dispersion simulation for caustics AIR now reads from the standard input stream if a file name is not provided To display help information use a command line argument of or A new TIFF display driver supports Izw compression on Windows and on Linux systems whose libtiff library supports Izw compression The texture shading language function now supports a filter parameter though its use is discouraged as it incurs a performance penalty and may produce inferior results if used improperly cosine distribution for gather now respects the angle parameter New mktexui graphical user interface for the AIR texture making utility mktex 2001 2014 SiTex Graphics Inc History 458 29 15 RiDeformation has been de supported BakeAIR improvements e BakeAIR now implements the indirect and occlusion prepasses e A new option allows control of the border created around rendered regions in a baked map AIR Show improvements e AIR Show reads image files in any format supported by AIR e AIR Show options are now saved between sessions The multithreaded version of the Cilver floating license manager is now included in the AIR distribution All users are encouraged to upgrade to this version if they have not already done so The default shading type for shadows is now Os use the object s opacity attribute For shaders with complicated opacity e g a screen shader yo
270. e default number of threads was 1 Process Priority The priority of the rendering process can be set on Windows systems with Option runtime integer priority n Valid values are 0 normal and 1 low Rendering at low priority allows a foreground application such as a modeler to run unimpeded while Air renders in the background Tiled Rendering Air renders a scene using small tiles or buckets Bucketed rendering can be very efficient for rendering large scenes The size of the buckets can be set with Option limits bucketsize 80 80 Larger buckets render faster smaller buckets use less memory The order in which buckets are rendered is determined by Option render string bucketorder rows The default rows order marches from top to bottom across the screen in a zig zag pattern To 2001 2014 SiTex Graphics Inc Options 56 minimize memory use for an image that is wider than it is high use columns order spiral order will render from the center of the image outward allowing the middle of the scene to be viewed sooner Different orders usually have different peak memory requirements and different rendering times for a given scene Progress and Statistics Reporting The following option controls progress and statistics reporting Option runtime string verbosity normal Valid verbosity modes are normal Progress report no statistics stats Progress report and final stastics silent No pro
271. e following lines before any Display call Quantize rgba 0 0 0 0 Declare __gBufferID constant float Declare __mBufferID constant float The Display call must include rgba output Additional variables can be included for storing extra information as a comma separated list Here s an example Display call that includes all optional output variables Display test rpf rpf 2001 2014 SiTex Graphics Inc Output 48 rgba z s t P dPdtime __gBufferID __mBufferID Additional Output Channels Depth z By including z in the Display call the z depth of each pixel will be saved at floating point precision Saved values are the camera space z values multiplied by 1 Texture Coordinates s t Two dimensional texture coordinates can be saved in the file by including s t or u v in the Display call A custom pair of texture coordinates can also be saved by passing the variable names to the display driver E g Display rgba ul vl1 string xcoordname ul string ycoordname v1 Custom texture coordinates must be assigned to an output variable in a surface shader in order to be saved Motion Vector P dPdtime Include P and dPdtime in the Display call to save a two dimensional motion vector in the RPF file Motion blur has to be enabled for the scene to produce meaningful values Material Identifier __mBufferlD This identifier will saves an 8 bit channel with a per material number The __mBuff
272. e image from left to right e Elapsed time e Image resolution and data format 8 bit 16 bit or floating point e Zoom level e Memory usage while a rendering is in progress memory in use is the amount of memory used by the rendering process Once a render has completed memory in use reports the memory used to store the image e Ray tracing object retention indicator This block contains letters indicating if any primitives have been stored for ray tracing S for objects visible to shadow rays R for objects visible to reflections and for objects visible to indirect rays If you are using a particular ray tracing feature be sure the corresponding letter is present indicating that objects are available for interesection with the corresponding ray type Conversely if you are not using ray tracing features make sure than no letters appear ensuring that AIR will be able to dispose of primitives as soon as they are processed by the scanline renderer 24 3 2 View Navigation Zooming Click an image with the left mouse button to zoom in and with the right mouse button to zoom out Panning 2001 2014 SiTex Graphics Inc Tools 404 24 3 3 Scroll bars appear if the image is larger than the window The image can be scrolled using the scroll bars arrow keys or by moving the mouse while holding down the middle mouse button Syncing Views If the Sync Views option is checked in the Options menu AIR Show will s
273. e map can be specified e The new texture file is a mip map it stores multiple pre filtered copies of the texture at different resolutions When accessing the texture the renderer will use an appropriate resolution based on the region of the texture visible in the area being shaded resulting in fewer aliasing artifacts Texture files are tiled allowing the renderer to selectively load only the portions of an image that are needed Texture files are compressed to minimize disk space and bandwidth usage AIR limits the memory used by tiled texture maps to a user defined maximum dynamically loading 2001 2014 SiTex Graphics Inc 2D Texture Mapping 306 and unloading tiles as needed Automatic Texture Conversion at Render Time Air 14 introduces a new option to automatically convert source images to Air texture maps internally at render time providing the same high quality texture filtering as that obtained by pre converting images to Air texture files for rendering Enable this automatic mip mapping with Option texture boolean automipmap 1 When this features is enabled Air will resize all source images so the width and height are both a power of 2 The following option controls how an image is resized Option texture string autoresize nearest The default resize mode rounds each dimension to the nearest power of 2 If the resize mode is set to down each dimension is reduced to the next lower power
274. e minimum of the samples making it easier to generate a depth map along with a beauty pass Global illumination improvements e Optimized texture access when shading indirect rays e Caustics are no longer evaluated during the indirect prepass Ray tracing improvements e Optimized shadow tracing for many semi transparent objects e Ray tracing storage reduced 2 3 for large scenes e Improved trace blur for interreflections 2001 2014 SiTex Graphics Inc History 456 Displacement improvements e Automatic true displacement detection in AIR displacement shaders Users no longer need to set a TrueDisplacement parameter for AIR shaders this feature is now completely controlled by the true displacement attribute e Primitives with custom user data no longer use excessive shading structures with true displacement Photon map queries are about 10 faster e New reader and display driver for Radiance HDR image files New AIR texture display driver for rendering AIR texture maps directly with BakeAIR or AIR Shader additions and changes e New VScreen surface shader replaces the old Slscreen and Slholes shaders the old source code can still be found in SATRHOME shaders oldsrc for those interested New DarkTreeDisplacement shader allows DarkTree shaders to be used for displacement New VFog volume shader for fast volumetric fog New V2SidedPlastic shader allows separate shading for each side of surface New VShadowedC
275. e name for the cache file Each call to bake3d adds a new point to the cache file specified by the filename parameter An arbitrary list of user supplied values is associated with each position and normal entry If no applicable normal is available the normal parameter should be set to 0 The channels parameter can be used to select a subset of the user supplied values to save to a file Each entry also has an associated radius that is automatically computed based on the location value P An optional radius parameter can be used to set an explicit radius value The optional radiusscale parameter acts as a multiplier for the associated radius Points can be added to an existing file by including an append parameter with a float value of 1 Example normal bent_normal color occ occlusion P Nf PI 2 bent_normal bake3d cachename P Nf occlusion occ bent_normal bent_normal j The collect can be used to bake values for points distributed over an entire surface By passing a maxsearchdistance of 0 to collect the normal automatic generation of a subsurface scattering cache can be suppressed See Also 3D textures texture3d collect Bake3d surface shader 10 15 4 blinn color blinn string category normal Nf vector V float eccentricity float rolloff The blinn function computes a specular highlight using the popular Blinn illumination model The eccentricity parameter between 0 and 1 determines the ove
276. e png to C image png As an aid to configuring directory mapping some basic debugging information can be enabled with the following option Option searchpath dirmapdebug 1 Simple RIB Filtering AIR provides a simple mechanism for disabling specific commands in a RIB stream Option render string commands cmd Option render string commands cmd The first statement disables the specified command the second statement re enables it Example To override the surface shader for every object in a RIB stream one could use Surface plastic 2001 2014 SiTex Graphics Inc Options 58 Option render commands Surface Air 14 extends simple command filtering to allow individual options and attributes to filtered with the following syntax Option render string commands Option name token Option render string commands Option name token Option render string commands Attribute name token Option render string commands Attribute name token Example Option occlusion prepass 0 disable occlusion prepass Option render commands Option occlusion prepass See Also RIB Filters 6 4 Shading Global Shading Rate Multiplier The frequency with which a surface is shaded is determined by the shading rate attribute The following option serves as a global multiplier for the shading rate property of all objects Option render float sh
277. e point being shaded and the incoming light is modulated by the opacity of any intervening objects To use ray traced shadows 1 Make objects that will cast shadows visible to shadow rays with Attribute visibility integer shadow 1 By default all objects are invisible to shadow rays 2 Enable shadow ray tracing for one or more lights Your plugin may provide a special control to enable ray traced shadows for a given light For custom light sources ray traced shadows can be enabled by providing the special shadow name raytrace LightSource spotlight 3 string shadowname raytrace This special name tells the renderer to cast shadow rays instead of looking for a shadow map Shadow Quality The quality of ray traced shadows can be improved by casting more shadow rays Most light shaders provide a shadowsamples parameter that sets the number of rays that are traced to compute the shadow value Shadow Acne and Shadow Bias Occasionally some objects may exhibit incorrect self shadowing usually visible as small random dark dots or shadow acne A light shader typically provides a shadowbias parameter to help prevent incorrect shadows by providing a small offset for the depth information in the shadow map Each primitive also has a bias attribute used for all ray tracing operations that can be set with Attribute trace float bias 0 01 Soft Shadows Most light shaders provide a shadowblur parameter that can be used to produ
278. e primitive Number of Vertices float nvx 0 meshinfo count vertices nvx Number of Faces float nfaces 0 meshinfo count faces nfaces 10 15 2 microcylinder color microcylinder string category normal Nf vector V vector T float ior float spread float isotropy float specularspread The microcylinder function implements a shading model for cloth threads based on the paper A Practical Microcylinder Appearance Model for Cloth Rendering by Sadeghi et al The returned value is the sum of light scattered through the volume of the microcylinder which can be used to modulate the base color of the thread The function also provides optional output variables with a specular component Input Parameters 2001 2014 SiTex Graphics Inc Shader Guide 298 Nf V T ior spread isotropy specularspread vectors normal vector vector f1 fl fl f1 oat oat oat oat array of vectors shading normal unit vector pointing away from the surface in the view direction tangent vector index of refraction of the material angle in radians for volume scattering extent to which volume scattering is isotropic range of 0 to 1 angle in radians for reflection at the microcylinder surface piece wise curved tube in the local coordinate system In the simplest case the microcylinder function returns the results for a single microcylinder with main axis parallel
279. e rays with the following attribute Attribute visibility integer trace 1 The plugin for your modeling package should provide a control for this property or translate the modeler s equivalent property Trace Bias Occasionally you may observe spots or other artifacts in ray traced reflections due to incorrect self intersection of a reflected ray with the reflecting object These artifacts can often be eliminated by providing a small bias used to offset each traced ray from its original position Attribute trace float bias 0 01 Note that the bias setting affects all ray tracing operations Blurry Reflections Most shaders supporting reflections have a ReflectionBlur or envblur parameter for producing blurry reflections Larger values produce blurrier reflections To reduce the noise in blurry reflections increase the number of reflection samples using the ReflectionSamples or envsamples parameter Maximum Ray Depth The maximum depth to which AIR will recursively trace rays for reflection and refraction is set with Option trace integer maxdepth 6 Reflected Background AIR provides options to specify a color or environment map used to color reflection rays that miss all objects ina scene A background color can be given with Option reflection color background 0 0 0 A background environment map can be declared with Option reflection string envname Option reflection float envstrength 1
280. e scale of the object E g a sphere with radius 100 would need an opacity value 01 times smaller to match the appearance of a sphere of radius 1 Unlike shader results for surface primitives there is no general expectation that the output color will be proportional to the output opacity with one exception if the output opacity is O the volume is transparent at this location the output color should be set to 0 Opacity Modulation for Different Ray Types To accelerate rendering AIR stores surface shader results in a 3D cache and only one set of values is stored at each shading location for all ray types AIR provides two custom attributes for modifying the base opacity stored in the shading cache independently for shadow rays and camera or reflection rays Attribute volume color shadowdensity 1 1 1 Attribute volume color viewdensity 1 1 1 Shader Optimization For volume primitives with complex opacity and self shadowing AIR often evaluates the surface shader twice at each shading location once for a shadow ray then a second time for a camera or reflection ray AIR provides a method of optimizing the second evaluation by supplying the opacity result from the first evaluation in the Oi global opacity variable If the shader is being executed for the first time at this location Oi is set to 1 A surface shader can test Oi and avoid recomputing an expensive opacity function if it has already been evaluated if co
281. e scene Tokens in the parameter list must have full inline type definitions 20 3 9 IrNewlmager C int IrNewImagerV IPR ipr char shadername int ntk char tk void ENII Text IrNewImager shadername parameter list This function replaces the current imager shader with a new one Tokens in the parameter list must have full inline type definitions 20 3 10 IrNewLight C int IrNewLightV IPR ipr char shadername char handle float xtransform int ntk char tk void v Text IrNewLight shadername handle matrix parameter list This call adds a new light to the scene Tokens in the parameter list must have full inline type definitions The transform parameter is a pointer to a matrix with the shader to world transformation Special Parameters float locallight 1 By default a new light illuminates all primitives in the scene If this parameter is present the new light illuminates only the currently selected primitives 20 3 11 IrNewSurface C int IrNewSurfaceV IPR ipr char shadername int ntk char tk void V Text IrNewSurface shadername parameter list This function assigns a new surface shader to the selected primitives Tokens in the parameter list must have full inline type definitions 20 3 12 IrOpacity C int IrOpacity IPR ipr float r float g float b 2001 2014 SiTex Graphics Inc TweakAir for Interactive Rendering 364 Text IrOpacity rgb This command changes the opacity attribute
282. e superior results Other values of maxerror give the maximum error allowed in an occlusion estimate before a new sample is generated The occlusion cache can be saved to a file with Option occlusion string savefile filename and later re used with Option occlusion string seedfile filename Re rendering with a seed file does not require ray tracing The occlusion cache can be saved to any of the 3D point file formats supported by Air For normal re rendering with a saved cache the Air Point Cloud format apc is recommended Occlusion Prepass Air supports an optional automatic pre pass that records occlusion samples for re use on a second pass resulting in a smoother final image The prepass is enabled with Option occlusion integer prepass 1 Air can use different quality settings on the prepass than the second pass Using higher quality parameters on the first pass results in a better final image A scaling factor for the maxerror and 2001 2014 SiTex Graphics Inc Lighting 328 maxpixeldist attributes is given by Option occlusion float prepassfactor 0 5 Normally you will not need to change this option Air 13 introduces a new option to force Air to wait until an indirect or occlusion prepass has finished before rendering the final pass Option render syncprepass 1 This option provides a solution in cases where a bucket has not finished computing in the prepass when it is
283. ecords 8 bit data A Display call to save 16 bit data would look like Display t pic_diffuse tif file rgb quantize 0 65535 0 65535 Multiple variables may also be saved to a single file by providing a comma separated list of output variables to a Display call For example Declare __ diffuse varying color Declare __specular varying color Declare __reflection varying color Display mp psd file rgba __diffuse __specular __reflection quantize 0 255 0 255 float 2 exposure 1 1 Only a few file formats support more than 4 channels of output The Photoshop TIFF and OpenEXR drivers can all save additional channels Disabling Gamma Correction Gamma correction should normally be disabled for an image being assembled in a compositing program You can do this by adding an Exposure command at the beginning of a scene file Exposure 1 1 or by adding the following parameter to a Display Call exposure 1 1 Both set gain and gamma correction to 1 Depth Pass AIR has a special option for selecting the range of depth values to be saved as part of a multipass render Option render float 2 zrange zmin zmax If zmin is not equal to zmax z depth values are scaled so that z is 0 at zmin and 1 at zmax and clamped to the range 0 1 By default AIR filters depth values by taking the minimum depth value in each pixel You can apply the same filtering used for color to depth values by setting t
284. ectangle Each coordinate should lie in the range 0 to 1 This switch is equivalent to the CropWindow call with the same coordinates q Forces the rendered image to appear in Air Show 2001 2014 SiTex Graphics Inc 17 AIR User Manual e filename Saves error messages and warnings to a file echoproc Echoes the output from any procedural RunPrograms to stdout echorif Echoes the output from any RI filters to stdout file imagenam Forces image output to the specified file This switch overrides any Display Call in the scene frames start end Restricts rendering to frames numbered between start and end inclusive AIR 8 and later will also use this range for expanding a frame number range in a RIB file name E g air frames 19 21 scene 4f rib would render scene0019 rib scene0020 rib and scene0021 rib g n Sets the default gamma indirect Enable object visibility to indirect rays ipp Enabled the indirect diffuse prepass mf n Sets the default value for GeometricApproximation motionfactor mode rgb rgba Selects the channels for output This setting may be overridden by a subsequent Display call nodisp Ignore suppress Displacement calls 2001 2014 SiTex Graphics Inc Geiting Started 18 noerror Ignore suppress all error and warning messages nosurf Ignore subsequent Surface calls The surface shader used wi
285. ected in AIR the framebuffer driver will automatically set the AIR Show gamma for that image to 1 no correction The gamma correction applied to an image by AIR Show is determined as follows 1 Ifan ATRSHOWGAMMA environment variable is defined that value is the default gamma otherwise the default gamma is 1 2 Ifa gamma factor is provided using the g command line option that gamma becomes the default for all images 3 Ifthe display driver call passed to AIR contains a float gamma variable that variable s value is used for that image only Applying gamma correction to an 8 bit image can result in banding artifacts If you plan to gamma correct in AIR Show and not in the renderer prior to quantization render 16 bit or floating point data to avoid banding To repeat a point mentioned above the gamma correction used by AIR Show for display purposes does not affect the image data that is saved sRGB The latest versions of AIR Show have a new option to apply sRGB gamma correction to an image with the corresponding toolbar button sRGB correction overrides any custom gamma defined for the image in AIR Show Image Background Images with an alpha channel can be displayed over a background image or pattern by toggling the background button in the AIR Show toolbar By default the background is a simple checked pattern Use the Load Background item in the View menu to load an image to use as the background for the current image M
286. ed Level of Detail e Improved automatic LOD for polygon meshes custom user data is now handled properly and edges and overall shape are better preserved Procedurals e A RunProgram procedural declaration may omit the bounding box in which case the procedural is evaluated immediately e The option to set the number of RunProgram threads has been converted to an attribute e RIB processing e Air BakeAir and TweakAir now define a user option with the renderer name e New directory mapping capability for translating path names depending on the rendering machine s environment Handles for Ob jectBegin and ObjectInstance can be strings instead of numbers RIB filters for Procedural now trap DelayedReadArchive procedurals Added limited support for ScopedCoordinateSystem converted to CoordinateSystem Archives can be found in the resource search path e Reorganized the processing of the RIB Option call e Shaders e Fix for VPlastic to avoid tracing reflections twice e Updated the bumpmap_polys displacement shader used by Massive to scale the bump amplitude so it is relative to a local coordinate system so scaling the agents also affects the bump amplitude e Updated MassiveAgents instancer shader e Messages e Missing shaders are only reported once e Missing textures are reported once instead of once per thread e Error message for a missing texture reports the shader containing the texture call e Errors in the RIB commands issued by an instan
287. ee Seed value for random variation The overall shape of the tree is determined by the TreeShape parameter which selects from among the following 8 basic tree shapes toT 0 cone 1 sphere 2 hemisphere 4 tapered 5 flame 6 inverse cylinder cone 3 cylinder 7 tend flame There overall size of the tree is determined by the trunk height given as an average TrunkHeight and an allowed variation TrunkHeightVary The actual height is chosen within that range based on the random Seed value Other size parameters for the trunk branches and twigs are given relative to the trunk height The only other absolute size parameter is the LeafSize value Trunk Parameter Default Value Range TrunkHeight 4 TrunkHeightVary 0 5 TrunkWidthRatio 0 04 TrunkWobble 0 1 TrunkBend 0 0 TrunkSurface VRubber TrunkColor iD 5 45 TrunkColorMap ue TrunkBumpMap a TrunkBump 0 1 TrunkTextureSize 11 TrunkCurveType tube Description Average trunk height Allowed variation in trunk height Ratio of trunk width at base to trunk height Random variation in trunk orientation angle range for bent trunk in degrees surface shader for trunk base surface color for trunk optional color map for trunk optional bump map for trunk bump amplitude texture map scale trunk curve type The trunk width at the base of the tree is computed by multiplying the trunk height by TrunkWidthRatio Trunk width at the top is the produce of the base width and TrunkTaper
288. eeeesseeeseeneseneneneeees IrTweakDisplaCemMent cccscecssseesssseeessneeessneeeesseeeeessneeeesseeeesseneeessnensasseeeesens IrTWeakENVironMe nt 0 cccccseeeeesseeeeseneeeeseneeessneeeesseeeessneeenseneseeseneeessnenensseeeesans Ir TWeAKIMAGE cccsceesseseerenenenenenceesseceenensnensnaceeesssneneneneeenaeessasenenenaneeenaceeeeanens IPT WOAKLIQNE E IT wWeakOptionn 2 csecccescccccss sctetsnces sectecsczecevescaecias schetsnces aaa andaa araoa aio raaraa IFT WO AKSUM ACE ised E E T E secede coteecnarsuted scucvanesseceseeasroveruca Ir WritelMage a BakeAir for Baking Textures and Meshes 2001 2014 SiTex Graphics Inc AIR User Manual a fF WN Part XXII OMAN OA RAON ee ee A OND oOo 15 Part XXIII N Oo oO fF WD a Part XXIV Baking Textures with BakeAir Baking PTEX Textures with BakeAir Writing Bake Aware Shaders Baking Meshes with BakeAir massrib Ambient Occlusion in Massive Maites Layers and Groups Automatic Level of Detail Rendering a Depth Pass Adding a background image Applications for Baked Textures Massive Rendering with AIR from Massive Command Line Rendering of Massive Scenes Display Customization and Multipass Rendering Shading and Lighting in Air Space Eliminating Shadow Artifacts on Terrain Rendering Massive Agents with Maya amp MayaMan Massive Agent Light Tool malt Rendering Massive Agents in Rhino Optimization
289. een processed Materials Air 14 includes a new material library for Air An Air material consists of the following e A surface shader that computes the output color and opacity for an object e Anoptional displacement shader that moves the surface to produce bump effects such as ripples gouges or engraving e An optional instancer shader that adds new entities to the scene near the base object e Attributes or per object properties that affect how an object is rendered such as the base color and opacity Each material is stored in a separate small text file with the extension amf You can use Air materials with most Air compatible programs including SketchAir RhinoAir and Air Space Standard Material Library The standard material library can be found in the materials directory of your Air installation The following material types are included Brick 2D brick procedural brick patterns in various common sizes DarkTrees Materials for the DarkTree procedural shaders included with Air Metals Shiny rough and brushed metals Many of the metal colors are specified using a color spectrum file Pavers Procedural paver patterns in common sizes Surfaces Materials for most of the surface shaders included with Air Textiles Various types of cloth velvet and leather Tile Clay and ceramic procedural tile pattern in common sizes Material Color A material file may define a specific color for the material or
290. een regions so that continuity is preserved for the displaced surface The maximum number of faces per region can be set with Option limits integer splitpolyfaces 25 Automatic Level of Detail AIR 7 and later can automatically reduce the number of polygons in a polygon mesh based on an object s on screen size and other factors Automatic LOD applies only to polygon mesh primitives Enable automatic level of detail for an object with the following custom attribute Attribute render float autolod n where n gives an error tolerance when simplifying a model Reasonable values to try are 0 1 to 0 3 A level of 0 disables automatic LOD Automatic LOD is also influenced by the flatness attribute GeometricApproximation flatness 0 5 which gives the maximum difference in pixels between the original surface and the simplified surface The default flatness value is 0 5 A value of 1 or 2 will produce smaller final meshes A reasonable set of values to start with are Attribute render float autolod 0 2 GeometricApproximation flatness 1 Subdivision Surfaces AIR supports Catmull Clark subdivision surfaces with holes and creases Creases Semi sharp creases are implemented using a new linear crease subdivision algorithm and AIR adds a new linearcrease tag to provide direct control of crease sharpness The linearcrease tag uses the same syntax as the standard crease tag Linear crease values should lie between 0 no
291. efesucvesiguacssezeeees 79 BD nEared a EE E sei A E EAE E E E E E E E N E EE E 81 2001 2014 SiTex Graphics Inc AIR User Manual 2D Patterns 3D to 2D Projections Coordinate Spate Sarisin naranasan aaae bAa ara AKDA Eara danced dei stand NAA eraen EAA Ea Asaa 82 2 DISPIACOMONG is scnces sccs ces oy chee edec awe ce aa 83 Displacement Shaders sin iiis iioii daraa niare oasi r sinara peidied ara parii r asao digia aeae A Saa adasa poidan 86 b mpy gesessen araea arap ra aae aeea aaa a E apaa eae ee aar a SEAE ESE Ee riaa aaae SE daara Naca sadap eSE 88 DarkTreeDisplaceMent sisirin iostan sious ra biesas ia aaner a tatara aaay p Enara a aesaad AAS cate shueevendetcescdsveutevieycenceetee 88 OceanWaves secseeeeee VBrickGrooves bdeli elate liol nk ae e E E E E E E E E E 92 VCracks VDents VDimples VHammered VNicks VNorimal ET o a E E E TEE E E AE E E NA 96 VPIIOWS Sisececcedecseecelececech teceneetcecctecetccenecesedeveus cecetestecicie ctbeceuersieceunes deceeuetecccts sbiccauessiecesecscececeaes dices sedeccueseueistectt 96 MRIDDCG E EE E S E E cpsced sciuuasuce T sues cbesctesueyeadesncyocrductbuxsudecenadevaasuesecucstdscnend 96 VRIPPIOS cccccedcecedscccescdccces finia feirar Sancra nndeb drda aandra r Adara a An raas seteecestecdesenevgeucesecessceucedceceescocessergentsnccesecnys 97 bA aee o E EEEE E E cece EEEE E T E E A E E E E E 98 VTangentNormalMap w 98 VText redBUMP ae e aere ra e
292. efine one or more maps to bake file name data values map size and image quality e Choose a point of view in light of its effect on tessellation 2001 2014 SiTex Graphics Inc 369 AIR User Manual e Select the texture coordinates used for indexing the bake maps e Assign one or more bake maps to each primitive Displays as Texture Maps The Display command defines a new texture map to be rendered with the current scene Display name driver data float 2 exposure gain gamma float 4 quantize zero one min max string coordinatesytem name The new display inherits the current Format PixelSamples PixelFilter Exposure and Quantize settings Note that pixel filter pixel sampling and shading rate settings all behave as one would expect when baking For example PixelFilter gaussian 2 2 PixelSamples 2 2 ShadingRate 0 5 results in 4 samples per texel to anti alias facet edges in texture space and 2 shading samples per texel to anti alias shading processed with a gaussian filter with a width of 2 in x and y in texture space Any data value supported by Air can be baked to a texture map including the standard rgb and rgba outputs global variables and any output variable from a surface or displacement shader When baking the global position P and and shading normal N BakeAir recognizes an additional string coordinatesystem display parameter that specifies the coordinate syst
293. eflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup ScatterDistanceSc 0 3 Multiplier for ScatterDistance N 1 0 1 0 1 0 Average scatter distance for r g b SubsurfReflectanc 0 9 0 9 0 9 Diffuse reflectance indexOtRetraction 1 3 Index of refraction SampleDistanceOv i Maximum distance between erride subsurface samples or 1 for default MarblePatternSize 0 4 Size of one marble layer MarbleVeinColor 0 0 0 0 0 2 Color of marble veins MarbleSharpness 0 5 0 0 1 0 Sharpness of transition MarbleVeinFraction 0 4 0 0 1 0 Vein fraction of each layer MarbleTurbulence 0 5 Amount of turbulence to apply MarbleAxis 3 100 Axis perpendicular to marble layers MarbleFilterWidth 1 0 Filter width multiplier MarbleSpace shader spaces Coordinate space for shading calculations Description The VTranslucentMarble shader simulates translucent marble using subsurface scattering with the same marble pattern as the VMarble shader See Also Subsurface scattering VTranslucent shader 10 10 8 VWatercolor surface shader for watercolor painting 2001 2014 SiTex Graphics Inc Shader Guide 270 IIlumination Model diffuse Features texture map Parameter Default Value Range Description Diffuse 0 7 0 0 1 0 Diffuse reflectivity ltemVaryHue 0 0 0 0 1 0 Per item variation in color hue ltemVarySaturation O 1 Per item variation in c
294. eflectionSpace current spaces Coordinate space for reflection lookup TextureSizexY LL Size of texture map in X and Y TextureOriginXY 0 0 Position of left top corner TextureAngle 0 0 Rotation angle in degrees ColorMapName me Color map name ColorMapBlur 0 0 Color map blur SpecularMapName ae Specular map name SpecularMapBlur 0 0 Specular map blur OpacityMapName Opacity map name OpacityMapBlur 0 0 Opacity map blur BumpMax 0 0 Bump amplitude multiplier BumpSpace shader space in which to measure displacement BumpMapName iii Bump map name BumpMapBlur 0 0 Bump map blur Projection st Projection to use for 2D coordinates ProjectionSpace shader Coordinate space for projection Transform 1000 Transformation applied prior to 0100 projection 0010 000 1 2001 2014 SiTex Graphics Inc 253 AIR User Manual Description This shader produces a reflective plastic surface with separate texture maps to control the surface color opacity and specularity or shininess An additional texture map is provided for bump mapping All maps use the same texture coordinates See Also V2SidedPlastic shader VDecal2DPlastic shader VDecal3DPlastic shader 10 10 6 VRubber as rubber IIlumination model rough matte with specular Features texture maps Parameter Default Value Diffuse 0 6 DiffuseRoughness 0 8 Specular 0 5 SpecularRoughness 0 2 ColorMapName ColorMapBlur 0 0 SpecularMapName mn SpecularMap
295. egory lensflare Light category __nondiffuse 0 0 1 If 1 light is excluded from diffuse light _nonspecular 0 0 1 If 1 light will not produce highlights foglight 1 0 1 If 1 light illuminates volumes _ channel 0 9 Output channel Description The pointlight shader emits light in all directions from the source point from Light Intensity The emitted light value is the product of the intensity and lightcolor parameters and an attenuation factor determined by the falloff parameter The falloff parameter allows the light s intensity to diminish with distance from the light A falloff value of 2 which is physically accurate reduces the incident light value by the square of the distance from the light Cl intensity lightcolor Distance Distance Although a falloff of 2 is physically correct it can produce very large intensity values at locations close to the light source The maxemission parameter can be used to set the maximum emitted intensity regardless of distance from the light source Alternatively a falloff value of 0 produces no attenuation with distance which may be easier to control Traced Shadows 2001 2014 SiTex Graphics Inc 145 AIR User Manual If the shadowname parameter is set to the special value rayt race shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace The shadowblur parameter gives an angle in rad
296. elberg Vileshin describe a method of improving the accuracy of RGB rendering without the performance degradation associated with full spectral rendering Their spectral prefiltering technique is based on a few simple observations 1 Direct lighting results are the most important for overall image accuracy Most scenes have a single dominant illuminant There may be many light sources but most tend to share the same spectral profile 3 Scenes with spectrally distinct light sources cannot be properly white balanced and will look wrong no matter how accurately the colors are computed These observations suggest the following prefiltering algorithm We apply a standard CIE formula to compute the reflected XYZ color of each surface under the dominant illuminant then transform this to a white balanced RGB color space for rendering and display The dominant sources are then replaced by white sources of equal intensity and other source colors are modified to account for this adaptation By construction the renderer gets the exact answer for the dominant direct component and a reasonably close approximation for other sources and higher order components In Air spectral prefiltering is enabled by using the following option to specify the dominant illuminant for 2001 2014 SiTex Graphics Inc 27 AIR User Manual the scene Option render string dominantilluminant_spd Lights with the same spectrum as the dominan
297. em in which to save the baked data The default is current space world and object spaces are also supported Point of View and Tessellation The camera defined for a conventional rendering of a scene is used by the baker to control adaptive tessellation of curved surfaces just as in a conventional rendering Since the baker produces texture maps not images of primitives you can often get by with a much coarser tessellation when baking A coarser tessellation will use less memory and render more quickly The standard way to decrease tessellation density is by increasing the flatness attribute setting from the default value of 0 5 GeometricApproximation flatness 1 Texture Coordinates for Baking The texture coordinates used for baking are specified with a custom attribute Attribute bake string coordinates st Possible values are st uv or any user defined varying vertex or facevarying variable of type float 2 Alternatively texture coordinates may be supplied as two arrays of floats Attribute bake string xcoordinate u0 Attribute bake string ycoordinate v0 2001 2014 SiTex Graphics Inc BakeAir for Baking Textures and Meshes 370 The texture coordinates used for baking should map primitives into the unit square in texture space More than one primitive may bake into the same map but no two points on any surface should share the same texture coordinates in a single m
298. en an object s shading is evaluated AIR provides independent control over the sampling of geometry and shading This is an important capability for many scenes rendering time is dominated by shading calculations With AIR you can increase the sampling of a scene s geometry to smooth out jagged edges without increasing the number of shading calculations that are performed Topics Geometry Sampling Shader Sampling Anti Aliasing Pixel Filters Clamp to Alpha Field Rendering Hidden Surface Methods Geometry Sampling The frequency with which scene geometry is sampled is determined by the PixelSamples setting PixelSamples xsamp ysamp which defines a xsamp by ysamp grid used to sample the scene at each pixel Use more pixel samples to smooth out jagged edges due to inadequate sampling of scene geometry Because geometric sampling is independent of shader sampling increasing the number of pixel samples will not usually result in a large increase in rendering time Sub pixel Edge Mask AIR provides another means of anti aliasing jagged edges If the following option is enabled Option render integer edgemask 1 AIR will compute a high resolution sub pixel edge mask at each pixel sample to better approximate the area covered by each surface The edge mask is particularly effective at anti aliasing nearly horizontal and nearly vertical edges as well as capturing very small objects Using a sub pixel edge mask can significantly slow down the
299. enabled TweakAIR will reshade an object whenever a reflected object s shading changes Automatic reflection updates will adversely affect the overall IPR refresh rate Geometric Anti aliasing Option ipr integer 2 pixelsamples 1 1 This option sets the number of pixel samples to use during IPR rendering Currently the only supported values are 1 1 and 44 Using more pixel samples can have a significant impact on re rendering time to the additional shading samples that are usually required TweakAIR Attributes Use the following attributes to tune the performance of TweakAIR Shading Attribute ipr string shading shade This attribute allows shading to optimized during an IPR session without affecting shading during a final render Supported types are 2001 2014 SiTex Graphics Inc TweakAir for Interactive Rendering 360 20 3 matte shade object using a simple fast matte shader relight optimize shading for re lighting shade shade object using its assigned surface shader The relight mode provides fast re rendering for even complex surface shaders with the following properties The surface shader must use only builtin illumination statements diffuse specular phong or blinn l e no custom illuminance loops The surface shader must provide __ diffuse and __ specular output variables TweakAlR is able to decouple lighting computations from surface shader evaluation for surface shaders that
300. enabled to generate sub pixel coverage information The deepimage hider has one optional parameter Hider deepimage boolean culloccluded 1 When culloccluded is enabled Air omits fragments that are completely hidden by surfaces nearer the camera Air includes a deep image display driver that stores deep image data in a simple text file Use the deeptxt file name extension to select the deep image display driver Hider deepimage culloccluded 0 Display test deeptxt file rgbaz subpixelweight quantize 0 0 0 0 Deep image data can also be saved to any standard image format as a series of layers Just include an extra deeplayer parameter in the Display declaration specifying the depth layer to record E g Hider deepimage culloccluded 0 Display layerO tif file rgbaz float depthlayer 0 Display tlayerl tif file rgbaz float depthlayer 1 Display tlayer2 tif file rgbaz float depthlayer 2 An image with no transparent surfaces will have at most 16 fragments or layers per pixel Air provides two additional output variables for deep images e A float subpixelweight variable gives the contribution of the current fragment to the final pixel value To reconstruct a final pixel value from a fragment list take the sum of the product of each fragment and its sub pixel weight 2001 2014 SiTex Graphics Inc Output 42 e A float subpixelmask variab
301. endering performance e Linux builds of Air now detect Python and Perl scripts and automatically invoke the corresponding helper application Texture maps e Unconverted textures are now loaded once and shared by all threads instead of being loaded separately by each thread Converting all textures to Air s texture format is still recommended for optimal rendering Subsurface scattering SSS e Subsurface cache generation is now multithreaded which can greatly accelerate SSS rendering Multithreading for cache generation is enabled by default It can be disabled with Option render integer sssmultithread 0 2001 2014 SiTex Graphics Inc 437 AIR User Manual e The subsurfacescatter function now handles varying parameter values properly However using a varying mean diffuse path reflectance or ior will be much slower When using varying parameters the max sample distance should be explicitly set to produce consistent results Use as large a max sample distance as feasible to save render time e SSS memory usage has been reduced by 20 Polygon meshes e Much more efficient rendering of quad meshes with mesh displacement e Mesh displacement on polygon meshes now applies the same normal correction code as the default displacement method e The split mesh attribute now works with polygon meshes There is a new option for the max number of faces in each sub mesh Option limits integer splitpolyface
302. endering process priority on Windows New _ threshold tag for blobbies 2001 2014 SiTex Graphics Inc 459 AIR User Manual Anew SAIRHOME usershaders directory in the AIR home directory included in the default search path has been added to provide a location for custom shaders that are not part of the standard AIR distribution Anew SAIRHOME procedurals directory is in the default procedural search path ArchivelInstance will now attempt to create an instance from an archive file if an existing instance is not found For shadeop DSOs AIR now looks for a DLL with an abbreviated name E g for shadeop MyTest AIR will look for MyTest d1l11 MyTes d1ll1 MyTe d11 and MyT d11 in that order Basic texture statistics are now reported in the stats output Faster ambient occlusion about 5 The gather instruction now accepts a distribution parameter that specifies the distribution of samples either uniform or cosine New shaders VGlass VSkin VTexturedBump VTranslucent VTranslucentMarble A link to Massive has been added to the Plugins and Companions page Bug fixes e Fix for a rare condition in blobbies Fix for user attributes and Procedural primitives Fix for case where a freed prim was queried for its motion position Fixed token handling for Procedural DelayedLoad DLLs e e e e Fixed bug where displaced surfaces were incorrectly culled 2001 2014 SiTex Graphics Inc
303. ents and changes e Much faster rendering of area lights with indirect illumination e New improved sampling pattern when rendering without an irradiance cache e The default indirect maxerror attribute value is now 0 which disables irradiance caching Better shadow maps with new options to tune depth values stored with the default midpoint depth filter New method for a shader to query if an output variable needs to be computed for display float saved 0 option display varname saved Sets saved to 1 if varname is being saved in an image New option to enable progress reporting equivalent to the Progress command line switch Option statistics integer progress 1 2001 2014 SiTex Graphics Inc History 448 Multisegment motion blur no long blurs when the shutter interval is 0 and an appropriate intermediate position is interpolated based on the shutter open time Vertex motion blur with all motion times the same now uses the first time position without blurring Array arguments are now supported in dynamic shade ops Support for vertex transform blur for dynamic blob ops without an ImplicitMotion function Primitives with constant user data no longer generate a unique shader instance per primitive AIR is able to share shader instances across primitives in more cases e Most AIR surface shaders have a new __constant output variable with the unlit surface color The shadowpass shader has a new bac
304. ents in the rib stream which means that massrib generates the agents before the options have been set To work around this problem massrib includes a massopt command line option that can be used to provide option information which massrib will use to initialize the procedural primitive To find the Massive procedural options look at the bottom of the main scene rib for a line that looks like Procedural RunProgram run_program exe options motion_blur off render_pass beauty air 2250 06 2249 94 262 813 281 777 2250 36 2249 64 The second string enclosed in quotes contains the options Pass that entire string including the quotes to massrib with massopt massrib massopt options motion_blur off render_pass beauty air render 0000 rib The options should be the same for every frame in a sequence By default massrib will look for the procedural primitive in usr local massive bin If Massive is installed in a different location include a procpath option prior to the massopt option with the path to the Massive procedural Additional Command Options ascii By default massrib produces a rib file in binary format for compactness Use ascii to generate a plain text rib file mapdir olddir newdir This option allows path and file references in the source scene to be remapped For example with the following massrib invocation massrib mapdir usr local texture i textur a reference in the source rib file to u
305. ep sea color result is emitted as an incandescence value and simply added to the other shading components When Transmission is not 0 refraction rays are traced to capture objects beneath the water The transmission result can be faded out based on distance if the TransmissionFalloff value is non zero Waves The companion OceanWaves displacement shader computes waves by evaluating a simulation In order for foam to appear in the proper location the common parameters between the OceanWaves and OceanSurfaceWithFoam shaders must be set to the same values The wave simulation is evaluated on a discrete grid which is mapped to the unit interval in texture space X corresponds to the first texture coordinate Y to the second coordinates The GridCountX and GridCountY parameters give the grid size A larger grid produces more detail but takes longer to compute SizeX and SizeY give the nominal size of the ocean area The waves can be tiled in X and Y WindSpeed gives the average wind speed Higher values produce larger waves WindDir can be used to change the wind direction by providing an angle in degrees about the vertical axis WindAlign controls how much the wind direction influences the wave directions by applying an exponent to the dot product of the wind direction and the direction of each wave Larger values reduce the amplitude of waves not in the direction of the wind base on the Dampen factor Chop 2001 2014 SiTex Graphics Inc
306. er allows the light s intensity to diminish with distance from the light A falloff value of 2 which is physically accurate reduces the incident light value by the square of the distance from the light Cl intensity lightcolor Distance Distance Although a falloff of 2 is physically correct it can produce very large intensity values at locations close to the light source The maxemission parameter can be used to set the maximum emitted intensity 2001 2014 SiTex Graphics Inc Shader Guide 154 regardless of distance from the light source Alternatively a falloff value of 0 produces no attenuation with distance which may be easier to control The emitted light also varies based on the angle between the shading location and the cone axis The beamdistribution parameter gives an exponent that is applied to the cosine of the angle The light intensity smoothly fades to 0 as the angle ranges from coneangle conedeltaangle to coneangle Traced Shadows If the shadowname parameter is set to the special value rayt race shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace The shadowblur parameter gives an angle in radians to distribute the rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to restrict shadow casting to the specified list of group
307. er ellipse somewhere in between wedge and hedg define a fuzzy region along the edges of the light shearx and sheary can be used to shear the light cone beamdistribution controls the falloff in intensity with angle from the central axis A value of 0 results in constant intensity across the light A value of 1 is physically correct for a spotlight A value of 2 matches the default behavior the spotlight shader Cookie or Slide The light can optionally project a texture map like a slide if a slidename is provided Fake Blocker Shadows The blocker parameters can be used to define a superellipse that casts fake shadows blockercoords gives a coordinate space for the blocker which should be defined in the scene file using CoordinateSystem Blockerwidth and blockerheight give the dimensions of the blocker which is defined to lie on the x y plane of the blocker coordinate system Blockerwedge blockerhedge and blockerround define the shape of the superellipse in the same manner as the corresponding parameters for the light shape Traced Shadows If the shadowname parameter is set to the special value raytrace shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace The shadowblur parameter gives an angle in radians to distribute the rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing Shadow mapped Shadows Assign the
308. er now accepts a comma separated list of channels for baking multiple maps Each channel is baked to a separate map Non standard channel names should include inline type declarations e AIR Control accepts command line file name as default scene new control for command line options passed to the renderer drag and drop support from Windows Explorer e Vortex Allows more than 16 workers Looks for max number of workers in a VORTEX_MAXWORKERS environment variable 2001 2014 SiTex Graphics Inc History 442 e Vshade 3 TweakAIR support new improved parameter list preview image size can be set to viewport drag and drop support from Windows Explorer mktex texture converter new compositing operations new info switch to display basic image information ch option supports a range of channels to extract improved cube face environment map conversion supersampling output to any supported display driver support for other output options new fov option new buffering when writing an AIR texture file greatly improves performance when writing to a network drive from Windows Bug fixes AIR quits if a vortex connection is refused instead of waiting on stdin Fix for sqrt range check Fix to allow instancers in inline archives AIR now clamps umin umax vmin and vmax to the valid range for NURB patches Fix for image scaling when FrameAspectRatio is set Point maps are now closed after rendering c
309. er shader creating a 2D array of objects on a surface Parameter CountX CountY Archive Scale ScaleVary JitterX JitterY Offset RotatexYZ RotateVary ColorMap Seed Default Value 10 10 we 0 0 0 0 0 0 0 0 0 593 Range Description Copies of archive in X direction Copies of archive in Y direction RIB archive file name Uniform scale applied to archive instances Per item variation in scaling Variation in X position Variation in Y position Translation applied to archive X Y Z rotation in degrees for archive Per item variation in rotation angles Optional color map Random seed for position variation The VArrayOnSurface instancer creates instances of a RIB archive in a 2D array over a surface using standard texture coordinates If no Archive name is supplied the shader places a small sphere at each instance location VExtrude instancer that extrudes curves or points along a straight line Parameter Distance Direction Default Value Range 1 100 Description Distance to extrude Extrusion direction 2001 2014 SiTex Graphics Inc 123 AIR User Manual 10 6 7 VGrowFur 10 6 8 grows short fur on a surface Parameter Default Value Range Density 200 Clumps 100 Width 0 01 LengthMax 0 2 LengthMin 0 15 LengthMap mn LengthVaryFreque 5 ncy TiltMin 0 90 to 90 TiltMax 20 90 to 90 TiltVaryFrequency 22 Twist 360 FurColor 222 15 01 FurRootCol
310. er the agents are missing or just lacking illumination Statistics 2001 2014 SiTex Graphics Inc 377 AIR User Manual 22 3 Rendering statistics can be enabled with stats air stats scene rib Rendering Multiple Frames AIR 8 allows a frame sequence to be rendered with simple frame number substitution For example air frames 8 10 scene f rib would render scene8 rib scene9 rib and scenel0 rib The frame number pattern can also be zero padded air frames 8 10 scene 3f rib would render scene008 rib scene009 rib and scene010 rib See Also Command Line Switches Display Customization and Multipass Rendering The output image or images generated by a rendering are defined by one or more Display callsina scene file The Render dialog in Massive allows you to set up a single Display call that will generate an 8 bit image with 4 channel output rgba This standard output can be customized and enhanced with the use of additional rib commands in an auxilliary text file that is passed to the renderer prior to the main scene file Quantization for the Main Display The output data type for the main display call can be changed from 8 bit to 16 bit or floating point using the Quantize rib command For 16 bit data quant16 rib Quantize rgb 65535 0 65535 0 5 Quantize rgba 65535 0 65535 0 5 For floating point data quanttfloat rib Quantize rgb 0 0 0 0 Quantize rgba 0 0 0 0 A sample command to re
311. erID must be set by an output variable from a surface shader Because the identifier may have been pre scaled for other purposes the RPF driver provides an optional Display parameter for re scaling the input value float materialidmultiplier 1 Object Identifier __gBufferlD This identifier will saves a 16 bit channel with a per object number The __gBufferlD must be set by an output variable from a surface shader Because the identifier may have been pre scaled for other purposes the RPF driver provides an optional Display parameter for re scaling the input value float objectidmultiplier 255 5 7 12 tga Targa Description saves images in Targa file format File extension tga Channels rgb rgba Data types 8 bit unsigned integer File data uncompressed 2001 2014 SiTex Graphics Inc 49 AIR User Manual 5 7 13 5 7 14 tiff Tag Image File Format Description saves images in Tag Image File Format File extension tif Channels up to 32 channels Data types 8 16 or 32 bit signed or unsigned integer IEEE single precision floating point File data compressed or uncompressed Parameters String description text Stores an optional description of the image String compression type Type is one of none packbits or 1zw By default no compression is used On Linux the tiff driver uses the libtiff library installed on the system which may or may not support Izw compressi
312. erWeight Reference Values In Principles of Digital Image Synthesis Glassner presents values for several common types of scattering summarized in the table below Type Examples PrimaryWeight PrimaryScatter SecondScatter Rayleigh dust cigarette smoke 0 5 0 46 0 46 Hazy Mie sparse water droplets fog 0 12 0 50 0 70 Murky Mie dense droplets thick fog 0 19 0 65 0 91 See Also Volume Primitives 10 10 2 plastic standard plastic surface shader Ilumination Model plastic Parameter Default Value Range Description Ka 1 0 0 0 1 0 Ambient reflectivity Kd 0 5 0 0 1 0 Diffuse reflectivity Ks 0 5 0 0 1 0 Specular reflectivity roughness 0 1 0 01 1 0 Specular roughness specularcolor 1 11 Specular highlight color Description The shader simulates a colored plastic surface with a usually white shiny specular highlight The base surface color is taken from the primitive s color attribute 2001 2014 SiTex Graphics Inc Shader Guide 206 The roughness parameter controls the size of the specular highlight larger roughness values produce larger highlights See Also VPlastic shader V2SidedPlastic shader VBrushedPlastic shader 10 10 2 ReelSmartMotion surface shader that computes a motion vector for the ReelSmart Motion Blur plugin from RE Vision Effects Inc www revisionfx com Parameter Default Value Range Description MaxDisplace 32 Max pixel distance that can be stored TargetSpace raster s
313. erate volume primitives should be tagged with the following attribute Attribute visibility integer volume 1 19 Pipeline Workflow and Optimization 2001 2014 SiTex Graphics Inc 355 AIR User Manual 19 1 19 2 Conditional RIB Syntax IfBegin condition ElseIf condition Else IfEnd Conditional RIB statements allow sections of RIB to be enabled or disabled based on an expression The expression may including tests on user defined options and attributes For example Attribute user string pass beauty IfBegin Suser pass shadow Surface constant ElseIf Suser pass beauty Surface vmarble Else Surface matte IfEnd RIB Filters AIR 6 and later provide a filter plugin capability for modifying the stream of RIB commands before they are processed by the renderer The current filter is defined using the following attribute Attribute render string rifilter filtername argl arg2 AIR will search the procedural search path for the filter program Because the current filter is an attribute a filter can easily be applied to only a subsection of a scene say just the Massive agents For example to replace the surface shader assigned to a group of objects one might use the following RIB snippit AttributeBegin Surface occlusionpass Attribute render string rifilter cullrib Surface ReadArchive agents rib AttributeEnd No
314. ered e Check Save to File and choose a file name with a psd extension Set Channels to rgba and Precision to 16 bit preferably or 8 bit Set Image gamma to 1 The composited image can always be gamma corrected in Photoshop Check Extra Output Channels and in single image Select the channels to save Here are some common combinations Diffuse Specular Reflections Unshadowed Shadows Specular Reflections if the scene has no indirect lighting Unshadowed Shadows Indirect Specular Reflections e Click the green render button You can also preview the layered image in AIR Show by checking Display in AIR Show and then save itas apsd file Set the AIR Show viewing gamma to the same gamma you will later apply to the composited image the AIR Show gamma doesn t affect the raw image data RIB Commands for Creating a Layered PSD File Declare __diffuse varying color Declare __specular varying color Declare __reflection varying color Exposure 1 1 Display mp psd file rgba __diffuse __specular __reflection quantize 0 255 0 255 All layers should be of type color except for AIR s special __toonline output variable which the driver recognizes as a single float ptx PTEX Description saves multiple images as a PTEX per face texture file File extension ptx Channels unlimited Data types 8 bit 16 bit half float File data compressed Parameters float half 1 2001 2014 SiTex Graphics
315. ersion when appropriate See Also Lighting 10 7 1 ambientlight RenderMan standard ambient light shader 2001 2014 SiTex Graphics Inc 127 AIR User Manual 10 7 2 Parameter intensity lightcolor Description Default Value 1 0 111 Range Description Light intensity Light color The ambient light shader simply sets the emitted light value to the product of the intensity and lightcolor parameters arealight arealight_baked area light shader for general area lights Parameter intensity lightcolor lightcolor_spd maxemission coneangle falloff shadowname shadowbias shadowcolor shadowgroups shadowattribute __nondiffuse __nonspecular __ foglight __ channel Description Default Value 1 0 111 wo 1 57 0 0 1 5 2 0 raytrace 0 01 000 we user shadowgroups 0 0 0 0 1 0 i 0 9 Range Description Light intensity Light color Light color spectrum file If greater than 0 the maximum emitted light intensity including falloff Angle for emitted light range Exponent for falloff in light intensity with distance Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes
316. es the color attribute of the selected primitives 20 3 3 IrDeleteLight C int IrDeleteLight IPR ipr char handle Text IrDelete handle The IrDeleteLight command deletes the light corresponding to the specified handle 20 3 4 IrEnd C void IrEnd IPR ipr Text IrEnd This call terminates the interactive rendering session 20 3 5 Irllluminate C int IrIlluminate IPR ipr char handle int on Text IrIlluminate handle 0 1 Use this command to turn the specified light on 1 or off 0 for selected objects 20 3 6 IrLightTransform C int IrLightTransform IPR ipr char handle float transform Text IrLightTransform handle matrix This function sets the shader to world transformation matrix for the indicated light In the C call the transform parameter should point to an array of 16 floats 20 3 7 IrNewDisplacement C int IrNewDisplacementV IPR ipr char shadername int ntk char tk void v Text IrNewDisplacement shadername parameter list This function assigns a new displacement shader to the selected primitives Tokens in the parameter 2001 2014 SiTex Graphics Inc 363 AIR User Manual list must have full inline type definitions 20 3 8 IrNewEnvironment C int IrNewEnvironmentV IPR ipr char shadername int ntk char tk void v Text IrNewEnvironment shadername parameter list This function assigns a new environment shader to th
317. es with Option indirect environmentcache 1 Using the cache typically produces smoother results with shorter rendering times If no environment shader is defined the returned color is based on the following legacy options The default returned color is set with Option indirect color background 0 0 0 Alternatively the background can be defined using an environment map specified with the following options Option indirect string envname Option indirect float envstrength 1 0 Option indirect float envblur 0 0 Option indirect integer envsamples 4 Option indirect string envspace 2001 2014 SiTex Graphics Inc 325 AIR User Manual 13 4 Radiosity Cache Air 13 introduces a new radiosity cache that accelerates indirect lighting computations by storing and reusing the shading results for indiret ray hits The cache can be enabled on a per object basis with the following atttribute Attribute indirect radiositycache 1 When enabled Air stores the result of shading each indirect ray hit with the associated polygon If that polygon is hit by another indirect ray the saved shading result is re used instead of evaluating the shaders at the new hit point By default one indirect shading sample is stored with each polygon Large polygons can be shaded more accurately by setting a max size for each indirect shading sample with Option indirect radiositysize n
318. eshes Air 11 introduces a new mode for BakeAir that allows shading computations to be baked to mesh vertices and exported in various file formats See Also PTEX Per Face Texture Mapping 2001 2014 SiTex Graphics Inc BakeAir for Baking Textures and Meshes 368 21 1 Applications for Baked Textures This section lists a few of the applications for BakeAIR organized into three broad categories accelerating software rendering baking maps for hardware rendering and geometric manipulation Examples refer to the bakeexamples directory of the BakeAIR distribution Accelerating Software Rendering BakeAIR can be used to accelerate software re rendering with a renderer such as AIR by baking information that does not change from frame to frame or shot to shot Baked data can include e diffuse illumination e diffuse color pattern e indirect lighting e occlusion e shadows Examples The occlusion output and gourds directories contain examples of using baked data to accelerate software re rendering Baking Maps for Hardware Rendering Most recent graphics hardware supports real time rendering with texture maps BakeAIR can be used to prepare maps for a real time 3D engine for use in games or for visualization for product design architecture and production planning BakeAIR can produce maps containing final shading results color patterns bump maps normal maps light maps or maps to modulate any other shading p
319. ess Light Intensity The emitted light value is the product of the intensity and lightcolor parameters and an attenuation factor determined by the falloff parameter The falloff parameter allows the light s intensity to diminish with distance from the light A falloff value of 2 which is physically accurate reduces the incident light value by the square of the distance from the light Cl intensity lightcolor Distance Distance Although a falloff of 2 is physically correct it can produce very large intensity values at locations close to the light source The maxemission parameter can be used to set the maximum emitted intensity regardless of distance from the light source Alternatively a falloff value of 0 produces no attenuation with distance which may be easier to control The emitted light also varies based on the angle between the shading location and the cone axis The beamdistribution parameter gives an exponent that is applied to the cosine of the angle The light intensity smoothly fades to 0 as the angle ranges from coneangle conedeltaangle to coneangle Traced Shadows If the shadowname parameter is set to the special value rayt race shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace 2001 2014 SiTex Graphics Inc 157 AIR User Manual 10 7 21 The shadowblur parameter gives an angle in radians to distribute t
320. etry export Attribute render string meshfile filename When baking meshes you will typically want to export RIB files The values to be saved at each vertex are specified as a comma separated list Attribute render string meshoutput list of outputs Each vertex value is formatted as destination source where destination is the variable declaration that will appear in the output file and source is a declaration defining the data source Supported sources are any output variable from a surface or displacement shader and the global Ci color variable The default output list is Attribute render string meshoutput varying color Cs varying color ci For meshes exported in PLY format the Cs output variable is emitted as per vertex color values with red green amp blue channel labels An vertex variable can also reference a component of a shader output parameter e g Attribute render meshoutput float prim_occ Ci 0 By default a mesh will always include normal N and texture coordinate st data You can exclude one or more primitive variables from the exported mesh with Attribute render string meshexclude list of ids 2001 2014 SiTex Graphics Inc 373 AIR User Manual 22 Tessellation When baking a mesh you may wish to use the new edge length attribute introduced in BakeAir 11 to help control the density of the exported mesh gives the max edge length in the tessellated
321. etting the bound for an instancer shader Attribute instancerbound float sphere n This replaces the use of the displacement bound attribute for instancer shaders Air s builtin simple command filtering can now filter individual attributes and options Frame number formatting in image file names now supports no zero padding which is now the default if no padding digit is provided Under Windows the TIFF image readers have been updated to support JPEG and deflate compression Under Windows 32 bit Air is now limited to a maximum of 32 rendering threads to avoid a compiler bug New OpenEXR display driver for 64 bit Air under Windows e Bug fixes 64 bit Air bug when rendering with more than 32 threads Fix for TweakAir rendering with an Imager shader Fix for str_replace_last_number DSO function Fix for SimpleMetal SimplePlastic VPhysicalPlastic and VPhysicalMetal shaders to provide correct per light channels Fix to prevent raw texture color conversion from being incorrectly applied to Air texture maps in some cases Surface displacement and atmosphere shader declarations instanced with an inline archive are now passed through any relevant rib filter plugin Fix for separate s t texture data on convex polygon meshes with more than 4 sides on some faces Fix for diffuse so all output options supported for Oren Nayer shading Fix for solar to avoid illuminating a location that is back facing when adjacent locations are lit
322. ew OceanSurface and OceanSurfaceWithFoam shaders for oceans New BakedSurface surface shader for rendering with baked illumination maps New genQueryBakedMap generic shader for querying baked maps 2001 2014 SiTex Graphics Inc History 430 New genUserAttributes generic shader for querying color or float user attributes New genUV generic shader emits standard u v coordinates for use in Maya New genTextureUV generic shader queries a texture map using u v coordinates New instMultipleArchives instancer shader for instancing multiple archives The portallight shader has been updated to sample the global environment by default All indirect and envlight shaders have been updated to include indirect in the __ category parameter Updated VinstanceArchive shader with parameters for rotation and for converting color or float prim vars to user attributes which can be queried by a shader attached to an instanced object A new ArchivelsSimple parameter can be used to disable use of a temporary inline archive for instancing which doesn t work with archives created by RhinoAir that contain Rhino blocks The VCarPaint shader has new controls for metallic flakes The sunlight and envPhysicalSky shaders have new parameters to explicitly set the sun position The VBackdrop imager shader now supports an image sequence The VArrayOnSurface instancer shader has new parameters to vary scale and rotation for each item Shading Language
323. exture map for base color Texture blur Texture map for specular color Texture blur 2001 2014 SiTex Graphics Inc Shader Guide 230 OpacityMapName OpacityMapBlur BumpMax BumpMapName BumpMapBlur TextureSizexY TextureOriginXY TextureAngle Projection ProjectionSpace ProjectionTransform TopDecalName TopDecalOrigin 2 TopDecalSize 2 TopDecalColor SecondDecalName SecondDecalOrigin 2 SecondDecalSize 2 SecondDecalColor ThirdDecalName ThirdDecalOrigin 2 ThirdDecalSize 2 ThirdDecalColor Description shader 1 0 0 0 st 0 1 0 0 we 0 0 1 0 0 0 1 0 S aces Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection Decal file name Location of top left decal corner Width and height of decal Decal color Decal file name Location of top left decal corner Width and height of decal Decal color Decal file name Location of top left decal corner Width and height of decal Decal color This plastic shader provides a base texture map with up to 3 decals on top The decals and texture map are positioned using the object s standard texture coordinates 10 10 4 VDecal3D reflective plast
324. f the Air home directory to the PATH e Define an AIRHOME environment variable that points to the Air home directory on the server e Ifthe RLM license file is not in the bin directory of the Air installation create a SITEX_LICENSE environment variable with the port and host name of the license server in the format port hostname For example 2192 MYSERVER The port number is the last number on the HOST line in the RLM license file Separate Installation for Each Machine In this approach Air is installed separately on each machine After installing Air each client machine must be configured to find the license server by defining a SITEX_LICENSE environment variable with the port and host name of the license server in the format port hostname For example 2192 MYSERVER The port number is the last number on the HOST line in the RLM license file 1 2 Gamma Correction It is important to view rendered images with proper gamma correction for the display device When rendering to the Air Show window use the sRGB button to view a linear image with sRGB gamma correction For more information on color conversion for Air see the Color section of this document 2001 2014 SiTex Graphics Inc 15 AIR User Manual 1 3 Rendering The easiest way to render with Air is use one of the many plugins available for popular modeling and animation programs A plugin will provide a render button or command that
325. fects An occlusion map is basically just a collection of individual shadow maps The key difference from an ordinary shadow map or a cube face shadow map is that an occlusion map query returns the combined shadow results for all the shadow maps Querying an occlusion map created with shadow maps from a range of directions around an object can be used to estimate ambient occlusion Creating an Occlusion Map Method 1 Combine multiple depth maps into an occlusion map with the RIB MakeShadow command 2001 2014 SiTex Graphics Inc 329 AIR User Manual 13 4 3 MakeShadow sShadowl z shadow2 z shadow3 z sShadow4 z shadowN z occlusion sm Method 2 An occlusion map can be built incrementally using the append parameter of the AIR shadow display driver The first shadow map is rendered with a Display call such as Display occlusion sm shadow z Subsequent shadow maps use Display occlusion sm shadow z float append 1 to add to the occlusion map Using an Occlusion Map The occlusion function accepts an occlusion map as the first parameter The optional bias blur and samples parameters function as they do for a shadow map The envlight and occlusionpass Shaders included with AIR both work with occlusion maps For example to add an environment light with an occlusion map you might use LightSource envlight 9 string mapname occlusion sm When using an occlusion map
326. fficiency and flexibility of image creation by rendering different attributes of a scene as separate images Rendering in passes allows the final image to be created by combining and fine tuning individual passes in a compositing program in real time without the need to re render Air can produce multiple images from a single render recording arbitrary output values created by a surface shader permitting multipass rendering to be accomplished with a single invocation of the renderer Most of the surface shaders included with Air have extra output variables containing a breakdown of the emitted color into the following components Name Description _ ambient ambient color _ diffuse diffuse color _ specular specular color __ reflect reflected color __refract refracted color __environment reflected background color __incandescence self illuminated color constant unlit color All the above variables are of type color Most surface shaders only export a few of these variables E g a surface without reflections obviously has no need to export a reflection output variable Many shaders further break down the diffuse component into 3 parts Name Description __diffuse_unshadowed unshadowed direct lighting __diffuse_shadow shadowed portion of direct lighting __indirect indirect lighting The 3 passes above can be combined to produce a diffuse layer in a compositing program __ diffuse __diffuse_unshadowed __diffuse_shadow __indirect
327. file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows Credits Original shader coded by Larry Gritz based on Ronen Barzel s paper Lighting Controls for Computer Cinematography in Journal of Graphics Tools vol 2 no 1 1 20 Procedures AIR 8 introduces a new procedure shader type for generating new primitives on demand at render time An instance of a procedure shader is created with the new RIB Procedure Call 2001 2014 SiTex Graphics Inc Shader Guide 168 10 8 1 10 8 2 Procedure shadername minx maxx miny maxy minz maxz parameter list The array of 6 floats after the shader name gives a bounding box in object space encompassing all objects that will be created by the procedure shader If and when AIR encounters the bounding box during rendering the procedure shader will be executed and the resulting objects inserted into the scene Writing Procedure Shaders A procedure shader creates new geometry by emitting RIB commands using the new ri
328. files in one of two formats LIF shader information files used by the RhinoMan PaxRendus and Liquid plugins and dialog scripts for use with Houdini 2001 2014 SiTex Graphics Inc Tools 410 Usage makelif options source Options 0o outputdir output directory for created files ds create Houdini dialog scripts 5pad create SPDL files for Softimage surf surface shaders only disp displacement shaders only Light light shaders only vol volume shaders only MakeLIF reads compiled AIR shader s1b files and VShade source vs1 files The source parameter may be a wildcard pattern Creating Houdini Dialog Scripts When a Houdini dialog script is created makelif prints a line to the console for adding the dialog to Houdini To make the dialog available in Houdini add the line to the SATRHOME houdini shop SHOPsurface file for surface shaders or to the SHOPlight SHOPdisplace or SHOPfog files for light displacement and volume shaders respectively After modifying the SHOP file you will need to re start Houdini or reload the dialogs in Houdini with dsreload before the dialog will appear Technical note MakeLIF uses the dictionary 1if file in SATRHOME viztools as well as some builtin heuristics to produce a help file for a shader 24 5 Shading Compiler shaded Before shaders can be used they must be compiled using the shading compiler shaded If you are using a plugin the plugin may autom
329. float Set quantization to floating point for rgb and rgba output as well as any channels specified in the mode option reflect Enable object visibility to reflection rays Shorthand for Attribute visibility integer trace 1 res width height Sets the resolution of the rendered image This option overrides any subsequent Format call in the RIB stream If height is omitted a square image is rendered rif rifiltername args Define a default RIB filter plugin for the scene rows Use row tile order samples xsamples ysamples Sets the size of the array of geometry samples per pixel This option overrides any subsequent PixelSamples Call shadows Enables object visibilty to shadow rays Shorthand for Attribute visibility integer transmission 1 showpath Print the full path name for each resource as it is loaded silent Suppresses the progress report when rendering spiral Use spiral tile order stats 2001 2014 SiTex Graphics Inc Geiting Started 20 Print statistics for the rendered scene surf shadername Overrides all surface shaders with the provided shader Shader parameters can be set by including a comma separated list air surf plastic Kd 1 Ks 0 myscene rib Only float and string type parameters are supported step n Specifies an increment to use when rendering animation frames For example if step 2 every other frame will be
330. for all three images and the geometric edges are smooth in all of them Understanding the difference between geometric sampling and shading sampling and the relation between the two is key to generating nice anti aliased images In particular increasing the number of pixel samples will not in itself alleviate aliasing in the shading On the other hand increasing pixel samples to deal with jagged edges doesn t incur any additional shading cost Micropolygon Shading AIR 9 introduces a new method of shading surfaces enabled with Attribute shade integer mode 1 The new mode breaks surfaces into small polygons sometimes called micropolygons for shading with each micropolygon covering approximately the area in pixels specified by the shading rate This new mode may produce smoother images for highly reflective surfaces and may produce smoother results in slow motion animation Anti Aliasing The section describes how to eliminate common sources of aliasing in rendered images Jagged Edges Try one or more of the following suggestions e Increase the number of PixelSamples e Use a smooth PixelFilter with a wide filter width such as PixelFilter gaussian 2 2 e Enable the sub pixel edge mask Option render integer edgemask 1 Shading Aliasing Shading can introduce aliasing from a procedural pattern specular highlights small bumps shadow edges and other sources The simplest way to improve shading quality is to increase the num
331. formation about the falloff in light intensity with distance which can be set with the optional falloff parameter The default value is 2 The optional samples parameter gives the number of rays used to sample the area light If the area light geometry is two sided light will be cast from both sides of the surface if the area light primitive is single sided light is cast from the front facing side as determined by the orientation 2001 2014 SiTex Graphics Inc 285 AIR User Manual areashadow is amore efficient way to render area lights than methods that rely on supersampling a light because it avoids multiple passes through the light shader and the corresponding illuminance loops The function is however only an approximation It works best on convex light shapes disks rectangles and other convex polygons spheres etc For complex shapes better results may be obtained by decomposing the shape into simpler sub shapes which are each defined as a separate area light 10 15 3 bake3d bake3d string filename string channels point P normal N float radius radius float radiusscale radiusscale token value Bake3d generates a 3D point cache with an arbitrary list of per point values A cache file created with bake3d can be queried with texture3d If a cache file is generated with the collect statement it can be read during the same rendering used to create it The first parameter gives the fil
332. frame automatically If opentime lt closetime AIR will blur the appearance of moving objects described using motion blocks To calculate the position of objects for motion blur AIR records the position of objects at the open and close times and linearly interpolates between those positions for intermediate times The smoothness of motion blur depends directly on the number of pixel samples used AIR employs brute force supersampling for motion blur The number of copies created of each object is currently set by the total number of pixel samples The copies are scan converted and averaged to produce a motion blurred image More samples produce smoother blur but also take longer to render The shutter for a typical motion picture camera is open about half the time between frames You may wish to set the shutter times for animation to mimic that behavior Motion blur typically requires a large number of samples 8 x 8 or higher to achieve good results Multi segment Motion Blur AIR supports multi segment vertex and transformation motion blur with up to 32 time values AIR ignores the time values and uniformly interpolates among the supplied transformation or vertex values Ray Tracing Motion Blur Ray tracing results will include motion blur for primitives that have the following attribute set Attribute trace integer motionblur 1 Motion blur is supported by caustics as well as the shading language functions environment shadow
333. from a command shell and then type update commands E g tweakair myscene rib IrColor 110 change all objects to yellow IrNewSurface VMetal change all surface shaders to metal IrWriteImage gold tif IrEnd You may need to press the Enter key twice after each command to send it to the rendering process A more flexible means of sending updates is to pipe a text file with commands to the standard input stream tweakair myscene rib lt myupdates txt An example of this method can be found in SATRHOME examples tweakair Error Handling Most calls return a non zero error code if the call fails Pretty much the only reason for failure is that the communication link with TweakAIR has been broken in most cases because the TweakAIR instance has been shutdown by the user In the event of an error an application should call IrEnd to free the IPR structure and terminate the current IPR session IrBegin IPR IrBegin char cmdline This call starts an interactive rendering session TweakAIR is started with the provided scene file The 2001 2014 SiTex Graphics Inc TweakAir for Interactive Rendering 362 call returns a pointer to an IR session that should be used as the first parameter for all IR functions The IR library supports multiple simultaneous interactive sessions 20 3 2 IrColor Ce int IrColor IPR ipr float r float g float b Text IrColor rgb The IrColor command chang
334. from multiple cameras in a single rendering pass Rendering stereo pairs is one possible application of this capability Stereo rendering requires two modifications to a typical RIB scene file 1 Define an additional world to camera space transformation for the alternate viewpoint using the new Camera rib command 2 Assign the alternate camera to at least one Display call with the new string camera extra parameter Here s a simple example Display left tif framebuffer rgba Display right tif framebuffer rgba string camera right Projection perspective fov 11 6855 TransformBegin ConcatTransform transform for right view Camera right TransformEnd ConcatTransform transform for left view WorldBegin A Display call with a camera parameter may appear before the definition of the camera transformation Each bucket is rendered once per camera so with two cameras each bucket will be rendered twice Unlike some other stereo rendering implementations view dependent shading computations will be correct for every camera and no shader modifications are required There should be at least one Display call for each camera including the main or default camera The current implementation assumes that all cameras have approximately the same view of the scene Using cameras with very different points of view may produce unexpected results and degrade performance Air Show 5 has a ne
335. fuse path can be calculated from the reduced scattering sigma_s and absorption coefficients sigma_a mdf 1 sqrt 3 sigma_s sigma sigma_a reflectance is the average diffuse reflectance maxsampledist is the maximum distance between samples in the point cloud If maxsampledist is less than 0 AIR will automatically calculate the distance based on the meandiffusepath and reflectance values This parameter is provided to allow users to override the default behavior Real world values for meandiffusepath and reflectance can be found in Jensen et al A Practical Model for Subsurface Light Transport in the SIGGRAPH 2001 Proceedings When subsurfacescatter is first called AIR generates a set of points covering all surfaces in the point set Each point is shaded by querying its shaders with a ray type of collector points are shaded on the outside of the surface as determined by the current orientation A shader should test for evaluation by a collector ray and return the irradiance to be stored in the point cloud For example string raytype rayinfo type raytype if raytype collector raytype photon Ci Cs Ka ambient Kd diffuse Nf else Ci Oi subsurfacescatter P Nf SSDistance SSDistanceScale SSReflectance IndexOfRefraction SSSampleDistance Ks specular Nf normalize I roughness Sample shaders that use subsurfacescatter include VSkin VIranslucent and VTransluce
336. g features that depend on ray tracing and or the ray tracing extensions supported by AIR E g ifdef RAYTRACE fulltrace P R Crefl hitdist Phit Nhit Pmiss Rmiss endif Some shaders conditionally include ray tracing features based on the symbol BMRT To compile such shaders for AIR use the Dsym option For example air DBMRT glass s l Shader Info slbtell Usage slbtell obi shader slb SLBTell prints a list of all parameters for a compiled shader Using redirection the output can be saved and included in a RIB file If the o option is specified the output is in a format similar to that used by the BMRT program slctell If the i option is included any parameters of type integer will be declared as such By default integer parameters are declared as float for backwards compatibility If the b option is included any parameters of type boolean will be declared as such By default boolean parameters are declared as float for backwards compatibility 2001 2014 SiTex Graphics Inc Tools 412 24 7 Texture Converter mktex Mktex is the command line texture conversion utiltiy provided with AIR The primary purpose of mktex is to convert source images to the special formats AIR uses for texture environment and shadow maps mktex is also useful as a general purpose utility for converting between a variety of image and data formats mktex is a command line utility that is normall
337. g this shader because the preview render can take a long time e Set the SizeX and SizeY parameters to the width and length of the carpet rectangle SizeX gives the size along the first texture coordinate axis SizeY the size along the second texture coordinate axis Set StrandLength to the length of the carpet fibers which should be less than or equal to the height of the polygon above the floor That completes the the required steps to use the FakeCarpet shader You should then be able to render a test image of your scene and see some carpet Carpet Shape The carpet is modeled as a grid of carpet fibers The geometric model of the fibers can be tuned using the following parameters StrandCount StrandWidthFraction The overall density of the fibers is set with StrandCount which gives the number of fibers per unit length The diameter of a fiber is given by the StrandWidthFraction parameter as a fraction of the fiber length StrandTiltAngle StrandTiltVary StrandTiltFrequency StrandStiffness StrandPolarAngle StrandPolarVary StrandPolarFrequency Individual fibers are represented as curved tubes StrandTiltAngle gives the average angle in degrees between the vertical direction and the tip of a fiber The tilt angle can be varied for each fiber using StrandTiltVary and StrandTiltFrequency StrandTiltFrequency is relative to the entire patch of carpet StrandStiffness controls how each fiber bends Higher values push the curve more toward
338. g to a mid range grey Middle Grey the output value for the middel luminance between 0 and 1 Maximum Luminance the input luminance value that should be mapped to 1 The tone mapping operator is inspired by the zone system in photography First the image luminance is scaled linearly to map the Middle Luminance value to the Middle Grey output value The dynamic range is then non linearly compressed so that the maximum luminance value is mapped to 1 If the maximum luminance parameter value is less than the maximum luminance in the image sections of the image will appear overexposed For speed Air Show and the ToneMap shader use an approximation that in some cases can produce output values that are still greater than 1 The ClampToAlpha parameter in the ToneMap imager shader can be used to ensure that all output values are less than or equal to 1 Image Quality High quality images require the elimination of aliasing artifacts in an image due to undersampling some aspect of the scene AIR provides extensive support for fine tuning the sampling in a scene The following three commands that determine overall image quality e The PixelSamples option determines how often the scene s geometry is sampled 2001 2014 SiTex Graphics Inc 29 AIR User Manual 4 1 4 2 e The PixelFilter option determines how individual pixel samples are combined into the final pixel color e The ShadingRate attribute determines how oft
339. ge one row at a time currently limited to TIFF BMP and PSD formats This option can drastically reduce the amount of memory needed to convert large images fromsrgb tosrgb Convert the image from or to SRGB color space 2001 2014 SiTex Graphics Inc Tools 414 24 7 2 24 7 3 24 7 4 resize up down round none Controls how an image is resized when converted to an Air texture map The default resize mode rounds each dimension to the nearest power of 2 If the resize mode is set to down each dimension is reduced to the next lower power of 2 When resize mode is set to up the next higher power of 2 is used Here are the corresponding output values for a 640x480 input image round 512x512 down 512x256 up 1024x512 none 640x480 Sample Use mktex smode periodic tmode clamp grid tif grid tx Creates a texture file that is periodic in the first texture coordinate and clamps the second texture coordinate Shadow Maps Make an AIR shadow map from one or more depth maps with mktex shadow zfilel zfile2 outfile Up to 6 depth maps may be combined into a single shadow map All depth maps should have the same dimensions Multiple maps are useful for adding shadows to a source such as a point light that illuminates a wide range of directions When accessing a shadow map with multiple depth maps the renderer will use the first map whose viewing frustum contains the point being sampled Maps whose
340. gents to restrict occlusion testing to just the agents 3 Assign the massive_occlusionpass shader to the agents leaving the shadowgroups parameter with its default empty value so all objects occlude the agents See Also 2001 2014 SiTex Graphics Inc 385 AIR User Manual 22 7 Ambient occlusion Mattes Layers and Groups This note describes two methods of rendering mattes for Massive scenes with AIR as well as an extension of the second method for rendering by layers or groups A Simple RGB Matte Shader The AIR distribution includes a very simple surface shader called rgomatte for rendering an rgb matte pass in Massive Since Massive does not allow an object s base color to be changed on a per pass basis this shader provides parameters for directly setting the output red green and blue channels This shader is about as simple as a surface shader can get surface rgbmatte float r 0 float g 0 float b 0 Oi 1 Ci color r g b Rendering Mattes using Groups AIR allows any object to be assigned to one or more groups Include an object in a group with Attribute grouping string membership mygroupname The objects which appear in each output image can be restricted to members of particular groups by providing a string subset parameter with a list of groups in a Display call Only objects in the listed groups will appear in the display image other objects will be treated as matte objects for th
341. ghting to a model See the separate Air Space User Manual for more information Windows only Air texture baking tool 64 bit bakeair binary under Windows Command line tool for creating help files for shaders Interactive tool for creating and editing Air material files See the separate Air Material Editor User Manual for more information Interactive tool for editing materials as a post process See the separate Retexture User Manual for more information Windows only Compiler used to compile shaders for use with Air Command line tool for querying the parameters of a compiled shader Command line texture conversion tool User interface for mktex Interactive version of air Distributed rendering tool Visual interface for building shaders See the separate Vshade User Manual for more information Air Control is a simple user interface and render queue for rendering scene files with Air Air Control also accepts rendering jobs submitted from the companion airq batch render command To render a single frame 2001 2014 SiTex Graphics Inc Tools 400 24 2 e Enter the RIB file name in the Scene control or click the button to the right to display a dialog for choosing a RIB file e Set the number of threads to use for rendering Note that the Air demo is limited to a single thread e f Low priority process is checked the rendering process will run at a lower Windows priority minimizing the impact
342. ginXY TextureAngle DisplacementSpace Description 10 2 20 VWeaveDisplacement Default Value O 1 t5 0 5 shader 1 displacement shader for a weave pattern Range 0 0 10 00 150 Description Multiplier for displacement values Copies in X direction Fractional gap between each column Amplitude for wavy pattern Cross sectional rounding Copies in Y direction Fractional gap between rows Amplitude for wavy pattern Cross sectional rounding Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees space for displacement The VWeaveDisplacement shader generates a large scale woven pattern on a surface This shader 2001 2014 SiTex Graphics Inc 101 AIR User Manual 10 3 may be usefully used in conjunction with the VWeave surface shader See Also VWeave surface shader Environments Air 11 introduces a new environment shader type for shading rays that miss all objects in the scene There is one environment shader or shader network for the entire scene The current environment shader is set with a new RIB Environment command Environment shadername parameter list As an option the Environment statement must appear before WorldBegin in the RIB stream Additional environment shaders can be added to the current environment shader list by prepending the shader name with a Environment Shader Evaluation The current enviro
343. gress report or statistics silentstats Statistics but no progress report Identifier Retention Air normally discards names to save memory and permit better sharing of attributes among primitives Some shaders however require name information to work properly When this option is enabled Air will save identifier names so they can be queried by a shader Option render integer savenames 1 A name can be assigned to a primitive with the following attribute Attribute identifier string name name Memory Use The maximum memory the renderer may use can be set with Option limits memory n gives the upper limit in megabytes If memory use exceeds the limit the rendering will be aborted By default there is no upper limit 6 2 Search Paths Option searchpath string texture SATRHOME texture Option searchpath string archive SAITRHOME archives Option sSearchpath string shader SAITRHOME usershaders SAIRHOME shaders Option searchpath string display SAIRHOME displays Option searchpath string procedural SATRHOME procedurals Option searchpath string spectrum SATRHOME spectra Option searchpath string resource These options set the search path for texture files archive files shader files display drivers and procedural primitives respectively The resource search path is searched for any resource not found in 2001 2014 SiTex Graphics I
344. group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Shadow mapped Shadows Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows 10 7 22 sun_window_light light shader for sun shining through a window 2001 2014 SiTex Graphics Inc Shader Guide 160 Parameter intensity lightcolor use_sun_color turbidity date_month date_day date_hour latitude_longitude time_zone animate_hour animate_time_scale override_zenith override_azimuth coord_sys y_is_up coord_sys_north_angle coord_sys_right_handed shadowname shadowbias shadowblur shadowsamples shadowcolor shadowgroups shadowattribute Default Value 1 47 45 122 3 we 1 0 11
345. guage function 10 10 14massive_occlusionpass surface shader for rendering an ambient occlusion pass with Massive Parameter Default Value Range Description coneangle 1 57 Half angle for cone of directions to sample invert 0 When set to 1 the output value is inverted samples 256 rays to trace to estimate occlusion maxhitdist 500 max distance to search for occluding objects shadowbias O 1 offset to prevent incorrect self shadowing Description The massive_occlusionpass surface shader sets the output color to the ambient occlusion value at the surface location The average unoccluded direction is emitted in the Nunoccl output variable Output only variables 2001 2014 SiTex Graphics Inc Shader Guide 198 normal Nunoccl Average unoccluded direction See Also Ambient occlusion envlight light shader Ambient occlusion in Massive 10 10 1 matte 1 standard matte surface shader Illumination Model matte Parameter Default Value Range Description Ka 1 0 0 0 1 0 Ambient reflectivity Kd 0 0 0 1 0 Diffuse reflectivity Description The shader simulates a flat or matte shaded surface The surface color is taken from the object s color attribute For a matte surface with a texture map use the VClay shader with the Dif fuseRoughness parameter set to 0 See Also VClay surface shader 10 10 1tmetal 4 simple metal shader with no reflections Illumination Model metal Parameter Default
346. hader name of the second and later imagers with a Multiple imager shaders will be executed in the order in which they were declared 2001 2014 SiTex Graphics Inc Shader Guide 110 background constant background color LensFlarelmager adds lens flares to the output image r Paper rough paper effect using a bump map b sRGB applies sRGB gamma correction ToneMap tone mapping for HDR images VBackDrop texture mapped background VBgEnvironment environment mapped background VBgGradient 2 color vertical background gradient VGreyscale convert output color to grey level WatercolorPaper add watercolor paper effects Bead 10 5 1 background sets the image background color Parameter Default Value Range Description background 0 0 0 background color for image Description The background imager shader simply sets the color of all unrendered pixels to the color of the 2001 2014 SiTex Graphics Inc 111 AIR User Manual 10 5 2 background parameter The output alpha value is also set to 1 Unlike all other shaders the background shader is internal to AIR and cannot be modified LensFlarelmager imager shader that adds lens flare effects Parameter Default Value Range Description Intensity 1 overall intensity scale for flare effects BloomIntensity 0 4 Intensity multiplier for bloom effect BloomRadius 0 1 Nominal radius of bloom spot BloomPoints 13 Number of points in bl
347. hado Cs diffuse_shado wed diffuse_un wed diffuse_unsh shadowed adowed 0 0 0 0 1 0 1 0 or 1 0 or 1 Description Switch to enable baking 1 or reading 0 Name of 3D texture to read or write Channels to bake Max distance between shading samples if baking with collect Blur distance to add to query region Multipler for sample region size Whether to use the surface normal when baking or reading the map If 1 ensure that the shading or query normal is forward facing The Bake3d surface shader shows how to bake diffuse illumination to a 3D texture and reuse baked data for accelerated rendering Baking The Bake3d shader creates a 3D texture map named BakeMap when the Bake parameter is set to 1 The point map format is based on the file name extension In most cases the Air Point Map format extension apm is the most efficient format for storing and accessing 3D data Bake3d supports two methods of sampling a surface during baking Image based sampling When the BakeRadius parameter is 0 the default the shader simply records every shading sample to the bake map as the image is rendered Only those parts of the object visible in the image will have shading samples recorded Surfaces that are nearly parallel to the camera direction will be more sparsely sampled than those that are nearly perpendicular to the camera Multiple threads can write to the same point cloud in this mode The baked point cloud cannot b
348. have parameters for the tile size tile color and grout width By altering the default values for a shader s parameters you can create a variety of different looks from a single shader Creating Shaders AIR shaders are written in the industry standard RenderMan shading language AIR ships with a visual tool for creating shaders called Vshade Even if you are not a programmer you can easily create shaders with Vshade See the separate Vshade documentation for tutorials and hints on building your own shaders Why do many AIR shader names begin with V A shader name prefixed with an upper case V indicates that the shader was created with the Vshade shader creator included with AIR You can find the source code for these shaders in the vshaders subdirectory of your AIR installation The source code can serve as a good starting point for building your own customized version of a shader See Also Shading Language Extensions Layered Shaders and Shader Networks Common Shader Features DarkTree Shaders Common Shader Features Topics Illumination Models 3D Patterns 2D Patterns 3D to 2D Projections Coordinate Spaces illumination Models An illumination model that describes what happens to light that strikes the surface whether it is reflected transmitted absorbed or some combination of all three Most AIR surface shaders incorporate one of the following illumination models Matte A matte surface uniformly scatters incoming ligh
349. he diffuse color unlike plastics which typically have white highlights regardless of the diffuse surface color Polished metals often exhibit coherent reflections Most metal shaders do not apply Fresnel effects to metallic reflections varying the reflection strength based on viewing angle because the Fresnel phenomenon is much less noticable for metals Reflections are typically tinted by the same color as the diffuse and specular components Clay The clay illumination model is a more general type of matte illumination model AIR s shaders use the model for rough surfaces developed by Michael Oren and Shree Nayar in their SIGGRAPH 94 paper This model adds a diffuse roughness parameter to the basic matte illumination model When the roughness value is 0 the clay model produces the same results as the matte illumination model Larger values of roughness cause the surface to act more as retroreflector reflecting light coming from the same direction as the viewer in a manner that does not depend on the orientation of the surface The general effect is to make objects look flatter compared to a simple matte illumination model Ceramic The ceramic illumination model is useful for glossy or wet surfaces This model is similar to the plastic 2001 2014 SiTex Graphics Inc 81 AIR User Manual 10 1 2 10 1 3 10 1 4 model with the addition of a Sharpness parameter that controls the edge of the specular highlig
350. he distribution 2001 2014 SiTex Graphics Inc 447 AIR User Manual 29 8 AIR 6 0 New user manual section with tips for rendering Massive scenes New massrib tool for manipulating Massive scenes RIB filters Adaptive motion blur New shading compiler optimizations can reduce initial code size by a factor of 3 or more for complex shaders generated by MayaMan Runtime performance is also improved New bake3d and texture3d shading functions for general point set caching and filtering New implicit surface primitive for rendering grid data as an isosurface The Reprise License Manager RLM is now supported in addition to AIR s cilver license manager Mesh displacement is now supported for polygon meshes and NURB surfaces New attribute to simplify facevarying data on polygon meshes New attribute to apply additional smoothing to displaced normals New options to cache texture maps locally for improved performance with textures stored ona network drive Overlapping volume primitives are now handled properly Occlusion improvements e New improved sampling pattern when rendering without the occlusion cache e New intermediate screen space cache when maxerror gt 0 and maxpixeldist 0 e Better performance with multiple reflection samples and no occlusion cache e Occlusion can be used with any light source with a shadow name parameter by setting the parameter value to occlusion Indirect illumination improvem
351. he filter option Option render string zfilter normal 2001 2014 SiTex Graphics Inc Output 38 5 2 5 3 Example A sample RIB file for rendering multiple passes can be found in SATRHOME examples multipass Rendering in Layers Rendering in layers refers to the process of rendering different elements or objects in a scene as separate images which are used to assemble the final image in a 2D compositing or paint program Beginning with version 5 Air supports rendering multiple layers in a single rendering pass by allowing user selection of the objects that appear in each output image using groups Specify the objects visible in a given Display call by providing a string subset parameter with a list of groups Display background tif file rgb string subset ground tree Only objects in the listed groups will appear in the display image other objects will be treated as matte objects for this image only A matte for a set of objects can be generated by rendering an alpha channel for the group Display matte tif file a string subset tree Air 11 and later allow a separate group to be specified for each output variable in a multichannel file by providing a comma separated list of groups as the subset value For example Display all tif file rgba rgba rgba string subset terrain agents An empty entry in the list of groups corresponds to no group subset The above Dis
352. he following options apply to importance based rendering Option trace float minweight 0 01 gives a minimum weight below which ray tracing will stop AIR fades trace results near the threshold to help avoid popping artifacts This optimization can be very effective in scenes with many levels of interreflection Option trace float reducesamples 0 1 gives a weight threshold below which Air will begin reducing the quality of shadow and reflection results Shader Writing and Importance Specifying Importance A shader is responsible for passing importance information to the renderer The importance or weight of a ray is specified by providing a color weight parameter to a trace environment or shadow function call In a surface shader that supports reflections the weight of the trace or environment should be the total multiplier applied to the traced results E g if the reflection component calculation were color Crefl Kr BaseColor trace P R an updated version with a weight parameter might look like color weight Kr BaseColor color Crefl weight trace P R weight weight In a light shader with a shadow call the shadow weight should be the unshadowed output color from the light E g Cl intensity lightcolor L L color inshadow 0 if shadowname inshadow shadow shadowname Ps samples shadowsamples blur shadowblur bias shadowbias weight Cl Query
353. he instancer shader automatically sets the indirect shading mode to constant for the carpet fibers so if they are struck by an indirect ray they simply return the fiber color multiplied by IndirectStrength If IndirectSamples is greater than 0 it gives the number of rays to trace for indirect lighting The instancer automatically sets the indirect maxerror value to 0 to disable use of an indirect or occlusion cache ExportT extureCoordinates When ExportTextureCoordinates is set to 1 each fiber inherits the texture coordinates of its root position on the base polygon See Also VShadeCarpet surface shader FakeCarpet surface shader instMultipleArchives particle instancer for multiple archives Parameter Default Value Range ArchiveName nu Archivelndex 0 ArchivelndexPrimVar ue Scale 1 ScaleByWidth 1 0 or 1 ApplyMotionBlur 0 Oor1 ApplyColor 0 Oor1 XAngle 0 XAnglePrimvar a YAngle 0 YAnglePrimVar ma ZAngle 0 ZAnglePrimVar mu PrimVarToAttribute1 sas PrimVarToAttribute2 ve PrimVarToAttribute3 Sa PrimVarToAttribute4 uii PrimVarToAttribute5 T PrimVarToAttribute6 me Description File name for one of the numbered archive files Index for archive file name If specified a primitive variable holding an index value for each vertex Uniform scale applied to archive instances When non zero scale archive by point width When non zero apply translation motion blur When non zero apply vertex color to archive Rotation about X
354. he object will not receive shadows Shadow mapped Shadows 2001 2014 SiTex Graphics Inc 137 AIR User Manual 10 7 9 Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow color __unshadowed_Cl Shadow value envlight envlight_baked environment light using ambient occlusion Parameter intensity lightcolor sampleenvironmen t samplelikediffuse envmap envspace envsamples envblur mapname mapblur mapbias maxsolidangle shadowcolor shadowgroups _ Category __nonspecular ___foglight __indirectlight _ channel Default Value 1 0 1 1 1 0 we world 64 0 5 raytrace 0 01 0 01 indirect Range Oor1 Oor 1 spaces 0 0 1 0 Emitted illumination without shadows Description Light intensity Light color When enabled the scene environment is sampled for unoccluded rays and the envmap value is ignored When enabled the environment is sampled using a lambert braf producing a result more similar to indirect diffuse lighting Optional environment map fo
355. he rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Shadow mapped Shadows Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows spot_window_light spot_window_light shader for shining light through a paned window Parameter
356. hedir Option netcache integer cachesize 1000 Option netcache integer debug 0 Baking Option bake integer 2 bucketsize 64 64 Option bake float border 1 Option bake integer borderwrap 1 2001 2014 SiTex Graphics Inc 55 AIR User Manual 6 1 Search Paths Option searchpath string dirmap Option searchpath string dirmapzone UNC for Windows NFS for Linux Option searchpath boolean dirmapdebug 0 Option searchpath string texture SATRHOME texture Option searchpath string archive SATRHOME archives Option searchpath string shader SATRHOME usershaders SAIRHOME shaders Option searchpath string display SAIRHOME displays Option searchpath string procedural SATRHOME procedurals Option searchpath string spectrum SATRHOME spectra Option searchpath string resource Runtime Control Multithreading Air can use multiple rendering threads on machines with more than one processor to accelerate rendering The number of threads can be set with a command line option air p 2 myscene rib or a custom option in a scene file Option limits integer nthreads 2 Each extra thread uses some additional memory The special value 0 may be used to indicate that all detected processing cores should be used which is now the default value In Air releases prior to version 10 th
357. hics be liable for any damages whatsoever including without limitation damages for loss of business profits business interruption loss of business information or any other pecuniary loss arising out of the use of or inability to use the SOFTWARE PRODUCT Because some states do not allow the exclusion or limitation of liability for consequential damages or incidental damages the above limitation may not apply to you This agreement is governed by the laws of the State of Texas USA By installing the supplied SOFTWARE PRODUCT you acknowledge that you have read understood and agreed to these terms 2001 2014 SiTex Graphics Inc Copyrights Trademarks and Credits 424 28 Copyrights Trademarks and Credits Copyrights and Trademarks AIR and the Visual Shading and Lighting Tool Kit software and documentation are Copyright 2000 2004 SiTex Graphics Inc All rights reserved The RenderMan Interface Procedures and RIB Protocol are Copyright 1988 1989 Pixar All rights reserved RenderMan is a registered trademark of Pixar Rhinoceros Rhino is Copyright 1993 00 Robert T McNeel amp Associates All rights reserved OpenEXR software Copyright c 2002 Industrial Light amp Magic a division of Lucas Digital Ltd LLC All rights reserved Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met e Redistributions of
358. hifting the surface laterally Because the chop displacement shifts the surface in arbitrary directions you ll need to tell Air that the displacement is not strictly in the direction of the surface normal by applying the following attribute Attribute render normaldisplacement 0 Note that too much chop can tear the surface apart Foam The waves simulation can compute a foam value which can be used by the companion OceanSurfaceWithFoam surface shader to add a foam effect to the waves In order for the foam to appear in the proper location the common parameters between the OceanWaves and OceanSurfaceWithFoam shaders must be set to the same values If you do not need to render foam set the FoamEnabled parameter to 0 to reduce computation time for the waves Animation The waves will be animated based on the current frame number The current time value is the current frame number divided by the FramesPerSecond value For speed the simulation is computed using the seawave dynamic shadeop DSO included with Air See Also OceanSurfaceWithFoam surface shader VBrickGrooves eee brick grooves 2001 2014 SiTex Graphics Inc Shader Guide 92 Name Default Value Range Description GrooveDepth 0 01 Groove depth BrickWidth 0 25 Brick width BrickHeight 0 08 Brick height MortarWidth 0 01 Mortar width Stagger 0 5 0 0 1 0 Fraction to offset every other row EdgeVary 0 01 Unevenness of brick edges EdgeVaryFrequenc 4 Frequen
359. ht When sharpness is set to 0 the ceramic model produces the same results as the plastic model When sharpness is 1 the highlight edge is maximally sharp 3D Patterns Solid textures define a pattern for points in 3D space Solid textures are used to model materials such as wood marble and granite An object shaded with a solid texture looks like it is carved out of the corresponding material In order to generate a 3D pattern a shader must know the coordinates of the point being shaded Solid texture shaders usually provide a ShadingSpace parameter for selecting the coordinate system in which shading calculations are performed That coordinate system is referred to as the shading space for that shader It will normally be object shader or world space Note that shader space is the coordinate system in which a shader is declared which may be different from the shading space in which calculations are performed Solid texture shaders also usually have a PatternSize FeatureSize or ShadingFrequency parameter that controls the overall size of the 3D pattern PatternSize orFeatureSize give the size of one copy of the pattern in 3D space ShadingFrequency sets the size indirectly by specifying how often the pattern repeats per unit interval 2D Patterns 2D patterns include texture maps and procedurally generated patterns such as tiles bricks stripes and dimples Each type of geometric primitive has a default mapping for the gl
360. i 9 including the ability to build and compile shaders within Houdini New prefilterclamptoalpha option for better filtering of rendered images with high dynamic range New alternate noise algorithm Most Air light shaders have been extended to allow precise specification of shadow casting groups for raytraced shadows New shading language extensions and optimizations to facilitate per light output values for diffuse specular etc Field rendering ClippingP lane RIB statement for arbitrary clipping planes only affecting camera visibility Indirect illumination and occlusion e Occlusion prepass now respects attribute indirect reflective 1 e Attribute indirect prepass 0 is now compatible with attribute indirect reflective 1 e f an object has complex opacity as indicated by attribute transmission hitmode a prepass will also sample surfaces behind the object e New option to specify a subset group to use for the indirect or occlusion prepass Option indirect string prepassgroup Outlines e Toon ids are now handled in a manner that eliminates most extraneous lines on transparent surfaces e New global multiplier for outline ink width Option toon float inkwidthmultiplier 1 Subsurface Scattering e New option to set the max error tolerance for subsurface scattering Option render float subsurfacetolerance 0 005 e New default subsurfacetolerance of 0 005 vs 0 05 previously to eliminate artifacts in some cases
361. iangles where necessary The threshold used to detect nonplanar quads can be set with Option render float quadtolerance 0 99 Higher values force more quads to be split into triangles The maximum value is 1 Triangulation The following attribute can be used to force AIR to convert all polygons in a mesh to triangles Attribute render integer triangles 1 Simplifying Mesh Data In some cases the memory required for polygon meshes with facevarying data can be reduced by converting the facevarying data to vertex data with Attribute render integer simplifyfacedata 1 This optimization is often effective for Massive agents Mesh Displacement AIR usually performs true displacment by splitting a mesh into individual polygons and then displacing each of the polygons independently on demand AIR 5 introduces a new option to displace an entire 2001 2014 SiTex Graphics Inc 67 AIR User Manual 8 3 polygon mesh at once Attribute render integer meshdisplacement 1 Mesh displacement may take longer to render and use more memory during tessellation but the resulting mesh will be smaller and it will be continuous even if the driving displacement function is discontinuous To help reduce memory with mesh displacement AIR can automatically split a large mesh into smaller subregions when the following attribute is enabled Attribute render integer splitmesh 1 AIR processes the boundaries betw
362. ians to distribute the rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Shadow mapped Shadows Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows Baked Shadows AIR includes an extended version of the pointlight shader p
363. ic shader with base texture map and up to 3 decals 2001 2014 SiTex Graphics Inc 231 AIR User Manual Illumination model plastic Features reflections texture map projected decals Parameter Diffuse Specular SpecularRoughness SpecularSharpness Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace ColorMapName ColorMapBlur SpecularMapName SpecularMapBlur OpacityMapName OpacityMapBlur BumpMax BumpMapName BumpMapBlur TextureSizexY TextureOriginXY TextureAngle Projection ProjectionSpace ProjectionTransform raytrace current shader oOOOrF 0 1 5 0 0 wo st oo kreo OrROO Default Value rFOoOOO Range S aces Description Diffuse reflectivity Specular reflectivity Specular roughness Sharpness of highlight edge Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Texture map for base color Texture blur Texture map for specular color Texture blur Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur Texture size in X and Y direction Location of left top texture corner Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection 2
364. ied list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows Baked Shadows AIR includes an extended version of the arealight shader arealight_baked with additional parameters for creating 3D shadow textures and using 2D or 3D baked shadows bakemap mu Bake map file name bakemode i Bake mode bakemapblur 0 Blur for bake map query bakemapfilterwidth 1 Filter width for bake map query motionbound 000000 bounding box for moving objects motionspace world space coordinate space of motionbound See Baking Shadows and Illumination for more information Note that the arealight_baked shader does not support the write or append bake modes The arealight_baked shader does support the read mode for 3D shadow data baked with the arealight2 baked shader See Also 2001 2
365. ier Exponent applied to the variation in scattering due to angle Optional color map Color for the rectangle patch under the strands Shadowing the rectangle base due to the carpet strands Grid size for internal ray tracing Multiplier for the diffuse result returned when the shader is queried by an indirect ray 2001 2014 SiTex Graphics Inc Shader Guide 194 TestForIntersections 1 0 or 1 Whether to trace rays to test for objects intersecting the carpet TraceBias 0 02 Offset used when tracing for intersections TraceMargin 0 05 Border region with no strands TraceTip 1 0 or 1 Whether to trace a sphere at the tip of each strand TraceJoints ii 0 or 1 Whether to trace a sphere at the joint between each curve segment ShadingSpace world spaces Coordinate space for shading Air 13 introduces a new FakeCarpet surface shader that turns a simple rectangle into a patch of fuzzy carpet The carpet effect is produced by ray tracing a virtual field of carpet fibers inside the surface shader no additional geometry is created in the scene Getting Started Here s how to add carpet to a room model e Create a four sided polygon and position it slightly above the floor The polygon should represent the top of the area to be covered by the carpet Make the polygon invisible to shadow rays Assign the FakeCarpet surface shader You will probably want to disable the material preview window in your application when tunin
366. ies in the Y direction Texture origin in X Texture origin in Y constant colored shader with shadows and optional texture map and reflections Features texture map shadows reflections 2001 2014 SiTex Graphics Inc 257 AIR User Manual Parameter Intensity ShadowiIntensity ShadowColor ColorMapName ColorMapBlur TextureRepeatX TextureRepeatY TextureOriginX TextureOriginY TextureProjection TextureSpace TextureTransform Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace Description Default Value Range T0 0s 0 10 1 0 0 0 1 0 O 0 0 0 0 0 0 0 0 1 0 1 1 0 0 0 0 st projections shader spaces 1000 0100 0010 0001 0 0 0 1 0 1 1 256 0 0 0 0 1 0 raytrace current spaces Description Color brightness multiplier Multiplier for shadow value Shadow color modifier Texture name Texture blur Copies of texture in X direction Copies of texture in Y direction Location of left texture edge Location of top texture edge Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup The VShadowedConstant shader produces a constant colored surface with shadows This shader only works properly with lights that have a__ unshadowed_
367. ilename name of the driver file prompt description of this driver for dialog windows A sample display driver is available by request 6 Options An option is a property of the scene as a whole in contrast to an attribute which is a property of an individual object A custom option can be added to a scene file using the Opt ion command Option optionname type parameter value Options must appear before the Worl dBegin statement in a RIB file Most plugins provide a mechanism for adding custom options to a scene The RenderMan standard allows custom options to be defined for renderer specific features The following list enumerates the custom options supported by Air Shading Option render float shadingmultiplier 1 Option render integer prmanspecular 1 Option render boolean clampbrdf 1 Option noise string algorithm air Option limits integer shadingcache 1024 2001 2014 SiTex Graphics Inc 53 AIR User Manual Option limits integer texturememory 64000 Option limits integer automapmemory 10000 Sampling Option render integer edgemask 0 Option render integer fields 1 Option render integer prefilterclamptoalpha 1 Ray Tracing Option trace integer maxdepth 6 Option trace float minweight 0 01 Option trace float reducesamples 0 1 Option render boolean optimizetracememory 1 Geometric Representation
368. iles Color variation tile to tile Width of grooves between tiles Depth of groove between tiles Groove color Maximum bump height Average size of noisy bumps Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection The VShinyTile2D shader produces a 2D pattern of ceramic tiles See Also 2001 2014 SiTex Graphics Inc 259 AIR User Manual VCeramic shader VBrick2D shader 10 10 7V SketchOutline KR wr surface shader producing uneven sketch outlines when used with AIR s outline capability a Parameter Default Value Diffuse 0 0 DiffuseRoughness 0 0 Specular 0 0 SpecularRoughness 0 4 Incandescence 1 0 PatternSize 10 0 PatternSpace raster LineWidthMax 2 0 LineWidthMin 0 0 LineWidthBias 0 5 LineWidthSharpness 0 5 Description Range 0 0 1 0 0 0 1 0 0 0 21 0 0 0 12 0 0 0 1 0 spaces 0 0 1 0 O 0 1 0 Description Diffuse reflectivity Diffuse roughness Specular reflectivity Specular roughness Self illumination Size of random pattern Coordinate space for pattern Maximum line width in pixels Minimum line width in pixels Bias for line width change Contrast control for line width change This shader generates randomly varying line widths for objects rendered with AIR s outline capability Outlining mus
369. in the AIR distribution in AIRHOME examples tweakair To begin an interactive rendering session create a RIB file as usual and start a tweakair session with the IrBegin call Then call the appopriate interface routine to update the rendering as the user changes the shading and lighting for the scene The following interactive functionality is provided 2001 2014 SiTex Graphics Inc 361 AIR User Manual 20 3 1 Primitive selection Use IrSelect call to select one or more primitives to modify Shader parameter tweaking Use IrTweakSurface IrTweakDisplacement and IrTweakLight to modify shader parameters for the selected primitives or light New shader assignment Use IrNewSurface and IrNewDisplacement to assign new shaders to selected primitives New lights Use IrNewLight to add new lights to the scene Moving a light Use IrLightTransform to update the transformation applied to a light source Moving the camera Use IrTweakCamera to change camera position or field of view Attribute tweaking Use IrColor and IrOpacity to change the corresponding color and opacity attributes Use IrTweakAttribute to change general attributes be sure to consult the list of tweakable attributes The C API uses a TCP IP socket connection to communicate with the TweakAIR process TweakAIR Text API TweakAlR also accepts update commands from a command line or piped input stream For simple changes you can start TweakAIR
370. in the list of images Sound Windows only Select Sound Clip Select a WAV file to play with an animation Use Sound Clip Play sound clip when animation is played Options Always on Top Windows only If checked the AIR Show window remains on top of all other windows on the screen Sync Views Synchronize pan and zoom for same sized images Show Toolbar Display toolbar 2001 2014 SiTex Graphics Inc 409 AIR User Manual 24 3 8 24 4 Auto Restore Size When checked a minimized AIR Show window will restore to normal size when a new rendering starts Uncheck this option to allow the window to stay minimized while rendering a sequence of frames Default Gamma Sets the default gamma correction applied to images Keyboard Shortcuts Channels red channel green channel blue channel alpha channel RGB channels ovora OrwgoI Decrement channel Increment channel ee Animation Previous image Next image First image Last image Q V Play animation once Play animation in reverse once Cycle animation Cycle animation in reverse Animate frames in pong mode space bar Stop animation aga amp WO Swap with previous frame Swap with next frame Make first frame Make last frame Qo NI Miscellaneous Ctrl F fit window to image size J jump to last image viewed MakeLliF MakeLlIF is a command line utility that generates shader help files MakeLIF can generate help
371. inates A 2D device independent coordinate system defined on the screen with x running from 0 to 1 left to right and y increasing from 0 to 1 top to bottom raster A 2D coordinate system where x and y are the pixel coordinates of a point after projection to the screen Displacement Displacement shaders add small topographical features to a surface such as bumps wrinkles or dents Your plugin should provide a means of assigning a displacement shader to an object If not you can add the following line before the object definition in the scene file Displacement shadername The AIR distribution includes a number of displacement shaders and you can write your own using AIR s Vshade shader creation tool Bump Mapping vs True Displacement AIR offers two methods of rendering displacements Bump mapping Displacement is simulated by altering the surface normal The surface itself does not move True displacement The internal representation of the surface is displaced 2001 2014 SiTex Graphics Inc Shader Guide 84 The two methods differ in cost and appearance Bump mapping is faster and uses less memory but silhouette edges will not exhibit displacement and shadows will not reflect the displacement True displacement is slower and potentially uses much more memory because the renderer must dice the surface down to sub pixel size polygons which are then displaced However truly displaced surfaces will have ap
372. information as a text string of 16 numbers Assign a shader that supports texture projection to the object Many of the shaders included with AIR that generate 2D patterns provide texture projection Assign the texture name to the texture map name parameter Select the parameter for the transformation applied to the projected point and paste from the clipboard by pressing Ctrl V or by using the right mouse button pop up menu If the shader takes a projection type set it to planar Set the projection space to world Render the same view again to verify that the texture is correctly positioned e Render the scene from another view to see that the texture remains in place Because the texture is projected in world space the texture will remain in place if the camera moves The texture will not move with the object if the object moves You can use this technique to position any 2D pattern not just those that rely on texture maps In all cases the rectangle drawn in the display window defines the unit square in 2D texture coordinates 11 2 Vector Textures Beginning with release 3 0 AIR can use vector graphics files as texture maps with the aid of the Vtexture DSO shadeop written by Alex Segal Vtexture can be downloaded from http Awww renderman ru vtexture indexe html Copy the vtexture DLL or shared object file to the shaders directory of your AIR installation With Vtexture installed you can use a vector graphics file in Adobe I
373. ing Importance The importance of the current shader evaluation can be queried with the rayinfo function color weight 1 rayinfo weight weight 2001 2014 SiTex Graphics Inc Ray Tracing 340 Importance information can be used to further optimize a shader for situations where lower quality results are acceptable E g a shader that computes a detailed pattern might substitute a simpler pattern that is less costly to compute when the importance drops below a certain threshold 14 2 Optimizing Memory for Ray Traced Objects Air 11 introduces a new option for optimizing the memory used when storing objects that are ray traced Enable memory optimization with Option render optimizetracememory 1 The basic idea some objects need to be ray traced but do not need to be shaded when they are hit by traced rays Once such objects have been processed by the main scanline renderer we can saved memory be freeing shading data such as surface normals and texture coordinates if that data is not required for ray tracing queries Specifically Air can free at least some shading related primitive data for traced objects that are e Invisible to reflection rays e Invisible to shadow rays or visible to shadow rays with transmission hit mode opaque or primitive e Invisible to indirect rays or visible to indirect rays with indirect shading mode constant or matte For a typical Massive agent this optimization can reduce ray traci
374. ion For complex scenes using Procedural primitives to generate or load primitives on demand can dramatically reduce peak memory use e Insome cases of extreme motion blur the memory used by the shading cache can become significant You can lower the cache size using an option e For scenes with many large shadow maps you may need to increase the texture cache size to avoid thrashing Blobbies e Using a higher tessellation factor can significantly reduce peak memory and render time e For true displacement enable the meshdisplacement Attribute render meshdisplacement 1 20 TweakAir for Interactive Rendering TweakAlR is an interactive rendering tool based on the AIR renderer TweakAlR is designed to allow interactive tweaking of high quality images with the full range of advanced rendering effects supported by AIR TweakAlR accepts regular RIB files as input At the beginning of an interactive rendering session TweakAlR creates a deep framebuffer for the current view that stores information about the visible surfaces at each pixel Once the deep framebuffer has been generated shading and lighting settings for the scene can be changed interactively and the rendered image will automatically update to reflect the changes TweakAIR employs various caching mechanisms and re evaluation heuristics to accelerate the re rendering of scene elements Users will typically interact with TweakAIR via their plugin or modeling software T
375. ion Description The occlusionpass surface shader sets the output color to the ambient occlusion value at the surface location The average unoccluded direction is emitted in the Nunoccl output variable When the mapname parameter is set to raytrace ray tracing is used to compute the ambient occlusion at each point Otherwise mapname is treated as the file name for an occlusion map with occlusion information Output only variables normal Nunoccl Average unoccluded direction 2001 2014 SiTex Graphics Inc Shader Guide 200 See Also Ambient occlusion envilight light shader massive occlusionpass surface shader 10 10 1SO0ceanSurface surface shader for ocean water no wave simulation is included in this shader IIlumination Model custom Parameter Diffuse DiffuseColor DeepSealntensity DeepSeaColor Specular SpecularRoughness Reflection ReflectionSamples ReflectionBlur Transmission TransmissionMaxHitDist TransmissionSamples TransmissionFalloff TransmissionBlur TransmissionNearColor Description Default Value 0 44 47 6 wall 21 29 47 055 0 1 0 9 1 Description Diffuse reflectivity Diffuse color Deep sea color multiplier Deep sea color Specular intensity Specular roughness Reflection multiplier Number of reflection rays to trace Blur angle for reflection in radians Transmission multiplier Max distance to trace transmission rays Ray
376. ion cache If 0 the occlusion cache is not used If less than 0 or omitted from the occlusion call the indirect maxerror attribute value is used maxpixeldist maximum distance in pixels between samples in the occlusion cache If omitted or less than 0 the indirect maxpixeldist attribute value is used adaptive controls adaptive sampling 1 enables 0 disables any other value defaults to the indirect adaptivesampling attribute setting ncecache This function has been deprecated in AIR 10 and later AIR exposes the irradiance caching functionality used by the indirectdiffuse and occlus ion functions so that users can create and access custom caches for special purposes The irradiancecache function has two operating modes insert and query Cache Insertion irradiancecache insert string cachename string cachemode point P vector N harmonicmeandist float hmean values 2001 2014 SiTex Graphics Inc 295 AIR User Manual Inserted values can be any of irradiance color irrad coverage float alpha environmentdir vector dir The harmonic mean distance is the reciprocal of the average of the reciprocal hit distances of the rays that went into calculating the inserted values presumably with a gather statement Cache Query float irradiancecache query string cachename string cachemode point P vector N maxerror float maxerror maxpixeldist float maxpixe
377. ional rib statement to optionally include or exclude features based a particular version of the renderer e TweakAir e Support for opacity values attached to a primitive variable list e Fix for uniform primitive variable indexing when redrawing the camera view e Fix for varying facevarying prim var indexing when re tracing the camera view Shading Compiler e The noise function may now specify the type of noise to use with an initial string The options are the same as those for Option noise string algorithm e The error message for undefined var declared with extern now includes the variable name e Boolean variables can now be used as the target in option or attribute Air Show 8 e Support for the new __ diffuse shadow output variable in composite mode e New simple Print command in the File menu Windows only e Status bar text is no longer sometimes reversed under Windows 7 Texture Conversion tools mktex and mktexui e New options to convert to and from sRGB color space e Unrecognized options are reported but no longer cause the conversion to fail e New check box in mktexui to convert all files in a directory e Massive e New user note on adding a background image Bug fixes Texture lookups when shading indirect rays Fix in ray traced hider jitter computation Tweak for trace quad intersection under 64 bit explicitly use double precision for sqrt Fix for texture coordinate computation when shading triangular micr
378. iplier for indirect rays CameraVisibility 1 Oor 1 whether the environment is visible to camera rays Cameralntensity 1 0 intensity multiplier for camera rays Cameratint 1 1 1 color multiplier for camera rays Description The envColor environment shader returns a constant color value for each ray type The returned color value can be the same for all ray types or adjusted individually for each type of ray using the Intensity and Tint parameters Output only parameters color _ background environment shader color result 10 3 2 envMap environment shader with a common environment map for all rays 2001 2014 SiTex Graphics Inc 103 AIR User Manual 10 3 3 Parameter MapName MapIntensity MapBlur MapSpace MapSamples RotateX RotateY RotateZ Reflection Visibility ReflectionIntensity ReflectionAddBlur IndirectVisibility IndirectIntensity IndirectAddBlur CameraVisibility Cameralntensity CameraAdaBlur Description Default Value Range T0 0 01 world spaces 4 90 0 0 1 Oor 1 1 0 0 0 1 Oor 1 L0 0 0 1 Oor 1 10 0 0 Description file name of environment map intensity multiplier for all rays blur for map look up samples for environment map query rotation angle in degrees about the X axis rotation angle in degrees about the Y axis rotation angle in degrees about the Z axis whether the environment is visible to reflection rays intensity multiplier for reflection rays
379. irect integer moving 0 Attribute indirect integer reflective 0 Attribute indirect integer adaptivesampling 0 Attribute indirect integer prepass 1 Caustics Attribute caustic integer ngather 75 Attribute caustic float maxpixeldist 20 Attribute caustic color specularcolor 0 0 0 Attribute caustic color retractioncolor 0 0 6 Attribute caustic float refractionindex 1 Attribute caustic float dispersion 0 Subsurface Scattering Point Sets Attribute pointset string handle Attribute pointset string cachemode Geometric Approximation 2001 2014 SiTex Graphics Inc Attributes 62 7 1 Attribute limits integer divisionlevel 16 Attribute divisions integer udivisions 1 integer vdivisions 0 Attribute render float trimborder 0 Attribute curve string type polyline Attribute point string type default Attribute point integer clustermax 5000 Attribute render string flatnessspace raster GeometricApproximation edgelength 0 Toon Rendering Attribute toon integer id 1 Attribute toon color ink 0 0 0 Attribute toon float inkwidth 1 Attribute toon float zthreshold 0 0 Attribute toon float silhouette 0 5 Attribute toon integer frontback 0 Attribute toon integer nakededges 0 Attribute toon integer faceangle 0 Attribute toon
380. irradiance method for indirect illumination calculations AIR calculates the incoming indirect light at a point by sampling the hemisphere of directions above the current shading location using ray tracing Each ray contributes illumination from the surface it strikes or a contribution from the indirect environment if no object is hit Adding Indirect Light Many user interfaces for AIR provide special controls for enabling indirect illumination often grouped under a section called GI or Global Illumination Indirect lighting can also be added to a scene manually as follows e Add an indirect light source to a scene e Make objects that contribute indirect illumination visible to indirect rays with Attribute visibility indirect indirect 1 2001 2014 SiTex Graphics Inc 321 AIR User Manual Quality The main control over the quality of the indirect illumination results is the number of rays cast which can be set with the following attribute Attribute indirect integer nsamples 256 More rays produce more accurate and smoother results at the expense of longer rendering time Sometimes it is only important to capture the indirect light from objects that are nearby the current shading location The following attribute can be used to restrict the distance to search for objects that contribute indirect light Attribute indirect float maxhitdist 100000 Shorter distances can reduce rendering
381. is the current shading location 2001 2014 SiTex Graphics Inc History 452 29 11 Fix for builtin blinn function Per curve s t data is supported Volume primitives accept user attributes Fix for using a SSS cache with true displacement AIR 4 0 Volume primitives for fast volumetric rendering Automaps automatic shadow maps TweakAIR improvements e New fast re lighting shading mode e TweakAIR now supports the indirect and occlusion prepasses e New option for anti aliasing with multiple pixel samples Option ipr integer 2 pixelsamples 1 1 Simple RIB command filtering Improved curve rendering e More efficient rendering of catmull rom and b spline curves e Memory reduced up to 50 for general curve rendering Subdivision mesh improvements e Optimized tessellation reduces memory usage and render time e Better interpolation of facevarying variables e Rendering of border faces with sharp edges w o the interpolate boundary flag Points primitives may now be rendered as bilinear patches for sprites Shading language extensions e new builtin blinn function implements a Blinn specular illumination model e new builtin brushedspecular function implements an anisotropic specular function similar to Ward s diffuse accepts an optional roughness parameter for Oren Nayer shading specular accepts an optional fourth sharpness parameter for sharp edged specular highlights phong accep
382. istance to search for traced objects string subset restricts intersection tests to members of the specified groups as determined by Attribute grouping membership float othreshold gives an opacity threshold Tracing stops when the cumulative opacity along the ray exceeds the threshold The default threshold is 0 Optional Output Parameters 2001 2014 SiTex Graphics Inc 293 AIR User Manual Type and Name Description point ray origin location from which the ray was traced vector ray direction normalized ray direction float ray length distance from ray origin to hit location or 1 0E15 if the ray missed all objects primitive name Returns the value of the named global variable of the object intersected by a ray prior to shader evaluation Supported variable names are P N Cs and Os surface name Returns the value of the corresponding variable after execution of the intersected object s surface shader Supported variables are Ci Oi P N and any surface output variable point name Returns the value of the named variable associated with a point sample in a point cloud Point Cloud Sampling Air 12 extends the gather construct to allow querying of point cloud data Sample usage color csum 0 integer count 0 color tcolor gather pointcloud filename P N maxsamples maxdist maxdist point mycolor tcolor csum tcolor count 1 color caverage 0 if cou
383. ith Air are available for many major modeling and animation programs Other programs provide builtin support for rendering with Air 2001 2014 SiTex Graphics Inc 421 AIR User Manual Here is a partial list of compatible plugins for Air SketchAir new Our new plugin for SketchUp currently in development Air Stream Our plugin for Maya available as a separate download from the SiTex Graphics web site RhinoAir Our own plugin for Rhino 4 and 5 available as a separate download from the SiTex Graphics web site CineMan A new plugin for Cinema4D Companion Products Houdini www Ssidefx com SideFx s advanced 3D products for visual effects offers good support for rendering with Air See the Houdini section of this manual for more information Massive www massivesoftware com Massive is the crowd simulation program from Massive Software used to generate crowds for the Lord of the Rings movies Massive is the premier 3D animation system used for generating crowd related visual effects and character animation based on artificial life technology The Massive section of this guide has an extensive list of tips and tools for rendering Massive crowds with Air CityEngine www procedural com Procedural city construction from Procedural Inc RealFlow Rendering Toolkit www realflow com Rendering toolkit for the RealFlow fluid and dynamics simulation software Temerity Pipeline 2001 2014 SiTex
384. ius radius For locations close to the sphere surface the light source no longer behaves as an idealized point light The shader accounts for this by supersampling the sphere surface to account for the variation in incoming illumination from different parts of the sphere surface The images below compare the results for a true spherical area light top with 64 light samples and the spherelight shader bottom using 64 shadow rays 2001 2014 SiTex Graphics Inc 151 AIR User Manual 2001 2014 SiTex Graphics Inc Shader Guide 152 Light Intensity The emitted light value is the product of the intensity and lightcolor parameters and an attenuation factor determined by the falloff parameter The falloff parameter allows the light s intensity to diminish with distance from the light A falloff value of 2 which is physically accurate reduces the incident light value by the square of the distance from the light Cl intensity lightcolor Distance Distance Traced Shadows If the shadowname parameter is set to the special value rayt race shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace The shadowblur parameter gives an angle in radians to distribute the rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to re
385. ive variables Shadow maps with no blur and shadows at edges Illuminance cache category comparison Fix for outlining with an indirect or occlusion prepass Fix for runtime shading optimization that very rarely caused a silent crash Fixed failure to fully reset occlusion cache between frames AIR 3 0 Geometry export for displacement baking and modeling Improved toon rendering e The viewport of a rendering with outlines now matches the view without outlines e New depth based edge detection method e New silhouette edge detection method based on detecting boundaries between front and back facing polygons in the rendering mesh e Outlines may now be saved as a separate output image with the new __toonline output variable e Faster rendering with large maxinkwidth settings e New special region id of 2 can be used to outline every polygon in a rendering mesh Fast volumetric fog with a new foglight function Vector texture support with Alex Segal s Vtexture New FreeObject RIB command frees an object created with ObjectBegin ObjectEnd New FreeArchive RIB command frees an inline archive created with ArchiveBegin ArchiveEnd Shading improvements e New dead code elimination and constant folding capabilities in the shading compiler produce better code e Shader execution optimization yields better performance with many AIR shaders New depth z filtering for multiple pixel samples with multiple pixel samples the output depth is now th
386. ke map query bakemapfilterwidth 1 Filter width for bake map query See Baking Shadows and Illumination for more information See Also Ambient occlusion 10 7 10 indirect indirect_baked light source emitting indirect diffuse illumination Parameter Default Value Range Description intensity 1 0 Light intensity intensity_indirect 1 0 Light intensity for indirect rays lightcolor i 11 Light color environmentmap mn Optional environment map for background environmentspace world spaces Coordinate space for environment map _ category indirect Light categories __nonspecular 1 0 1 If 1 light will not produce highlights _ foglight 0 0 1 If 1 light illuminates volumes __indirectlight 1 0 1 Flag indicating indirect light status for multipass rendering _ channel 1 0 9 Output channel Description The indirect light shader encapsulates AIR s indirect diffuse illumination capability sometimes referred 2001 2014 SiTex Graphics Inc 139 AIR User Manual 10 7 11 to as global illumination The emitted light value is the indirect light incident at the current shading location scaled by the intensity and lightcolor parameters which can be used to tweak the indirect diffuse results The optional environmentmap parameter gives an environment map to query with indirect sample rays that miss all objects in the scene A better way of setting the background environment map is with the following optio
387. kshadow switch to enable shadows on surfaces facing away from a light A sample dynamic shadeop DSO with source code is now included in the AIR distribution in SATRHOME examples shadeop e AIR Show has a new button to display a checker background under images with an alpha channel On Linux AIR Show and mktexui no longer reference libglade mktex and mktexui have a new option to apply gamma correction to an image AIR Space 0 3 see the separate AIR Space user manual for more information Area light support BakeAlR support including OpenGL viewport display of baked maps and VRML export Turntable and camera path animation OpenGL display of texture maps Material import from RIB files e e e e e e Many bug fixes and user interface enhancements Bug fixes Motion vector output with Pixel Samples 1x1 e Runtime shader optimization for vt ransform Spiral bucket order with crop window and a prepass Subsurface scattering and true displacement Area computation for triangles during subsurface scattering collection phase Shading compiler optimizer bugs affecting array references Handling of separate alpha channel for matte objects Compiler bug affecting aligned memory address computation in airmt on Linux 29 9 AIR 5 0 e Fragment shadow maps for deep mapped shadows e Output enhancements e Per light output channels e Multilayer rendering in a single pass 2001 2014 SiTex Graphics Inc 449 AIR Use
388. l DynamicLoad maketree height 10 width 2 branches 5 2 2 2 2 0 10 The first argument is the name of the dynamic object minus the so or dll extension The second argument is a string that is meaningful to the DynamicLoad procedural The Air distribution includes source code for sample DynamicLoad procedural in AIRHOME examples primitives procedurals Air s support for DynamicLoad procedurals makes use of a DLL shared object on Linux that acts as a bridge between Air and the DynamicLoad DLL shared object This mechanism requires that the DynamicLoad module be compiled with certain extra options The ri n header file in the include subdirectory of the Air distribution contains sample compile commands for Windows and Linux See Also Procedure shaders 2001 2014 SiTex Graphics Inc Primitives 76 8 8 Implicit Surfaces AIR 6 introduces a new Implicit primitive for rendering grid data as an isosurface RIB syntax Implicit minx maxx miny maxy minz maxz nx ny nz constant float _ threshold 1 vertex float density nx ny nz values parameter list The only required parameter is a list of density values for the 3D grid The density value at which the surface is created can be set by providing aconstant __ threshold parameter or by using an attribute Attribute render float thresholdmultiplier 1 Additional user data can be included in the parameter list in the usual way Vertex or varyi
389. l t if files in the c temp directory Map Type This control specifies the type of map to be created or the source format in the case of environment maps X Wrap Mode Y Wrap Mode For texture maps the wrap mode determines how texture queries outside the range 0 1 are handled black return color 0 0 0 for texture access outside the range 0 1 clamp clamp the coordinate value to the range 0 1 periodic wrap the texture coordinate e g use S s floor s Transformations The following transformations can be applied to an image during the translation process Flip X Flip the image horizontally Flip Y Flip the image vertically 2001 2014 SiTex Graphics Inc Tools 418 24 9 Rotate Rotate the image in increments of 90 degrees Rotate 3D For angular maps only rotates the coordinate system for the environment map lookup Output Data Type Specifies the data type of the output image 8 bit 16 bit or float By defaul the output image will have the same data format as the source image Output Size Specfies the size of the output image Output Directory The directory in which to place the created file View Source Press this button to view the source image in AIR Show On Linux AIR Show must already be running for this command to work Preview Use the Preview button to view the converted image in AIR Show with any transformations applied On Linux AIR Show must already be running Make M
390. l GI options and attributes e Select the RIB output operator that will be used for rendering Under the Properties tab select the GI sub tab e Check Visible to indirect rays to make all objects contribute to global illumination by default e Render a small test image The scene must include some direct illumination in order to see any GI results Global Illumination Cache Acceleration With the default settings indirect diffuse illumination can be quite slow as AIR computes a new Gl sample at every shading location Gi can be accelerated by enabling the irradiance cache e Inthe GI subtab change the Max Cache Error to 0 25 to enable the GI cache e For smooth results check the Indirect Prepass e Another test render should finish much more quickly The quality of the GI cache is controlled by the Max Cache Error and Max Spacing settings Max Cache Error takes a value between 0 and 1 giving the maximum error allowed when trying to re use samples in the cache A max error of 0 disables the GI cache The Max Spacing value gives the maximum distance in pixels between samples in the cache ensuring that all areas of the image receive at least some GI samples Global Illumination Background Use the controls at the bottom of the GI sub tab to specify incoming illumination from the environment surrounding the scene The GI background can be either a simple color or an environment map For an environment map the map intensity and map blur ca
391. l Illumination dialog You can also add ambient occlusion to a scene manually by either 1 Assigning an occlusionpass or massive occlusionpass surface shader to all objects 2 Adding an envilight or massive envlight light shader to the scene Because traced occlusion casts shadow rays to estimate occlusion any objects that contribute to occlusion must be made visible to shadow rays A plugin may provide a control for enabling traced shadow visibility or visibility to shadow rays can enabled with Attribute visibility integer transmission 1 Occlusion Quality The main control over occlusion quality is the number of rays cast to estimate occlusion Some shaders such as massive_envlight and massive_occlusionpass provide a parameter for setting the number of rays to cast for occlusion Shaders that do not provide such a parameter will inherit the number of rays from the corresponding indirect attribute Attribute indirect integer nsamples 256 Using more rays will produce more accurate and smoother ambient occlusion results at the cost of longer rendering times A useful guideline when making adjustments is to increase or decrease the number of rays by a factor of 2 Often it is only important to capture the occlusion resulting from objects that are nearby the current shading location The following attribute can be used to restrict the distance to search for occluding objects 2001 2014 SiTex Graphics Inc
392. l blur coordinate space for window directions optional texture map texture blur If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel parameters This meant as an efficient way to simulate an external light source such as the sun shining into a room The window opening is centered at the to location The window rectangle is defined by window_size_x window_xdir window_size_y and window_ydir The window may optionally be subdivided into panes horizontally and or vertically If a texture map is provided it is assumed to cover the entire window opening Traced Shadows If the shadowname parameter is set to the special value rayt race shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace The shadowblur parameter gives an angle in radians to distribute the rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups 2001 2014 SiTex Graphics Inc 159 AIR User Manual The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting
393. label user assigned name for rays cast by this call float maxdist maximum distance to search for intersecting objects float samples number of rays to trace string subset restricts intersection tests to members of the specified groups vector majoraxis tangent vector for anisotropic reflections float majorblur blur factor in majoraxis direction for anisotropic reflections float minorblur off axis blur for anisotropic reflections color weight weight or importance of this trace call for importance based ray tracing Optional Output Parameters The trace function accepts an optional alpha output parameter that returns the fraction of the sampled environment cone occluded by reflected objects The alpha value returned by the ray tracer can be used to composite tracing results with a background environment map In AIR 9 and later trace provides a background output parameter of type color that stores the contribution of the background environment map or color for reflection rays Beginning with AIR 9 trace can return arbitrary output variables from the surface shaders of intersected primitives in the same manner as the gather construct For example 2001 2014 SiTex Graphics Inc 305 AIR User Manual color renv color Crefl trace P R surface __environment renv See Also environment Ray Traced Reflections 10 15 3 visibility color visibility point pl point p2
394. lar reflectivity Specular roughness Sharpness of highlight edge Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Width of tile Blur for antialiasing tile edges Color variation tile to tile Mortar width as a fraction of tile size Mortar color Groove depth Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection The VHexTile shader produces a 2D pattern of ceramic hexagonal tiles See Also VCeramic surface shader VBrick2D surface shader VShinyTile2D surface shader 2001 2014 SiTex Graphics Inc 241 AIR User Manual 10 10 5 VLayeredMaterials surface shader with base material and 3 layers of different materials IIlumination model plastic or metal Features reflections textures bump mapping Parameter Default Value Range Description Diffuse 0 7 0 0 1 0 Diffuse reflectivity DiffuseMap Diffuse color map DiffuseSizexY 1 1 Size of texture map in X and Y DiffuseOriginXY 0 0 Map position of left top corner Specular 0 5 0 0 1 0 Specular reflectivity SpecularRoughness 0 2 0 0 1 0 Specular roughness size SpecularSharpness 0 0 Sharpness of highlight edge SpecularMetallic 0 0 Whether surface is metallic SpecularMap iii
395. lations Description The VCellBumps displacement shader produces a 3D pattern of similarly sized but irregular rounded cells The overall size of the cells is set by the Cel 1Width parameter with the CellHeight parameter giving the maximum displacement distance The Jitter parameter controls deviation from a regular grid The Power parameter influences the profile and shape of the cells 2001 2014 SiTex Graphics Inc 95 AIR User Manual 10 2 10 VHammered 10 2 11 hammer dents Parameter BumpMax Jitter PatternSize PatternOrigin PatternSpace Description Default value 0 02 1 0 0 2 0 0 0 shader Range 0 01 1 0 spaces Description Maximum depth of hammered dents Deviation from a regular grid pattern Overall scale of pattern Pattern offset Coordinate space for shading calculations The VHammered displacement shader produces the effect of hammered metal The DentSize parameter sets the overall scale of the pattern VNicks nicks Parameter BumpMax Coverage FilterWidth PatternSize PatternOrigin PatternSpace Description Default value 0 2 0 0 0 shader Range 0 01 1 0 S aces Description Maximum depth of nicks Fraction of surface covered with nicks Filter width multiplier Overall scale of pattern Pattern offset Coordinate space for shading calculations The VNicks shader produces small nicks in a surface
396. ldist values A cache query returns 1 if the cache holds values that satisfy the constraints of the maxerror and maxpixeldist parameters If maxerror or maxpixeldist are omitted or are negative the value of the corresponding indirect attribute for the primitive is used cachemode is used to control whether the cache is written to a file or loaded from a file If cachemode contains w the cache will be written to file cachename when rendering is complete If cachemode contains r the cache will be initialized with data from file cachename if it exists 10 15 1iisbaking float isbaking returns 1 if the shader is being executed by BakeAIR the Shading and Lighting Baker 10 15 1 sindirectray float isindirectray Returns 1 if the shader is being executed to estimate indirect illumination otherwise returns 0 10 15 19sphoton float isphoton returns 1 if a light shader is being executed for a photon 10 15 2 isshadowray float isshadowray Returns 1 if the shader is being executed to determine visibility for a shadow ray or shadow map otherwise returns 0 10 15 2 meshinfo float meshinfo token variable AIR 8 introduces a new instancer shader type that can create new geometry at render time based on an existing primitive The meshinfo function provides access to information about the base primitive to which an instancer shader is attached Meshinfo is only valid inside an instancer shader 2
397. le The depth information can be saved in a floating point TIFF file which AIR can use directly as a shadow map However it is better to first convert the depth map to an AIR shadow map with the MakeShadow RIB command or the mkt ex utility program An AIR shadow map uses a tiled compressed format that allows AIR to efficiently cache shadow map requests and minimize memory use during rendering Instead of rendering a depth file and then converting that to a shadow map AIR allows a shadow map to be rendered directly with the special shadow display driver Using the shadow driver avoids creating a potentially large intermediate depth file Depth Map Values AIR supports an optional parameter for the Hider command for choosing the type of depth values that are stored in a shadow map Hider hidden string depthfilter midpoint By default AIR writes a depth value that is the average of the two closest surfaces this midpoint 2001 2014 SiTex Graphics Inc Lighting 318 algorithm helps to minimize shadow artifacts caused by incorrect self shadowing If a depthfilter value of min is specified the shadow map file will contain the nearest depth value at each pixel Shadow maps generated with the midpoint depth filter generally provide better shadows than maps generated with the min filter However midpoint shadow maps can cause artifacts where there is a discontinuity in the second surface visible from the light which re
398. le in radians of the cone of directions that is sampled for the occlusion result If the optional mapname parameter is not provided or it has the special value raytrace AIR uses ray tracing to estimate the occlusion Otherwise mapname is the name of an occlusion map See Ambient Occlusion for more information Optional Input Parameters Type and Name Description float bias offset to prevent incorrect self intersections string label user assigned name for rays cast by this call float maxhitdist maximum distance to search for intersecting objects float maxerror maximum error allowed when re using samples from the occlusion cache If 0 the occlusion cache is not used If less than 0 or omitted from the occlusion call the indirect maxerror attribute value is used float maxpixeldist maximum distance in pixels between samples in the occlusion cache If omitted or less than 0 the indirect maxpixeldist attribute value is used float samples number of rays to trace when ray tracing string subset restricts intersection tests to members of the specified groups float adaptive controls adaptive sampling 1 enables 0 disables any other value defaults to the indirect adaptivesampling attribute setting float maxsolidangle for point base occlusion the maximum solid angle in radians for approximated point groups float for traced occlusion set to 0 to use the optimizenormal normal value passed to occlusion as is rather
399. le stores a 4x4 sub pixel coverage mask as an integer between 0 and 65535 The sub pixel mask can be used to accurately handle object edges when performing operations on deep images 5 7 Display Drivers The raster image created by Air is passed to a display driver which may display it in a window or save it to disk Air comes with the following display drivers File Format Device Name Extension Data Channels Windows Bitmap bmp bmp 8 bit 3or4 OpenEXR exr exr float arbitrary Radiance hdr shar float 3 JPEG jpeg Jpg 8 bit 3 Portable Network Graphics png png 8 bit 16 bit 1 4 Rich Pixel Format rpf rpf special special SGI Image Format sgi Sgi 8 bit 16 bit arbitrary AIR Shadow Map shadow shd float 1 Targa tga tga 8 bit 3or4 AIR Texture Map texture TX 8 bit 16 bit float arbitrary TIFF tiff tLe 8 bit 16 bit float arbitrary Photoshop File Format psd psd 8 bit 16 bit arbitrary Softimage PIC pic pic 8 bit 3or4 Deep Image Text File deept xt deeptxt float arbitrary PTEX ptex ptx 8 bit 16 bit arbitrary half float See Also Output 5 7 1 bmp Windows Bitmap Description saves images in Windows Bitmap format File extension bmp Channels single channel or 3 channels rgb Data types 8 bit unsigned integer File data uncompressed Parameters float 2 resolution x y Gives the resolution of the image in x and y in pixels per unit given by resolutionunit 2001 2014 SiTex Graphics Inc 43 AIR Use
400. le to all primitives that are part of the current shading object with for example Attribute pointset String handle head pts AIR shades points in the point cache from the outside of the object as determined by the current orientation If your object looks unlit with subsurface scattering try reversing the orientation of the object The ScatterDistance and SubsurfaceReflectance parameters are set to values appropriate for human skin The ScatterDistance parameter is in units of millimeters use the ScatterDistanceScale parameter to scale the scatter distance to an appropriate distance for the size of your model Larger values of ScatterDistanceScale produce more blur and generally take less time to render Sheen The Sheen parameter controls the specular component of the skin model 2001 2014 SiTex Graphics Inc Shader Guide 262 Base Color The base color is taken from the object s color attribute multiplied by the texture map color if any Tip When tweaking parameters for this shader it may be helpful to work on one component at a time by setting the strength of the other components to 0 For example setting the SingleScatter and Sheen parameters to 0 will allow you to view the results of only the multiple scattering component The skin model is based on Matt Pharr s talk at SIGGRAPH 2001 See Also Subsurface scattering VTranslucent shader 10 10 76VSmokeSurface smoke surface shader for vol
401. leaf length LeafTilt 35 55 Leaf angle relative to twig axis LeafTwist 70 80 Angle of rotation about twig for successive leaves LeafColor 18 45 04 Base leaf color LeafColorVaryHSL 2 2 2 Per leaf variation in hue saturation lightness LeafSurface VClay Leaf surface shader LeafMask E Optional opacity mask for leaf Leaves sets the maximum leaves per twig If Leaves is 0 no leaves will be rendered The leaf length varies randomly within the range given by LeafSize By default leaves are represented as a polygonal leaf like pointed oval Use LeafAspectRatio to set the leaf width as a fraction of the leaf length LeafTilt and LeafTwist have the same meaning as the equivalent twig and branch parameters LeafColor gives the average leaf color The color for an individual leaf is randomly chosen based on the average color and the maximum variation in hue saturation and lightness specified in 2001 2014 SiTex Graphics Inc Shader Guide 172 LeafColorVaryHSL LeafSurface defines the surface shader to use for the leaves LeafMask allows an opacity map to be used to define more complicated leaf shapes If a leaf mask is provided the leaves are rendered as square patches using a Points primitive with point type patch Note that using a mask requires that the leaf surface shader be evaluated during shadow ray evaluation which can substantially slow down rendering of traced shadows You may wish to use shadow maps
402. lectivity Specular reflectivity Specular roughness Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup How rusty the surface is Base rust color Variation in rust hue saturation and value Overall pattern size Pattern offset Coordinate space for shading calculations 2001 2014 SiTex Graphics Inc 255 AIR User Manual Description The VRustyMetal surface shader simulates a metallic surface partially covered with rust Rust covered regions do not have specular highlights or reflections Rustiness gives the approximate fraction of the surface covered with rust See Also VMetal shader 10 10 6 VScreen 4 plastic or metallic surface with round or square holes IIlumination model plastic or metal Features reflections Parameter Diffuse Specular SpecularRoughness Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace Metallic HoleSizexY Round TextureSizexY TextureOriginXY TextureAngle Projection ProjectionSpace ProjectionTransform Default Value 0 5 0 5 0 2 L0 1 0 0 raytrace current 0 Oat OF 0 5 st shader OoOO OOrFRO OHOO HOOO 0 0 1 0 S Range aces Description Diffuse reflectivity Specular reflectivity Specular roughness Reflection strength Number of rays when ray traci
403. licenses may upgrade their licenses to unlimited threading for a fee Stereo and Multicamera Rendering Ambient Occlusion e New point based ambient occlusion method e Additional optimization accelerates rendering when the max hit distance is small relative to the overall scene size think local occlusion in a Massive crowd Spectral color definition using spectral power distribution SPD files Spectral Prefiltering and Chromatic Adaptation Photometric lights and IES light profiles e New image reader for IES light profile files which converts IES data to a lat long environment map e New photometric _pointlight shader for use with IES profiles Shading Language e User structures e Support for option searchpath texture path and option searchpath resource path meshinfo vertex sampling now returns a value for facevarying data it just picks one face s value for the query vertex e New sRGB and 1itRGB color spaces e Shaders can query the toon id attribute with attribute toon id id Deprecated irradiancecache function Multithreading e The default number of rendering threads is now equal to the number of detected processing cores e Air no longer limits the number of rendering threads to the number of detected cores Procedural primitives e Air can now execute multiple instances of a RunProgram procedural primitive to accelerate multithreaded rendering Massive users in particular can use this option to improve r
404. lict background color and object color Stripe frequency Fraction of stripe covered by line Line coverage 0 no lines Rotation angle in degrees for lines Explicit line color Blend between explicit line color and object color Stripe frequency Fraction of stripe covered by line Line coverage 0 no lines Rotation angle in degrees for lines Explicit line color Blend between explicit line color and object color Use the VLines shader to shade a surface by filling it with parallel lines Up to two non parallel sets of lines are supported Colors for the background and lines can be explicitly specified or based on the object s color attribute 10 10 6 VMarble IR layered marble with reflections IIlumination model plastic Features reflections 2001 2014 SiTex Graphics Inc 245 AIR User Manual Parameter Default Value Range Description Diffuse 0 7 0 0 1 0 Diffuse reflectivity Specular 0 3 0 0 1 0 Specular reflectivity SpecularRoughnes 0 1 0 0 1 0 Specular roughness Reflection 0 5 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup VeinColor 0 0 0 0 0 2 Color of marble veins VeinSharpness 0 5 0 0 1 0 Contrast adjustment VeinFraction 0 5 0 0 1 0
405. lighting in a project can be applied to an entire sequence You can change the reference frame at any time using the Switch Model item in the File menu For a new project you will have the option of importing the existing shaders and lights from your rib file allowing you to utilize the shaders assigned to agents in Massive If your scene contains references to texture maps make sure you use the mapdir option in massrib to remap the texture file references if necessary Note distant lights imported from Massive will appear quite small near the scene origin Rendering a Frame Sequence To render a sequence of frames select File Sequence in the Animation section of the Render page and enter a frame range in the text box such as 20 30 Click the Render Animation button in the toolbar to render the sequence or choose Export Animation from the Render menu to export frames without rendering Exported frames reside in a subdirectory of the current project directory For a project named stadium with version number 1 the exported frames will be e g stadium_vl stadium_v1 0020 rib stadium_vl stadium_v1 0021 rib stadium_v1l stadium_v1 0022 rib 2001 2014 SiTex Graphics Inc Massive 382 While a sequence is being rendered it is important not to overwrite the files in the export directory You can continue working and rendering in Air Space by incrementing the version number which will create a new export directory No
406. like some other renderers the quality of the blending between levels of detail does not depend on the PixelSamples setting Alternate Detail Camera AIR allows an alternate camera to be used for determining the level of detail in a scene The following option Option render integer detailcamera 1 marks the current camera definition Projection ScreenWindow Format and world to current transformation as the camera to use to calculate level of detail This option is followed by the normal camera definition for the scene An alternate camera is useful for rendering a shadow map that uses the same detail models as the beauty pass Limitations Blending between levels is not supported in the ray tracer only the representation with the greatest blend weight is retained for ray tracing Similarly the shadow hider only tests the model with the largest blend weight in a transition region Automatic Level of Detail AIR can automatically reduce the density of polygon meshes using an automatic LOD capability described here 17 Outlines for Toon Rendering and Illustration AIR can automatically draw outlines for cartoon rendering and illustration Outline generation takes place at the sub pixel level producing smooth lines without the need to render large intermediate images or post process the rendered image Outlining is enabled with the following option Option toon float maxinkwidth n where n gives the maximum line width in pixels
407. ll be defaultsurface or the surface shader declared in an air rib file in AIRHOME or the local directory nowarn Suppresses warning messages during rendering opp Enable the occlusion prepass opt name token value Define a custom option with a string or float value the equivalent of Option name token value p nthreads or threads nthreads Sets the number of processor threads to use This option overrides any option that sets the number of threads in the RIB file A value of 0 means use all detected processor cores the default pri priority Sets the task priority for the renderer under Windows Possible values are 0 normal priority or 1 low priority Rendering at low priority allows foreground applications such as a modeler to run unimpeded while Air renders in the background Progress Causes the renderer to print progress information to the standard output stream Progress is reported as a string formated as R90000 xxx mmmK nnnK tttS where xxx is the percentage complete mmm is the current memory used in kilobytes nnn is the peak memory used in kilobytes and tit is the elapsed time in seconds q8 Set quantization to 8 bit for rgb and rgba output as well as any channels specified in the mode option q16 Set quantization to 16 bit for rgb and rgba output as well as any channels specified in the mode 2001 2014 SiTex Graphics Inc 19 AIR User Manual option q
408. ll filter has a finite support Filter width should be 4 in each direction for the mitchell filter Lanczos Filter The lanczos filter is like a sinc filter with a finite support Filter width should be 6 in each direction for the lanczos filter Clamp to Alpha Output values much greater than 1 can be difficult to adequately filter even with many pixel samples To improve filtering of high dynamic range images Air will clamp output values to the current alpha value if the following option is enabled Option render integer prefilterclamptoalpha 1 When this option is enabled all output values will be less than or equal to 1 Field Rendering AIR 7 and later can render motion blurred frames on fields if the following option is enabled Option render integer fields 1 Half the motion samples go to field 1 half to field 2 so the results are only fully correct for full frame motion blur For best results pixel samples should be a power of 2 4 8 or 16 with 2001 2014 SiTex Graphics Inc 33 AIR User Manual 4 7 xsamples ysamples Hidden Surface Methods Air supports several primary hidden surface methods The method used for a given frame can be specified using the Hider command Hider name parameter list All methods render the image one tile at a time The following methods are supported Scanline Hider hidden The scanline method resolves hidden surfaces by scanning polygons and other
409. llustration 348 for edge detection is set with Attribute toon integer faceangle angle When angle is 0 angle based edge detection is disabled Edge Tagging Air 14 and later allow individual edges of a polygon mesh to be explicitly included in vector based outlines by providing a facevarying toonedge prim var of type float in the mesh definition Each entry is either 1 edge is visible or 0 edge is hidden Edge Merging Air 14 and later allow duplicate object based edges to be merged and treated as a single edge Merging edges can help avoid redundant drawing when using a stroke shader Enable edge merging with Attribute toon boolean mergeedges 1 Edges are considered to be the same if their end points are within a given tolerance Option toon mergetolerance 0 01 Edge Length Air 14 introduces a new option to limit the length measured in pixels of any one edge Option toon float maxedgelength 0 When this option is set to a positive value any edges longer than the specified limit are progressively split until the limit is satisfied This option can be useful when rendering with stroke shaders Line Color Line color can be set on a per primitive basis with Attribute toon color ink 0 0 0 Ink color can also be set by a surface shader with a ___ink output variable of type color Line Width Line width is set with Attribute toon float inkwidth 1 which gives a distance in pi
410. llustrator ai or EPS format for any shader parameter that expects a texture map When a file name with a ai or eps extension is passed to the standard shading language texture or environment functions AIR automatically calls Vtexture with the appropriate parameters 2001 2014 SiTex Graphics Inc 309 AIR User Manual See the Vtexture documentation for information on supported file formats and customizing the operation of Vtexture PTEX Per Face Texture Mapping Air 11 and later support per face texture mapping using the open source PTEX library Overview The PTEX library was developed to address several common problems with traditional 2D texture mapping e Assigning good texture coordinates to complex models can be difficult and tedious e Texture seams can be visible along discontinuities in the texture map e Large numbers of texture files can create a significant IO bottleneck The PTEX system addresses these concerns by eliminating UV assignment providing seamless filtering and allowing an arbitrary number of textures in a single file A PTEX file stores a separate texture map for each face in a mesh with adjacency information to allow proper filtering across face boundaries The PTEX library provides a texture cache for managing large numbers of textures efficiently PTEX files can store 8 bit 16 bit float and half precision data with an arbitrary number of channels Air PTEX Support Air supp
411. lor Texture blur Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur 2001 2014 SiTex Graphics Inc Shader Guide 214 TextureSizeXxY L Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform Transformation applied prior to projection OHOO rFoOoOOO 1 0 O 1 0 0 0 0 Description The VBlinn surface shader provides a plastic appearance using the Blinn specular model The optional color map if present is composited over the underlying base color given by the color attribute based on the texture alpha For a texture map without an alpha channel the map result replaces the base surface color The specular texture map modulates both the specular and reflection components Per light Output Variables In addition the standard output variables provided by most Air shaders the VBlinn shader provides output variables with per light results for diffuse unshadowed diffuse shadow and specular components of the shading model __lights i surface as illuminated by light channel i __lights_diffuse i diffuse component for light channel i __lights_unshadowed i unshadowed diffuse for light channel i __lights_shadow i shadow for light cha
412. ls Low percentages indicate that large sections of the shadow map are unused and that the user should consider refocusing the light A warning is issued in the status bar if any pixels along the edges of the image are non empty 2001 2014 SiTex Graphics Inc 405 AIR User Manual 24 3 4 Rendering to a Remote Machine 24 3 5 24 3 6 Not available in the demo version of AIR AIR Show and the AIR framebuf fer driver enable the output from a rendering process on one machine to appear in an AIR Show window on another machine The destination machine for framebuffer data can be set with the dhost AIR command line option air dhost 192 168 1 2 myfile rib or with a host parameter passed to the framebuffer driver in a RIB file Display remote tif framebuffer rgb String host 192 168 1 2 A host parameter in a Display call overrides any dhost command line option The host parameter should be the IP address of the host machine in dot 3 notation or aname for a DNS lookup AIR Show must already be running on the remote machine Framebuffer Parameters The AIR ramebuf fer driver accepts several optional parameters that are passed on to AIR Show float gamma n Sets the gamma correction value for the displayed image If provided this parameter overrides the default gamma in AIR Show If omitted the default gamma in AIR Show is used for the image String host ipaddress Gives the IP addre
413. ls from preceding image M A B blend between B M 0 and A M 1 group and order operations A B append channels in B to channels in A Note 1 Linux shells may expand to a wildcard mul should be used for multiplication Note 2 used as a divide operator must be separated by white space 2001 2014 SiTex Graphics Inc 417 AIR User Manual 24 7 7 Stitching Images 24 8 Version 12 of mktex introduces a new stitching mode for joining a grid of small images into a single large image The command syntax is mktex stitch nx ny basename00 tif outimage tx where nx and ny give the number of subimages horizontally and vertically All sub images must have the same width height number of channels and data type Each sub image should have a name like basenameXY tif where X between 0 and nx 1 and Y between 0 and ny 1 give the sub image index Image 0 0 is the top left image Stitching uses the new incremental conversion mode for handling large images The input file format must be compatible with that mode Texture Converter User Interface mktexui mktexui provides a graphical user interface for creating AIR texture maps from standard texture files The single window contains the following controls Image Source The source image file in any of the texture formats recognized by AIR The source can be a single file or a pattern for selecting several files E g c temp tif would select al
414. lt value is 0 5 Values of 0 7 or 1 can significantly reduce render times and memory use Threshold Tag AIR supports a special constant float __threshold tag for Blobbies that sets the distance at which the surface is defined The default value is 0 5 and the usable range is 0 1 to 0 9 Dynamic Blob Ops In addition to the standard Blobby features AIR allows users to define custom blob shapes with Dynamic Blob Ops A DBO is written in a programming language such as C and compiled as a DLL on Windows or a shared object on Linux The renderer automatically loads DBOs as they are needed by Blobby primitives DBO Structure Each DBO must implement the following functions void ImplicitBound State s float bd int niarg int iarg int nfarg float farg int nsarg char sarg The ImplicitBound function returns a bounding box for the blob op in bd The bound is six floats in the order minx maxx miny maxy minz maxz Arguments are those passed from the blob definition in the scene file see below void ImplicitValue State s float result float p int niarg int iarg int nfarg float farg int nsarg char sarg The ImplicitValue function returns a scaled distance from point p to the blob in result in the range 0 1 For blending purposes the surface of the blob is assumed to be at a distance of 0 5 Points further away than a distance of 1 are not affected by the blob void ImplicitRange State s float rng
415. lue for sun position local time location of observer difference between local time and GMT if non zero the end hour for sun animation multiplier for the global time value override for sun zenith angle in degrees override for sun azimuth angle in degrees ground diffuse reflectance ground reflections ground color angle in degrees over which the ground and sky transition at the horizon if 1 the Y axis is used as the up direction otherwise Z is up north as an angle in degrees relative to the x axis is the world space coordinate system right handed 105 AIR User Manual 10 4 10 4 1 Description The envPhysicalSky shader computes a physically plausible sky function based on observer position time and atmospheric conditions The sun position can optionally be expicitly set using the OverrideZenith and OverrideAzimuth parameters Reference A Practical Analytic Model for Daylight by A J Preetham Peter Shirley and Brian Smits Output only parameters color __background environment shader color result See Also sunlight light shader Generics The generic shader type is compatible with all other shader types Use generic shaders to build components for use with different shader types in shader networks genColor shader for selecting a color genOcclusion shader for adding an occlusion output value to a rendering genQueryBakedMap shader for querying a baked map
416. lumination using a seed file Using a Cache with Moving Objects An indirect illumination seed file can be re used in an animated sequence as follows 1 Setthe maxhitdist indirect attribute to a reasonably small value for all primitives 2 Render the scene with all moving objects removed to create an indirect seed file 3 Mark all animated objects as moving with Attribute indirect integer moving 1 4 Enable the following option Option indirect moving 1 5 Render each frame using the seed file AIR will cull samples from the indirect illumination cache in the vicinity of moving objects based on the maxhitdist attribute of the objects New samples will be generated in those areas Prepass In some cases indirect illumination results computed using indirect caching may appear splotchy due to the abrupt way in which new samples are added to the cache AIR supports an optional automatic pre pass that records indirect cache values prior to rendering the final image resulting in smoother indirect illumination The prepass is enabled with Option indirect integer prepass 1 AIR can use different quality settings on the prepass than the second pass Using higher quality parameters on the first pass results in a better final image A scaling factor for the maxerror and maxpixeldist attributes is given by Option indirect float prepassfactor 0 5 2001 2014 SiTex Graphics Inc 323 AIR User Manual If you
417. ly generate a point set handles Option render sssautocache 1 When this option is enabled Air generates a unique point set handle for each primitive whose surface shader contains a call to the subsurfacescatter function MayaMan users should use this option with caution MayaMan shaders always include a subsurfacescattering call even when that option is not used which will cause Air to retain objects for SSS cache generation when this option is enabled Custom Functions with collect If the builtin subsurfacescatter function doesn t meet your needs you can write your own 2001 2014 SiTex Graphics Inc 337 AIR User Manual 13 9 subsurface scattering function using the collect statement which exposes the underlying point set cache and query capability used by subsurfacescatter For an example of a custom subsurface scattering solution see SATRHOME examples surbsurface collectss Naturally collect is good for many other exotic effects as well See Also 3D Textures amp Point Sets VTranslucent surface shader VSkin surface shader Baking Shadows and Illumination Baked Shadows The new distantlight_baked pointlight_baked spotlight_baked and envlight_baked shaders extend the corresponding light shader with a few new parameters for baking The two most important are string bakemode bake mode string bakemap name of bake map Bake Modes The following bake modes are supported
418. maller maps with less precision which may render faster A format value of 1 stores more precise depth and coverage information You may wish to increase the texture cache limit when rendering with fragment maps because they tend to use more memory than conventional shadow maps Fragment Interpolation AIR 8 introduces a new option to enable interpolation between fragments in a fragment shadow map Option render integer lerpshadowmap 1 This option may reduce noise and jitter when render dense fur or hair Automaps Automaps are shadow maps automatically created by AIR on demand Automaps are currently supported for spotlights point lights and directional distant lights Using Automaps To enable automapped shadows for a light supply the special automap keyword as the shadow map name An object must be visible to shadow rays for it to cast automapped shadows Your plugin should provide a control to enable visibility to shadow rays Because automapped shadows use the mid point filtering method for depth values objects such as a ground plane that lie behind shadow casting objects must also be visible to shadow rays Automap Size The size of a light s automap is set with Attribute light integer automapsize 1024 Automap Coverage For spotlights AIR looks for a light shader s coneangle parameter to determine the region covered by the shadow map For distant lights the coverage of the automap must be set with Attribut
419. me allows a color map to be applied to the fibers BaseColor gives the color of the fabric under the fibers which is visible where fibers are missing IndirectDiffuse is a simple multiplier for the diffuse result returned for indirect illumination The shader does not trace fibers for indirect rays Carpet Trace Controls The FakeCarpet shader performs ray tracing to determine which fibers are visible at each shading location The following parameters control this internal ray tracing process SampleGridSize Because the carpet fibers will typically be much smaller than a pixel the shader provides an option to trace multiple rays to produce a smoother more accurate result SampleGridSize defines the size of an NXN grid of rays to trace at the current shading location The grid size is automatically reduced to 1 for reflection rays and IPR interactive preview rendering TraceMargin The FakeCarpet shader treats the rectangular polygon as a sort of window into a virtual grid of 3D fibers There can be artifacts along the edges if this window clips the carpet To help prevent those artifacts the TraceMargin parameter strips away a fraction of the fibers along the carpet border Larger values remove more rows of fibers TestForlntersections TraceBias TestForIntersections determines whether the shader checks for objects intersecting the carpet such as a chair leg If there are no objects on the carpet set this parameter to 0 to save some
420. me for every frame e In the MayaMan Globals dialog select the Advanced Options page e Scroll down to the section titled User Defined RIB Statements World and expand it e Paste the Procedural declaration you copied above into the text box Make sure the entire command line was pasted Click Save User RIB at the bottom of the section e Close the MayaMan Globals dialog Step 3 Add agents First create a new simple primitive such as a box or sphere to act as a standin for the agents With the new object selected add a MayaMan Model Attributes node Select the MayaManAttributes node and expand the section labeled ReadArchive Check Substitute RIB and use the file dialog to choose an agent file generated by Massive For an animated sequence MayaMan will replace a 4f pattern in the archive name with the frame number e Make sure the DelayedReadArchive option is NOT checked Step 4 Enable motion blur if applicable e In the MayaMan Globals dialog select the Motion Blur options page e Check Enable Motion Blur e Check Time in Zero to One Range e Set the Motion Blur Amount to correspond to the motion blur setting in Massive You should now be able to render your Maya scene with the agents appearing at render time in place of the proxy object The surface and displacement shaders used for the agents will be those configured for the selected render pass in Massive Automatic Level of Detail AIR 7 and later can automatically re
421. meet the above two conditions After the inital surface evaluation AIR can compute the effects of lighting changes on an object without having to re execute the surface shader which means that the refresh rate for relighting is independent of the complexity of the surface shader Although this mode is called relight it is still possible to tweak surface shader parameters though modifying a parameter of the surface shader will require re executing the shader Displacement Attribute ipr integer displacement 1 When set to 0 this attribute blocks execution of an object s displacement shader during an IPR session without affecting displacement during a final rendering Global Variable Storage Attribute ipr string globals This attribute defines a list of global variables to store at a surface in addition to the position normal and texture coordinate variables that are always stored Possible items dPdu dPdv TweakAlIR API Integration Adding support for TweakAIR to an application that already supports AIR is straightforward TweakAIR provides two mechanisms for managing an interactive session 1 A C based API for launching TweakAlIR as an external process and sending update commands via a TCP IP socket connection 2 Simple text commands that can be sent to TweakAlR via the standard input stream either from a command shell or via a connecting pipe TweakAIR C API The C based API header and source are included
422. ment The new algorithm is computed at double precision for better precision at very low frequencies The default noise algorithm can be restored with Option noise string algorithm air BRDF Clamping Air 14 introduces a new option to clamp BRDF sampling weights to 1 Option render boolean clampbrdf 1 By default BRDF clamping is enabled Network Cache AIR 6 and later can optionally create a local copy of texture maps stored on a network drive to speed texture access To enable local caching provide a directory to use for the local cache with Option netcache string cachedir cachedirectory The directory must exist The cache size in megabytes can be set with Option netcache integer cachesize 1000 There is also a debugging option Option netcache integer debug 1 In AIR 8 and later 3D point maps brick maps and point clouds will also use a network cache if available File Management These options apply to Linux only Air will limit the number of open file descriptors if the following option is enabled Option runtime boolean limitopenfiles 1 File descriptor management is currently limited to open texture files only The maximum number of open file descriptors can be set with Option runtime texturefilepool 512 2001 2014 SiTex Graphics Inc Options 60 6 7 User Defined Options Arbitrary data can be stored in a frame as a user option Declare bgenv st
423. minant via the option mentioned above under Spectral Prefiltering For images with an assumed sRGB color space a D65 display illuminant SATRHOME lights light_CIE_D65_noon_daylight is an appropriate choice SPD Data Air 10 includes sample SPD data in a new spectra directory The lights subdirectory includes SPD profiles for a number of standard CIE illuminants The colors subdirectory contains SPD data for colors in the Macbeth colorchecker chart The metals directory includes a few metallic profiles Material Reflectance When a color value is specified using an SPD file the effects of the dominant illuminant and chromatic adaptation are automatically included in the conversion to RGB By default the effects of DI and CA are not applied to colors specified as RGB values Those effects can be included by changing the current color space for RGB colors to the special litRGB space ColorSpace current litRGB When current color space is set to litRGB spectral prefiltering and chromatic adaptation are automatically applied to color attributes and shader parameters by first converting the RGB values to a spectral reflectance and then applying the spectrum to rgb conversion used for SPD files Shaders that allow the diffuse color to be modulated by a texture map can be modified to include the effects of spectral prefiltering and chromatic adaptation by converting the texture map color to current space color Ct texture
424. model for lighting volume and point primitives Isotropic Scattering When the PrimaryScatter parameter is 0 and the PrimaryWeight parameter is 1 this shader produces isotropic scattering in which incoming light is scattered equally in all directions The result is a simple sum of the incoming light This shader omits the 1 4PI term from the usual isotropic scattering equation you can adjust for this factor by setting the Diffuse parameter to 0 08 Anisotropic Scattering When the PrimaryWeight parameter is 1 anon zero PrimaryScatter value will produce preferential scattering in one direction If the scatter value is greater than 0 more light is reflected forward along the direction of the incoming light If the scatter value is negative more light is reflected back towards the light source The PrimaryScatterColor parameter can be used to adjust the 2001 2014 SiTex Graphics Inc 205 AIR User Manual scatter direction independently for each color channel The following image illustrates isotropic scattering forward scattering 0 5 and backward scattering 0 5 with blue light striking the front of the spheres and red light striking the back Scattering in Two Directions When the PrimaryWeight parameter is less than 1 the shader uses a weighted sum of scattering in two directions given by the primary and secondary parameter settings The second scattering contribution is weighted by 1 PrimaryScatt
425. mp 0i 0 lt 0 compute expensive opacity function Sample Shaders 2001 2014 SiTex Graphics Inc 353 AIR User Manual 18 2 The particle VCumulusCloud and VSmokeSurface shaders included with AIR are designed to shade volume primitives RIB Volume Primitive Volume shape xmin xmax ymin ymax zmin zmax Volume shape xmin xmax ymin ymax zmin zmax nx ny nz parameter list Volume shape xmin xmax ymin ymax zmin zmax O 0 0 P parameter list A Volume primitive describes a region of space to be shaded as a 3D volume based on the assigned surface shader The volumetric region is defined as a bounding box with one of the following shapes box ellipsoid cone cylinder Cone and cylinder shapes are oriented around the z axis in object space The cone tip is at zmin Grid based User Data Volume primitives provide two ways of assigning varying user data grid based and particle based The first method is useful for rendering the results of voxel based fluid simulations Grid based user data is assigned by defining a nx x ny x nz 3D grid Each varying variable should have nx ny nz values Typically one will want to assign varying opacity values AIR provides an efficient way to specify a single channel opacity instead of the usual 3 channel color Os in the form of a varying float floatOs parameter Volume box 2 2 2 2 2 2 2 2 2 varying float floatOs 1100 5 5 0O 0
426. mple large point maps as 3D textures using only a small fixed size cache Air Brick Map abm 3D data resampled into a hierarchy of 3D cells containing the original data filtered at different resolutions Like point maps sections of a brick map can be loaded on demand allowing cached access Like 2D texture maps the multiple levels of detail in a brick map allow the map to be sampled over large regions efficiently Loss of data inherent in the brick map creation process may result in artifacts when used for fine details Brick maps cannot be converted back into a point set RIB file crib Stores the point data as a RIB Points primitive If the file name contains the text ascii an ASCII RIB file will be written otherwise a more compact binary file is produced Text file txt A simple text format enabling data exchange with other programs and formats Maya PDC pdc read only Maya PDC file Maya position data is automatically converted to P data for RIB radiusPP is converted to width for RIB If the PDC file has no radius info a width variable with value 1 for all points is added Memory cache ram Creates a cache in memory for use only during the current rendering process Only useful for point sets created with the collect function Point File Manipulation Version 8 of AIR includes a new Air Point Tool airpt for converting between the different point based formats and performing other manipulations of 3D point d
427. mples may be needed to produce a smooth result See Also VMetal surface shader VPhysicalMetal surface shader 10 10 3 SimplePlastic i physically plausible plastic shader with simple parameters IIlumination Model physical plastic Parameter Default Value Range Description Diffuse 1 0 0 0 1 0 Multiplier for diffuse Specular 1 0 0 0 1 0 Multiplier for specular and reflections Roughness 0 03 0 0 1 0 Surface roughness Samples 4 1 1024 Number of rays traced for reflections Description This surface shader provides a physically plausible plastic or dielectric material The base color is taken from the standard color attribute The Specular parameter scales the result for both specular highlights and reflections Roughness controls the blurriness of reflections and the size of specular highlights larger values produce blurrier reflections and larger highlights Samples gives the number of rays to trace for reflections For larger Roughness values more samples may be needed to produce a smooth result See Also VPhysicalPlastic surface shader VPlastic surface hader 2001 2014 SiTex Graphics Inc Shader Guide 210 10 10 3 UseBackground surface shader that computes shadows and or reflections for compositing over a background image Parameter Default Value Range Description ShadowMask 1 0 0 0 1 0 Multiplier for shadow value Reflection 1 0 0 0 1 0 Multiplier for reflections ReflectionSamp 1 N
428. mpressed lossless Parameters integer 2 origin x y Specifies an offset in pixels for the upper left hand corner of the image float 2 resolution x y Gives the resolution of the image in x and y in pixels per unit given by resolutionunit string resolutionunit unit Gives the unit of measurement for the resolution of the image Unit must be one of inch meter centimeter or none The default is none string author name String copyright text string title title String description text Each parameter takes a string with the appropriate information By default none of these parameters are included in the output file psd Photoshop Synopsis saves images in Photoshop file format including layer information File extension psd Channels up to 32 channels Data types 8 bit or 16 bit unsigned integer File data compressed or uncompressed Parameters string compression type 2001 2014 SiTex Graphics Inc Output 46 5 7 10 Type is one of none or rle By default 8 bit data is compressed using RLE compression No compression is performed on 16 bit data Description The Photoshop display driver can write a simple Photoshop file with rgb or rgba information or a layered file with multiple output images ready for compositing in Photoshop or other applications Creating a Layered Photoshop File with AIR Control e Start AIR Control and select the scene to be rend
429. n Option indirect string envname Baked Illumination AIR includes an extended version of the indirect shader indirect_baked with additional parameters for baking indirect illumination to a 3D texture map and using 2D or 3D texture maps with stored indirect values bakemap ue Bake map file name bakemode idi Bake mode bakemapblur 0 Blur for bake map query bakemapfilterwidth 1 Filter width for bake map query See Baking Shadows and Illumination for more information See Also Indirect diffuse illumination envlight shader indirectchannels light shader for indirect diffuse illumination with light channel tracking Parameter Default Value Range Description intensity 1 0 Light intensity lightcolor 111 Light color environmentmap ji Optional environment map for background environmentspace world spaces Coordinate space for environment map __ category indirect Light categories __nonspecular 1 0 1 If 1 light will not produce highlights _ foglight 0 0 1 If 1 light illuminates volumes __indirectlight 1 0 1 Flag indicating indirect light status for multipass rendering _ channel L 0 9 Output channel _ bgchannel 1 0 9 Light channel for indirect bg value Output only variables color __background Background environment map contribution color 10 _ channels Per light output channels 2001 2014 SiTex Graphics Inc Shader Guide 140 Description The indirectchannels light
430. n The bumpy displacement shader uses a single texture map to displace a surface The texture map is positioned using an object s standard texture coordinates See Also VTexturedBump for displacement with a texture map with more controls 10 2 3 DarkTreeDisplacement 41 displace using a DarkTree shader 2001 2014 SiTex Graphics Inc 89 AIR User Manual Parameter DarkTreeShader BumpMax BumpMin Use2DCoordinates Texture2dSize Texture2dOrigin TextureAngle Pattern3dSize Pattern3dOrigin Pattern3dSpace TimeScale FloatTweak1Name FloatTweak1 FloatTweak2Name FloatTweak2 FloatTweak3Name FloatTweak3 FloatTweak4Name FloatTweak4 Description Default value Range wo 1 0 0 0 0 or 1 1 000 shader spaces Description Name of Darktree shader Bump multiplier Bump at 0 Set to 1 for a 2D pattern using an object s standard texture coordinates 2D pattern width and height 2D pattern origin Rotation angle in degrees for 2D pattern Overall scale for 3D pattern 3D pattern origin Coordinate system for 3D pattern Multiplier for global time variable Tweak name Tweak value Tweak name Tweak value Tweak name Tweak value Tweak name Tweak value The DarkTreeDisplacement shader allows any DarkTree shader to be used as a displacement shader in AIR The DarkTreeDisplacement shader provides a number of tweak parameters that can be used to alter the tweaks defined for a partic
431. n a paint program See Also 2001 2014 SiTex Graphics Inc 189 AIR User Manual Outlines for Toon Rendering and Illustration 10 10 6 constant constant colored surface Description The constant surface shader simply shades an object a constant color by applying the object s color attribute modulated by the object s opacity See Also VTexturedConstant shader VShadowedConstant shader 10 10 7 DarkTreeSurface 1 interface for Dark Tree shaders Illumination model custom Features reflections Parameter Default Value Range Description DarkTreeShader mag DarkTree shader file Diffuse 1 0 0 0 1 0 Diffuse multiplier Specular 1 0 0 0 1 0 Specular multiplier Reflection 1 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup Incandescence 1 Self illumination multiplier 2001 2014 SiTex Graphics Inc Shader Guide 190 Use2DCoordinates Texture2DSize Texture2DOrigin Texture2DAngle Pattern3DSize Pattern3DOrigin Pattern3DSpace BumpScale TimeScale ColorTweak1Name ColorTweak1 Colortweak2Name ColorTweak2 Colortweak3Name ColorTweak3 FloatTweak1Name FloatTweak1 FloatTweak2Name FloatTweak2 FloatTweak3Name FloatTweak3 FloatTweak4Name Float
432. n also be set See Also Indirect Diffuse Light 2001 2014 SiTex Graphics Inc Houdini 398 23 6 23 7 24 Creating Shaders for Air in Houdini Houdini allows RenderMan compatible shaders to be built in a manner very similar to building Mantra shaders RenderMan SHOPs are different from Mantra SHOPS Mantra cannot render RenderMan SHOPs and Air cannot render Mantra SHOPs An Air compatible RenderMan SHOP can be started in two ways Method 1 e Display the SHOP network e Inthe Tool menu go to the RenderMan Surface item and select the VOP RSL Surface Shader sub item This action provides a bare bones RenderMan surface shader You ll need to edit the network and add more nodes to create a usable shader For example e Edit the shader network e Go to the Tools menu Shading section and add a Lighting Model node e Connect the Lighting Model s clr output to the Ci input of the output node Ci is the emitted color result from an Air RenderMan surface shader e Assign your new SHOP to an object and test render to see a basic no frills surface shader Method 2 e Display the Material Palette e At the top of the lefthand pane select RenderMan as the gallery filter to display e Look in the General section for a Basic Surface entry and add it to the SHOP list e The new SHOP provides a surface shader with some basic controls and hooks into Houdini Compiling Houdini will automatically attempt
433. n utilize IES light profiles to simulate the illumination properties of specific light fixtures IES light simulation requires the new IES file reader and the new photometric _pointlight light shader included in AIR 10 IES Profiles IES light profile files represent the distribution of light from a fixture as a photometric web of measured intensity values over a range of directions IES file support is implemented as an image reader that converts the directional intensity information into a lat long environment map that can be queried using the standard shading language environment function The output of the IES reader is a single channel file at float precision storing the interpolated light intensity in candela Viewing IES profiles An IES file can be viewed in AIR Show just like images in any other image format supported by AIR By default AIR Show assumes a single channel file of float precision is a shadow map and applies some non standard display processing to the image You can turn off this special processing in AIR Show 4 03 or later by disabling the Detect shadow map option in the Options menu prior to loading an IES file Photometric lighting The new photometric pointlight shader in AIR 10 allows an IES profile to be used to illuminate a scene as follows 1 Set the iesname parameter to the file name of the IES profile 2 Optionally use the iesrotatex iesrotatey and iesrotatez parameters to rotate the orientation of the pr
434. nandsedvenuarssaoandsabcerssenuerssdsabesabacresuaed particle sessdscscesensicsssscscsdecesasduwerdedecvencdcuedeanededsubandvabandusduvursbassnendediedsentdtavandsdsebcsdusentardsdsdsdsabdaedeaded dsusabdvabandestuve Eei en E E ReelSmartMotion SNAAOWPASS a E E shinymetal sapeser asra aranana eenaa aaa Aeara aeaee Aaaa araa aa Anaa Aaa na aa aaaea aaa Caiana EAEE ShowNormal sssscccvcisaccscessscsesecenccsasssiesstesencesnscvaccerctunccesnssseesdatencennessseceusevacuencssbenedecensersecenesstcdstcvecsevieeesdiebissncetversts SHOWPOSILION A aa E E E E AE E E E E E E E SimpleMetal SimplePlastic USeBackQroun iicinccisscssscccscsssecsssrsscocsacasacesvensersvasapevascsateanuarsvabandsabcnedednuarsscoabenabadesecnuersbanandsabaceasentersvasabavancareeenze V2S IEP PIASHIC EES EE E E E E E E E E VAmimated Mapp ssisiisdiiisnesnisusnaisainaan nannaa aeoaea secceas ea cane a akapaa Sede ees iiaae iAd Eanna ERATA aa AAE atn A EEE E E E E E E E E E EE VBHICK2D ccsssescscdsaccccessicsesccenccsacssiesstctvnccecstvaeencubccesceevees atendsatcsvseccuacvasuetessbeseiedenserssceneestcsssacecscviesesddubisencetterets VBrushed Metall DRE EE E EEEE E E EE E VBrushedPlastic VC arPaint E AE EEE E EE E EE E E A E E E E ES ea E E E E e E re E E E eee heoi a E E E E E VClothAdvanced VCumulusCloud VCOOMCKOLS EEE E E E N P EAE EE E E E E VDashes VDecal2D VDecal3D Velvet VFabric VFur VGlass ALe Te Jt aN aa S E E P EE EE A E VGranite VGrid
435. nc 57 AIR User Manual 6 3 its resource specific search path A path is a colon separated list of directories The amp character will be replaced by the current path An environment variable can be included in a path by preceding its name with a For compatibility with other renderers and operating systems forward slashes should be used instead of backward slashes to separate directory names A directory name may be preceded by a drive letter followed by acolon AIR will distinguish between a colon after a drive letter and a colon used to separate directories Directory Mapping Air 11 introduces a new directory mapping option for automatically converting path names depending on the rendering machine s environment Option sSearchpath string dirmap list of mappings Each mapping is defined by 3 strings within brackets zone frompath topath The zone determines when the mapping is applied The zone for the current rendering process can be set with Option searchpath dirmapzone name The default zone is UNC under Windows and NFS under Linux When a directory mapping is active Air checks the beginning of each file name for a match with the frompath value If a match is found the frompath prefix is replaced by topath Here s an example Option searchpath dirmap NFS C usr local UNC usr local C With this mapping a Windows machine would convert a reference such as usr local imag
436. nce angle in degrees WeftColor 11 Color for weft threads WeftMapName me Texture map for weft color WeftDiffuseSpread 24 Volume scattering angle in degrees WeftDiffuselsotropy 0 3 0 0 1 0 Isotropic scattering tendency WeftSpecularSpread 12 Specular reflectance angle in degrees ThreadAngle 0 Rotation for thread directions in degrees ThreadAngleMap h j Texture map for rotation angle ThreadAngleMapMultiply 90 Multiplier for texture result TextureSizexY 11 Copies of texture in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle Description Texture rotation angle in degrees The VCloth surface shader provides a physically based shading model for woven cloth based on the paper A Practical Microcylinder Appearance Model for Cloth Rendering by Sadeghi et al Thread Directions Woven cloth is made by interleaving two perpendicular sets of threads or yarns known as warp and weft VCloth uses the tangent vectors for a surface which are usually based on the texture coordinates as the basis for the thread directions By default warp threads follow the tangent in the direction of the second texture coordinate Y weft threads follow the X tangent The thread directions can be rotated using the ThreadAngle parameters By setting the ThreadAngle to 90 you can effectively swap the warp and weft directions Rotating the thread directions does not affect the coordinates used for any texture maps Cloth appearance i
437. ncek 294 e O A E E 295 isindirectray wees 295 ISPNOLOM E E T E E E a 295 ISSNAGOWWAY scccvsessccssasessccscssssensarsedcscnacucveansdeseusspdvabaedesntarsbdccvendeddessansdtssancsdsasdsessenuardsdbapdsabcasseededtasanabdvabantestave 295 IM SMINTO seczzezeseceedscceczec scheceuessccessccceccnascceaas schecenessacesnccstedencses setae acne senesccarsoeaseadsnansydenes send saissccersneaspedeeanecasnpeacta 295 ITIGCOC YN o lE a A 2 seo ccs ect ke Se eee E E E vues couuegacus dussaucdaues tues saeseadevanaysteus 297 OCCIUSION e E E 298 EALL EE O E E E E E E E E E 300 rayinfo raylevel eToll aioa O D E 301 SNAGOW a Ee EE E E E E E AE E 301 2001 2014 SiTex Graphics Inc Vil AIR User Manual Part XI 1 2 3 Part XII Part XIII 1 2 Co OONO Part XIV 1 2 Part XV A OD a Part XVI specu lar siiisssssidsssssisdinsnarennnnnceoni inn benera AnA NS inanod nPar EAEn EAS Re Sda Ne eNA KANAREN ecean EAEri Enan EE ner N inne Nn kaAas EN ASEA d ENESA Ennn 301 Str_ replace last number ccesecsscccicssecsssecenecscecetesenesedvessscesccenssencsssnvsnsdvuecstestiecencsawscstecenecebedsvecedseruscescisesescstvecess 301 SUbSUrfacescatter siicisiscsiccscicascascessascssscccnscseseerssascvedendusdescearseabascsdccusensstavenndsencosssesuacasinatcsabcacusesssiddvdnabcsdveacesisca 302 texture acscscsescicascstcvaveccsdseacecesauessvedubasaucesdestasavasasdsatecsdetabisavdsabescasastesaves
438. nder 16 bit output might be air quantl6 rib scene rib When rendering 16 bit and floating point images be sure to use a file format that supports the corresponding data type 16 bit images are supported by the PNG PSD SGI and TIFF formats Floating point data is supported in the TIFF OpenEXR and HDR formats AIR Show can display images with 8 bit 16 bit or floating point data Multipass Rendering with Multiple Displays AIR provides two complementary features that enable multipass rendering 1 Multiple images can be produced from a single rendering by providing additional Display calls 2001 2014 SiTex Graphics Inc Massive 378 with the file name prepended with a 2 Any output variable from a surface shader can be saved in an image Most AIR surface shaders provide a standard set of color output variables _ ambient __ diffuse __ specular __ reflect __refract __incandescence constant __ diffuse is further broken down into __diffuse_unshadowed shadow __ indirect These extra output variables also sometimes referred to as arbitrary output variables or AOVs can be saved using an appropriate Display call A sample rib file that saves diffuse and specular passes in addition to a beauty image would look like Display mp_beauty tif file rgba quantize 0 255 0 255 Display mp_diffuse tif file varying color __diffuse quantize 0 255 0 255 Display mp_specular tif
439. ndex 1 For caustics to be visible there must be at least one object that is lit by the caustic light and at least one object that reflects or refracts photons The specularcolor and refractioncolor attributes determine what happens to photons that intersect a surface Photons will be reflected refracted or absorbed in proportion to respectively the average intensity of soecularcolor the average intensity of reflectioncolor and 1 minus the sum of the average intensities The sum of specularcolor and reflectioncolor should be less than or equal to 1 If the sum is greater than or equal to 1 no photons will be stored on that surface and no caustics will be visible Example 2001 2014 SiTex Graphics Inc Lighting 334 Attribute caustic color specularcolor 4 4 4 Attribute caustic color refractioncolor 25 25 25 In this case 40 of incoming photons light would be reflected 25 would be transmitted and 35 would be stored and visible as part of the caustic illumination When simulating caustics AIR shoots photons for all lights to build the photon map prior to beginning the main rendering pass No separate prepass is required for caustics Caustic Quality The following attributes affect the quality of caustic results Attribute caustic float maxpixeldist 10 Gives the maximum distance in pixels over which to gather photons for a caustic estimate Larger values produce smoother re
440. nents that can be combined to generate almost any texture or surface effect you need An evaluation version of DarkTree is available from the Darkling Simulations web site See also the section on using DarkTree shaders with AIR HDR Shop HDR Shop is an interactive graphical user interface image processing and manipulation system designed to view and manipulate High Dynamic Range images HDR Shop is available from Paul Debevec s web site Vtexture Alex Segal s DSO shadeop for using vector file formats as textures 26 Resources The RenderMan Interface AIR is compatible with the RenderMan standard for the description of 3D scenes To learn more about RenderMan consult the resources below Online documentation The RenderMan Interface Specification 3 2 Books The RenderMan Companion A Programmer s Guide to Realistic Computer Graphics by Steve Upstill Old but still a good introduction to RenderMan 2001 2014 SiTex Graphics Inc 423 AIR User Manual 27 Advanced RenderMan Creating CGI for Motion Pictures by Anthony A Apodaca and Larry Gritz An essential reference for RenderMan Contains some introductory material as background to the advanced techniques discussed Also has a good section on digital cinematography Essential RenderMan Fast by lan Stephenson This book is specifically designed as an introductory text covering the nuts and bolts of rendering and writing shaders
441. ng Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup 0 for plastic 1 for metal Hole size in X and Y 0 to 1 value transitioning from a rectangle to an ellipse Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection 2001 2014 SiTex Graphics Inc Shader Guide 256 Description This surface shader produces a pattern of holes on a plastic or metallic surface The hole pattern uses the primitive s standard texture coordinates 10 10 7 VShadeCarpet mS Parameter Default Value Diffuse 1 Specular 0 SpecularRoughnes 0 2 s ShadeLikeCylinder 1 FiberBounceLight 0 3 ColorMapName ColorMapBlur 0 OpacityMapName me OpacityMapBlur 0 0 TextureRepeatX 1 TextureRepeatY 1 TextureOriginX 0 TextureOriginY 0 See Also instCarpet instancer shader 10 10 7 VShadowedConstant Range 0 0 1 0 0 0 1 0 0 0 1 0 0 or 1 companion surface shader for the instCarpet instancer shader Description Diffuse reflectivity Specular multiplier Specular roughness Whether to shade each curve as if it were a cylinder Indirect light bouncing from nearby carpet strands Color map name Color map blur Opacity map name Opacity map blur Texture copies in the X direction Texture cop
442. ng memory by 1 3 to 1 2 See Also Lighting gt Indirect Lighting Shading for Indirect Illumination Lighting gt Shadows gt Ray Traced Shadows Ray Traced Shadow Attributes 15 Reflections Topics Ray Traced Reflections Reflections using Environment Maps Anisotropic Reflections BRDF Reflection Sampling 15 1 Ray Traced Reflections AIR can simulate reflections using ray tracing or environment maps Both methods may be used in the same scene with some objects using environment maps and some using ray tracing Ray tracing reflections is accomplished with the aid of a suitable surface shader Many of the shaders included with AIR support reflections including the VMetal shader and the vPlastic shader Most shaders that support reflections offer the option of using either ray traced reflections or some sort of reflection map e To enable ray traced reflections set the envname or Reflect ionName parameter of a surface shader to the special name raytrace e If the shader has a parameter such as ReflectionSpace or envspace for the coordinate space 2001 2014 SiTex Graphics Inc 341 AIR User Manual for the reflection vector set that to current Most shaders included with AIR will automatically detect the special raytrace keyword and use current space regardless In addition to enabling ray tracing in a surface shader objects that will appear in reflections must be made visible to reflection or trac
443. ng point 22 9 Rendering Massive Agents with Maya amp MayaMan This page describes how to render Massive agents as part of a Maya scene using Animal Logic s MayaMan plugin for Maya Background Massive creates two RIB files when it exports a scene for rendering with AIR a main RIB file 2001 2014 SiTex Graphics Inc 387 AIR User Manual 22 10 containing the terrain lights and global scene options and a second RIB file that defines the agents The agents file can be rendered as part of a Maya scene with the aid of MayaMan Step 1 Modify the procedural search path Massive uses a procedural primitive named run_program exe to generate agents at render time for AIR We need to add the location of that program to the procedural search path so that AIR will be able to find it From the MayaMan menu select MayaMan Globals In the MayaMan Global Options dialog select RenderMan Search Paths Select the Procedural tab Type the path to the bin directory of your Massive installation which contains the Massive run program e Click Add Step 2 Define options for the Massive procedural primitive The main RIB file generated by Massive contains a special command that initializes the procedural primitive with various options for the agents This line must be duplicated for MayaMan Look in the main rib file for a frame and find the line that begins Procedural Copy that entire line This line will be the sa
444. ng variables should have nx ny nz values Uniform or constant variables should have 1 value 8 9 Trim Curves Trim curves are supported and they require Phong per pixel shading Cracking between adjacent trimmed surfaces is a common problem when rendering NURB surfaces AIR provides a method of patching cracks by allowing the border of a trimmed surface to be slightly expanded Attribute render trimborder n gives a distance in uv space to expand the border of a trimmed NURB surface 8 10 Instancing with Inline Archives AIR supports an inline archive extension to the RI interface for efficient creation of multiple instances of the same RIB commands ArchiveBegin identifier ArchiveEnd ArchiveInstance identifier An inline archive block can be used to encapsulate a sequence of RIB commands in a single entity that can then be efficiently instanced multiple times Primitives and shaders declared within an inline archive will share data across instances of the archive RIB options are not currently supported in an inline archive See SAIRHOME examples instances for an example Freeing Instances Once created an instance will persist as long as the renderer is running If a given instance is no longer needed it can be freed with FreeArchive identifier 2001 2014 SiTex Graphics Inc 77 AIR User Manual which allows AIR to free the memory used by the instance once all references have b
445. ng wrapx periodic Option texture string wrapy periodic Other valid wrap values are black and clamp Projecting Textures Decaling Here s how to use the AIR Show display window to position textures for projective mapping A projected texture is mapped onto an object as though it were shown through a slide projector AIR Show allows you to use the camera positioning controls in a modeling program to position a texture for 2001 2014 SiTex Graphics Inc 2D Texture Mapping 308 projection Shaders included with AIR that can project texture maps include VDecal3DPlastic e Pretend that the camera is a light that is going to shine the texture map onto an object e Choose or create a view window in your modeling program If you have a choice use an orthographic view or a perspective view with a small field of view to reduce distortion Position the camera so the object you want to map is visible and so that you could draw a rectangle on the object that would define the texture map position e Export the scene and render a quick small draft image to AIR Show the AIR framebuffer In the display window drag out a rectangle with the mouse to define the placement of the texture map The texture map will exactly occupy the rectangle You do not need to draw a rectangle if you want the texture to fill the entire window Select Copy Decal Projection from the Edit menu in AIR Show This copies the projection
446. ngle for second half of branch BranchTwist 135 145 Angle of rotation about trunk applied to successive branches BranchStart 0 4 Relative position of first branch along trunk BranchCurveType tube Branch curve type BranchSurface mn Optional branch surface shader Branches gives the maximum number of branches for a tree of height TrunkHeight For trees shorter or taller than the average height the Branches value is scaled proportionally Nominal branch length is given as a range of ratios relative to the tree height The actual branch length at any position along the trunk is also strongly influenced by the tree shape BranchStart gives the position of the first branch relative to the base of the trunk BranchTilt gives the angle as a range in degrees to tilt the branch away from the trunk E g a BranchTilt of 90 would result in a branch perpendicular to the trunk If the BranchTilt values are negative a special mode is enabled that smoothly interpolates the tilt angle from tree base to tree tip instead of choosing the tilt angle for each branch randomly BranchBend defines an angle range used to bend each branch along its length If the BranchBendBack range is defined the BranchBend range is used for the first half of the branch and the BranchBendBack range is used for the second half allowing simple S shaped branches to be generated 2001 2014 SiTex Graphics Inc 171 AIR User Manual BranchTwist is a range
447. nlines in order from top to bottom data is a pointer to the data for the rectangle packed bytes in machine byte order A non zero return value should abort rendering but this action is not presently implemented 2001 2014 SiTex Graphics Inc Output 52 SID_CloseDisplay __declspec dllexport void SID_CloseDisplay SID_Info di SID_CloseDisplay is called once to close the display and to allow the driver to free any internal resources di points to the same structure passed to open display This function may be called before all or any of the image has been passed to SID_WriteRect if the user aborts the render for example It is up to the display driver to handle partially rendered images The driver should either produce a valid image file perhaps filling in missing image data or delete an incomplete and invalid file Compiling a display driver A display driver should be compiled as a DLL under Windows or a shared object on Linux Exported function names must be in the DLL not in a separate LIB file Making a driver available To make a driver available for use by the renderer 1 Place the driver in SAITRHOME displays 2 Add a new entry to the driver list in SATRHOME displays displays txt A driver entry is four comma separated fields devicename extension filename prompt devicename name passed to RiDisplay to select this driver extension filename extension associated with this driver f
448. nment shader is called automatically in the following cases e When a reflection or indirect ray exits the scene e For non opaque pixels in the rendered image with the ray type defined as a camera ray If the scene also has an imager shader the imager shader is executed after the environment shader at each pixel Shaders can also explicitly sample the current environment using the environment call with the special map name environment The optional samples parameter to the environment function can be used to super sample the environment shaders over a cone of directions defined by the blur parameter This brute force super sampling can be time consuming if the environment shader is computationally intensive Environment shaders have access to the ray direction via the global variable I and the ray origin in the global variable P An environment shader should set the output color ci and output opacity Oi just like a surface shader The behavior of an environment shader can be customized for different ray types by querying the current ray type with the rayinfo shading language function Environment Cache Air 12 introduces a new option to automatically build an in memory cache for environment queries from indirect rays Option indirect environmentcache 1 Using the cache produces much smoother results and is usually at least twice as fast for environment queries than rendering without The only drawback is that the cache
449. nnel i __lights_specular i specular for light channel i Each per light array holds up to 10 channels of data numbered 0 through 9 Assign a light to a particular channel by setting the light shader s __ channel variable Sample RIB usage Declare __lights varying color 10 Declare __lights_diffuse varying color 10 Declare __lights_unshadowed varying color 10 Declare __lights_shadow varying color 10 Declare __lights_specular varying color 10 Display lightO tif framebuffer _ lights 0 __lights_diffuse 0 __lights_unshadowed 0 __lights_shadow 0 __lights_specular 0 quantize 0 255 0 255 Display light1 tif framebuffer _ lights 1 __lights_diffuse 1 __lights_unshadowed 1 __lights_shadow 1 __lights_specular 1 quantize 0 255 0 255 2001 2014 SiTex Graphics Inc 215 AIR User Manual LightSource spotlight 22 float _ channel LightSource pointlight 23 float _ channel See Also Light Channels 10 10 3 VBrick2D basic brick shader with grooves Illumination Model matte Diffuse DiffuseRoughness BrickWidth BrickHeight BrickColorVary MortarWidth MortarColor Stagger EdgeVary EdgeVaryFrequency GrooveDepth PockDepth PockWidth TextureSizexY TextureOriginXY TextureAngle Projection ProjectionSpace ProjectionTransform Description 0 25 0 08 0 6 0 6 0 0 5 0 01 0 01 0 01 st shader
450. nsityunit parameter to one of the following supported values none intensity acts as a simple scalar with no conversion candela intensity is divided by illuminanceunity lumen intensity is converted to candela by dividing by 4 PI watt intensity is converted to lumen using lumensperwatt value When the watt unit is selected the lumensperwatt parameter should be set appropriately for the type of illuminant e g 8 17 for an incandescent bulb 60 72 for a compact flourescent Caustics Caustics are illumination effects from light that has been reflected or refracted in a focused manner onto a surface AIR simulates caustics using photon mapping Producing Caustics Producing caustics requires several steps 1 Add a caustic light source to the scene LightSource caustic 99 Turn the light on for any surfaces that are to receive caustics and off for all other surfaces 2 Set the number of photons to trace for each light that is to produce caustics Attribute light integer nphotons 100000 3 Make primitives that are to receive or produce caustics visible to indirect photon rays with Attribute visibility integer indirect 1 4 For each primitive that is to produce caustics by reflecting or refracting light set the reflective color refractive color and refraction index for caustics Attribute caustic color specularcolor 0 0 0 Attribute caustic color refractioncolor 0 0 0 Attribute caustic float refractioni
451. nt gt 0 caverage csum count The normal vector is ignored The query will return up to maxsamples points from the cloud within the search radius specified with the maxdist parameter Values associated with a given point can be queried by including point varname queries in the list of gather parameters Limitations gather statements should not be nested 10 15 14indirectdiffuse color indirectdiffuse point P normal N float samples parameterlist indirectdiffuse returns the indirect illumination at point P If the samples parameter is less than 2001 2014 SiTex Graphics Inc Shader Guide 294 1 the number of samples is taken from the indirect nsamples attribute indirectdiffuse accepts the following optional parameters Type and Name Description float blur blur factor for optional environment map string environmentmap environment map used to provide color for string string string float float float float 10 15 1tirradia rays that miss all objects environment space coordinate space for environment map lookup label user assigned name for rays cast by this call a shader can query the label with rayinfo subset restricts intersection tests to members of the specified groups as determined by Attribute grouping membership maxhitdist maximum distance to search for intersecting objects maxerror maximum error allowed when re using samples from the occlus
452. ntMarble Varying SSS Parameters In Air 10 the subsurfacescatter function handles varying parameter values properly However using a varying mean diffuse path reflectance or ior will be much slower When using varying parameters the max sample distance should be explicitly set to produce consistent results Use as 2001 2014 SiTex Graphics Inc 303 AIR User Manual large a max sample distance as feasible to save render time See Also eollect 10 15 3 texture color texture alpha alpha The standard texture accepts an optional alpha parameter that returns the next channel after the channels returned by the texture call For an RGBA file accessed with a color texture read starting at channel 0 the returned value will be the alpha channel of the file The extra channel does not significantly slow down rendering so it is always better to request an alpha channel if it might be needed rather than making an extra texture call Air 13 and later provide a builtin antialiased 2D noise pattern which can be generated by providing the special value noise as the texture map name 10 15 3 texture3d texture3d string filename point P normal N float blur blur float width filterwidth float fill fillvalue token value Texture3d returns a filtered sample from a 3D texture file generated by bake3d The filter region is automatically computed based on the input query position The opti
453. o current frame number to obtain sequence number for texture map Description The VBackDrop imager shader allows a texture map to be used as a background for the rendered image When IsSequence is set to 1 the texture map name is assumed to be one frame in a numbered sequence of images The image for the current frame is chosen replacing the last number in the image name by the sum of the current frame number and the FrameOffset 10 5 7 VBgEnvironment 4 imager shader using an environment map for the background Parameter Default Value Range Description Intensity 1 0 Map result intensity multiplier we EnvironmentName Environment map for background EnvironmentSpace world spaces Coordinate space for environment map lookup EnvironmentBlur 0 0 0 0 1 0 Environment map blur Description Use this imager shader to apply an environment map as the image background 2001 2014 SiTex Graphics Inc 115 AIR User Manual 10 5 8 VBgGradient 2 color vertical gradient background Parameter Default Value Range Description TopColor ds Ded Color at top of image BottomColor 000 Color at bottom of image Sharpness 0 0 0 0 1 0 Sharpening factor for transition MidPoint 0 5 0 0 1 0 Location of half way point in transition from top color to bottom color Description The VBgGradient imager shader provides a simple 2 color vertical background gradient 10 5 9 VGreyscale converts output color to grey scale Par
454. o match the appearance of a window with indirect lighting Updated VBlinn and VPhong shaders to include __ environment AOV and to support tracing light channels through reflections e Updated Emitter surface shader with texture option and separate intensity controls for different ray types Disabled the builtin background imager so the shader file is always run instead This change solves an issue where the standard background color was not applied to rgb or rgba outputs contained in a multichannel file e Atmosphere Interior and Exterior shaders may now use shader networks e Curves e New attributes to allow curves to be tapered at either or both ends e Miscellaneous e Settting the number of rendering threads to 0 can now be used to reset the thread count to the number of detected processor cores the default e The shading language texture function can be used to generate an antialiased 2D noise 2001 2014 SiTex Graphics Inc History 428 pattern by supplying the special texture name noise e Volume rendering ray marching now applies the view density and shadow density attributes e The q16 and qfloat command line options now apply the appropriate quantization when the d or file options are used A new q8 option forces quantization to 8 bit e Air now defines a user option of type float with the current version number in the format major minor This user option can be referenced in a condit
455. obal s t texture coordinates Some shaders simply use these s and t global variables as the shading coordinates Many are more flexible allowing you to choose a projection for transforming a 3D point into 2D texture coordinates 3D to 2D Projections The shaders that are included with AIR recognize the following projection types 2001 2014 SiTex Graphics Inc Shader Guide 82 10 1 5 st Use the default s t texture coordinates planar Use the x and y components of the point box Project the point onto a plane orthogonal to the x y or z axes based on the largest component of the surface normal This projection is useful for walls boxes and other shapes with flat sides that are perpendicular to a coordinate axis spherical Project the point onto a sphere centered at the origin with the poles on the z axis The latitude and longitude of the sphere are used as the texture coordinates cylindrical Project the point onto a cylinder wrapped around the z axis The first texture coordinate is the angle around the axis of the point measured counter clockwise from the x z plane scaled to the range 0 1 The second texture coordinate is the z component Projection Space For projection types other than st the coordinate system for the point used for projection may also often be chosen just as the shading space for a solid texture is using a ProjectionSpace or equivalent parameter Texture Coordinate Transform
456. ocation of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform 1000 Transformation applied prior to 0100 projection 0010 000 1 Description The VTranslucent surface shader simulates translucent surfaces using subsurface scattering with optional texture map When a subsurface scattering object is first encountered AIR calculates and stores a set of shaded points distributed over the object s surface You may notice a delay as AIR performs these computations After the point cache is generated rendering should proceed relatively quickly 2001 2014 SiTex Graphics Inc Shader Guide 268 To use subsurface scattering assign the same point set handle to all primitives that are part of the current shading object with for example Attribute pointset String handle head pts AIR shades points in the point cache from the outside of the object as determined by the current orientation If your object looks unlit with subsurface scattering try reversing the orientation of the object Use the ScatterDistance parameter to define the scatter properties for a particular type of material e g skin A table of real world values can be found in Jensen et al A Practical Model for Subsurface Light Transport in the SIGGRAPH 2001 Proceedings The default scatter
457. ocation to a light source the location is in shadow if the ray strikes any intervening objects Ray traced shadows can easily accomodate colored shadows and shadows for semi transparent objects Ray traced shadows are easy to use you only need to set the appropriate rendering options and attributes However they have several drawbacks e Memory usage Ray tracing requires that the entire scene be kept in memory for the duration of rendering including parts of the scene that are off screen which can use a lot more memory than normal scanline rendering e Speed Ray traced shadows can be slow for a large scene e Quality You will notice that the shadow edges are jagged Smoothing them requires casting extra shadow rays which increases rendering time proportionally Shadow Mapped Shadows Shadows can also be simulated using shadow maps A shadow map is made by rendering an image of a scene from the point of view of a light source and recording the depth of the nearest object at each pixel location The renderer can use the depth information to determine if a given point is in shadow by comparing its distance from the light source with the depth stored in the corresponding location in the shadow map Shadow maps are slightly more difficult to use than ray tracing but they have other significant advantages e Memory usage Shadow map size is independent of the complexity of a scene e Speed Shadow mapping is usually faster than ray tra
458. odessecsuaneas VSNOWBOUNG Pene E SE P EE E E E E 7 ame au a Sn nS oe a Ser SSS er eo ere NaS UES ae Pr a ambientlight siie Se irirna cute dee oenar Natari aana Nerana aena AE aaar Sanae Viera a a ada p Saara aana Ei Sae airna is arealight arealight_baked arealight2 arealight2_baked eede Nre na a E A E T E N E E E E ET CAUSTIC CAUSTIC DAKO cccisccccessccceissceccaecceencseseseucessccecerseuessssuctcvdesess seatvivedvausscecessvseterdsbaceceaheeesdvacesvvecussaueveecvie distantlight distantlight DAKCO i 2 2 2 lt ciccecciccccneececcecendeseces sees souczecccssccescceseitedeescoees douctduersteecacderaedecees duced scesteuerets 132 distant_projector distat window ghi s siescvvcccsessccecerssceteteen cavecs covesescsesctceresustctvsscetedussendssuesccieccsavetetvevsstctussueservonssdesteped atesncesseeeses envilight envlight baked iiss cccens se cedancevecesecty cenendec aenar assanar Vrendan aoa ara Vaar aaaea Horisont aiara indirect indirect baked is cccescdecedssccsescecteesesstcssscenssancecssesberesadeeasscecssseeetisusseeseaccecesdeset eacesaseoessesecuucesssessseneeisceee arolia ece oE E A E A E E AAE E TEE EE E EE E E E E T Massive envhght ss co cece cesecccsecpecccsendeccedeceecedueesuetcecepteuevendctedecpacectdesuesstecyeoderenauccecedsidecteatuedveuephetesaecveneveests massive INGIFECE sc ccesscccesssscccesssserdecessesddeussseevecssisecessucecevdesseedesntcevenctssscuccevseteecenacedddetsetvedessceaucessrsesaessene
459. of 2 When resize mode is set to up the next higher power of 2 is used Here are the corresponding output values for a 640x480 input image nearest 512x512 down 512x256 up 1024x512 Texture Input Formats AIR and its texture conversion tools can read image files in a variety of popular graphics formats AIR selects a texture reader based on the file name extension If a file does not have an extension associated with a particular driver AIR assumes the file is an AIR texture map The following is a list of currently supported raster image formats Format Extension Data Types Channels TIFF tif tiff 8 bit 16 bit float unlimited Portable Network Graphics png 8 bit and 16 bit 1 4 SGI File Format sgi rgb 8 bit and 16 bit unlimited JPEG Format jpg jpeg 8 bit 1or3 HDR Format hdr rad float 3 Photoshop Format psd 8 bit 16 bit 3or4 Windows Bitmap bmp 8 bit 3or4 Softimage PIC pic 8 bit 3or4 IES light profile ies float 1 PTEX ptex ptx 8 bit 16 bit unlimited float half High Dynamic Range HDR Images 2001 2014 SiTex Graphics Inc 307 AIR User Manual 11 1 AIR can use High Dynamic Range HDR images as texture maps and environment maps AIR can read images in the Radiance HDR image format that is popular for storing high dynamic range images As with other texture and environment maps conversion to an AIR texture file using AIR s texture conversion utilities is recommended for best performance and re
460. of angles used to rotate the starting position of each successive branch about the trunk axis The branch geometry is defined using a RIB Curves primitive The curve definition includes values for the second standard texture coordinate t giving the length along the branch This information allows textures to be applied to branches of different lengths without unnatural stretching BranchCurveType gives the curve type to use for rendering defaulting to a tube For trees that are far away the polyline or ribbon curve types may be used If the BranchCurveType is set to the empty string branches will not be rendered Twigs Parameter Default Value Range Description Twigs 30 Max number of twigs per branch TwigLengthRatio 0 6 0 6 Twig length relative to branch length TwigTilt 35 55 Twig angle relative to branch TwigBend 10 90 0 360 Bend angle along twig TwigTwist 135 145 Angle of rotation about branch applied to successive twigs TwigStart 0 Relative position of first twig along branch TwigCurveType ribbon Twig curve type TwigSurface ms Optional twig surface shader Twigs sets the maximum number of twigs per branch TwigStart is the relative position of the first twig along a branch Other parameters behave similarly to the equivalent branch parameters Leaves Parameter Default Value Range Description Leaves 25 Max leaves per twig LeafSize 0 06 0 08 Leaf size range absolute values LeafAspectRatio 0 9 Leaf width relative to
461. of shadow rays to trace The shadowblur parameter gives an angle in radians to distribute the rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Shadow mapped Shadows Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows Baked
462. ofile 3 Set the sceneunitsize parameter to size of one unit in world space in meters E g if your scene is modeled in centimeters sceneunitsize should be 0 01 4 Set illuminanceunity to the illuminance in lux corresponding to a non physical light source intensity of 1 This value is used as a divisor for the light s emitted intensity larger values will cause the light to appear dimmer Notes The illuminanceunity parameter tells the renderer how to map the physical light data into a rendering environment that lacks a physical camera model and may include non physical lights All lights in a scene and in any scenes that will be compared should have the same illuminanceunity value To make it easier to specify a common value the photometric_pointlight shader looks for a unity value in the following user option Option user float illuminanceunity 200 When the user option is present in the scene rib file the illuminanceunity parameter value is ignored Similarly the photometric_pointlight shader looks for the scene unit size in Option user float sceneunitsize 0 01 cm tom and ignores the sceneunitsize parameter value when the option is detected 2001 2014 SiTex Graphics Inc 333 AIR User Manual 13 7 Photometric illumination without an IES profile When the photometric light shader is used without an IES profile the light intensity can be specified in physical units by setting the inte
463. ointlight_baked with additional parameters for creating 3D shadow textures and using 2D or 3D baked shadows bakemap mm Bake map file name bakemode me Bake mode bakemapblur 0 Blur for bake map query bakemapfilterwidth 1 Filter width for bake map query motionbound 000000 bounding box for moving objects motionspace world space coordinate space of motionbound See Baking Shadows and Illumination for more information 10 7 16 portallight shader for area lights representing windows or other openings 2001 2014 SiTex Graphics Inc Shader Guide 146 Parameter Default Value Range Description intensity 1 0 Light intensity lightcolor 141 1 Light color maxemission 0 When greater than 0 max emitted intensity falloff 2 Exponent for attenuation with distance environmentmap aii Optional environment map for background environmentspace world spaces Coordinate space for environment map environmentblur 0 5 Blur for environment map lookup environmentsampl 16 Samples for environment map lookup es shadowname raytrace raytrace for traced shadows or for no shadows shadowbias 0 01 Offset for traced rays shadowcolor 0 0 0 Shadow color shadowgroups ad Shadow casting groups _ category indirect Light categories __nonspecular 0 0 1 If 1 light will not produce highlights _ foglight 0 0 1 If 1 light illuminates volumes __nondiffuse 0 0 1 If 1 light contributes diffuse illumination __ channel 1 0 9 Out
464. oking up a word s definition in a dictionary The dictionary function looks for a text file named dictname and tries to load a list of token value pairs one per line The token values should look like LightBlue 0 6 0 6 1 The dictionary call returns 0 if it succeeds If an error occurs the function returns one of the following error codes 1 unable to find or read dictionary file 2 key name not found 3 unable to convert value to the requested type Examples and source code SAIRHOME examples shadeop dictionary 10 15 1 diffuse color diffuse string category normal Nf roughness roughness Diffuse roughness 2001 2014 SiTex Graphics Inc Shader Guide 288 The diffuse function supports an optional roughness input parameter of type float giving the roughness used in the Oren and Nayer illumination model for rough diffuse surfaces such as clay The roughness parameter defaults to 0 which is the value for the regular diffuse computation The valid range for roughness is 0 to 1 Diffuse output variables The diffuse function provides the following optional color output variables unshadowed color diffuse lighting without shadows for all non indirect lights shadow color shadow value complementing the unshadowed output value indirect color indirect lighting channels color array per light diffuse values indexed by a light s __ channel output variable unshadowe
465. olor saturation ltemVaryBrightness 0 1 Per item variation in color brightness PaintVary 0 2 Variation in color over the image PaintVaryFrequency 6 Frequency of variation PaintVaryCenter 0 35 Zero point for random offset Seed 301 Random number seed ColorMapName N Texture map for base color ColorMapBlur 0 0 0 0 1 0 Texture blur OpacityMapName a Texture map for opacity OpacityMapBlur 0 0 0 0 1 0 Texture blur BumpMax 0 0 Maximum bump height BumpMapName ai Texture map for bump mapping BumpMapBlur 0 0 0 0 1 0 Texture blur TextureSizexY 11 Copies of texture in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform 1000 Transformation applied prior to 010 0 projection 0010 000 1 Description The VWatercolor shader simulates the effects of painting with watercolor by randomly varying object color over the surface The shader uses the toon id attribute to identify regions in the scene The ltemVary parameters can be used to vary the hue saturation and brightness of the color in each region In addition to the per item variation the shader adds a smooth variation in color across each region controlled by the PaintVary parameters The PaintVaryCenter parameter controls the extent to which colors are brightened values less than 0 5 or d
466. om a set of input files 2001 2014 SiTex Graphics Inc 401 AIR User Manual 24 3 Options 0o filename Specify the name of an output file to which the point set is saved after any modifications are applied The point set file format is based on the file name extension info Print information about the point set including the number of points and the channel names rench oldname newname Rename a channel in the point set The new name must not currently be in use by any other channel delch name Delete a channel from the point set The position channel P and width channel cannot be deleted scalech name scale Multiplies values in the named channel by the specified scale value maxch name max Limits the values in the named channel to be less than or equal to the specified maximum minch name min Limits the values in the named channel to be greater than or equal to the specified minimum range Prints the min and max value of each channel AIR Show AIR Show is the standalone program that serves as a framebuffer for AIR Images rendered to the framebuffer device in AIR appear in AIR Show If AIR Show is not running the framebuffer driver will automatically start AIR Show on the local machine AIR Show is much more than a simple framebuffer e As a separate program AIR Show remains open after a render has completed AIR Show can display any number of rendered images limited only by available
467. ompletes Modified test for degenerate polygons in ray tracer to be relative to coordinate size updated shadeop h file to include extern C declaration for shadeop table for C compatibility 29 6 AIR 8 0 e Procedure shaders generate new primitives on demand at render time using the shading language Instancer shaders create new geometry at render time based on an existing primitive e 3D Textures and Point Clouds New common set of 3D point file formats for all 3D data AIR Brick Maps AIR Point Maps AIR Point Tool airpt for converting and manipulating 3D point sets Point Maps and Point Clouds can be rendered as geometry using the RIB Geometry call e Points Renamed Attribute render string pointtype toAttribute point string type New point type disk Patches and disks can be oriented perpendicular to a normal vector Non square patches can be specified with a pat chaspect ratio primitive variable New attribute to automatically subdivide large point sets into smaller clusters for more efficient rendering Point width is scaled by a scaling transform e Curves New attribute Attribute curve string type name 2001 2014 SiTex Graphics Inc 443 AIR User Manual replaces Attribute render integer beveledcurve New curve type tube Ribbon curves compute a more accurate value for the global variable v along the curve length Ribbon curves work with uniform normal data Fix for
468. on All modes are supported on Windows The default compression type can be set with an AIR_TIFF_COMPRESSION environment variable E g AIR_TIFF_COMPRESSION l1zw float 2 resolution x y Gives the resolution of the image in x and y in pixels per unit given by resolutionunit String resolutionunit unit Gives the unit of measurement for the resolution of the image Unit must be one of inch or centimeter sgi SGI Image Format Description saves images in SGI image format File extension sgi Channels any number Data types 8 bit unsigned integer 16 bit unsigned integer File data uncompressed Parameters String description text 2001 2014 SiTex Graphics Inc Output 50 Stores an optional description of the image 5 7 15 shadow AIR Shadow Map File Description saves a depth channel as an AIR shadow map file File extension shd Channels z Data types float File data compressed tiled TIFF Parameters float append 1 Signals the driver to append the current shadow map to the given file This option can be used to generate a cube face shadow map or an occlusion map without creating temporary depth files float lerp 1 Enables smooth interpolation of deep shadow map data when rendered 5 7 16 texture AIR Texture Map Description saves images as AIR texture files compressed mip mapped TIFFs File extension t x Channels up to 32 channels Data types 8 bit
469. on meshes and subdivision surfaces AIR generates approximate tangent vectors based on the standard texture coordinates defined for the mesh BRDF Reflection Sampling Air 13 and later can sample the environment using reflection rays based on a particular BRDF bidirectional reflection distribution function This importance sampling method allows the behavior of reflections and specular highlights to be controlled using the same parameters while producing consistent results The new functionality enables a new set of shaders that implement physically plausible shading models while reducing the number shader parameters and unifying the behavior of specular highlights and reflections SimpleMetal SimplePlastic VPhysicalMetal VPhysicalPlastic For programmers the documentation for the environment function has a list of supported BRDFs 2001 2014 SiTex Graphics Inc Reflections 344 and technical information on how to sample based on a BRDF 16 Motion Blur DOF amp LOD Topics Motion blur Depth of field Level of detail 16 1 Motion Blur AIR can blur the appearance of fast moving objects in an animated scene The shutter command gives the open and close times for the camera shutter In a scene file this command appears as Shutter opentime closetime There should be an equivalent setting in a user interface that supports animation An animation program will set the appropriate shutter times for each
470. on model metal Features texture map reflections Parameter Diffuse Specular SpecularRoughness Reflection ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace ReflectionGroups ColorMapName ColorMapBlur OpacityMapName OpacityMapBlur Default Value 0 05 0 95 0 95 1 0 0 raytrace Current wee we 0 0 1 0 0 0 1 0 Description Diffuse reflectivity Specular reflectivity Specular roughness Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Groups to test for traced reflections Texture map for base color Texture blur Texture map for opacity Texture blur 2001 2014 SiTex Graphics Inc 247 AIR User Manual TextureSizeXxY L Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform Transformation applied prior to projection OHOO rFoOoOOO 1 0 O 1 0 0 0 0 Description The VMetal shader provides a basic metallic appearance with reflections and optional texture map controlling the base metal color The base metal color is taken from the object s color attribute multiplied by the color texture map if p
471. on the performance of foreground applications such as a modeling program e Click the Render button to start rendering The rendering job will appear in the list of tasks on the Jobs page As the frame renders you can check the console on the Jobs page for any error messages To rendering multiple frames e Enter the RIB file name for one frame in the sequence The file name must include a frame number left padded with zeroes E g scene0001 rib e Check the Frame range control and enter the first and last frame numbers in the appropriate boxes e Click Render Submitting Batch Render Jobs The companion airg program can be used to submit rendering jobs to the Air Control queue from a script or application If Air Control is not already running airg will automatically start Air Control For a single frame just submit the frame name airq scene rib The number of rendering threads can be set with a threads option airq threads 4 scene rib For multiple frames use one of the scene files as the rib name and specify the frame range with the frames option airg frames 0 19 threads 4 scene0001 rib AIR Point Tool airpt Airpt is a command line tool for converting and manipulating 3D point sets Airpt reads and writes the same point set file formats as AIR Airpt accepts one or more point set files as input airpt options pointfilel Airpt can print information about a point collection and or create a new output file fr
472. on values Using Baked Maps with Moving Objects Some baking shaders provide additional parameters that allow baked maps to be used in scenes with moving objects float 6 motionbound 6 numbers defining a bounding box for moving objects in a scene as minx maxx miny maxy minz maxz string motionspace the coordinate space for the motion bound A shader with these parameters will not query a baked map on points inside the motion bound or for shadows on points where a shadow ray might intersect the bound Normal shadow computations are performed in those areas Food for Thought It is perhaps worth mentioning that the 2D or 3D texture file used with one of the bake light shaders need not have been generated with that light For example it s possible to use an occlusion pass as the bakemap with bakemode readNDC for a spotlight or say paint a 2D light map for use with the indirect_baked shader 14 Ray Tracing Topics Importance Based Rendering Optimizing Memory for Ray Traced Objects 2001 2014 SiTex Graphics Inc 339 AIR User Manual 14 1 Importance Based Rendering Air optimizes ray tracing calls based on how important they are to the overall shading result For example if a shader indicates that a reflection call will contribute only 1 to the final pixel color Air can use that information to produce a faster lower quality result than a reflection that contributes 50 to the final pixel color T
473. onal width and blur parameters can be used to scale or increment the sample region respectively Texture3d will filter all points whose region of influence overlaps the query filter region If a given token does not have an associated value in the point file the corresponding variable value is filled in by the fillvalue 0 if the fill parameter is not specified Example surface bakematte3d float Diffuse 1 string BakeMapName float BakeMapBlur 0 float BakeMapFilterWidth 1 float BakeIt 0 float BakeRadius 0 1 normal Nnrm normalize N string raytype rayinfo type raytype if BakeMapName amp amp raytype collector if BakeIt 0 texture3d BakeMapName P Nnrm width BakeMapFilterWidth blur BakeMapBlur MCs ab gt else collect P 0 BakeRadius Ci 1 else 2001 2014 SiTex Graphics Inc Shader Guide 304 normal Nf faceforward Nnrm I1 j Ci Diffuse Cs diffuse Nf if BakeMapName bake3d BakeMapName Cs P Nnrm Cs Ci Oi Os Ci Oi See Also bake3d Bake3d surface shader 10 15 34trace color trace point pos vector dir parameterlist Optional Input Parameters The standard trace function accepts several optional input parameters Type and Name Description float bias offset to prevent incorrect self intersections float blur blur factor for fuzzy reflections string
474. one is found at the currrent level for more consistent results New optimizations for indirect irradiance cache management speed up rendering The radiosity cache now works when tracking light channels through indirect bounces though this scenario can use a lot of memory Statistics output now includes a stat for radiosity cache efficiency Change to behavior of indirect sampling when maxerror 0 and radiosity cache is enabled to produce much better indirect estimates at higher bounce levels This greatly reduces artifacts and noise at the expense of longer render time New option to decrease the detail in the radiosity cache at higher levels of indirect lighting saving time and memory Option indirect reduceradiosityquality 1 New handling of radiosity maps for triangles provides better mapping Increased max radiosity map size to 2048 2 Shading New stroke shader type for custom drawing of vector based outlines Sample strokePencil stroke shader New optimization reduces the overhead of networked shaders saving up to 30 on shading time for modest to large networks New option to clamp BRDF sampling weights to 1 Option render boolean clampbrdf 1 2001 2014 SiTex Graphics Inc What s New 22 By default BRDF clamping is enabled New displacement shader VWeaveDisplacement based on the VWeave surface shader New light shaders distant_window light and spot window light cast light only through
475. onment raytrace R surface __environment renv y BRDF Sampling Air 13 introduces a new option to importance sample the environment based on a BRDF When sampling based on a BRDF the environment function should be passed the shading normal vector instead of the reflected vector BRDF parameters are passed as extra parameters to the environment call prefixed with brdf Here s an example Cr color environment raytrace Nf samples Samples weight weight brdf cooktorrance brdf roughness Roughness brat rior Ler brdf absorption absorption Currently only ray traced environment evaluation supports BRDF sampling The following BRDFs are supported lambert standard diffuse BRDF no extra parameters air BRDF for the builtin specular function one extra parameter brdf roughness blinn BRDF for the builtin bolinn function two extra parameters brdf eccentricity bordf rolloff ward BRDF for the bultin brushedspecular function two parameters brdf xroughness brdf yroughness 2001 2014 SiTex Graphics Inc 291 AIR User Manual phong BRDF for the builtin phong function one parameter brdf exponent cooktorrance BRDF for the cooktorrance function Three parameters brdf roughness brdf ior prdf absorption See Also trace Environment shaders BRDF Reflection Sampling 10 15 1 foglight color foglight point from point to
476. onstant shader provides a constant colored surface with shadows Most displacement shaders have been updated with more descriptive parameter names and automatic true displacement detection e The SlGlass surface has been deprecated in favor of the new VGlass shader e AIR Show 2 e Tabbed output windows have been replaced by a list of images with thumbnails along the right side of the main AIR Show window Among other benefits this change circumvents the Windows limit on the number tabs in a single window The new AIR Show largely eliminates a problem on Linux where the display window would sometimes freeze during a rendering The toolbar may now be hidden and shown without restarting AIR Show On Windows the currently displayed image may be copied to the clipboard The image will copied as displayed i e the raw output data will not be copied e New and improved mktex and mktexui texture conversion utilities e Angular probe images can be converted to AIR environment maps e Source images may be flipped rotated and resized e Output data format may be specified as 8 bit 16 bit or float independent of source format e mktex can output to any image format recognized by AIR Vshade 0 4 See the separate Vshade manual for detailed information Bug fixes Important bug fixed in insertion amp sorting code Ray tracing hang bug Spiral bucket order with a crop window failed sometimes pow x y now works properly with negative y Rare divide
477. oom star BloomFalloff 2 Intensity falloff with distance BloomTint 1 1 1 Bloom color Starlntensity 0 4 Intensity multiplier for star effect StarRadius 0 3 Nominal star radius StarPoints 50 Number of points in star StarFalloff 3 Intensity falloff with distance StarTint oe oe Star color RingIntensity 0 1 Intensity multiplier for rings RingRadius 0 05 Nominal ring radius RingWidth 0 07 Ring width RingTint 1 25 35 Ring color FilterWidth 2 Filter width multiplier for antialiasing MinLightIntensity 0 01 Minimum light intensity Apply_sRGB 0 Oor1 if non zero apply sRGB gamma correction LightCategories lensflare Categories identifying lights that contribute to lens flare RandomSeed 137 Seed number for random effects Description The LensFlarelmager shader adds lens flare effects to an image It is inspired by the lensflare shader in the Advanced RenderMan book This version is an imager shader not a surface shader and differs substantially from the original in many other ways The flare effect has three independent components Bloom a glow effect representing the visible light source Star a star shape with thin points Ring a single ring around the light source Each effect is exported in a corresponding output variable __bloom __star and __ ring for use in post processing The flare is generating by looping over the lights in the scene Only lights in the categories listed in the 2001 2014 SiTex Graphics Inc
478. opolygons Fix for fragment shading in 64 bit Air for Windows workaround compiler bug Fix for unfiltered texture read of images with fewer than 3 or more than 4 channels Tweak for shading optimizer to provide derivs inside a loop with multiple iterations Shader files that have been truncated are now reported as corrupt Fix for rendering curves with uniform width as tubes or ribbons Fix for memory use reporting to prevent erroneous extreme values due to thread interference When Air is unable to save an occlusion file the error message includes the file name 2001 2014 SiTex Graphics Inc 429 AIR User Manual 29 2 AIR 12 0 First official release of the Air Stream plug in for Maya available as a free download from the SiTex Graphics web site 64 bit build for Windows the Windows distribution of Air now includes a 64 bit version of Air named air64 exe New ray tracing primary hider Occlusion e New axis parameter for the occlusion function takes a vector value If non zero the vector defines the up direction for hemisphere of incoming light Any occlusion rays pointing down with respect to the up direction will be considered occluded by a virtual ground plane and not traced at all Occlusion optimize normal option is now disabled by default when an occlusion cache is not used which produces more detail for bump mapped surfaces Important fix for occlusion to prevent recursive calls for surfaces
479. opriate software To render agents the ribs generated by Massive use a small procedural primitive a program to generate agents on demand That procedural and the agent data must be available to all machines used for rendering If changes are made to an agent inside Massive the agent must be re saved for the changes to show up in a rendering Some older sample agents included with Massive must be re saved to render properly even if no changes have been made to the agents AIR 8 allows a frame sequence to be rendered with simple frame number substitution For example air frames 8 10 scene f rib would render scene8 rib scene9 rib and scenel0 rib The frame number pattern can also be zero padded air frames 8 10 scene 3f rib would render scene008 rib scene009 rib and scene010 rib Command Line Rendering of Massive Scenes The scene files generated by Massive can be rendered by invoking AIR from a terminal window or command shell An individual frame can be rendered by providing the name of the main rib file as an argument to air air rib frame0001 rib AIR accepts multiple rib files on a single command line Multiple files are processed in order from left to right Additional small files with RIB commands can be used to customize a rendering without modifying the main scene file For example one could use the small file quant16 rib to render an output image with 16 bit values air quantl6 rib scene rib Command Line Switches AIR
480. or Specular intensity Specular roughness Reflection multiplier Number of reflection rays to trace Blur angle for reflection in radians Transmission multiplier Max distance to trace transmission rays Rays to trace for refraction Exponent for transmission decay with distance Blur angle for transmission rays Color for sea close to observer Foam multiplier Foam color Extent to which foam obscures water Multiplier for foam lighting Constant added to foam lighting Raw offset added to the base foam value Multiplier for raw foam value Exponent for foam value 2001 2014 SiTex Graphics Inc Shader Guide 202 GridCountX 128 Grid size in X direction GridCountY 128 Grid size in Y direction SizeX 200 Nominal size of X dimension SizeY 200 Nominal size of Y dimension WindSpeed 5 Wind speed WindAlign 8 Wave alignment with wind direction WindDir 0 Wind direction as an angle in degrees SmallWave 0 1 Small waves will be ignored Dampen 0 75 Amount to dampen waves not aligned with the wind Chop 1 Amount of chop to add to waves FramesPerSecond 24 Value used to compute current time for animation FoamEnabled 1 Oor 1 Whether foam needs to be simulated for the surface shader RandomSeed 123 Base for random number generator Description The OceanSurfaceWithFoam shader provides a basic illumination model for a deep ocean surface with a foam option for use with the OceanWaves displacement shader The de
481. or 0 5 0 5 0 5 FurTipColor 1141 FurColorMap a FurDiffuse 0 7 0 1 FurDiffuse 0 3 0 1 Description Description Max hairs per clump Clumps per surface Hair width Max hair length Min hair length Optional map for hair length Frequency of length variation Min tilt angle in degrees Max tilt angle in degrees Frequency of tilt variation Random twist angle per hair Base fur color Fur root color multiplier Fur tip color multiplier Optional fur color map Diffuse reflectance Specular reflectance The VGrowFur instancer shader creates short fur on a surface The fur is positioned using standard texture coordinates so the underlying surface must have a well defined set of standard texture coordinates The fur is created as a set of clumps For each clump a single RIB Curves primitive is created with up to Density individual hairs Each hair is represented as a simple linear line segment The shader adjusts the number of hairs in a clump based on the area of the surface covered by the clump smaller areas receive fewer hairs The shader assigns the VFur surface shader to the fur The FurRootColor FurTipColor FurDiffuse and FurSpecular values are passed to the corresponding VFur parameters VinstanceArchive simple instancer creating copies of a RIB archive at particle locations 2001 2014 SiTex Graphics Inc Shader Guide 124 Parameter Default Value Range Description Archive a RIB archive file
482. or importance of this trace call for importance based ray tracing 10 15 2 specular color specular string category normal Nf vector V float roughness sharpness The specular function accepts an optional sharpness parameter with a value between 0 and 1 A value of 0 produces the normal specular result Larger values produce a highlight with a sharper edge giving a glossy appearance The specular function also provides a channels output variable an array of colors holding per light specular values indexed by a light shader s __ channel output variable A nchannels output variable gives the number of valid channels 10 15 3 str_replace_last_number string str_replace_last_number string olds float newnum This function searches backwards from the end of the string looking for an integer value If one is found it is replaced with the provided new value 2001 2014 SiTex Graphics Inc Shader Guide 302 This function may be useful when dealing with a numbered sequence of file names 10 15 3 subsurfacescatter color subsurfacescatter point P normal N vector meandiffusepath color reflectance float ior float maxsampledist The subsurfacescatter function returns an estimate of the multiple scattering component of subsurface scattering at P meandiffusepath is the average distance light diffuses through the material for the red green and blue color components The mean dif
483. orted by a surface shader When this feature is enabled the _ reflect and __ refract output variables are no longer applicable to the composite However the light channels will not include the contribution of the background environment map for reflections if any The __environment output variable from the surface shader will contain that contribution Tracking Light Channels through Indirect Illumination AIR 9 and later can track light channels through indirect diffuse light bounces This capability is provided in the indirectchannels light shader which can be substituted for the indirect light shader normally used for indirect diffuse illumination 2001 2014 SiTex Graphics Inc Output 40 Shading Language Support for Light Channels AIR enables shaders to efficiently provide per light output values with special extensions to the standard diffuse specular phong blinn and brushedspecular illumination functions These functions provide a channels output variable an array of colors containing the function result for each light indexed by a light shader s __channe1 output variable A nchannels output variable gives the number of valid channels The diffuse function also provides an unshadowedchannels output with unshadowed diffuse results for each channel Example SAIRHOME examples multipass perlightpasses rib 5 4 Stereo and Multicamera Rendering AIR 10 introduces the capability to render images
484. orts PTEX for the following applications Surface and displacement textures for arbitrary convex polygon meshes Surface and displacement textures for subdivision meshes that are all triangles or all quads Cube faced environment maps Texture baking for polygon meshes and subdivision surfaces with BakeAir e e e e Using PTEX Textures PTEX textures can be used with any shader that accesses texture maps using the standard texture coordinates s t Just enable the following attribute to have Air automatically assign the necessary face indices and texture coordinates Attribute render boolean ptex 1 The PTEX library maintains its own texture cache The maximum memory used by the cache can be set with Option limits ptexmemory 100 giving the memory limit in MB The maximum number of open PTEX files can be set with Option limits ptexfiles 100 By default the texture coordinates generated by Air for Ptex textures will be the standard texture coordinate pair st You can change the name for ptex coordinates with 2001 2014 SiTex Graphics Inc 2D Texture Mapping 310 Attribute render string ptexcoordinates st Limitations Ptex support for subdivision meshes is limited to meshes that are all quads or all triangles Using 3DCoat Textures The PTEX files exported by the 3DCoat paint program appear to have the texture coordinates swapped You can compensate for that in most Air surface shaders
485. orus with a larger minor radius than the glowing torus The Glow shader interpolates opacity based on the facing ratio which is the cosine of the angle between the viewing direction and the surface normal The facing ratio ranges from 0 when looking at a surface on edge to 1 when looking directly at a surface The AlphaFalloff parameter controls how quickly the opacity value changes with angle When EdgeColorEnable is set 1 color is also interpolated based on the facing ratio 2001 2014 SiTex Graphics Inc 197 AIR User Manual 10 10 1 IndirectPass surface shader recording indirect diffuse illumination Parameter Default Value Range Description Intensity 1 0 Multiplier for recorded value Samples 1 0 0 1 0 If greater than 0 the number of rays to trace for each indirect sample Description This surface shader stores the indirect diffuse illumination result at the current shading location as returned by the indirectdiffuse function Note that this shader REQUIRES use of an indirect shade mode that does not evaluate the surface shader mode matte or mode constant If the Samples value is less than 1 the number of traced rays is taken from the indirect nsamples attribute value for the object This shader may be useful when baking indirect illumination for use with AIR s indirect_baked light shader See Also Indirect lighting indirect_baked light shader indirectdiffuse shading lan
486. osition values When set to 1 emitted values are clamped to the unit interval When set to 1 emitted values will repeat over the unit interval coordinate space for emitted values The ShowPosition surface shader sets the output color to the X Y Z coordinates of the current shading position P with optional offset and scaling Output Color Position Origin UnitSize When the Clamp parameter is set to 1 the output color is clamped to the unit interval When the Cyclic parameter is set to 1 the output color is restricted to the fractional part of the offset and scaled position 10 10 2 SimpleMetal a physically plausible metal shader with simple parameters 2001 2014 SiTex Graphics Inc 209 AIR User Manual IIlumination Model physical metal Parameter Default Value Range Description Reflectance 0 9 0 0 1 0 Reflectivity Roughness 0 03 0 0 1 0 Surface roughness Samples 8 1 102 Number of rays traced for reflections Description This surface shader provides a physically plausible metallic appearance The metal s color is taken from the standard color attribute The Reflectance parameter scales the result for both specular highlights and reflections Roughness controls the blurriness of reflections and the size of specular highlights larger values produce blurrier reflections and larger highlights Samples gives the number of rays to trace for reflections For larger Roughness values more sa
487. ot aligned with the wind Amount of chop to add to waves Value used to compute current time for animation Whether foam needs to be simulated for the surface shader Base for random number generator The OceanWaves displacement shader simulates deep ocean waves using the method described in Jerry Tessendorf s 2004 paper Simulating Ocean Water The waves are computed by evaluating a simulation on a discrete grid which is mapped to the unit interval in texture space X corresponds to the first texture coordinate Y to the second coordinates The GridCountX and GridCountY parameters give the grid size A larger grid produces more detail but takes longer to compute SizeX and SizeY give the nominal size of the ocean area The waves can be tiled in X and Y WindSpeed gives the average wind speed Higher values produce larger waves WindDir can be used to change the wind direction by providing an angle in degrees about the vertical axis 2001 2014 SiTex Graphics Inc 91 AIR User Manual 10 2 5 WindAlign controls how much the wind direction influences the wave directions by applying an exponent to the dot product of the wind direction and the direction of each wave Larger values reduce the amplitude of waves not in the direction of the wind base on the Dampen factor Chop The appearance of waves in windy conditions can be improved using the Chop parameter which sharpens wave peaks and stretches troughs by s
488. output image by adding a Display call to the occpass rib file Display occlusion 4f png file rgb Option render commands Display When rendering multiple frames you ll need to include a frame block with the frame number in the air command line to generate a unique image name for each frame For example air occpass rib FrameBegin 22 render 0022 rib FrameEnd will render to occlusion 0022 png The shell script generated by Massive can be modified to include the additional command line parameters in the line that begins air This method can be used to render an occlusion pass with the RIB files generated for a beauty pass in Massive there is no need to generate a separate set of RIB files for the occlusion pass The same workflow can be used without the occlusion cache and prepass To disable the occlusion cache change the maxerror value to 0 in the auxilliary rib file To disable the occlusion prepass set the prepass option value to 0 Here s a sample rib for rendering without an occlusion cache override all surface shaders 2001 2014 SiTex Graphics Inc Massive 384 Surface occlusionpass Option render commands Surface disable occlusion prepass Option occlusion prepass 0 disable occlusion cache Attribute indirect maxerror 0 0 set quality attributes Attribute indirect nsamples 256 set max distance to search for occluding
489. ovided to control the orientation along the entire curve length Shading Curves When rendering hair or fur it is useful to shade the ribbon like 3D curves to appear cylindrical to mimic the appearance of the corresponding natural fiber AIR includes two surface shaders designed specifically to shade hair or fur VHair and VFur The different names aside either shader may be used for either hair or fur Curve Tapering Air 13 introduces new attributes that allow curves to be tapered at either or both ends Attribute curve string tiptapertype none Attribute curve float tiptaper 0 5 Attribute curve string roottapertype none Attribute curve float roottaper 0 5 2001 2014 SiTex Graphics Inc 71 AIR User Manual 8 6 For tube shaped curves tapering seals the end of the tube For ribbon curves tapering produces a leaf like shape By default no tapering is applied The tiptaper and roottaper values determine where along the curve the tapering begins based on the tiptapertype or roottapertype selection width taper value is multiplied by the curve width length taper value is multiplied by the curve length absolute taper value is treated as a fixed length Set the taper type to none to disable tapering NuCurves AIR implements a NuCurves primitive for rendering NURB curves in addition to the standard Curves primitive which only supports linear and cubic curves The RIB
490. owgroups es shadowattribute user shadowgroups __nondiffuse 0 __nonspecular 0 __ foglight 1 _ channel 1 Description Range Oor1 1 12 o 0 24 Oori Oor1 0 0 0 5 1 256 Description Light intensity Light color whether to use the computed sun color atmospheric turbidity integer 2 9 date month day of month time of day 24 hour clock observer location difference between local time and GMT When non zero the end time for animation Multiplier for the global time value When positive sets sun zenith position Override for sun azimuth position when 1 Y is up otherwise Z is up North direction as an angle in degrees relative to the X axis Set to 1 for a right handed coordinate system Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for traced shadows Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel The sunlight shader computes the position and color for a sun like light source based on the observer s position the local data amp time and the atmospheric turbidity The turbidity parameter sets the relative portion of atmospheric scattering due to haze instead of molecules Larger values model atmospheres with more l
491. pDiffuseSpread or WeftDiffuseSpread determines how light scattered through the thread is emitted The volume scattering is also affected by the isotropy parameter WarpDiffuselsotropy or WeftDiffuseIsotropy which specifies the threads tendency to scatter light in all directions versus scattering preferentially along the incoming light direction Threads are constructed from cloth fibers in two different ways and the method of construction affects the optical properties of the thread Staple threads such as cotton are made out of twisted fibers and they are held together by friction Filament threads are made of long straight fibers such as silk with little twist Here are some measured values for different thread types from the above cited paper Thread Type IOR Diffuse Spread Diffuse Isotropy Specul ar Spread Linen flax 1 46 24 0 3 12 Flat silk 1 35 10 0 2 5 Twisted silk 1 35 32 0 3 18 Flat polyester 1 54 5 0 1 2 5 Twisted polyester 1 54 60 0 7 30 See Also VCloth surface shader VFabric surface shader 10 10 4 VCumulusCloud cloud surface shader for volumetric primitives IIlumination Model particle 2001 2014 SiTex Graphics Inc 227 AIR User Manual Parameter Default Value Range Description Diffuse 19 Diffuse reflectivity Incandescence 0 0 Self illumination value Ambient 0 0 0 0 1 0 Ambient reflectivity OpacityMultiplier 1 0 Opacity multiplier PrimaryScatter 0 1 1 to 1 Primary s
492. pace for reflection lookup Index of refraction Fraction of light transmitted through the glass The VThinGlass surface shader is intended for glass surfaces modeled as a single surface in which the effects of refraction are not noticable See Also VGlass shader for thick glass with refraction effects 10 10 7 VTone surface shader for illustration Illumination model custom 2001 2014 SiTex Graphics Inc 265 AIR User Manual Parameter Diffuse Specular SpecularRoughness SpecularSharpness CoolDiffuse CoolColor WarmDiffuse WarmDiffuseColor Description Default Value Range O 0 2 0 0 0 1 0 0 0 1 0 Description Diffuse reflectivity Specular reflectivity Specular roughness Specular sharpness Amount of base color to add to cool Cool diffuse color Amount of base color to add to warm Warm diffuse color This surface shader implements the lighting model described in the paper A Non Photorealistic Lighting Model for Automatic Technical Illustration by Gooch et al The illumination model shades objects based on the cosine of the angle between the light ray and the surface normal Surfaces facing completely away from the light are shaded the CoolColor A surface facing the light is shaded the WarmColor Orientations in between smoothly blend between the two colors The CoolDiffuse and WarmDiffuse parameters control how much of the base surface color is added into the cool
493. paces Coordinate space for output vector Description This surface shader computes a motion vector compatible with the ReelSmart Motion Blur plugin To obtain useful output the scene must have motion blur defined and enabled Set the MaxDisplace parameter to the same value used in the plugin The vector image should be rendered with the following settings e PixelSamples 1 1 e A box filter with a filter width of 1 e Gamma correction disabled gamma set to 1 e For an 8 bit image quantization should be set as Quantize rgba 254 0 255 0 For a 16 bit image quantization should be Quantize rgba 65534 0 65535 0 Reference This shader is based on the information at http www revisionfx com generalfaqsMVFormat htm alpha 10 10 2 shadowpass surface shader that computes a shadow pass 2001 2014 SiTex Graphics Inc 207 AIR User Manual Parameter Default Value backshadow 0 fuzz 0 05 Description Range Oor 1 0 1 Description Set to 1 for shadows on surfaces facing away from a light Transition softness along silhouette edges when backshadow 1 This shader sets the output color to a shadow value for the current shading location This shader only works properly with lights that export a color __unshadowed_C1 output variable All AIR light shaders as well as the MayaMan and RhinoMan light shaders should work properly 10 10 2tshinymetal a metal shader with reflections Illumination model metal
494. pacity For surface shaders without opacity controls an auxiliary shader can be used to control the opacity Hereisa simple generic shader that sets the input opacity value generic OpacityMap string OpacityMapName float SetOpacity 1 output varying color __Opacity 0 if OpacityMapName _ Opacity color texture OpacityMapName s t fill 1 if comp __Opacity 1 1 __Opacity comp __Opacity 0 handle Single channel texture if SetOpacity 1 Os __Opacity 2001 2014 SiTex Graphics Inc 279 AIR User Manual This shader allows any surface shader that modulates its output color by the input opacity to be composited over another shader Most surface shaders modulate their output color in this way Here is how the OpacityMap shader might be used to add a marble decal to a 2D grid Surface VGrid2D Surface OpacityMap OpacityMapName sitex tx Surface VMarble To optimize the evaluation of composited shaders Air will skip any shader layer whose input opacity value is 0 Sample rib compshaders2 rib Shader Networks Multiple shaders can be used to re construct a general shader network by defining connections among the shaders assigned to an object Connections are defined by including additional parameters in the shader declaration First each shader declaration is assigned a name using String layername componentname Naturally 1ayername does not need to be
495. pattern is not visible this is enough information to compute the reflectance for the simple weave patterns supported by this shader simple or plain weave twill and satin The weave pattern affects the final appearance in a two ways First it determines how much of each thread type is visible Second it determines the shape of the threads as they are interwoven which affects how light responds to each thread The shader automatically estimates the thread profiles based on the weave pattern Here are two sample patterns with the corresponding parameter values the warp threads are vertical and blue green weft threads are horizontal and orange WeavePattern 111 311 WeaveWarpWidth 1 1 WeaveWarpGap 1 0 1 WeaveWeftWidth 1 1 WeaveWeftGap 1 1 2001 2014 SiTex Graphics Inc Shader Guide 224 Thread Properties The way thread scatters light is computed as the sum of two functions a diffuse component computed as the effect of volume scattering in the thread and specular component for light that is reflected at the thread surface The specular reflection scattering behavior of the thread is determined by the thread shape and the shininess value WarpShininess or WeftShininess Smaller values produce a broader but dimmer highlight The shininess value is also used to determine how light scattered through the thread is emitted The volume scattering is also affected by the isotropy parameter WarpIsotropy or Wef
496. ped e Updated the Photoshop display driver to support the new __ diffuse_shadow layer with a subtract blend mode e Shaders e New spherelight light shader allows a point light to be used to mimic the effect of a spherical area light New spot projector and distant_projector light shaders project a texture map like slide projector New FakeCarpet surface shader makes a rectangle look like a fuzzy carpet New instCarpet instancer shader for growing carpet fibers on a rectangular patch New VShadeCarpet surface shader to use with the above instCarpet shader New VHexTile surface shader for hexagonal ceramic tiles New UseBackground surface shader for computing reflections and shadows for compositing over a background image e New maxemission parameter for all light shaders that vary emitted intensity based on distance from the light source Useful for limiting the maximum light intensity on near surfaces for lights that use a linear or quadric falloff of light intensity with distance Updated VFur and VHair shaders new rootcolor and tipcolor parameters to work with Shave export from Maya New ColorBias parameter for tweaking the interpolation between root and tip colors The shaders now pass a valid normal to illuminance to work better with occlusion and indirect lighting e Updated envPhysicalSky shader to include parameters to tune intensity based on ray type and visibility toggles for indirect and reflection rays Updated portallight shader t
497. play call would produce an image with three layers containing respectively all objects terrain objects and agent objects Examples A sample RIB file for rendering layers in a single pass SATRHOME examples multipass multilayer rib A sample RIB that renders mattes for different elements SATRHOME examples multipass mattes rib Light Channels Air 5 0 and later provide shaders and shading language functions for per light output channels from surface shaders Per light channels can then be combined in a compositing or paint program to produce a final image The availability of per light output depends on cooperating light and surface shaders All Air lights provide a___channe1 output variable for per light output Set the __ channel parameter to the channel number in which to store the light s output Note that more than one light may share the same 2001 2014 SiTex Graphics Inc 39 AIR User Manual channel each channel holds the sum of the illumination of all lights with that channel number If you do not wish to store a per channel value for a given light set it s __ channel parameter to 1 Surface shaders provide per light output as a__1 ight s output variable which is an array of color values one color for each channel The surface shaders included with Air provide up to 10 channels of per light output with channel numbers 0 to 9 To save light channels first declare the __ lights array De
498. points in the point cache from the outside of the object as determined by the current orientation If your object looks unlit with subsurface scattering try reversing the orientation of the object Subsurface Quality To save rendering time AIR aggregates points in the SSS cache that are far away from the current shading location If this optimization is performed too aggressively it can result in rendering artifacts in the form of spots of darker color in the subsurface scattering result The max error tolerance for this optimization can be set with Option render float subsurfacetolerance 0 005 Setting the tolerance to 0 disables the optimization entirely Saving and Re using a Subsurface Cache The point cache used to accelerate subsurface scattering can be saved to a file using the filemode attribute Attribute pointset string filemode w The point set will be saved to the file name given by the point set handle To re use a point set on a subsequent render set the i1lemode to read with Attribute pointset string filemode r Subsurface scattering point sets can be saved in any of the 3D point formats supported by Air Multithreading In AIR 10 and later versions subsurface cache generation is multithreaded for better performance Multithreading for SSS cache generation can be disabled with Option render integer sssmultithread 0 Automatic Point Set Handles Air 11 introduces a new option to automatical
499. propriate silhouettes and shadows True Displacement By default displacement shaders only perform bump mapping True displacement is turned on with Attribute render integer truedisplacement 1 Truly displaced surfaces also need to have a displacement bound set giving the maximum distance the surface will be displaced Attribute displacementbound float sphere radius A plugin should provide controls for setting these attributes For displacement shaders included with AIR the above instructions are sufficient for true displacement Some other displacement shaders also contain a truedisplacement parameter which should be set to correspond with the truedisplacement attribute For true displacement the shader parameter tells the shader to modify the global position variable P and the attribute tells the renderer to move the surface point to the new position Displacement Methods AIR has two methods of performing displacement The default method takes the polygon mesh normally generated for rendering and displaces each facet by dividing it into one or more grids of micropolygons The default method is normally fairly fast and distributes well over multiple processors However it has some drawbacks e If the initial tessellation of a curved surface such as a subdivision mesh is too coarse the displacement may show artifacts of the initial tessellation e With some shaders small differences in the exact values used for displacement
500. provides many command line options for customizing the renderer s behavior without modifying the main rib file A list of command line options can be printed with air A list of options with brief descriptions can be found in the Reference section of this manual This tutorial introduces a few of the more commonly used options Multithreaded Rendering The number of threads can be set with a p or threads option air p 2 rib frame0001 rib The default number of rendering threads is equal to the number of detected processing cores Image Size and Output Destination 2001 2014 SiTex Graphics Inc Massive 376 Use res to override the image width and height set in the rib file air res 320 240 scene rib The output image file generated by the rendering can be set with file air file occlusion tif scene rib The image type is determined by the file name extension To force output to the AIR Show framebuffer instead of to a file use the a switch air d scene rib Pixel Samples and Shading Rate AIR has two main controls for image quality The pixel samples option determines the number of times the scene geometry is sampled per pixel E g a pixel samples setting of 4 will use a 4x4 grid of samples at every pixel Use samples to override the pixel samples setting on the command line air samples 4 scene rib Increase the number of pixel samples to improve the quality of geometry sampling The shading rate
501. ps The shading language environment call now respects the samples parameter allowing users to fine tune the speed and quality of environment map queries New options to set the number of environment samples for the indirect and reflected background environment maps Option indirect integer envsamples 4 Option reflection integer envsamples 8 e New micropolygon shading mode Attribute shade integer mode 1 e New attribute to apply the flatness tessellation criterion as an absolute tolerance in object space Attribute render string flatnessspace object e Geometry export in PLY format e Added Perspective RIB command e Increased max rendering threads from 8 to 16 e RIB filter additions ScreenWindow Projection e Area lights Fix for area light normals Better handling of geometry with facevarying data e Shaders New surface shaders BakeTangentNormalMap CausticPass IndirectPass MotionPass VAnimatedMap VFabric New light shader portallight New MassiveAgents instancer shader Most surface shaders with ray traced reflections now have a__ environment output variable 2001 2014 SiTex Graphics Inc 441 AIR User Manual holding the contribution of the background environment map for reflection rays All displacement shaders now provide __ bump and __undisplaced_N output variables Updated shadowpass shader provides per channel shadow values e TweakAIR Camera view can
502. put channel index Description Use the portallight shader for area lights representing a window or other opening admitting illumination from an external source captured in an environment map For interior scenes using an area light with this shader can be more efficient than trying to capture the effects of an external environment with indirect diffuse illumination The quality of the illumination and shadows is controlled with the light s nsamples attribute Attribute light integer nsamples n A large number of samples produces smoother results Output only variables color __shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows See Also area lights arealight shader 2001 2014 SiTex Graphics Inc 147 AIR User Manual 10 7 17 sky_portallight area light shader for a portal admitting sky light 2001 2014 SiTex Graphics Inc Shader Guide 148 Parameter intensity lightcolor maxemission falloff turbidity date_month date_day date_hour latitude_longitude time_zone animate_hour animate_time_scale override_zenith override_azimuth ground_diffuse ground_reflection ground_color ground_blend_angle ground_self_illum coord_sys y_is_up coord_sys_north_angle coord_sys_right_handed divisor divide_by_average shadowname shadowbias shadowblur shadowsamples shadowcolor Default Value 10 1 a l 0 2 5 4 15 12 47 45
503. quency for angular variation PatternSize 1 Overall scale of pattern PatternOrigin 00 0 Pattern offset PatternAxis 001 Axis of trunk PatternSpace shader spaces Coordinate space for calculations Description The VWood shader simulates a solid wood texture with grain throughout WoodGrain and VeinGrain control the graininess of the base wood and the vein of darker wood respectively VeinWidth gives the fraction of each ring that is part dark material VeinFuzz is the fraction of VeinWidth devoted to the transition between light and dark wood VeinBias is the relative sharpness of the transition entering and leaving the dark material A value of 0 5 results in equal transition regions on both sides See Also VPlanks shader 10 11 Volumes Volume shaders simulate volumetric effects such as smoke or fog 2001 2014 SiTex Graphics Inc Shader Guide 274 10 11 1 fog simple fog shader defined by the RI Spec VFog fast volumetric fog VSmoke volumetric smoke fog simple fog shader defined by the RenderMan Interface Specification Parameter Default Value distance 1 0 background 00 0 Description Range Description distance beyond which fog completely obscures fog color The fog volume shader implements a simple fog function fading to a background color with distance This shader does not show the effects of light and shadow on the fog The VFog shader provides such volumetric effects See Also VFog shader 10
504. r background Coordinate space for environment map Samples for environment map lookup Blur for environment map lookup raytrace or name of occlusion map Blur for occlusion map Bias for occlusion map Max solid angle in radians for grouping of points in point based occlusion Shadow color Optional list of groups to query for occlusion Light categories If 1 light will not produce highlights If 1 light illuminates volumes Flag indicating indirect light status for multipass rendering Output channel 2001 2014 SiTex Graphics Inc Shader Guide 138 Description The envlight shader simulates light incident from a surrounding environment with ambient occlusion The incoming light can be a constant color or taken from an environment map specified with the envmap parameter Shadows are simulated using AIR s occlusion function When the mapname parameter is set to raytrace ray tracing is used to compute the ambient occlusion at each point Otherwise mapname is treated as the file name for an occlusion map with occlusion information Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows Baked Shadows AIR includes an extended version of the envlight shader envlight_baked with additional parameters for creating 3D shadow textures and using 2D or 3D baked shadows bakemap Bake map file name bakemode ue Bake mode bakemapblur 0 Blur for ba
505. r Manual 5 7 2 5 7 3 5 7 4 String resolutionunit unit Gives the unit of measurement for the resolution of the image Unit must be one of inch or centimeter deeptxt Deep Image Text File Description saves deep image data to a simple text file File extension deeptxt Channels arbitrary number of channels and arbitrary fragments per pixel Data types float File data uncompressed ASCIl text exr OpenEXR Description saves data in OpenEXR format File extension exr Channels rgba z Data types float Parameters string exrpixeltype half Defines the data type in which variables other than r g b a z are saved Supported types are half 16 bit floating point or float 32 bit IEEE floating point r g b and alpha channel data is always saved at half precision Depth data z is always stored at 32 bit float precision string exrcompression zip Compression method none rle zip zips piz piz12 framebuffer Description displays an image in a window in the AIR Show display utility Channels any Data types 8 bit unsigned integer 16 bit unsigned integer floating point Parameters integer 2 position x y Specifies an offset in pixels for the upper left hand corner of the display window 2001 2014 SiTex Graphics Inc Output 44 String description text Stores an optional description of the image 5 7 5 hdr Radiance Image Format
506. r Manual Ray Tracing e Much better sample distribution for shadows and reflections viewed in reflections e New options provide a coordinate space for background environment map lookups Option reflection string envspace Option indirect string envspace Subdivision meshes New attribute to displace an entire subdivision mesh at once Attribute render integer meshdisplacement 1 This method helps avoid cracks when the displacing function has discontinuities New attribute to split a mesh into subregions for tessellation Attribute render integer splitmesh 1 The following option gives the maximum number of faces per subregion Option limits integer splitmeshfaces 25 Smoother seams between primitives stitched together by MayaMan Better true displacement for Blobby primitives with the new meshdisplacement method Points primitives e New mode to render points as spheres Attribute render string pointtype sphere e Much better shading cache performance for motion blurred points e Bug fix for ray traced points Volume primitives e Support for mpoint data e Support for dPdt ime for point based data e New attribute indicating when a procedural primitive contains a volume primitive Attribute visibility integer volume 1 Much more efficient memory use for particle systems instanced with individual primitives with constant primitive shader variables Much more efficient sh
507. r atmospheric effects such as fog and smoke light calculates the light emitted from a light source environment shades rays that miss all objects in the scene imager modifies final pixel values after rendering is complete instancer creates new geometry on demand based on the underlying primitive procedure creates new geometry on demand at render time generic shader type for components that may be used with different shader types stroke custom drawing of vector based outlines Using Shaders If you are using a plugin for a modeling program some shaders will be used automatically to simulate the lighting and materials present in the host program Most plugins also provide a way to attach custom surface displacement and atmosphere shaders to objects AIR comes with a sizable collection of custom shaders which are documented in the following sections of this user manual The AIR shader library is located in the shaders directory of your AIR installation Because AIR supports the industry standard RenderMan shading language you can also use any of 2001 2014 SiTex Graphics Inc 79 AIR User Manual 10 1 10 1 1 the hundreds of freely available RenderMan shaders available on the web New shaders first need to be compiled with the AIR shading compiler shaded before they can be used Each shader has a set of parameters that can be used to control a shader s appearance E g a tile floor shader might
508. r gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows See Also area lights arealight shader arealight2 shader 10 7 25 uberlight multipurpose light shader 2001 2014 SiTex Graphics Inc 165 AIR User Manual Parameter lighttype intensity lightcolor cuton cutoff nearedge faredge falloff falloffdistance maxintensity parallelrays shearx sheary width height wedge hedge roundness beamdistributio n slidename noiseamp noisefreq noiseoffset Default Value spot 0 01 1000000 0 0 0 0 0 e re o o O O oO POORER orrooOo Range spot omni arealight 0 0 1 0 Description Light type Light intensity Light color Min depth value that is illuminated Max depth value illuminated Transition region at near end of depth range Transition region at far end of depth range Exponent for falloff with distance Distance at which falloff begins Maximum intensity
509. r map VBrushedMetal brushed or anisotropic metal VPhysicalMetal physically plausible metal with color map VRustyMetal metal with a rust pattern Glass and Water OceanSurface ocean water surface no waves OceanSurfaceWithFoam ocean water with foam glass shader for thick solid glass with VGlass refraction effects VThinGlass shader for thin glass without refraction Constant 2001 2014 SiTex Graphics Inc 179 AIR User Manual constant simple constant colored shader Emitter makes a surface behave like an area light when used with indirect diffuse illumination constant color with opacity falloff based on facing ratio VTexturedConstant constant colored shader with texture map VShadowedConstant constant colored shader with shadows a fa VShadowedTranspare transparent surface with shadow used for nt opacity Subsurface Scattering VTranslucent basic subsurface scattering shader VSkin skin shader using surface scattering VTranslucentMarble marble with subsurface scattering 29 Rough Materials 2001 2014 SiTex Graphics Inc Shader Guide 180 matte VClay VRubber Shiny Materials E _ rw VCarPaint Textiles VCloth i poe Velvet gt VEabric VConcrete basic matte flat shaded material rough diffuse surface with optional color map concrete with grooves rubber ceramic with reflections and op
510. r map parameter now convert the map color to current color 2001 2014 SiTex Graphics Inc History 438 space to work with spectral pre filtering and chromatic adaptation Statistics e Statistics now reports total memory used by unconverted textures e New option to report statistics on SSS cache reads Option runtime integer sssinfo 1 e Stats include total memory used by all subsurface caches e Stats include memory used for occlusion and irradiance caches 3D Point clouds e Point clouds with N values that are all 0 no longer save N to point cloud files e Support for reading Maya PDC files e Fixed bug in brick map loader that prevented Air from finding already loaded maps e Fixed texture3d filtering of general point clouds not applicable to Air Point Maps or Air Brick Maps e DSO shade ops e Shade ops that return a string type are now supported e Fix to generate standard texture coordinates when only referenced by a shade op e Shade op calls now make string parameters available at auxilliary shading locations Reprise License Manager RLM version 8 See the separate RLM End User Manual in the doc directory of the Air installation for information on new and improved features Command line switches e Added rows and columns as shorthand for the corresponding bucket orders e Added switch for custom float or string options opt name token value e Updated the list of switches in this manual e R
511. r shaders Imager shaders may now have arbitrary output variables Each imager AOV that is being saved will be initialized to the current pixel value for that AOV the filtered result of the normal rendering process The standard Air imager shaders now provide a__ background output variable with the imager shader contribution to the final image Imager shaders now show up in images with multiple output channels Imager shaders may be defined in inline archives Imager shaders can query light sources with illuminance The imager shader is illuminated by all lights Imager shaders initialize s t coordinates so the unit square covers the output image New LensFlarelmager shader Output e A Display declaration may now specify a different subset group for each output variable by 2001 2014 SiTex Graphics Inc History 434 including a list of groups separated by commas in the optional subset parameter instead of a single group New display channel __CPUt ime gives the time in minutes to render each bucket e User defined attributes can be saved to output images Declare objectid varying float Display myuserdata tif file user objectid e An object s toon id can be included in an output image with Display tooninfo tif file toon id e Geometry Export e Export to PLY format now includes vertex color values when available e Geometry export now issues an INFO message for each file creat
512. r using the new Instancer RIB call Instancer VInstanceArchive string Archive teapot rib As with true displacement objects with an instancer shader must also give the renderer a bound on the region within which new primitives will be created Attribute instancerbound float sphere n The bound gives a distance used to expand the bounding box for the base primitive to encompass the region occupied by any primitives created by the instancer Writing Instancers AIR 8 introduces two new shading language features to enable the creation of instancer shaders The meshinfo function allows an instancer shader to query properties of the base primitive The ribprintf statement allows an instancer to send a stream of RIB commands to the renderer to create new primitives The Vshade source code to all instancer shaders included with AIR can be found in SAITRHOME vshaders Instancers instCarpet instancer shader for growing carpet fibers on a rectangular patch 2001 2014 SiTex Graphics Inc Shader Guide 118 Parameter StrandCount StrandLength StrandWidthFraction StrandTaper StrandBaseVary PolarAngle PolarVary PolarFrequency TiltMaxAngle TiltPower Stiffness StiffnessVary StiffnessFrequency StiffnessAtEdge EdgeWidth EdgeVary Color ColorVary ColorMapName MaskName MaskThreshold IndirectStrength IndirectVisibility IndirectSamples CurveType ExportTextureCoordinat es Seed
513. rall size of the highlight The rolloff parameter controls how rapidly the highlight intensity diminishes If rolloff is less than 0 its absolute value is treated as the index of refraction of the material for compatibility with SoftImage 2001 2014 SiTex Graphics Inc Shader Guide 286 The blinn function also provides a channels output variable an array of colors holding per light specular values indexed by a light shader s __ channel output variable A nchannels output variable gives the number of valid channels See Also VBlinn surface shader 10 15 5 brushedspecular color brushedspecular string category normal Nf vector xdir vector ydir vector V float xroughness float yroughness float gloss The brushedspecular function computes an anisotropic specular highlight The xroughness and yroughness parameters control the highlight size along the xdir and ydir tangent vectors respectively The gloss parameter provides an inverse exponent applied to the final result When gloss is set to 1 the brushedspecular illumination model differs from Greg Ward s model only in omitting division of the result by 4 xroughness yroughness 10 15 6 caustic color caustic point P normal N Returns the result of a photon map lookup at point P 10 15 7 collect collect point P float maxsearchdist float maxsampledist parameterlist statements AIR exposes the underlying point set
514. ray traced shadows Per object shadowgroups override attribute name If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel This area light shader combines the portallight shader with the envPhysicalSky environment shader for more efficient rendering Output only variables col col or shadow or __unshadowed_Cl See Also area lights arealight shader portallight light shader envPhysicalSky environment shader 10 7 18 spherelight light shader to make a point light behave like a spherical area light Parameter Default Value intensity Lsp lightcolor 111 lightcolor_spd lightradius 1 0 from 000 falloff 2 shadowname mm shadowbias 0 01 shadowblur 0 01 shadowsamples shadowcolor 00 0 Shadow value Emitted illumination without shadows Range 0 0 05 1 256 Description Light intensity Light color Light color spectrum file Radius of the virtual sphere Source position of light Exponent for falloff in light intensity with distance Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for traced shadows Color of shadows 2001 2014 SiTex Graphics Inc Shader Guide 150 shadowgroups Optional groups for ray traced shadows shadowattribute user shadowgroups Per object shadowgroups override attribute name _ category oe Ligh
515. rd et al The tone mapping operator is inspired by the zone system in photography First the luminance is scaled linearly to map the MiddleLuminance value to the MiddleGrey output value The dynamic range is then compressed with new lum 1 lum MaxLuminance 2 1 1lum MaxLuminance gives the luminance value corresponding to a display value of 1 By lowering the MaxLuminance value you can allow sections of an image to appear overexposed For speed this shader does not perform the rgb gt xyY gt rgb color space conversions described in the paper Instead the r g b values are linearly scaled by the ratio of the output luminance from the tone mapping operator and original luminance In some cases this shortcut can produce output values that are still greater than 1 If ClampToAlpha or Apply_sRGB is enabled the final channel values will be less than or equal to 1 The same tone mapping operator is available as a display option in Air Show 2001 2014 SiTex Graphics Inc Shader Guide 114 Output only variables color __tonemap Tone mapped color 10 5 6 VBackDrop applies a texture map to the background Parameter Default Value Range Description Intensity 1 Texture result multiplier TextureName i Texture map for background TextureBlur 0 0 Blur for texture lookup RepeatX 1 Horizontal copies RepeatY 1 Vertical copies IsSequence 0 0 or 1 Is the map a sequence of frames FrameOffset 0 Offset added t
516. reduce peak memory use and produce faster rendering in some cases The following option gives the maximum number of faces per subregion Option limits integer splitmeshfaces 25 When split mesh is enabled AIR has another optimization that allows facevarying data to be simplied to varying or vertex data on submeshes where possible ie where a given vertex has the same values for each adjoining face Attribute render integer simplifyfacedata 1 This optimization can reduce memory requirements significantly for objects with facevarying texture coordinates Mesh Displacement AIR usually performs true displacment by first converting a primitive to a polygon mesh and then displacing each of the polygons AIR 5 introduces a new option to displace an entire subdivision surface at once Attribute render integer meshdisplacement 1 Mesh displacement may take longer to render and use more memory during tessellation but the resulting mesh will be smaller and it will be continuous even if the driving displacement function is discontinuous Points The Points primitive is useful for efficiently rendering large numbers of tiny particle like objects By default points are represented as tiny hexagons by the main scanline renderer and this underlying geometric representation will be visible if a point is large By default the ray tracer treats a point as a disk oriented perpendicular to the incoming ray Points as Patches for Sprites
517. renderered vhost ipaddress Connect to an instance of Vortex executing on the machine at ipaddress Not available in the demo version See Also Command Line Rendering of Massive Scenes 2 What s New What s new in Air 14 For information on prior releases see the History section e New standalone Air Material Editor for Windows See the separate Material Editor help file for more informatin e New material library for Air which can be found in the materials directory of your Air installation Textures e All rendering threads now share a single texture cache which reduces memory use and network bandwidth and improves performance e The default texture cache size is now 64mb total In prior releases each thread managed its own cache and the default size was 20mb e Air can now automatically convert source images to Air texture files internally at render time providing the same high quality texture filtering as that obtained by pre converting images to Air texture files for rendering Enable this automatic mip mapping with Option texture boolean automipmap 1 When this features is enabled Air will resize all source images so the width and height are both a power of 2 The following option controls how an image is resized Option texture string autoresize nearest The default resize mode rounds each dimension to the nearest power of 2 If the resize mode is 2001 2014 SiTex Graphics Inc 21
518. request workers from a central render manager Vortex performs the following substitutions on the command string SHOST ip address and port number of vortex instance SNWORKERS number of requested workers Number of Workers The maximum number of workers used by a particular Vortex instance can be set with the w 2001 2014 SiTex Graphics Inc Tools 420 command line option The default maximum is 5 workers Vortex will reject connection attempts by additional workers once the maximum has been reached Command Line Options local n Sets the number of local AIR instances to launch novol Don t broadcast a request for VoluntAIR workers port n Set the port number on which to accept connection requests from workers w n Sets the maximum number of workers to use for a job bs width height Sets the size of the buckets used for rendering crop left right top bottom Restricts rendering to a subrectangle d This option forces output to a window It overrides any Display call in the RIB stream reflect Shorthand for Attribute visibility reflection 1 res width height Sets the resolution of the rendered image This option overrides any subsequent Format call samples xsamples ysamples Sets the number of samples per pixel This option overrides any subsequent PixelSamples call shadows Shorthand for Attribute visibility shadow 1 25 Plugins and Companions Plugins compatible w
519. resent See Also VRustyMetal shader 10 10 6 VPhong 4 plastic surface using the Phong specular model IIlumination model diffuse plus Phong highlight Features reflections texture map Parameter Default Value Range Description Diffuse 0 5 0 0 1 0 Diffuse reflectivity Specular 0 5 0 0 1 0 Specular reflectivity SpecularRoughnes 0 1 0 0 1 0 Specular roughness speculersics 1 Size control for Phong highlight Reflection 0 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup 2001 2014 SiTex Graphics Inc Shader Guide 248 TextureSizexXY Aa Size of texture map in X and Y TextureOriginXY 0 0 Position of left top corner TextureAngle 0 0 Rotation angle in degrees ColorMapName An Color map name ColorMapBlur 0 0 0 0 1 0 Color map blur SpecularMapName Specular map name SpecularMapBlur 0 0 0 0 1 0 Specular map blur OpacityMapName jki Opacity map name OpacityMapBlur 0 0 0 0 1 0 Opacity map blur BumpMax 0 0 Bump amplitude multiplier BumpSpace shader space in which to measure displacement BumpMapName aa Bump map name BumpMapBlur 0 0 0 0 1 0 Bump map blur Projection st projections Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for p
520. rface shader is currently assigned to a primitive 20 3 24 IrWritelmage 21 C int IrWriteImage IPR ipr char filename Text IrWriteImage filenam The command writes the image buffer to an image file The file type is determined by the file name extension TweakAlR waits for any pending updates to complete before writing the image BakeAir for Baking Textures and Meshes BakeAir is a special purpose 3D renderer for rendering baking shading and lighting results to texture maps or meshes Baking to Textures In texture baking mode BakeAir produces one or more texture maps containing shading and lighting information for each primitive BakeAir is based on Air and fully supports all applicable Air features including indirect illumination ambient occlusion caustics area lights true displacement and programmable shading Rendered data can include global color opacity position and normal information as well as indirect illumination and any user defined output variable from a surface displacement or atmosphere shader BakeAir allows considerable freedom in the mapping from primitives to texture maps e Asingle primitive can output different channels to different maps e Multiple primitives can bake into a shared texture e The coordinates used for indexing textures can be standard s t or u v coordinates or any user defined 2D texture coordinates BakeAir 11 can also bake to PTEX per face texture maps Baking to M
521. rial e g skin A table of real world values can be found in Jensen et al A Practical Model for Subsurface Light Transport in the SIGGRAPH 2001 Proceedings The mean scattering distance can be calculated from the reduced scattering sigma_s and absorption coefficients sigma_a msd 1 sqrt 3 sigma_s sigma_a sigma_a The default scatter distances in the shaders provided with AIR are all in units of millimeters Use the ScatterDistanceScale parameter to adjust the distance to the scale of your object Larger distances produce more blur and generally take less time to render Subsurface Reflectance This parameter sets the nominal reflectance for subsurface scattering Real world values can be found in Jensen et al Although it is possible to control the color of an object by changing this parameter the net effect in interaction with the scattering distance parameter can be difficult to predict Instead use the primitive s color attribute or other color options in the shader to tweak the overall color with the SubsurfaceReflectance value set for a particular material type When a subsurface scattering object is first encountered AIR calculates and stores a set of shaded points distributed over the object s surface You may notice a delay as AIR performs these 2001 2014 SiTex Graphics Inc Lighting 336 computations After the point cache is generated rendering should proceed relatively quickly AIR shades
522. rib export for preview rendering and normal rendering If you do not wish to include the background image in final rendering you ll need to remove the options reference prior to exporting ribs for the final render Option 2 Use Air Show to view the rendered preview image with a background plate Air Show has an option to display a rendered image over a background plate but that option is only available for images with an alpha channel Unfortunately the Massive preview image is always rgb only so again this is not as easy as one might hope A solution is to render the preview rib from a command shell and use Air s command line options to override the output declaration to include an alpha channel When rendering a preview image with Air Massive exports the rib files and other data to TEMP massive To render the preview rib from a command shell cd STEMP cd massive air d mode rgba massive rib You can leave the command shell open and re launch the last command for each preview Note that this means each preview will be rendered twice If the preview render takes more than a few seconds you can use the red stop button in Air Show to abort the first preview render To load the background image in Air Show select Load Background from the View menu Use the checkered toolbar button to enable or disabled display of the background for the current image Houdini Side Effects Software s Houdini Escape and Houdini Master support Air as
523. ric shader for querying a baked map 2001 2014 SiTex Graphics Inc 107 AIR User Manual 10 4 4 10 4 5 Parameter Default Range Description AttributeName user bakedmap user attribute to query for baked map name DefaultColor 0 5 0 5 0 5 default color to emit if no baked map Channel 0 first channel to query Description The genQueryBakedMap generic shader can be used to query a map baked using Air Stream Output only parameters color OutputColor output color float OutputRed red component float OutputGreen green component float OutputBlue blue component float OutputAlpha alpha component genTextureUV generic shader that queries a texture map using standard u v coordinates Parameter Default Range Description TextureName pii texture map DefaultColor 000 default color value DefaultAlpha 0 default alpha value Description The genUV shader exports the standard u v coordinates assigned to an object Output only parameters color Color emitted color float Alpha emitted alpha float Grey grey value average of r g b genUserAttributes generic shader for querying float and color user attributes 2001 2014 SiTex Graphics Inc Shader Guide 108 Parameter Default Range FloatiName ms Float Default 0 Float2Name um Float2Default 0 Float3Name me Float3Default 0 Color1Name un Color1 Default 0 Color2Name un Color2Default 0 Color3Name eN Color3Default 0 Output only par
524. ring Option user bgenv sky tx Use the option function to query user option values in a shader string bgmap if option user bgenv bgmap 1 Default User Options Air BakeAir and TweakAir define a user option with the renderer name air bakeair or tweakair respectively Option user string renderer air Air 13 and later builds define a user option of type float with the current version number in the format major minor These options may be useful in conditional RIB statements See Also Attributes gt User Defined Attributes 7 Attributes Attributes are properties of a particular object in contrast to options which apply to the scene as a whole A custom attribute is assigned by placing an Attribute command in the scene file prior to the definition of an object Attribute name type parameter value Most plugins provide a facility for assigning custom attributes The RenderMan standard allows custom attributes to be defined for renderer specific features The following list enumerates the custom attributes supported by AIR Each attribute links to its description in this manual Lighting Attribute light integer nsamples 1 Attribute light float maxdist 1 0 Attribute render has shadows yes Attribute light integer automapsize 1024 Attribute light float 4 automapscreenwindow 0 1 O 1 Visibility Attribute visibility integer camera 1 Attribute visibility
525. rojection Transform 1000 Transformation applied prior to 0100 projection 0010 0001 Description This shader produces a reflective plastic surface with separate texture maps to control the surface color opacity and specularity or shininess An additional texture map is provided for bump mapping All maps use the same texture coordinates 10 10 6 VPhysicalMetal 1 physically plausible metal shader with texture maps IIlumination model physical metal Features texture map reflections 2001 2014 SiTex Graphics Inc 249 AIR User Manual Parameter Default Value Range Description Reflectance 0 9 0 0 1 0 Specular reflectivity Roughness 0 03 0 0 1 0 Specular roughness Samples 8 1 256 Number of rays when ray tracing IndexOfRefraction 0 37 Index of refraction Absorption 2 8 Absorption ColorMapName mu Texture map for base color OpacityMapName ai Texture map for opacity TextureSizeXY 1 1 Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform 1000 Transformation applied prior to 0100 projection 0010 000 1 Description This surface shader provides a physically plausible metallic appearance with optional color and opacity maps The metal s color is taken from the standard color attribute The
526. roup has the special value null no shadow rays will be traced and the object will not receive shadows Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows Baked Shadows AIR includes an extended version of the arealight2 shader arealight2_baked with additional parameters for creating 3D shadow textures and using 2D or 3D baked shadows bakemap me Bake map file name bakemode a Bake mode bakemapblur 0 Blur for bake map query bakemapfilterwidth 1 Filter width for bake map query motionbound 000000 bounding box for moving objects motionspace world space coordinate space of motionbound See Baking Shadows and Illumination for more information See Also area lights arealight shader Baking Shadows and Illumination 10 7 4 cardlight area light shader that emulates adding a constant shaded card 2001 2014 SiTex Graphics Inc 131 AIR User Manual 10 7 5 Parameter intensity lightcolor coneangle falloff shadowname shadowbias shadowcolor shadowgroups shadowattribute __nondiffuse __nonspecular __ foglight __ channel Description Default Value 1 0 LI 1 57 2 raytrace we user shadowgroups eo O Range 0 0 1 OF Ty 5 2 Description Light intensity Light color Angle for emitted light range Exponent for falloff in light intensity with distance Name of shadow map or raytrace for
527. rs By default the sample region is equal to the area of the current shading sample The QueryBlur parameter can be used to specifier a larger sample region for a blurrier result See Also 3D Textures collect 10 10 2 BakedSurface surface shader using baked maps for diffuse illumination IIlumination model plastic with Blinn specular 2001 2014 SiTex Graphics Inc 187 AIR User Manual Parameter Default Value Range Description MapAttributeName user bakedmap user attribute holding the baked map name MapFileName Direct file name for baked map to use instead of querying the above user attribute ChannelWithUnshadowed First channel for unshadowed diffuse values ChannelWithIndirect i First channel with indirect diffuse values Diffuse 1 0 0 1 0 Diffuse reflectivity Specular 0 0 0 1 0 Specular reflectivity SpecularEccentricty 0 3 Specular size Blinn eccentricity SpecularRolloff 0 7 Blinn rolloff parameter SpecularColor 14 1 Specular color SpecularApplyShadow 0 Whether to apply the diffuse shadow value to the specular lighting Reflection 0 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup Description The BakedSurface surface shader provides a s
528. rs that use ambient occlusion which is encapsulated in the shading language 2001 2014 SiTex Graphics Inc Lighting 326 function occlusion The envlight and massive _envlight light shaders provide a dome or sky lighting effect with occlusion used for shadowing The massive_envlight shader has parameters for most properties affecting ambient occlusion This shader is a good choice when not using AIR s occlusion cache feature With the envlight shader most occlusion properties are controlled with AIR attributes This shader is recommended when using the occlusion cache feature The occlusionpass and massive _occlusionpass surface shaders set the surface color to the occlusion value allowing a separate ambient occlusion pass to be rendered and used for compositing The occlusionpass shader is recommended when using an occlusion cache The massive_occlusionpass shader provides fairly complete controls for rendering occlusion without an occlusion cache Examples Examples using occlusion can be found in AIRHOME examples occlusion 13 4 1 Ray Traced Occlusion Ray traced occlusion estimates the occlusion at a location be casting shadow rays distributed over a cone of directions usually a hemisphere testing for shadowing or occluding objects Many applications and plugins provide a special interface for enabling and configuring ray traced ambient occlusion often grouped with other controls under a GI or Globa
529. rt end myscene 4f rib Each frame is assigned to one worker No output redirection is performed e Number of local workers now defaults to 0 Bug fixes e Many fixes specific to the 64 bit linux build of Air e Several fixes for vector based edge detection and vector outline export e Fix for a bug that could cause a crash with multiple threads in some rare conditions specifically when the bounding box of a primitive is much larger than the contained mesh or objects Fix for xyY gt rgb color conversion with ct ransform Fix for environment read of texture with fewer than 4 channels Increased buffer limits and added error checks for large numbers of output channels Shader interpreter modified to clamp the third argument of float mix a b c to 0 1 Fix for map handling when map used as environment and texture Fix for rgbaz output Fix for stereo rendering with indirect or occlusion prepass Fix to prevent matrix lock corruption Fix to avoid using multiple instances of a DSO shadeop Fix for runtime shading optimizer Fixed voronoi grid2d to initialize the z component of the cell centers Updated OpenEXR driver for Windows fixes a bug with pixel aspect ratio 2001 2014 SiTex Graphics Inc History 436 29 4 AIR 10 0 64 bit Air binary for Linux Support for new unlimited threading licensing option new Air licenses allow an unlimited number of rendering threads on a single machine Users with older 4 core
530. rt the RLM license server Here are brief instructions for starting the RLM server e Check the HOST line in the license file and make sure it contains the host name of the server If you see a string such as localhost or hostname change it to the name of the server You may also change the port number last number on the HOST line Don t change anything else in the file e Start the license server from a command shell If the RLM license file is saved in the bin directory of the Air installation cd to that directory and type rim If the RLM license file was saved to a different location start rim using the c option and a path to the 2001 2014 SiTex Graphics Inc Geiting Started 14 license file E g rlm c c mylicenses sitex lic The server should start and you should then be able to render Full documentation for the Reprise License Manager can be found in a separate document in the doc directory of the Air installation Network Installation There are two common methods of organizing Air on a render farm Central Installation for Clients and Server In this approach Air is installed once on a central file server and the license server and each client machine reference the same installation To use this method follow the installation instructions above for Windows or Linux to install Air on the central file server Then for each client machine including the license server e Add the bin directory o
531. s 25 Subdivision meshes e Simplification of facevarying data on subdivs is now supported when the split mesh attribute is enabled Enable simplification with Attribute render integer simplifyfacedata 1 This optimization can save significant memory on objects with facevarying texture coordinates Micropolygon shade mode e Support for multisegment motion blur e Fix for polys without vertex normals e Fix for dof or motion blur with clipped objects Motion blur e new attribute to enable disable adaptive motion blur on a per primitive basis Attribute render integer adaptivemotionblur 1 Instancer shaders objects with vertex motion blur can be sampled at a given time with meshinfo sample time Geometry export meshes can now be exported in STL format New image readers for Softimage PIC Windows Bitmap and IES files New display driver Softimage PIC Outlines e New option to export outlines in SVG vector format e New attribute to include border edges in vector based outline rendering e New attribute to include edges in vector based outlines based on angle between faces Shaders e New surface shaders ClownPass Glow VGradient New light shader photometric _pointlight New displacement shader VThreads New imager shader sRGB Updated VinstanceArchive instancer shader to use a temporary inline archive for instances for much more efficient rendering of large point clouds e Most surface shaders with a colo
532. s The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Shadow mapped Shadows Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows Baked Shadows AIR includes an extended version of the spotlight shader spotlight_baked with additional parameters for creating 3D shadow textures and using 2D or 3D baked shadows 2001 2014 SiTex Graphics Inc 155 AIR User Manual bakemap bakemode bakemapblur b
533. s If you wish to use the occlusion cache with an occlusion prepass use the standard envlight and occlusionpass shaders with the process described below under occlusion caching For ambient occlusion to function properly ray traced shadows must be enabled in Massive s render dialog Shader Parameter Quick Reference The massive_envlight and massive_occlusionpass shaders add the following parameters to those in the envlight and occlusionpass shaders The main quality control is the samples parameter which gives the number of rays cast for each occlusion estimate Use more rays to produce a smoother image with less noise at the expense of longer rendering time It normally makes sense to increase or decrease the number of samples by a factor of 2 The maxhitdist parameter sets the maximum distance to search for occluding objects Lower values will reduce rendering time as well as noise The coneangle parameter gives the half angle in radians of the cone of directions within which occlusion rays are distributed The default value of PI 2 1 57 distributes rays over a hemisphere Use smaller values to concentrate the rays more in the normal direction producing a more focused occlusion result The shadowbias parameter is used to prevent incorrect ray object intersections by giving an offset to add to each ray s starting location 2001 2014 SiTex Graphics Inc 383 AIR User Manual AIR 6 introduced a new special
534. s Outlining must be enabled as well as one or more of the object based edge detection methods Each edge is rendered as a thick line segement using the stroke shader Stroke width is taken from the current toon inkwidth attribute and stroke length is the edge length extended at either end by half the stroke width This extension allows strokes for adjacent edges to potentially overlap The amount of overlap can be increased by using a large ink 2001 2014 SiTex Graphics Inc Shader Guide 174 10 9 1 width and probably compensating for that in the shader by reducing the area covered by the output pattern Writing Stroke Shaders The following global variables are initialized when a stroke shader is executed Ci output color at the current sample alpha output alpha at the current sample U V 2d coordinates mapping the unit rectangle to the rendered stroke rectangle u runs across the stroke v runs along the stroke length s t 2d coordinates mapping the unit rectangle to the output image A stroke shader can obtain additional information about the current stroke with the following code f loat strokeinfo 3 attribute StrokeInfo strokeinfo f Hh f loat areaLength strokeinfo 0 loat areaWidth strokeinfo 1 loat strokeId strokeinfo 2 The length and width values are in pixels The stroke id is a unique identifier assigned to each stroke useful for generating per stroke
535. s ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform Transformation applied prior to projection oOOOrF oo reo OrROO rFOoOOO Description The VToon surface shader provides a basic cartoon shader with optional texture map 10 10 8 VTranslucent translucent shader using subsurface scattering with optional texture map 2001 2014 SiTex Graphics Inc 267 AIR User Manual Illumination model custom Features subsurface scattering reflections texture map Parameter Default Value Range Description Diffuse 0 5 0 0 1 0 Diffuse reflectivity Specular 0 5 0 0 1 0 Specular reflectivity SpecularRoughnes 0 2 0 0 1 0 Specular roughness s Reflection 1 0 0 0 1 0 Reflection strength ReflectionSamples 1 1 256 Number of rays when ray tracing ReflectionBlur 0 0 0 0 1 0 Blur for reflections ReflectionName raytrace Name of reflection map or raytrace for ray tracing ReflectionSpace current spaces Coordinate space for reflection lookup ScatterDistanceSc 0 3 Multiplier for ScatterDistance ale ScatterDistance 1 0 1 0 1 0 Average scatter distance for r g b SubsurfReflectanc 0 9 0 9 0 9 Diffuse reflectance e IndexOfRefraction 1 3 Index of refraction SampleDistanceOv 1 Maximum distance between erride subsurface samples or 1 for default ColorMapName ve Texture map for base color ColorMapBlur 0 0 0 0 1 0 Texture blur TextureSizexY 14 Texture size in X and Y direction TextureOriginXY 0 0 L
536. s 257 VShiny TEZ D erescczcesccccccsccesseccess cacti ceceecetescceceue sees tees decenescte setezcee cones Eoee a cevbaescbeceuestecebiedsscestues seuvecnenscetesceucenescts 257 VSketchOuthinne scsisecsc E ceca cate cee Lede eee ccc E E 259 a E A E tape catesstcenstiegdafbaccyecuessegecaieccts 259 VSMOKCSUMACE sis se estes ince l cca cdetesca ce cedeescee aaae papaa daa a aaan aa aa satesdede diced E aa ada Aaaa A satescudstucnetuaeandecudesacusseuendvevaus 262 VTexturedConstant wes 263 SANLE C ne ee OP OA O E 263 ATeno E E 264 VTOOM E e E E 265 VT PANSIUCONW sseicisiscccceesasesesccancasesavesntassvaoansavencerdsabdsanccaiecsdaiundoabesabeceuedseacandvabasebecuusenuasebanabdsabcneascsvacsbdtabasancsbeereve 266 VTranslucemt Marble E ce cesceis A E E O E 268 VWaterCOlr E E E VWEAVE E EE E VWOOd E 11 VolUMES ceceteceescccteececane catsencnceseesnscesexead decveenecndeaandecueenetedeques dentcenststenndecessoeestedeenascecetensteueunsedsces TOG Gasbebassucicaveauadececenadapeaestiucecpeatenanaucdeeccpeutapecawancdeastssavuesscedasshsdsswensanueucebaignuenvasutucsbdbepsaaubeucecsuagapasaudsduuenty MOQ E A E E E E E P E ceceraeeserses A E E E EEEE VSmoke seeccsscedtescdicctdiccznceccecs sesctcccectceedeceeccdesscecseds cetcsscneccegsauezcceesueucsues cetceccarchdes sauctcnenauencatiesetdceceschdeesiesecuiece 12 DarkTree Shaders 13 Layered Shaders and Shader Networks ccsecseseesseeeeseeeeeeneeseeseseeeensneeeeeeeeseaeseseenenseeeees 276 1
537. s affected by the type of weave pattern that is used and by the physical properties of the threads This shader allows both sets of properties to be controlled Weave Pattern The VClothAdvanced shader provides low level controls over the thread curves in each direction The thread profile is defined as one or more curve segments with the WarpCurve and WeftCurve parameters Each curve segment is defined as three values start angle end angle and length The angles are relative to the tangent direction with negative angles pointing up and 2001 2014 SiTex Graphics Inc Shader Guide 226 positive angles pointing down with respect to the surface normal The shading computations return the length weighted average response for the set of curves defined for each thread For an alternate method of specifying weave curves see the VCloth shader Thread Properties The way thread scatters light is computed as the sum of two functions a diffuse component computed as the effect of volume scattering in the thread and specular component for light that is reflected at the thread surface The specular reflection scattering behavior of the thread is determined by the thread shape and the specular spread value WarpSpecularSpread or Weft SpecularSpread which gives an angle in degrees over which reflected light is scattered Larger values produce a broader but dimmer highlight Similarly the diffuse spread parameter War
538. s and the following disclaimer in the documentation and or other materials provided with the distribution The names Disney Walt Disney Pictures Walt Disney Animation Studios or the names of its contributors may NOT be used to endorse or promote products derived from this software without specific prior written permission from Walt Disney Pictures Disclaimer THIS SOFTWARE IS PROVIDED BY WALT DISNEY PICTURES AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE NONINFRINGEMENT AND TITLE ARE DISCLAIMED IN NO EVENT SHALL WALT DISNEY PICTURES THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND BASED ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES Credits The JPEG display driver is based in part on the work of the Independent JPEG Group The PNG display driver uses libpng History Change log AIR 13 November 2013 AIR 12 August 2012 AIR 11 July 2011 AIR 10 July 2010 AIR 9 September 2009 AIR 8 December 2008
539. s for many older shaders have been made consistent with more recent shaders For example the diffuse strength parameter is now named Diffuse instead of Kd Anew VMetal shader is the new standard metal shader replacing the Slshinymetal shader New VGranite shader replaces VGranite2 Several shaders have been renamed Dashes to VDashes RustyMetal to VRustyMetal Concrete to VConcrete e The ambient_indirect and ambient_envlight shaders are no longer included Their functionality has been replaced by the addition of an__ indirect output variable to the AIR shaders The following shaders are no longer included with AIR wood2 VLaqueredInlaidWood Sldents use VDents backgroundgradient use VBgGradient VShinyCeramic use VCeramic e AIR Show enhancements e On Windows a sequence of images can be saved as an AVI file e New Channels window displays the extra channels for images with multiple output variables New redesigned AIR Control tool Several old tools have been removed form the AIR distribution Visual Browser LightEd MatMap 2001 2014 SiTex Graphics Inc 455 AIR User Manual 29 13 and the old AIR Control The last versions of these tools are available for download http www sitexgraphics com oldtools zip Bug fixes e Important fix for illuminate bug that caused surfaces facing away from a light to be lit anyway shader space for shader declarations in inline archives Uniform primit
540. s should be set so their product is the total surface area of the associated primitive See Also cardlight light shader arealight light shader 10 10 1 FakeCarpet surface shader for turning a rectangle into a simple carpet 2001 2014 SiTex Graphics Inc 193 AIR User Manual Parameter Sizex SizeY StrandCount StrandLength StrandWidthFraction StrandTiltAngle StrandTiltVary StrandTiltFrequency StrandPolarAngle StrandPolarVary StrandPolarFrequency StrandStiffness StrandSelfShadowMax StrandColorVary StrandBaseVary FrontScatter BackScatter ScatterPower ColorMapName BaseColor BaseSelfShadow SampleGridSize IndirectDiffuse Default 10 10 20 0 2 0 1 90 100 40 360 30 Range Description Width of box in the X direction Width of box in the Y direction Strand count per unit length Strand length Strand width as a fraction of strand length Average angle in degrees between a strand tip and the vertical axis Variation in tilt angle Frequency of variation relative to the patch as a whole Base rotation about the vertical axis Variation in polar angle Frequency of polar variation relative to the carpet rectangle Stiffness affects the curve shape of each strand Self shadowing at the base of each strand Variation in color of each strand Variation in the base position of each strand Forward scattering light multiplier Backward scattering multipl
541. s the zrange option Then render from a command shell including the extra file prior to main scene name air zdepth rib scene0001 rib For a sequence use air frames 1 100 zdepth rib scene 4f rib Method 2 Render a depth gradient using Air s depthpass surface shader As in method 1 first create a small text file with a few RIB commands Display depth 4f tif file r Option render commands Display Surface depthpass mindistance 1000 maxdistance 10000 Option render commands Surface Then include the extra file on the command line air depthpass rib scene0001 rib Adding a background image It may sometimes be useful to render a preview image with Massive that includes a background plate The Massive camera node includes an option to specify a background image but that setting is not exported to rib for rendering with Air Hopefully Massive Software will add this feature in a future release until then here are a couple alternatives Option 1 Use a small options file with an imager shader to add a background image e Create a small text file with the following imager declaration 2001 2014 SiTex Graphics Inc Massive 392 23 23 1 Imager VBackdrop string TextureName filenameofbgimage e Enter the options rib file name as the options rib include entry in the render parameters tab of the renders dialog Drawback the imager shader will be included in the
542. s to trace for refraction Exponent for transmission decay with distance Blur angle for transmission rays Color for sea close to observer The OceanSurface shader provides a basic illumination model for a deep ocean surface No waves are provided use a displacement shader for those The deep sea color result is emitted as an incandescence value and simply added to the other shading components When Transmission is not 0 refraction rays are traced to capture objects beneath the water The transmission result can be faded out based on distance if the TransmissionFalloff value is non zero See Also OceanSurfaceWithFoam surface shader 2001 2014 SiTex Graphics Inc 201 AIR User Manual OceanWaves displacement shader 10 10 2 0ceanSurfaceWithFoam shader Illumination Model custom Parameter Diffuse DiffuseColor DeepSealntensity DeepSeaColor Specular SpecularRoughness Reflection ReflectionSamples ReflectionBlur Transmission TransmissionMaxHitDist TransmissionSamples TransmissionFalloff TransmissionBlur TransmissionNearColor Foam FoamColor FoamOpacity Foamlllumination FoamlIncandescence FoamRawOffset FoamRawMultiplier FoamPower Default Value 0 44 47 6 wl 21 29 47 0 5 0 1 surface shader for ocean water with foam companion to the OceanWaves displacement Description Diffuse reflectivity Diffuse color Deep sea color multiplier Deep sea col
543. screen space caching mechanism that does not require an occlusion prepass The screen space cache stores an occlusion sample at each pixel and reuses that sample if possible for nearby shading locations You can enable this mode by setting the maxerror parameter to a positive number usually 0 2 to 0 5 A higher value allows AIR to reuse samples more often This new mode produces an appearance similar to rendering without a cache while reducing render time by 10 20 in many cases Occlusion Caching with Massive The occlusion cache accelerates rendering by storing occlusion estimates and re using them at nearby locations Obtaining smooth results with the occlusion cache typically requires enabling the occlusion prepass The easiest way to employ the occlusion cache with Massive is to use a small auxilliary text file with the RIB commands required for occlusion rendering Here s a sample file for rendering an occlusion pass override all surface shaders Surface occlusionpass Option render commands Surface nable occlusion prepass Option occlusion prepass 1 set quality attributes Attribute indirect maxerror 0 1 Attribute indirect maxpixeldist 10 Attribute indirect nsamples 256 set max distance to search for occluding objects Attribute indirect maxhitdist 500 Save the above text in a file called occpass rib Then from a command shell render with air occpass rib myscene rib You can specify the
544. se color ColorMapBlur 0 0 0 0 1 Texture blur OpacityMapName a Texture map for opacity OpacityMapBlur 0 0 0 0 1 Texture blur TextureSizexY 11 Copies of texture in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection ProjectionTransform 1000 Transformation applied prior to 0100 projection 0010 000 1 Description The VTexturedConstant surface shader produces a constant colored surface using a texture map See Also VShadowedConstant shader constant shader 10 10 7 amp ThinGlass 2001 2014 SiTex Graphics Inc Shader Guide 264 Illumination model custom Features reflections Parameter Default Value Ambient 0 01 Diffuse 0 01 Specular 0 5 SpecularRoughnes 0 1 s SpecularSharpnes 0 8 s Reflection 1 0 ReflectionSamples ReflectionBlur 0 0 ReflectionName raytrace ReflectionSpace current IndexOfRefraction 1 5 Transmission 1 0 Description Range 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 1 0 1 256 0 0 1 0 spaces 0 0 1 0 Description Ambient reflectivity Diffuse reflectivity Specular reflectivity Specular roughness Sharpness of highlight edge Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate s
545. seeeeeseeescaesenneeenseeeseeseseaeensneeeennes 2 TweakAIR Attributes sessnseeuunnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnmnnn nnmnnn na 3 TWOAKAIR API a aoaaa aaaea aaaea aaa aaa aao Aaaa aaia aian aaan i ai iiy IrBegin IrColor IFDEIStOLIQNt e WREMO 9 E E E E citieaente akan ccs alio Teat RNG Taa E EEEE E E E A T A E IrLiQhtTranSfOrm ccccsseeeeseteeessneeeeseneeeeseneeeeseeeeeeseeeeessneeeasseeseeseneeessneneasseeeesens IrNewDisplacement ccccssenessseeeessseeeesseeensneeeesseeeeeseneeseseaeeeaseeeeessneneessneeeesens IF NEWENVITONMEOIE sciec5 coco cde cestie sense ccteceeecececekesccececs cseecttecdoeceut cedezecenssecteGaacensieesiecs ING WIMAGEN sicccesseiccscncncsdecasascatascedscnencasessensedecocsepceensastssavasssdccbecsesecrenabdsevencusenence IINOWLIGNKE siscscatestntecsscsascocscdsaessecsavaccnecanecsseraessvacabenensediecabasabadenddouncaratabasandoaiecseata ING WSUNPAGCG 22555 occ sesso cece See ce A ee ncaciuecaccevyuccescueveues sdacvedeseuveeuna lrOpacity IPREfreESNWINGOW scccciccccsicccccccseccctsececcstccssccsteececeetcectcutsndecietcneaccntencsctatsnascentancsctarcas IrSelect IrTweakAttribute cccsseeeessneeessneeeeseneeeessneeensseeeeseeeeessneeeaseneseaseneeensneneasseeeesens IPT Weak Cametancssacesciccaicsccecsccieecedee cee sececece cats cccecsettendagvessedcurecede cies lt ctecsttesneateocseds IrTWeakCoordinateSySstem csccsecssesseeseeesseeesseeeeeesseeesseeesseee
546. shade now adds SAIRHOME shaders and SAIRHOME usershaders to the include search path when compiling shaders e New DarkTree library category with components for accessing DarkTree shaders Windows only e Vshade now converts block names into valid identifiers when necessary Grouping e Group membership has been modified so a group of resets to no membership in any group rather than leaving the current group unchanged e A null subset value passed to trace and other ray tracing calls now selects all objects equivalent to no subset parameter e Shaders e New shaders VShadowedTransparent VFur VLayeredMaterials VLines VBumpRegions VBgEnvironment VBlinn provides per light output channels for diffuse specular etc VToon supports multiple diffuse illumination levels or bands e VDashes supports line patterns Bug fixes e Air now checks the number and type of RIB shader parameter values against those in the shader and issues an appropriate error message when there is a mismatch Fix to prevent negative weights for importance sampling Important fix to eliminate shadow map request for tile outside the map Fix for true displacement with mulitsegment motion blur Global time and dtime variables are initialized for auxilliary shading points Fixed number of varying values expected for NuCurves Corrected spherical projection in many Air surface shaders The old lightdome and shadowmap utilities have been removed from t
547. shader tracks light channels through indirect diffuse illumination bounces The resulting __ channels output value is automatically picked up by the standard diffuse function and incorporated into its light channel output variables The __bgchannel parameter can be used to store the contribution of the background environment map in an otherwise unused light channel so the bg contribution can also be traced through reflections See Also indirect light shader Light channels 10 7 12 massive_envlight environment light using ambient occlusion without the occlusion cache designed for use with Massive Parameter intensity lightcolor samples maxhitdist adaptivesampling shadowbias coneangle envmap envspace envblur envsamples rotate_x rotate_y rotate_z shadowcolor _ category Default Value Range 1 0 1 11 256 1 1024 500 Sl 1 0 or 1 world spaces 00 0 indirect Description Light intensity Light color Rays to cast to estimate occlusion Maximum distance to search for occluding objects Whether to use adaptive sampling O no 1 yes 1 inherit from adaptivesampling attribute Offset to prevent incorrect self shadowing Half angle in radians of the sample cone Optional environment map contributing background illumination Coordinate space for environment map Blur for environment map lookup Number of samples for map lookup map rotation angle in degress about the x axis map
548. shaders can be configured to cast only diffuse light or only specular light by setting the following parameters To make a light diffuse only i e produce no specular highlights set the __ nonspecular parameter of a light shader to 1 To make a light cast only specular light but not diffuse light set the __ nondiffuse parameter of a light shader to 1 Optimizing Distance Based Lights Often the illumination emitted by a light decreases with distance from the light source until it becomes a negligible part of the lighting at locations far from the light You can help Air to avoid evaluating a light source at locations where it has little impact by setting the maxdist light attribute to the maximum distance at which the light should be evaluated E g Attribute light float maxdist 1000 Area Lights Any primitive in a scene can be turned into a light source by attaching a suitable light shader to it E g AreaLightSource arealight 33 Trim curves are ignored by area lights In principle an area light casts light from the entire source surface onto the current shading location Air provides two methods of simulating an area light Brute Force True Area Lights One method of simulating an area light is to run the light source shader on a user specified number of sample locations distributed over the surface area of the light The number of samples is given by Attribute light integer nsamples n Shadows for an area light c
549. shaders included with AIR Rendering the scene with Air should now use the assigned surface shader Image Quality Basic image quality controls can be found in the Quality sub tab of the Properties tab of a RIB output op The Pixel Samples setting determines how often the scene geometry is samples per pixel defining an NxM grid of pixel samples The default setting of 4x4 should be adequate for images without fine detail or motion blur When using motion blur or depth of field pixel samples may need to be increased to 8x8 or higher Shading Quality sets the number of shading samples per pixel the inverse of the RIB shading rate property More shading samples produce smoother shading at the expense of longer render times Pixel Filter and Filter Width specify how the pixel samples are combined to produce final pixel values The defautl gaussian filter with a filter width of 2 is somewhat blurry For a sharper filter try a mitchell filter with a filter width of 4 Multithreading Set the number of threads or processors used for rendering on the Render sub tab under Properties for a RIB output driver Rendered Output Select the desired output image name and display device on the Display sub tab of the Properties tab of the RIB output op By default the rendered image will be sent to the standalone Air framebuffer Air Show To render to the Houdini framebuffer change the Display Device to Houdini To render to a file select the
550. shaders provide extra parameters that allow shadow casting to be restricted to a particular group of objects string shadowgroups String shadowattribute user shadowgroups The first parameter takes a list of groups to test for ray traced shadows This covers the common case in which one wants to restrict shadows cast by a specific light and all objects receive shadows from the same groups The shadow casting groups can be overridden for a particular object by specifying a user attribute Attribute user string shadowgroups my custom groups The second parameter above shadowattribute gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows See Also 2001 2014 SiTex Graphics Inc 317 AIR User Manual Ray Tracing gt Optimizing Memory for Ray Traced Objects 13 2 2 Shadow Maps Shadow mapping is a fast and flexible method of producing shadows A shadow map is generated by storing depth information for a scene when it is rendered from the point of view of a light source When the scene is rendered normally the light source can
551. sible to all ray types if the scene does not use raytracing When rendering out of Massive unchecking the Shadow control on the Render page should be sufficient There are two easy ways to see whether objects are being retained for ray tracing In the Air Show status bar the 5th section from the left will contain S R or if any objects are visible to shadow reflection or indirect rays respectively The statistics generated by Air report the memory used by objects retained for ray tracing Statistics can be enabled with the stats command line switch 2 Render by column instead of by row By default Air renders an image from top to bottom one row of tiles at a time For a typical wide crowd shot peak memory can often be reduced by instead rendering from left to right in columns The bucket or tile order can be changed to left to right using the columns command line switch or the following option Option render string bucketorder columns 3 Use a smaller bucket size to reduce memory use and improve load balancing when rendering with multiple threads The bucketsize can be set using the bs command line switch air bs 16 scene rib or using the following option Option limits bucketsize 16 16 The default bucket size is 32 x 32 pixels A smaller bucket size will typically increase render time so use as large a bucket size as feasible 4 Convert all texture maps to Air texture files with mktex or mktexui to optimize memory use
552. sing Environment Maps ccccsssecccsseeeeeeseeeeeeenseeeeeenseeeeeenseeeeeenseeeeeeeseeneeenseeenens 342 Anisotropic Reflections cccceeeeeceeeeneeeeeeeeeeeeeeeneeseeenneeseeenneeseeesneeseeesneeseeenneesesesneeseeeseeeseeeenees 343 BRDF Reflection Sampling srren snene aeea anaana eaa ateena erena aaar aa ar kaanan aanas anapa 343 Motion Blur DOF amp LOD 344 2001 2014 SiTex Graphics Inc Contents Vill Part XVII 1 Part XVIII 1 2 Part XIX A OD Part XX Part XXI Motion Blur iisiicccesai cc lisidiceceunsade treed ncaciancaue evar seaucuuvuedeswacduasedaetauevwadduaseuuet Depih of Field oiiae aaan KRENN RA AARNEN AAAA E A Ke1 D e 1 a S E E E Outlines for Toon Rendering and Illustration lllustration Shaders and Examples s sssnssunnsunnnunnnunnnunnnunnnnnnnnnnnnnnnnn Volume Rendering Writing Shaders for Volume Primitives s ccseeseeeesseeeeseeeeeees RIB Volume Primitive cccseecceceseeeeeeeseeeeeeeseeeeeessneeeeeesneeeesssneeeesesnee Pipeline Workflow and Optimization Conditional RIB sctcsicsschecccectdeeccctucssecteteccerctucssstestececcetuaresetsteaderesuecssuaet RIB fe eee eee eee Geometry EX DOME is erae ecco ar ar rea ds ects aaneen aaa eaaa aa ae naaar aaraa General Optimization TipS cceeceeseeseeeceseeeeneeeeeeeeeeeeeesesneeenseeeeeeees TweakAir for Interactive Rendering TweakAIR Options cccseccsseeeeeseeeseeeen
553. source code must retain the above copyright notice this list of conditions and the following disclaimer e Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution e Neither the name of Industrial Light amp Magic nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE LIBTIFF Copyright c 1988 1997 Sam Leffler Copyright c 1991 1997 Silicon Graphics Inc Permission to use copy modify distribute and sell this software and its documentation for any purpose is hereb
554. source point spherelight emits light like a spherical area light spotlight emits light in a cone of directions Area Lights arealight shader for area lights using light supersampling arealight2 shader for area lights using Air s fast areashadow function cardlight emulates adding a constant shaded card portallight area light shader for windows with environment map sky_portallight area light shader for windows admitting sky light texturedarealight area light with optional texture map Lights with Texture Maps distant projector projects a texture using a distant light base spot projector projects a texture using a spotlight uberlight multipurpose light with many controls Lights for Windows distant_window light directional illumination through a paned window spot window light spotlight shining through a paned window sun window light sunlight shining through a paned window Special Lights photometric_pointlight point light source with IES support and physical illumination units caustic caustics envlight adds indirect illumination using ambient occlusion indirect adds indirect diffuse illumination Gl or global illumination sunlight sun light based on position date time amp atmosphere Lights for Baked Shadows and Illumination Many light shaders have an extended version that allows shadows or illumination to be baked to 3D texture maps and re used The documentation for each light shader includes information on the bake v
555. space to world transformation matrix for the named coordinate system The transform parameter should point to an array of 16 floats 20 3 18 IrTweakDisplacement C int IrTweakDisplacementV IPR ipr int ntk char tk void v Text IrTweakDisplacement parameter list Use this function to modify displacement shader parameters for the selected primitives Tokens in the parameter list must have full inline type definitions The selected primitives need not have the same displacement shader assigned This function simply looks for matching parameters in whatever displacement shader if any is currently assigned to a primitive 2001 2014 SiTex Graphics Inc TweakAir for Interactive Rendering 366 20 3 19 IrtweakEnvironment C int IrTweakEnvironmentV IPR ipr int ntk char tk void v Text IrTweakEnvironment parameter list Use this function to modify environment shader parameters Tokens in the parameter list must have full inline type definitions 20 3 20 IrTweakIimager C int IrTweakImagerV IPR ipr int ntk char tk void v Text IrTweakImager parameter list Use this function to modify parameters for the current imager shader Tokens in the parameter list must have full inline type definitions 20 3 21 IrTtweakLight C int IrTweakLightV IPR ipr char handle int ntk char tk void v Text IrTweakLight handle parameter list Use this function to modify the parameters of the ligh
556. splacement to a tangent space normal map Parameter Default Value Range Description RightHand 1 0 1 whether the current coordinate system is right handed Description Use this surface shader with BakeAIR to produce a tangent space normal map from a displacement shader This shader works best when the displacement shader provides the undisplaced normal vector in a__undisplaced_N output variable If the displacement shader does not provide such an output variable the BakeTangentNormalMap shader computes the undisplaced normal using the tangent vectors and accounting for the handedness of the coordinate system 10 10 4 CausticPass surface shader returning photon based caustics at the current shading location Parameter Default Value Range Description Intensity 1 0 Multiplier for recorded value Description The CausticPass shader returns the caustics visible at the current shading location if any This shader may be useful for baking caustics for use with the caustic baked light shader See Also caustics caustic baked light shader 10 10 5 ClownPass surface shader that assigns a random color to each object based on its toon id attribute Parameter Default Value Range Description Seed 0 Seed for random number generator Description The ClownPass surface shader assigns a unique color to each object or facet based on the toon id attribute used for outline rendering The clown pass image can be used to as a source for selection masks i
557. sr local texture shirt tif would become 2001 2014 SiTex Graphics Inc 381 AIR User Manual 22 5 i texture shirt tif in the output rib file Useful for changing texture references for rendering under Windows optrib ribfilename This option inserts additional rib commands from the specified file into the output stream just prior to the WorldBegin statement Useful for adding custom options and attributes to a scene Start massrib with no arguments to display a list of command line options Shading and Lighting in Air Space A file Massive rib file that has been converted with massrib can be moved to Windows and edited with Air Space the standalone shading and lighting tool included with the Windows distribution of AIR Air Space provides an interactive shading and lighting environment utilizing TweakAIR the interactive version of AIR Air Space provides a simple means of lighting a scene and customizing the shading for individual agents More information about Air Space can be found in the separate Air Space user manual Preparing a Massive Scene for Air Space When preparing rib export in Massive make sure the main rib file name is of the form basename framenumber rib Air Space looks for a frame number between periods just before the rib extension Creating a New Air Space Project A new project is created using a single frame as reference for the IPR preview and opengl window The shading and
558. ss of the machine to which the image data is sent If omitted data is sent to the local machine If data is sent to a remote machine AIR Show must already be running on that machine The IP address can be in dot 3 notation e g 192 168 1 1 or a name for a DNS lookup float share 0 When set to 1 AIR Show will attempt to merge output with that from other processes writing to the same image integer port 47349 Gives the TCP port number to use when connecting to an external display program such as AIR Show The default port number used by AIR Show is 47349 Command Line Options The following options may be included on the command line when starting AIR Show res width lt height gt Sets the default width and height of the client area of the AIR Show window This is the maximum image size that can be displayed without scroll bars pos left top 2001 2014 SiTex Graphics Inc Tools 406 24 3 7 24 3 7 1 Sets the position of the upper left corner of the display window on the screen g gamma Sets the default gamma correction applied to images for display This options overrides a gamma defined with the optional AITRSHOWGAMMA environment variable fps framespersecond Sets the default frames per second for animation playback This option overrides the frames per second defined with the optional AIRSHOWFPS environment variable Loading Images at Startup AIR Show also accepts a list of file names
559. ssenaceevaeeee PHOtoOMetric ool niitto n aa a E EE coces cheed uceosedeuerdudesscedeedendheesesteceeeceuetdudesactdsteaedhersects pointlight pointlight_baked ololar ilI pi Ana E N EE E E E E A E E E A Sky Portallighat ico ccnccs ctscces aossen sanaa iaeiae Naane cessed cesrceuev sect ceaty cetcedenccteesseecgeucvsccudesevcedeeceds cccesteergeuestes SPMOrelig ht a EE EE I A A E ieuveduerscs spotlight spotlight baked virs cs cesies cccceccetccscecseiecees iderat diaos idiin enoro ddiet diako seiecauersieceecsdecrecaes docessedecauesece spot_projector spot_window_light sun_window_light S nlight aeececsecccctesecegacccthedvceee cecencedd sdcuecttccace tiedezeas ceceuaaneedeuesobcceue cieedewece cecceuaessdensoiccanessieceuecececredues deuevotevauaseds TexturedarealiQht sssaaa aaaea saadaa aaeeea eaa ae PASU Seaia paaa aaa ei E deasa eaaa eia aara aa Eda aaaea uberlight 8 Procedures EDDAN T y A e e E E E E A N E E E E E T aa E E E E EE EEE EE E E E E E EE EEE EAE E o RS Ro eTe A E E TE E A E E E E E StrokeEPenell sissiencisscsececscecscceiessestencsnncdencosesceusececdebensssansesasdencenscssvucceddviseeedsanessnddsnserssteneessddetccenddvuenseddenstenctsectess strokeWatercolorEd ge 10 SUPPACCS cacieccdccesedeeecec a aa a SSE hc sca weed sh aa anaa a aa aa aaa a aa raa iaai aa eN ee e E E EA EAE ENEE EE E E EE E E EE EE E E E EEEE artro be uNa aCe REE E A ET E A E A A A S BakeTangentNormalMap CAUSTICPASS
560. ssive agent light tool for rendering per agent lights e AIR Show 3 0 e Histogram display e Integrated pixel zoom for viewing pixel values e Wipe between images for comparison e Simple compositing of multilayer images e Faster sRGB conversion for 16 bit and float images e Quick help for mouse actions and keyboard shortcuts e AIR User Manual e Command line option list moved from Reference to the Getting Started section e Attributes list moved from Reference to the Attributes section e Options list moved from Reference to the Options section e Reorganized many topics including ambient occlusion and indirect lighting Vshade 2 0 see the separate Vshade documentation for details Many internal changes for the forthcoming 64 bit version of AIR Bug fixes e Fix for mktex e Fix for shading interpreter runtime optimizer recognize that attribute may write to array elements Flx for extended phong per channel output Prefilterclamptoalpha no longer clobbers outline data Points as spheres now clipped correctly by near clipping plane Fix for z channel output in a multichannel Display call Outlines fix for front back edge detection Fix for shading cache size without motion blur 29 7 AIR 7 0 e New RhinoAir plugin for Rhino 4 available as a separate download from the SiTex Graphics web site 2001 2014 SiTex Graphics Inc 445 AIR User Manual Automatic level of detail for polygon meshes Support for Houdin
561. stration you may wish to use the constant shader in conjunction with outlining Cartoon Shading For cartoon rendering try the VToon shader included with AIR Because toon style shading often has sharpen transitions between dark and light regions you may need to user a lower shading rate to produce smooth shading results 2001 2014 SiTex Graphics Inc Outlines for Toon Rendering and Illustration 350 Ambient Occlusion and Outlines for Illustration For a softer look try a matte surface shader with ambient occlusion and outlines More examples of toon rendering and illustration can be found in SAIRHOME examples toon 18 Volume Rendering AIR 4 introduces a new volume primitive type for efficient rendering of volumetric effects Although AIR can still produce volumetric effects by ray marching in a volume shader volume primitives are typically much more efficient Defining Volume Primitives A volume primitive defines a volume as a basic shape within a bounding box The shape can be a box ellipsoid cylinder or cone Volume primitives can have arbitrary user data applied either as a 3D grid of data values or as a point set with associated per point data values Your RIB export plugin may automatically export fluid simulation or particle simulation data as a volume primitive Users interested in creating their own volume primitives should see the section on the RIB Volume statement Shading
562. strict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Shadow mapped Shadows Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows 10 7 19 spotlight spotlight_baked spotlight shader 2001 2014 SiTex Graphics Inc 153 AIR User Manual Parameter intensity lightcolor lightcolor_spd maxemission from to coneangle conedeltaangle beamdistribu
563. sults Texture Cache AIR loads texture files shadow maps and environment maps as they are needed by the renderer AIR uses a simple least recently used cache to keep only the most recently accessed sections of texture in memory thereby keeping the memory used by all types of textures to a minimum The texture cache size is set with Option limits integer texturememory 64000 which gives the maximum cache size in K Beginning with AIR 13 all rendering threads share the same texture cache In prior releases each rendering thread managed its own cache Textures and Gamma Correction When a final image has gamma correction applied you may find that your texture maps appear washed out or faded This problem occurs most often with commercial texture libraries that have been pre gamma corrected to display properly on a CRT To get such textures to render properly with AIR apply an inverse gamma correction factor during the texture conversion process with the mktex or mktexui tools Here are some common gamma factors and the corresponding inverses Gamma Inverse 1 8 0 56 2 0 0 5 2 2 0 45 You may also perform this conversion by using the color space conversion options in mktex or mktexui to convert from sRGB color space to a linear color space Texture Wrap Modes For images used as textures that have not been converted to Air texture maps the default wrap mode can be set with the following options Option texture stri
564. sults and require that fewer photons be used overall Attribute caustic integer ngather 75 gives the minimum number of photons to gather for a caustic estimate No caustics will appear at locations where insufficient photons are found within the distance given by the maxpixeldist attribute Recycling Photons The photon map used for calculating caustics can be saved to a file with Option caustic string savefile filename and re used with Option caustic string seedfile filename Caustics can be saved and loaded from any 3D point format supported by AIR The recommended point format for caustics is an AIR Point Cloud extension apc Loading a seed file does not preclude shooting additional photons If you want to use only the photons in a seed file be sure to set the number of emitted photons for all light sources to 0 Note that while shooting photons requires ray tracing rendering caustics with only a seed file does not For example a seed a file could be created using a small subset of objects from a larger scene and re used for the entire scene Dispersion AIR can simulate the effects of dispersion e g prism like effects in the photon map Attribute caustic float dispersion 0 gives the variation in the index of refraction over the visible spectrum E g if the following caustic attributes were defined Attribute caustic float refractionindex 1 5 Attribute caustic float dispersion 0 3
565. sults in a large difference between adjacent depth values AIR 6 and later provide two options that can be used to limit how much the midpoint depth value differs from the min depth value The first option sets the maximum absolute distance between the midpoint value and the nearest surface position Option render float maxmiddistance 1000000000 The second option gives the relative position between the 2 closest surfaces of the value stored in the depth map Option render float midposition 0 5 The default value of 0 5 stores a depth value half way between the 2 nearest surfaces A value of 0 2 would produce a depth value closer to the nearest surface Cube Faced Shadow Maps Depth maps taken from multiple views can be combined into a single shadow map This capability can be used to make a cube faced shadow map for use with a point light The mktex utility will combine up to 6 separate depth maps into a single shadow map E g mktex shadow map px map nx map py map ny map pz map nz shadow shd The RIB MakeShadow command has been extended to accept an array of strings as the first parameter containing up to 6 depth maps to be joined into one shadow map AIR does not place restrictions on the views used for the depth maps that go into a multi depth map shadow map For a cube faced map the FOVs of the depth maps should slightly overlap to prevent gaps Another way to create a cube faced map is to use the shadow display
566. svedesedetscsestabesssdsubecausasieesbassbacasdcedoeerd 303 TOXTUNESA EEEE E 303 te D E E E 304 Aelia O OMME EAA EE N E E E E E E EEE 305 VOFOMON e E 305 2D Texture Mapping 305 Projecting Textures Decaling cccsssecccsseseeeenseeeeeeeseeeeeenseeeeeenseeeeeseseeeeesaseneeeeaseeneeseseenenens 307 Ae Co gid 40 AE aeeeeeenee pt eerererrere ree tere errrecrereretrer ere tereceeerrretrrrerrr cree rrer ere trrrcrererrrerrr errr ere tree erer errr cr ee 308 PTEX Per Face Texture Mapping ecceceeeeeeeeeeeeeeeeeeeenneenaeeeseeeensenenaeeeseeeseseneeneeeeseeeeas 309 3D Textures amp Point Sets 310 Lighting 312 Area LIGNIS oroesi a op a pn aon ee 313 SHAGOWS gt asingidan eddie os sk este es eee eee en es ee es eee 314 Ray Traced Shadows eiar na anera cadceeccdeceienacciccaecessncnusvdgnecsdeacdersvodcervadues avesedesecedsaucetsdedenesssoeverascdesrsaieie 315 Shadow Map sss soe iaeei ce cece ce renctcsceeecuecede opia aataid ea esecechdesstceeeagtsters La ep aie Eaa raian i eiras 317 Fragment Shadow Maps ciicic2c5 scccccescscccece ccceesctiecaccts cetencesccus cate naana steecaucsuceescssceaseauesvocedsieesauevecetsucersceseavecetercence 318 PUTOMAPS E E A seus souetececsuwedsucesszdedcarciees suvteuerstendacdeceitedccy ceeded ET 319 MPC CU Lighting nnee eee aaa a a ea raaa Aaa raaa ses eaaa ae Eee Aar erap aE anea En eaaet 320 Ambient OCCIUSION s iennnnonanin annen ataia naaa a anaa maaa Aaa Aaaa raam a aa A En A aa a
567. t be enabled with the maximum line width option set appropriately for this shader to function properly By default the shader produces a constant shaded surface with outlines Set the Incandescence parameter to 0 and increase Diffuse and Specular to obtain a standard matte or plastic illumination model See Also Outlines for illustration 10 10 7 VSkin kN a skin shader with subsurface scattering and optional texture map Illumination model custom 2001 2014 SiTex Graphics Inc Shader Guide 260 Features subsurface scattering texture map Parameter Default Value Range Description Ambient 1 0 0 0 1 0 Ambient reflectivity SingleScatter 1 0 Strength of single scattering MultipleScatter 1 0 0 0 1 0 Strength of subsurface scattering Sheen 1 0 0 0 1 0 Sheen strength SheenColor r4 Sheen color ScatterDistanceScale 0 1 Multiplier for ScatterDistance ScatterDistance 4 82 1 69 1 09 Average scatter distance for r g b SubsurfaceReflectance 0 63 0 44 0 34 Diffuse reflectance SampleDistanceOverrid 1 Maximum distance between subsurface e samples 1 for default ColorMapName _ Texture map for base color ColorMapBlur 0 0 0 0 1 0 Texture blur TextureSizexY ig Texture size in X and Y direction TextureOriginXY 0 0 Location of left top texture edge TextureAngle 0 Texture rotation angle in degrees Projection st type Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection
568. t category __nondiffuse 0 0 1 If 1 light is excluded from diffuse light __nonspecular 0 0 1 If 1 light will not produce highlights foglight 1 0 1 If 1 light illuminates volumes _ Channel 1 0 9 Output channel Description A spherical light source can provide more realistic illumination than a traditional point light because it gives the light an actual size and shape The usual way to render a sphere light is to use an arealight shader with sphere geometry That approach works but it has some drawbacks e Render time can be significantly slower because the area light shader must be evaluated at many different locations on the sphere to produce a smooth result e Some software such as Massive does not provide an interface for area lights To address those drawbacks we ve put together a spherelight light shader that can be used to simulate the effect of a spherical light source using a standard point type light The shader is similar to the pointlight shader with the addition of a 1ight radius parameter for the radius of the virtual spherical light source The shader uses the light radius in a couple computations that approximate the effects of a spherical source e Shadows are blurry close to the source and sharper farther away The shader simulates this effect by computing a shadow blur angle based on the distance to the light source and the light radius lenL max sqrt L L radius blur abs atan radius sqrt lenL lenL rad
569. t illuminant should emit white light Other lights will have their Lightcolor_spd if present divided by the dominant illuminant to compensate for the material color premultiplication Note that if all lights have the same spectral profile and default white light color adding the above option will effectively change the spectrum of all lights without requiring any change to the way the lights are declared in the RIB file Chromatic Adaptation Once we start using real spectral data for rendering we also need to take better account of how the human visual system processes that data According to Ward and Eydelberg Vileshin there is a strong tendency for viewers to discount the illuminant in their observations and the color one sees depends strongly on the ambient lighting and the surround For example our equation might compute a yellow orange color for a white patch under a tungsten illuminant while a human observer would still call it white if they were in a room lit by the same tungsten source To compensate for the viewer s chromatic adaptation they suggest transforming color data from the color space of the dominant illuminant to a that of an illuminant corresponding to the display viewing conditions In Air chromatic adapation is enabled by defining an illuminant for the display viewing conditions with Option render string displayilluminant_spd Chromatic adaptation also requires specification of a dominant illu
570. t in a single direction defined by the vector to from through a rectangle defined by the window parameters The window opening is centered at the to location The window rectangle is defined by window_size_x window_xdir window_size_y and window_ydir The window may optionally be subdivided into panes horizontally and or vertically If a texture map is provided it is assumed to cover the entire window opening Traced Shadows If the shadowname parameter is set to the special value raytrace shadows are generated by tracing shadow rays The shadowsamples parameter specifies the number of shadow rays to trace The shadowblur parameter gives an angle in radians to distribute the rays around the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and t
571. t shader attached to a light Tokens in the parameter list must have full inline type definitions Special Parameters float refreshshadows 1 Including this parameter flushes the shadow cache and forces the light to be re evaluated at all surfaces illuminated by the light 20 3 22 IrTweakOption C int IrTweakOptionV IPR ipr char name int ntk char tk void v Text IrTweakOption name parameter list Use this function to modify options for the current scene Tokens in the parameter list must have full inline type definitions The following options are tweakable Option indirect color background r g b Option ipr integer retrace n Option ipr integer 2 pixelsamples nx ny Option reflection color background r g b Option reflection float envblur n Option reflection float envstrength n Option reflection string envname nam 2001 2014 SiTex Graphics Inc 367 AIR User Manual Option trace integer maxtracesamples n Option trace integer maxshadowsamples n 20 3 23 IrtweakSurface C int IrTweakSurfaceV IPR ipr int ntk char tk void v Text IrTweakSurface parameter list Use this function to modify surface shader parameters for the selected primitives Tokens in the parameter list must have full inline type definitions The selected primitives need not have the same surface shader assigned this function looks for matching parameters in whatever su
572. t with no preferred direction The matte illumination model includes an Ambient parameter which scales the contributes of ambient light sources and a Diffuse parameter which sets the intensity of the diffusely scattered light from non ambient light sources Plastic A plastic surface typically reflects some light diffusely like a matte surface and some light in a 2001 2014 SiTex Graphics Inc Shader Guide 80 focused manner producing specular highlights A plastic illumination model adds parameters for specular highlights to the base Ambient and Diffuse parameters of the Matte illumination model A Specular parameter sets the intensity of the specular highlight To be physically plausbile the sum of the diffuse and specular intensities should be less than or equal to 1 Diffuse Specular lt 1 A Roughness or SpecularRoughness parameter determines the size of the highlight which is inversely proportional to the roughness value 0 05 Although most plastics have white highlights a surface shader may provide a SpecularColor parameter for customizing the highlight color Metal A polished metal surface typically reflects a high percentage of the incoming light coherently A metal illumination module provides Ambient Diffuse and Specular parameters like the plastic model The Diffuse strength should normally be much less than the Specular value For metals the highlight color is usually the same as t
573. tIsotropy which specifies the threads tendency to scatter light in all directions versus scattering preferentially along the incoming light direction Threads are constructed from cloth fibers in two different ways and the method of construction affects the optical properties of the thread Staple threads such as cotton are made out of twisted fibers and they are held together by friction Filament threads are made of long straight fibers such as silk with little twist Here are some measured values for different thread types from the above cited paper Thread Type Isotropy Shininess Linen flax 0 3 085 Flat silk 0 2 0 2 Twisted silk 0 3 0 22 Flat polyester 0 1 0 4 Twisted polyester 0 7 0 033 See Also VClothAdvanced surface shader VFabric surface shader 10 10 4 VCloth Advanced surface shader for cloth based on a physical model of woven fabric lllumination Model microcylinder Features texture map Parameter Default Value Range Description Diffuse 1 0 0 0 1 0 Volume scattering multiplier Specular 1 0 0 0 1 0 Reflection multiplier 2001 2014 SiTex Graphics Inc 225 AIR User Manual ColorMapName a Texture map for base color ColorMapBlur 0 0 0 0 1 0 Texture blur WarpColor 1 1 Color for warp threads WarpMapName me Texture map for warp color WarpDiffuseSpread 24 Volume scattering angle in degrees WarpDiffuselsotropy 0 3 0 0 1 0 Isotropic scattering tendency eE 12 Specular reflecta
574. tandard plastic material appearance with diffuse values taken from baked texture maps By default the shader queries the user attribute specified in MapAtt ributeName for the baked map file name If a MapFileName value is provided that will be used as the bake map name At a minimum each baked map should have 3 channels with the total diffuse lighting component illumination and surface color If the baked map also has 3 channels with the unshadowed diffuse value the shader will use that information to compute proper __ dif fuse_unshadowed and __ shadow output values The shader needs to be told where the unshadowed values are stored in the baked maps by setting the ChannelWithUnshadowed value to the index of the first channel of the baked values in the map Similarly if the baked map has indirect illum values again light plus surface color set the ChannelWithIndirect value to the index of the first channel Specular highlights using a Blinn BRDF can be added to the basic diffuse illumination If the SpecularApplyShadow value is set to 1 the diffuse shadow value will also be applied to the specular component which may allow final rendering to be done w o shadow computations in the light Assuming a pretty simple lighting setup Reflections can also be added by setting Reflection to a positive value 2001 2014 SiTex Graphics Inc Shader Guide 188 10 10 3 BakeTangentNormalMap surface shader for baking di
575. te indirect color averagecolor 1 1 1 Attribute indirect string averagecolor_spd The indirect shading attribute determines the type of shading performed when a surface is intersected by an indirect ray Possible values are shade Execute the surface s assigned shaders to determine the reflected color matte Use a matte surface shader with the color taken from strength averagecolor This is the default setting constant Use a constant surface shader with the color taken from strength averagecolor If the indirect averagecolor attribute is not set the renderer will use the standard color attribute for the surface Cs as the average color Matte shading can save a considerable amount of time if a primitive has a complicated surface shader assigned All that s required is an estimate of the average reflectance color over the surface Constant shading saves even more time because the renderer doesn t have to execute the light shaders assigned to the surface to calculate its contribution to indirect illumination For constant shading the product of the averagecolor and strength attributes should be a rough estimate of the average color including lighting of the surface Environment In Air 11 and later indirect rays that miss all objects return a color based on the current environment shader s assigned to the scene if any Air 12 introduces a new option to automatically cache the environment for indirect queri
576. te that the export directory contains only shading lighting and basic rendering options The scene geometry is stored in the mapped rib files created from the source ribs and those are shared across render versions Making Changes to Animation Air Space stores shading and lighting information in a manner that is independent of the underlying scene file If you make changes to your animation in Massive you can re export rib files convert them with massrib overwrite the current ribs used by Air Space and Air Space will automatically produce new mapped rib files and apply your current materials and lights to the new simulation Use the Refresh Model button in the Air Space toolbar to reimport geometry from a changed source rib file Limitations Shadow maps cannot be generated per frame Use ray traced shadows instead 22 6 Ambient Occlusion in Massive AIR provides two common ways of rendering ambient occlusion a special envlight light shader that uses ambient occlusion to compute its shadows and an occlusionpass surface shader The envlight and occlusionpass shaders included with AIR rely on attributes and options to control their behavior Because Massive does not provide a convenient way of setting custom attributes and options we have developed special versions of these shaders massive envlight and massive occlusionpass that do not rely on custom attributes or options These shaders should not be used with the occlusion prepas
577. ter 14 of Advanced RenderMan Creating CGI for Motion Pictures by Apodaca and Gritz Light Type The lighttype parameter determines how the shader casts light spot casts light towards the positive z axis omni casts light in all directions arealight casts light within a hemisphere on the front side of the light surface Distance Shaping and Falloff The cuton and cutoff parameters define the range of depths that are illuminated Emitted intensity will be zero outside that range nearedge and faredge give transition zones at either end of the range in which intensity smoothly diminishes to 0 falloff is the exponent for decay with distance A value of 0 produces no falloff a value of 2 produces the square law falloff The falloffdistance parameter gives the distance at which falloff with distance begins No distance based attenuation occurs at locations closer than falloffdistance maxintensity sets the maximum intensity preventing the emitted intensity from growing too large When the parallelrays parameter is 0 light rays diverge when the parameter is 1 light rays remain parallel Cross section Shaping Uberlight casts light with a cross sectional shape that can vary from a rectangle to a perfect ellipse 2001 2014 SiTex Graphics Inc 167 AIR User Manual 10 8 width and height give the width and height of the light opening roundness determines whether the shape is a rectangle 0 or ellipse 1 or a sup
578. tern of brick grooves VPillows 2D pattern of pillow like bumps a VRibbed 1D pattern of semi circular bumps VThreads 2D pattern of screw threads 3D Irregular Patterns 2001 2014 SiTex Graphics Inc 87 AIR User Manual VDimples pattern of rounded cells VCracks cracks VDents dents VHammered hammered surface VNicks nicked surface VRipples ripple like patterns VStuccoed stucco OceanWaves animated ocean waves Normal Mapping VNormalMap apply normal map holding object space or world space normals VTangentNormalMap apply normals stored in tangent space Additional Displacement Shaders 2 DarkTreeDisplace displacement shader for DarkTree shaders ment Displacement Output Variables All Air displacement shaders provide the following output variables which may be queried by a surface or atmosphere shader 2001 2014 SiTex Graphics Inc Shader Guide 88 _ bump the distance the surface was displaced at the current shading location __undisplaced_N the undisplaced normal vector at the current shading location 10 2 2 bumpy simple displacement with a texture map Parameter Default value Range Description Km 1 0 Displacement amplitude multiplier texturename a Texture file name repeatx 1 0 Copies of texture in X direction repeaty 1 0 Copies of texture in Y direction originx 0 0 Location of left texture edge originy 0 0 Location of top texture edge Descriptio
579. the point being shaded Adjust the shadowbias parameter to prevent incorrect self shadowing The shadowgroups parameter can be used to restrict shadow casting to the specified list of groups The shadow group can be overridden on a per object basis by providing a user attribute Attribute user string shadowgroups my custom groups The shadowattribute parameter gives the name of the user attribute to check for a custom shadow casting group By default all lights look for a custom shadow set in the same user attribute By providing a different user attribute for each light one can precisely specify for each object and each light which objects are tested for shadows If the shadow group has the special value null no shadow rays will be traced and the object will not receive shadows Shadow mapped Shadows Assign the file name of a previously generated shadow map to the shadowname parameter to generate shadow mapped shadows The shadowblur parameter gives a blur value as a fraction of the shadow map size AIR ignores the shadowsamples parameter for shadow mapped shadows but other renderers may use it to control the quality of mapped shadows Adjust the shadowbias parameter to prevent incorrect self shadowing Output only variables color _ shadow Shadow value color __unshadowed_Cl Emitted illumination without shadows distant_window_light directional light shader that emits light only through a rectangular opening with optional
580. tial tests you may also wish to set the falloff parameter to 0 If the lights are to cast ray traced shadows set the shadowname parameter to raytrace 2001 2014 SiTex Graphics Inc 389 AIR User Manual 22 12 3 Make sure the proxy geometry is tagged not to cast shadows in Massive 4 Sim to export rib files as usual 5 Use the malt tool to create agent lights for each frame malt scene0001 rib The malt tool parses through all the agent data looking for objects with a light surface shader For each such object malt creates a light in an agent light file named scene0001_agentlights rib After processing the agents malt re writes the main scene file adding a reference to the agent lights just after the WorldBegin statement 6 Render the main scene file as usual Rendering Massive Agents in Rhino This note describes how to include Massive agents when rendering a Rhino model with the RhinoAIR plug in This method uses the new MassiveAgents instancer shader to add agents at render time Preliminary Massive uses a small program called runprogram exe to create agents at render time AIR must be able to find the runprogram exe file at render time The easiest way to ensure that is to copy the runprogram exe file from your Massive installation to the procedurals directory of your AIR installation 1 Select the terrain object in the scene or another large object if there is no terrain Display the AIR M
581. tion falloff shadowname shadowbias shadowblur shadowsamples shadowcolor shadowgroups shadowattribute __category __nondiffuse __nonspecular _ foglight channel Description Default Value 1 0 111 wo O O O O Rr oO 0 4 52 0 087 wee wee user shadowgroups lensflare e m e Range o o ooo O hoh au 00 055 1 256 Description Light intensity Light color Light color spectrum file If greater than 0 the maximum emitted light intensity Source position of light Target of light Cone angle Angle for cone edge blur Exponent for cross beam falloff Exponent for falloff in light intensity with distance Name of shadow map or raytrace for traced shadows Offset to prevent incorrect self shadowing Blur for shadows Number of rays for traced shadows Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name Light categories If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel The spotlight shader emits a cone of light with apex at the source point from and direction given by the vector to from The coneangle parameter gives the half angle of the cone in radians Light Intensity The emitted light value is the product of the intensity and lightcolor parameters and an attenuation factor determined by the falloff parameter The falloff paramet
582. tion bake float border 1 Setting the border width to 0 disables padding of the rendered texture In some cases it may be useful to have the border filling wrap around in texture space which can be enabled with Option bake integer borderwrap 1 This option may be useful when baking Rhino polymeshes See Also Lighting gt Baking Shadows and Illumination 2001 2014 SiTex Graphics Inc 371 AIR User Manual 21 3 Baking PTEX Textures with BakeAir BakeAir 11 and later can bake data to PTEX per face texture maps for polygonal and subdivision meshes For PTEX textures the texture size for an individual face is computed automatically based on the following option Option bake float texelsize n which gives the size of a single texel in world space coordinates A smaller texelsize will produce a higher resolution and therefore more detailed map for each face Baking to PTEX also requires the following attribute for the baked objects Attribute render integer ptex 1 The PTEX display driver accepts two additional parameters in the Display parameter list float half 1 enables saving data as 16 bit floating point numbers half precision The display output quantization should also be set for float precision when saving half data float makemipmaps 1 enables mip map generation for the created PTEX file Each face map will be stored at multiple resolutions for faster higher q
583. tionSamples ReflectionBlur ReflectionName ReflectionSpace ColorMapName ColorMapBlur SpecularMapName SpecularMapBlur OpacityMapName OpacityMapBlur BumpMax BumpMapName BumpMapBlur TextureSizexY TextureOriginXY TextureAngle Projection ProjectionSpace ProjectionTransform Description raytrace current shader 1 0 0 0 0 1 0 5 s9 22 0 0 wo st 0 1 0 0 oroo Default Value eoOoOoOO S aces Description Diffuse reflectivity Specular reflectivity Specular roughness Sharpness of highlight edge Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Texture map for base color Texture blur Texture map for specular color Texture blur Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees Projection to use for 2D coordinates Coordinate space for projection Transformation applied prior to projection The VCeramic surface shader simulates a glossy surface with reflections and texture maps for color specular opacity and bump All texture maps use the same set of texture coordinates See Also VShinyTile2D shader 2001 2014 SiTex Graphics Inc 221 AIR User
584. tional texture maps metallic car paint with clear finish shader for woven cloth based on measured data velvet shader for fabric or cloth ad hoc leather surface shader 2001 2014 SiTex Graphics Inc 181 AIR User Manual 2D Patterns es R e s Gradient VGrid2D VHexTile VPlanks VScreen VShinyTile2D VWeave 3D Patterns VMarble VGranite VWood os Ss bricks color gradient grid of 2D lines hexagonal ceramic tile wooden planks metallic or plastic screen with round or square holes ceramic tiles basket weave pattern simple veined marble granite solid wood 2001 2014 SiTex Graphics Inc Shader Guide 182 Curve and Point Shaders Passes shader to make curves look like hair shader to make curves look like fur for Shave and a Haircut dashed curves surface shader for carpet created with the instCarpet instancer shader shader for particles and volumetric primitives 2001 2014 SiTex Graphics Inc 183 AIR User Manual CausticPass ClownPass gaa depthpass IndirectPass pass MotionPass occlusionpass ReelSmartMotion shadowpass ShowNormal ShowPosition UseBackground Baking emits caustics only at the current location assigns a unique color based on toon id z depth pass emits indirect diffuse illumination only massi
585. tional to the RoughnessX and Roughness Y parameters respectively to produce a consistent appearance However the RoughnessX value does not have to be exactly the same as the ReflectionBlurX parameter and the RoughnessyY value need not match the ReflectionBlurY value 2001 2014 SiTex Graphics Inc 217 AIR User Manual The illumination model is based on Measuring and Modeling Anisotropic Reflection by Greg Ward published in SIGGRAPH 92 See Also VBrushedPlastic shader 10 10 3 VBrushedPlastic a brushed plastic surface with reflections IIlumination model anisotropic plastic Features reflections Parameter Diffuse Specular SpecularRoughnessX SpecularRoughnessY Reflection ReflectionSamples ReflectionBlurX ReflectionBlurY ReflectionName ReflectionSpace ColorMapName ColorMapBlur SpecularMapName SpecularMapBlur OpacityMapName OpacityMapBlur BumpMax BumpMapName BumpMapBlur Default Value 0 45 raytrace current wo spaces Description Diffuse reflectivity Specular reflectivity Specular roughness in X direction Specular roughness in Y direction Reflection strength Number of rays when ray tracing Reflection blur in X direction Reflection blur in Y direction Name for reflection map or raytrace for ray tracing Coordinate space for reflection lookup Texture map for base color Texture blur Texture map for specular color Texture blur
586. tivity Specular roughness Reflection strength Number of rays when ray tracing Blur for reflections Name of reflection map or raytrace for ray tracing Coordinate space for reflection lookup Size or scale of pattern Pattern origin Coordinate space for shading calculations Fraction that is vein color Blur for transition region Vein color Levels of detail in pattern How much each level adds to the pattern Filter width multiplier The VGranite shader simulates a granite like material with optional reflections 10 10 5VGrid2D 1 2D grid of lines on plastic IIlumination Model plastic Parameter Ambient Diffuse Specular Roughness Default Value 1 0 O O O Poo Range OoOO ooo Psi a O O OO 0 01 1 0 Description Ambient reflectivity Diffuse reflectivity Specular reflectivity Specular roughness 2001 2014 SiTex Graphics Inc 239 AIR User Manual LineSpacing 0 1 Distance between line centers LineWidth 0 01 Line width LineColor 000 Line color ProjectionT ype st projections Projection to use for 2D coordinates ProjectionSpace shader spaces Coordinate space for projection Transformation 1000 Transformation applied prior to 0100 projection 0010 000 1 Description The VGrid2D surface shader generates an anti aliased 2 dimensional line grid on a plastic surface 10 10 5 VHair surface shader to make curves look like hair Illumination Model custom Parameter Def
587. tomized by providing a subset of groups to the shading language functions trace environment and gather used to cast reflection rays Visibility for Ray Traced Shadows Objects that should cast ray traced shadows must be made visible to shadow rays with one of the following attributes Attribute visibility integer shadow 1 Attribute visibility integer transmission 1 By default all objects are invisible to shadow rays When a shadow ray strikes an object AIR uses the following attribute to determine how the object affects the shadow ray Attribute shade string transmissionhitmode primitive For the default primitive mode AIR uses the object s opacity value at the intersection point as the transmission opacity This shortcut saves rendering time by not evaluating the surface shader at the intersection point For surface shaders that compute a complex opacity the transmission hit mode should be set to shader to force evaluation of the surface shader for shadow rays The shader transmission mode can be much much slower than the primitive mode See Also Ray Traced Shadows Ray Traced Reflections Sidedness AIR renders all objects as polygons For opaque objects only those polygons facing the camera need to be rendered For objects that are declared to be one sided AIR will remove back facing polygons By default all objects are two sided but making objects one sided can considerably improve perform
588. traced shadows Offset to prevent incorrect self shadowing Color of shadows Optional groups for ray traced shadows Per object shadowgroups override attribute name If 1 light is excluded from diffuse light If 1 light will not produce highlights If 1 light illuminates volumes Output channel The cardlight shader emulates the effect of adding a constant shaded diffuse emitter to a scene Output only variables color _ shadow color __unshadowed_Cl See Also Shadow value caustic caustic_baked light source returning caustics Parameter intensity lightcolor __nonspecular ___foglight _ channel Description Default Value 1 0 Emitted illumination without shadows Description Light intensity Light color If 1 light will not produce highlights If 1 light illuminates volumes Output channel index The caustic light shader returns any visible caustics at the current shading location 2001 2014 SiTex Graphics Inc Shader Guide 132 10 7 6 Baked Caustics AIR includes an extended version of the caustic shader caustic_baked with additional parameters for baking caustics to a 3D texture map and using a 2D or 3D texture for caustics bakemap me bakemode mm bakemapblur 0 bakemapfilterwidth a motionbound 000000 motionspace world See Baking Shadows and Illumination for more information See Also Caustics Baking Shadows and Illumination distantlight distantlight_baked
589. tream e The surf command line option has been extended to accept a comma separated list of parameter values for the override surface shader E g air surf massive_occlusionpass samples 1 myscene rib Float and string parameter types are supported e Shadows e Traced shadows with transmissionhitmode primitive now work for volume primitives with point based data and no per vertex opacity 2001 2014 SiTex Graphics Inc 431 AIR User Manual e Traced shadows with transmissionhitmode primitive now use prim var opacity Os data when available e Smooth interpolation for deep shadow maps can now be specified when the shadow map is created by including a float lerp parameter with value 1 in a Display call using the shadow display driver Points e The patch point type accepts a patchangle parameter to set a rotation angle in degrees for the patch rectangle for Maya sprite translation Curves e Polyline and ribbon curves now compute a primitive based dPdv value to match TweakAir e Tube curves now compute u v when required e Curve primitives used as area lights may now use width or constantwidth to specify a radius value for treating the curve as a tube Outlines e Vector outline export in DXF and Al file formats Textures e Faster texture lookups when all texture derivatives are close to 0 e The Windows TIFF imager reader has been updated to libtiff 4 0 1 which includes support for BIGTIFF files
590. ts an optional fourth argument for the extended Phong model New special spline types solvecatrom and solvelinear for spline New and improved shaders e Many shaders have been modified to take advantage of the new builtin illumination functions in AIR 4 yielding faster render times e The particle shader now supports a more general single scattering illumination model e New shaders VWeave VBlinn VSmokeSurface VCumulusCloud Better filtering of transparent and semi transparent objects for depth pass renders e No depth value is stored for completely transparent shading locations e For semi transparent surfaces only the nearest depth is stored with no transparency New option to map a range of depth map values prior to quantization Option render float 2 zrange zmin zmax 2001 2014 SiTex Graphics Inc 453 AIR User Manual 29 12 If zmin is not equal to zmax z depth values are scaled so that z is 0 at zmin and 1 at zmax and clamped to the range 0 1 AIR Show enhancements e New depth map display mode e New button to jump between the two most recently viewed frames New attributes to scale and offset the times passed in a motion block Attribute render float shutterscale 1 Attribute render float shutteroffset 0 These attributes are useful for re using archives in an animated sequence Display enhancements e The Display call accepts inline variable declarations E g
591. ts rendering curves using 3 different representations based on the curve type attribute Attribute curve string type name Where the type name is one of polyline ribbon or tube Curves as Polylines Curves are represented internally as a sequence of polyline segments This representation of curves is designed for rendering large numbers of thin hair like curves rapidly and it assumes that curves are at most a few pixels wide on screen Wide curves may exhibit gaps between successive segments The gaps can sometimes be closed by lowering the flatness criterion Very wide curves should be rendered as ribbons see next curve type Curves as Ribbons The ribbon curve type stores each curve as a strip of rectangles or quads The ribbon representation uses about twice as much memory as the polyine representation of curves Curves as Tubes The tube curve type converts each curve to a generalized tube whose diameter is determined by the curve width To maintain a consistent rotational orientation the curve data should include a per curve or per vertex normal value N Curve Orientation By default ribbon and polyline curves are oriented to face the incoming view direction If a per curve or per vertex normal N is provided in the curve data the curve will be oriented perpendicular to the normal vector For simple nearly straight curves one normal vector per curve may be sufficient For more complex curves one normal per vertex should be pr
592. u will need to set the shadow type to shade Bug fixes e Better handling of wide filter widths to prevent changes to the viewport based on filter width which could cause a misalignment when compositing AIR renders with output from other renderers Fix for bogus X shading location in motion blur Fix for stall condition with multiple threads and Gl Fix for process priority on Windows JPEG display driver fix Imager shaders now work with outlining Traced shadows with 1 sample blur properly Shadow map filtering fixed near map edges AIR 2 8 Subsurface scattering New collection capability to generate and query a set of points distributed over a group of surfaces the underlying capability on which the new subsurface scattering feature is built Outline rendering for cartoon rendering and illustration Semisharp creases for subdivision meshes have been implemented using a new linear crease tag Conversion of the standard crease tag takes place automatically A new shadow map filtering algorithm produces beautiful smooth results and no longer requires using and tweaking a shadow samples parameter Shadow maps now produce much nicer results with transparent and motion blurred objects Vortex now supports the indirect and occlusion prepasses Faster true displacement A new attribute controls whether an object is sampled during an indirect or occlusion prepass Attribute indirect integer prepass 1 New option to set the r
593. uality rendering 21 4 Writing Bake Aware Shaders With a little effort many shaders can be organized to work with the baker and baked maps Consider the following shading language snippit surface bakingsample string bakemap diffuse output varying color _ diffuse 0 other parameters if bakemap diffuse amp amp isbaking 0 use baked values assuming baking coordinates are s t __ diffuse color texture bakemap___diffuse s t else calculate value for use by the shader and possible baking normal Nf Nf faceforward normalize N I __ diffuse diffuse Nf 2001 2014 SiTex Graphics Inc BakeAir for Baking Textures and Meshes 372 rest of shader using _ diffuse If a bake map is provided and the scene is being rendered conventionally isbaking 0 the shader will use the values stored in the map Otherwise the diffuse value is calculated normally and saved in an output variable making it available for baking The output directory in the baker examples contains a scene illustrating use of a baker aware shader 21 5 Baking Meshes with BakeAir BakeAir 11 introduces a new mode for baking shader output values to mesh vertices Enable mesh baking with the following option Option bake bakemesh 1 or use the bakemesh command line switch bakeair bakemesh myscene rib A baked mesh is exported to the file specified for geom
594. uch as the image size Assigning Shaders Massive allows custom shaders to be assigned to agents terrain and lights on a per pass basis If no custom shader is assigned Massive will translate the basic shading and lighting information to a standard AIR shader Saving Simulation Data In order to render a Massive scene with AIR the simulation data must first be exported as a set of files e From the Run menu select Sim to display the Sim dialog In the list of Outputs select the sims button and choose an appropriate output path for the sims export Note that the export directory must exist Massive will not create it for you Select the ribs button and provide an output path and file specification for the exported rib files Next to the ribs export path change the DynamicLoad option to RunProgram for Air If the agents have cloth select the cloth button and provide an export path for cloth files In the list of renders at the bottom of the dialog select the Air render Choose a start and end frame at the top of the dialog Click go to export the files required for rendering Rendering 2001 2014 SiTex Graphics Inc 375 AIR User Manual 22 2 The scene is now ready for rendering using the rib files specified in the output ribs section of the render dialog Massive creates a small batch file in the output directory for rendering the frames Alternatively the frames can be sent to a render farm using appr
595. ue Use TreeScale to adjust the size of tree instances to match the scale of your scene The tree archives included with AIR are modeled in meters For a scene modeled in centimenters the appropriate TreeScale would be 100 TreeHeightOverride can be used to set a specific tree height for an individual tree The height should be in the same units as the tree archive The TreeRotateX parameter can be used to rotate a tree into the correct up position The tree archives included with AIR assume the positive Y axis in world space is up If the LeafColorOverride parameter is not 0 the average leaf color of each tree is taken from the LeafColor value with per tree variation in hue saturation and lightness based on LeafVaryHSL Note that the per leaf color variation specified in the tree definition is still applied See Also VTree procedure shader 10 6 10 VShowBound generates a wire frame bounding box for a primitive Parameter Default Value Range LineWidth 0 1 LineColor 1 1 1 Print 0 or 1 Lights 10 7 Light shaders are used to illuminate a scene Regular Lights Description Line width for wire frame box Line color If 1 prints the bound for each object to stdout 2001 2014 SiTex Graphics Inc Shader Guide 126 ambientlight emits constant illumination regardless of surface orientation distantlight emits illumination in a single direction pointlight emits light in all directions from a single
596. ular shader Some user interfaces such as AIR Space will automatically fill in the list of tweaks for a particular shader For those that do not the tweak names and values can be entered by hand 2D or 3D Shading The DarkTree shading pattern can be calculated in 2D or 3D If the Use2DCoordinates parameter is set to 1 the base shading location will be s t 0 where s and t are the standard 2D texture coordinates for a primitive Animation DarkTreeDisplacement uses the shading language time value set with the Shutter RIB call multiplied by the TimeScale parameter as the frame number input for DarkTree shaders By varying the time value in the Shutter call animated DarkTree shaders can be queried at different times 2001 2014 SiTex Graphics Inc Shader Guide 90 10 2 4 See Also DarkTree overview DarkTreeSurface shader OceanWaves animated ocean waves Parameter Default value Range BumpMax 1 0 GridCountX 128 GridCountY 128 Sizex 200 SizeY 200 WindSpeed 5 WindAlign 8 WindDir 0 SmallWave Oi Dampen 0 75 Chop 1 FramesPerSecond 24 FoamEnabled 1 Oor 1 RandomSeed 123 Description Description Displacement amplitude multiplier Grid size in X direction Grid size in Y direction Nominal size of X dimension Nominal size of Y dimension Wind speed Wave alignment with wind direction Wind direction as an angle in degrees Small waves will be ignored Amount to dampen waves n
597. ultilayer Images 2001 2014 SiTex Graphics Inc 403 AIR User Manual AIR can render a single image with multiple output values such as diffuse specular and reflection passes AIR organizes such an image into multiple layers with layer names displayed in the lower right section of the AIR Show window To view an individual layer left click on its name Composite View AIR Show 3 introduces a new simple composite view mode for multilayer images Click the Comp button in the AIR Show toolbar to enable composite mode The displayed image will then be the sum of all layers with each layer s contribution scaled by a weight factor In composite view mode the list of layers displays the layer weight as a percentage next to each layer To adjust the weight of a layer left click in the layer name row You may need to adjust the width and height of the layer list to facilitate manipulating the layer weights AIR recognizes __ shadow and ___1lights_shadow output values as special layers Shadow layers are assumed to apply to the immediately preceding layer which should contain the corresponding unshadowed output Histogram AIR Show displays a histogram for the currently displayed image layer or channel just above the list of image layers For 3 channel layers the histogram shows the luminance distribution Status Bar The status bar at the bottom of the AIR Show window displays the following information about the activ
598. umber of rays to trace for les reflections ReflectionBlur 0 Blur angle in radians for reflections ReflectionAlpha 1 Multiplier for the reflection alpha Description The UseBackground surface shader produces output useful for compositing over a background image The output color is the reflection result multiplied by the Reflection parameter A reflection alpha is value is provided in an extra output variable named __reflection_alpha If no reflections are desire set the Reflection parameter to 0 and no reflections will be traced The emitted opacity value is the maximum of the reflection alpha and the computed shadow value If no shadows are desired set the ShadowMask value to 0 and no shadows will be computed 10 10 3 V2SidedPlastic reflective plastic with separate controls for the front and back sides of a surface IIlumination model plastic Features texture maps reflections 2001 2014 SiTex Graphics Inc 211 AIR User Manual Parameter DiffuseFront DiffuseBack SpecularFront SpecularBack RoughnessFront RoughnessBack ReflectionFront ReflectionBack ReflectionSamples ReflectionBlur ReflectionName ReflectionSpace BackColor FrontTextureName FrontTextureBlur FrontTextureSizexY FrontTextureOriginXY FrontTextureProjection FrontTextureSpace FrontTransform BackTextureName BackTextureBlur BackTextureSizexY BackTextureOriginXY BackTextureProjection BackTextureSpace Back
599. umetric primitives Illumination Model particle Parameter Default Value Range Description Diffuse 1 0 Diffuse reflectivity Incandescence 0 0 Self illumination value Ambient 0 0 0 0 1 0 Ambient reflectivity OpacityMultiplier 1 0 Opacity multiplier PrimaryScatter 0 0 1 to 1 Primary scattering direction PrimaryScatterWeight 1 0 0 0 1 0 Relative weight of primary scattering PrimaryScatterColor 1 0 1 0 1 0 color Per channel scattering multiplier SecondScatter 0 0 1 to 1 second scattering direction SecondScatterColor 1 0 1 0 1 0 color Per channel scattering multiplier PatternSize 0 5 size of smoke pattern SmokeStrength 1 0 smoke variation SmokeLevels 3 1 9 octaves of fractal noise SmokeRoughness 0 5 relative strength of successive noise levels ShadingSpace shader space space for shading computations Description This shader produces a smoke like pattern using Brownian noise when applied to a volume primitive The illumination model is the same as that of the particle shader See that shader s documentation for 2001 2014 SiTex Graphics Inc 263 AIR User Manual details on the illumination parameters See also particle surface shader VCumulusCloud surface shader volume primitives 10 10 7 VTexturedConstant constant colored surface with texture map Features texture map Parameter Default value Range Description Incandescence 1 0 Multiplier for constant color ColorMapName me Texture map for ba
600. ups agents ProceduralCount 1 Procedural run_program exe See Also Rendering Massive Agents in Rhino VArrayOnCurve creates an array of objects along a curve Description Prefix for per frame agent rib archive generated by Massive the file name up until the trailing frame number Name of the Massive render pass to use Set to 1 to enable motion blur Rotation angle in degrees about the X axis Uniform scaling to apply to agents number added to the current scene frame number to obtain the index number for the agent archive When set to 1 the agents inherent the transformation applied to the base primitive List of groups in which to include the agents Number of instances of the Massive procedural primitive to allow to run simultaneously Name optionally including full path of the Massive procedural primitive RunProgram version 2001 2014 SiTex Graphics Inc Shader Guide 122 10 6 5 10 6 6 Parameter Default Value Range Count 10 Start 0 2 0 1 End 0 9 0 1 Archive uo Scale 1 0 Offset 00 0 RotatexYZ 00 0 TwistStart 0 TwistEnd 360 VArrayOnSurface Description Number of instances along each curve Position of first instance along curve Position of last instance along curve File name of RIB archive Uniform scale applied to archive Translation applied to archive Rotation in degrees about X Y Z axes Twist angle at start position Twist angle at end position instanc
601. ur machine See below for instructions on installing your license file If you are trying the Air demo you do not need to install a license file Installing Air under Linux e Unzip the distribution package to a directory For example cd usr local unzip airxl9 zip e Declare an AIRHOME environment variable to point to the directory containing the Air installation In the above example the directory would be usr local air For the bash shell export AIRHOME usr local air For tesh or csh setenv AIRHOME usr local air e Add SAIRHOME bin to the PATH environment variable e Make both of the above changes to the startup file for your shell bashrc for bash cshrc for csh or tcsh Installing the RLM license file When you purchase Air you will be issued an RLM license file named sitex lic There are two options for installing the license file e Place the license file in the bin directory of your Air installation Air will automatically look for a license file in that location e Save the license file to another location and create a SITEX_LICENSE environment variable with the full path to the license file The license file may be a node locked license or a floating license A node locked license file will not have a HOST line and the LICENSE line will include the string uncounted If you received a node locked license you are now ready to start using Air If you received a floating license you will need to sta
602. urface shader Surface LayerDecal ColorMapName sitex tx OriginxXY 3 67 vSizexy 23 3 DecalColor 1 1 1 Surface LayerDecal 2001 2014 SiTex Graphics Inc Shader Guide 278 ColorMapName sitex tx Originky 25 6 WSizexy 25 0 25 DecalColor 1 0 0 Surface plastic Sample rib decals rib Extra Passes Another simple use for multiple shaders is adding extra output values to a rendering pass Air 11 includes a new genOcclusion shader that can be added to any surface to produce an occlusion pass stored ina __occlusion output variable Sample usage Display extrapass tif framebuffer rgba color __occlusion Surface VMarble Surface genOcclusion setshaderoutput 0 Sample rib extrapass rib Shader Compositing Air s multi shader support includes an option to composite one shader on top of another Here s an example that adds a plastic decal to a metallic surface Surface VMetal Surface VPlastic OpacityMapName sitex tx ColorMapName square tx The before the shader name tells Air to blend the output color from the VPlastic shader with the output color of the VMetal shader using the output opacity from the VPlastic shader Any output variables shared by the two shaders will also be composited using the output opacity Sample rib compshaders1l rib The above example shows how to composite a shader with controls for its output o
603. ustration e The shadow function now accepts a maxdist parameter to limit the distance shadow rays are traced measured from the current shading location not the light source Outlines e Individual edges of a polygon mesh may now explicitly be included in vector based outlines by providing a facevarying toonedge prim var of type float in the mesh definition Each entry is either 1 edge is visible or 0 edge is hidden e New attribute to allow edges from different objects to be merged and processed together Attribute toon boolean mergeedges 1 Edges are considered to be the same if their end points are within a given tolerance Option toon mergetolerance 0 01 e New option to set a maximum edge length in pixels for object based outlines Option toon float maxedgelength 0 If greater than 0 longer lines are split until the subsegments are small enough e BakeAir e Baked maps are now rendered in tiles just like a regular image rendered with Air The tile or bucket size can be set with Option bake bucketsize 64 64 2001 2014 SiTex Graphics Inc 23 AIR User Manual There is now a 64 bit version of BakeAir for Windows bakeair64 exe The indirect prepass is now optimized for BakeAir BakeAir will now execute any declared imager shaders to allow post rendering color manipulation such as conversion to sRGB color space e Miscellaneous A new attribute for s
604. ve occlusion occlusion pass shader for use with Massive surface shader for recording a motion vector computes an ambient occlusion pass computes a motion blur vector for use with the Reel Smart Motion Blur plug ins emits shadow values displays the current shading normal emits the current shading location X Y Z values emits reflection and shadow values for compositing over a background image 2001 2014 SiTex Graphics Inc Shader Guide 184 Bake3d baking illumination to a 3D texture BakedSurface surface using baked illumination maps BakeTangentNormalMap bake displacement to a tangent space normal map NPR Shaders VSketchOutline uneven outlines for illustration VTone shader for Gooch style illustration VToon shader for cartoon style rendering Y VLines shader for line drawing illustration AI 11 16 WES F VWatercolor shader for watercolor painting Additional Shaders DarkTreeSurface shader for using Dark Tree shaders FakeCarpet turns a rectangle into a carpet shader with multiple materials per surface VLayeredMaterials 2001 2014 SiTex Graphics Inc 185 AIR User Manual 10 10 1 Bake3d a shader for baking diffuse illumination to a 3D texture Illumination Model diffuse Parameter Bake BakeMap BakeChannels BakeRadius QueryBlur QueryFilterWidth UseNormal FaceForward Description Default Value Range 1 0 or 1 we diffuse_s
605. ver file from the installation location to the displays directory of your AIR installation Update Air Output Dialog Script When a new RenderMan output operator is created in Houdini with Air as the default renderer Houdini automatically creates a dialog for setting basic rendering parameters and custom options That dialog has been updated with Air 7 release for Houdini 9 1 Compare the dialog script in the Air distribution SAIRHOME houdini air6 0 ds with the one in your Houdini installation SHFS houdini soho parameters air6 0 ds and keep whichever is more recent in your Houdini installation Rendering with Air from Houdini To render with Air from within Houdini 9 1 or later Display the Output network in a pane and add a RenderMan generator which should appear as an operator named ribl Display the parameters for the rib1 operator On the Main page of the parameters dialog make sure the Render Target is set to AIR 6 0 e Set the Camera control to the desired camera to use for rendering To render the scene Click the Render button in the rib1 properties dialog or In the Houdini Render menu choose Start Render gt rib1 Note that by default primitives in Houdini will not have any surface properties defined so all surfaces will appear with a simple default surface shader that shows the geometry but no other shading details By default Houdini starts the Air rendering process and sends the scene directly to Air vi
606. vves sn cetcuncndenves seceteueen cosvensecetecececersventceteus si daenda rideau asandan 409 5 Shading Compiler SHAdCd 2c0cccdsccceseseectecedccet ee stevecceedtect ed irens eieae artia aaan iaiaaeaia cance 410 6 Shader Info SIDtell ssns RAER E NEARER AAEREN 411 7 Texture Converter mktex s sssssusssuunnennnnnnnnnnnnnnnnn nunne nnnnnn mnnn nenn nnnn ener nnmnnn mnane nannan nennen 412 Texture MapSite aisea ideapad tccedcceacebeceeeccdvccuesudedancceddateaus scuey wundevadecbsdcanecetcereauySeuessaudevsdeceucvenerstecredaeee 412 Shadow Maps siperian apeere te re Se o piaia aaeain e p ra eaa aN aira haaraa o pE epea La aep aaea raana iie Feina 414 Latitude Longitude Environment Map ccsssseeesseesseeeseeeseeeeseenseeneeseeeseeeseeeeseeaseeeeaseeseensaeneeseeesseeeneeaseeeeneees 414 C b Face Environment Maps siiicccecc lt ccecsecciesccceeedeccecencesecesseesccuczecerstcedecersdicedcercceed saecieuerstecdaccereudsteesdecedsceszeueress 414 Mirror Balls and Angular Maps i iii iisa ionannas pridna sheczevesecccsucey draa pa ioiai idiay anadir ridse o idiay 415 COMPOSITING ccsccecccecescescce cence cee escecetennendcdvaevecte ccucdesuesccceteaces E ET 415 Stitching Image S sinsin aa Ear aasa arar A aenar N ESNA a aara aerar aona oS Erara Saena PIETAS anar S earan 417 8 Texture Converter User Interface mktexui cccsscceeesseeceenseeeeeenseeeeeenseeeeeenseaeeeenneeneeenees 417 9 VonexX eeeebeccceciececee Seca cec ech cece
607. w mode for viewing a stereo pair as an anaglyph image When the stereo button is enabled Air Show attempts to form a stereo pair with the current image and the following image if that fails Air Show tries the current image and the previous image Stereo pairs must have the same image size data format and number of channels 2001 2014 SiTex Graphics Inc 41 AIR User Manual 5 5 5 6 Use the Stereo Channels item in the Options menu to select which components of the anaglyph are taken from the first image Once a stereo pair is formed most display parameters will be synchronized for the pair Motion Vector Output The global shader variable dPdt ime stores the motion vector at the current shading location Typically the raw vector needs to be converted to a form usable by a 2D application for post process motion blur The Air distribution includes a ReelSmartMotion surface shader whose output is compatible with the ReelSmart Motion Blur plugin that illustrates this process The source code for the shader can be found at SAIRHOME shaders src surface ReelSmartMotion sl Deep Images Air 11 introduces a new hider for saving deep image data The deep image hider allows every fragment that contribute to a given pixel to be recorded to an output image Enable the new hider with Hider deepimage When the deep image hider is enabled the PixelSamples grid is set to 1x1 and the sub pixel edge mask is
608. want a surface to appear in ray traced reflections or participate in indirect lighting disable true displacement when the object is traced with Attribute trace integer displacements 0 Use single sided surfaces if possible The dicing rate for true displacement is inversely proportional to the flatness attribute GeometricApproximation flatness 0 5 Using values of 0 7 or 1 0 instead will reduce the micropolygon count by approximately a factor of 2 or 4 respectively 2001 2014 SiTex Graphics Inc Shader Guide 86 e Polygons and subdivision meshes usually use less memory than NURB surfaces for true displacement e Use as simple a shader as possible E g if you only need a simple bump map with standard texture coordinates use the standard bumpy shader which is faster than any custom shader e Compile the displacement shader to a DLL on Windows or a shared object on Linux 10 2 1 Displacement Shaders Displacement shaders are used to add small topographical features to a surface such as bumps wrinkles or dents Texture Mapped Displacement Simple shader for displacement with a single texture map using standard texture coordinates standard texture coordinates or a 3D to 2D projection with control of bump profile RA Displacement with a single texture map using VTexturedBump teed i HHS VBumpRegions Multiple regions with different bump maps Regular Patterns VBrickGrooves 2D pat
609. weakAlR is currently supported by AIR Space the RhinoAlR plugin for Rhino and the MayaMan plugin for Maya Features TweakAlR provides the following capabilities e Select primitives by name or shading group e Change any parameter for any assigned surface displacement or light shader e Move lights e Add new lights e Assign new surface and displacement shaders Limitiations The following features are not supported by TweakAIR 2001 2014 SiTex Graphics Inc 359 AIR User Manual 20 1 20 2 Motion blur Depth of field Level of detail PixelFilter PixelSamples use the corresponding ipr option instead Shading rate Developer s Kit Documentation for the TweakAIR API can be found in this section of this user manual TweakAIR Options The following options can be used to tune the performance of TweakAIR Deep Framebuffer Depth Option ipr integer mindepth 1 Option ipr integer maxdepth 4 These options set bounds on the number of surface layers TweakAIR stores at each pixel Ray Trace Sampling Option trace integer maxshadowsamples 4 Option trace integer maxtracesamples 4 These options set the maximum number of shadow and reflection rays to trace on any given ray tracing call Use these options to optimize interactive rendering while allowing higher samples for final rendering with AIR Reflection Updating Option ipr integer retrace 1 When this option is
610. write write shadow information to a 3D texture file Recommended file format is apm or apc read read shadow information from a 3D texture file If the bake map does not contain relevant shadow information for the current shading location the light shader executes the normal shadow evaluation code based on the shadowname setting append adds samples to an existing 3D texture file Useful for building a texture cache for an animated sequence readNDC read shadow values from a 2D texture map generated with a regular shadow pass The texture map is indexed using Normalized Device Coordinates NDC which map the unit square to the current rendered image The map is only used for primary camera rays Secondary rays generate shadows as usual readst read shadow values from a 2D texture map indexed using standard texture coordinates This mode is suitable for maps baked with BakeAIR This mode only works in AIR 8 16 or later which allows lights access to the standard texture coordinates of an illuminated surface The bake map parameter can reference either a 2D or 3D texture file depending on the bake mode Per object bake maps can also be specified by setting the bakemap value to the name of a user attribute storing the map for each object E g LightSource distantlight_baked 1 String bakemode readst String bakemap user bakedshadowl Attribute user string bakedshadowl shadowlobject1l tx Sphere 1 1 1 360 2001 2014
611. xels Line width can be set in a surface shader by exporting a ___inkwidth output variable of type float The following option can be used to globally scale the width of all outlines Option toon float inkwidthmultiplier 1 Line width can be automatically reduced with distance from the camera by setting a distance at which to begin fading with 2001 2014 SiTex Graphics Inc 349 AIR User Manual 17 1 Option toon float fadethreshold n Set the fade threshold to 0 to disable line width attenuation with distance When the fade with distance option is enabled a minimum ink width can be set with Option toon float mininkwidth 0 0 to prevent outlines from completely disappearing at large distances Saving Outlines The outline information may be saved to an image file by using the special __ toonline output variable ina Display call The __toonline output variable has a single value representing the fraction of each pixel that is covered by a line Exporting Outlines as Vectors AIR 10 introduces the ability to export outlines as vectors Specify the exported file name with Option toon string vectorexportfile filename svg Only outlines detected using one the vector based methods described above will be included The following file formats are currently supported SVG DXF Al See Also VToon surface shader Illustration Shaders and Examples Constant Shading For simple illu
612. y granted without fee provided that i the above copyright notices and this permission notice appear in all copies of the software and related documentation and ii the names of Sam Leffler and Silicon Graphics may not be used in any advertising or publicity relating to the software without the specific prior written permission of Sam Leffler and Silicon Graphics THE SOFTWARE IS PROVIDED AS IS AND WITHOUT WARRANTY OF ANY KIND EXPRESS IMPLIED OR OTHERWISE INCLUDING WITHOUT LIMITATION ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE INNO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR ANY SPECIAL 2001 2014 SiTex Graphics Inc 425 AIR User Manual 29 INCIDENTAL INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE DATA OR PROFITS WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE AND ON ANY THEORY OF LIABILITY ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE PTEX software Copyright 2009 Disney Enterprises Inc All rights reserved Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer Redistributions in binary form must reproduce the above copyright notice this list of condition
613. y invoked from a command shell You can see a complete list of command line options by entering mktex with no arguments at a command shell The mktexui program provides a user friendly interface for mktex Topics Texture Maps Shadow Maps Lat Long Environment Maps Cube Face Environment Maps Mirror Balls and Angular Maps Compositing Stitching Images 24 7 1 Texture Maps Create an AIR texture map from any image format recognized from AIR to an AIR texture map with mktex options infile s outfile Although AIR can use image files directly as texture maps creating a new texture file has several advantages The wrapping behavior of the texture map can be specified e The new texture file is a mip map storing multiple pre filtered copies of the texture at different resolutions When accessing the texture AIR will use an appropriate resolution based on the region of the texture visible in the area being shaded resulting in fewer aliasing artifacts Texture files are tiled allowing the renderer to selectively load only the portions of an image that are needed e Texture files are compressed to minimize disk space and bandwidth usage AIR limits the runtime memory used by tiled texture maps to a user defined maximum dynamically loading and unloading tiles as needed If no output file is given the name of the output file is derived from the input filename by changing the filename extension to tx Options smode tmode
614. yMapBlur BumpMax BumpMapName BumpMapBlur TextureSizexY TextureOriginXY TextureAngle Description 0 0 1 0 Sheen intensity Tendency to scatter light towards viewer Exponent applied to sheen strength Sheen roughness Texture map for sheen color strength Texture blur Texture map for base color Texture blur Texture map for specular color Texture blur Texture map for opacity Texture blur Maximum bump height Texture map for bump mapping Texture blur Texture size in X and Y direction Location of left top texture edge Texture rotation angle in degrees The VFabric surface shader provides a custom illumination model for shading cloth a combination of the VClay diffuse model the VBlinn specular model and the Velvet shaders sheen component See Also VCloth surface shader 10 10 5 VFur surface shader for fur modeled as curves primitives Illumination Model custom Parameter Default Value Range Description Ambient 1 0 0 0 1 0 Ambient reflectivity Diffuse 0 5 0 0 1 0 Diffuse reflectivity Specular 0 5 0 0 1 0 Specular reflectivity SpecularRoughness 0 1 0 01 1 0 Specular roughness 2001 2014 SiTex Graphics Inc 235 AIR User Manual SpecularColor r Highlight color SpecularStart 0 1 0 0 1 0 Distance from root to start specular SpecularEnd 1 0 0 0 1 0 Distance from root to end specular SpecularFadeRegion O 1 Transition region at specular start and end RootColor 0 5 0
615. ynchronize panning and zooming across images with the same width and height With Sync Views enabled you can pan and zoom while playing an animation Comparing Images AIR Show provides a couple mechanisms for comparing images The jump function can be used to quickly toggle between two images Click the Jump button in the toolbar or press J to jump from the current image to the previously selected image The current image and previously selected image can also be compared by wiping between the two with the mouse Hold down the CTRL key and left click and drag from an edge of the view window to reveal a section of the previous image next to the current image Viewing Pixel Values Hold down the SHIFT key while mousing over an image to see the image channel values at the current pixel listed in the upper right region of the AIR Show window Depth Map Display AIR Show has a special display mode for depth maps designed to allow a shadow map to be previewed by rendering to AIR Show Here s a sample depth map display AIR Show performs the following image manipulations e The bounding rectangle of the non empty pixels is computed and the region outside the used rectangle is colored red e Empty pixels within the bounding rectangle are colored purple Depth values for non empty pixels are displayed using a grey scale e The status bar reports the percentage of the total map that is inside the bounding rectangle of the non empty pixe
616. ype float Silhouette Edges AIR provides two methods of detecting silhouette edges By default AIR detects silhouettes using an image based technique that looks for differences in the surface normal The threshold for image based silhouette detection can be tuned with the following attribute Attribute toon float silhouette 0 5 The valid range is 0 to 1 To disable this method of silhouette detection set the silhouette threshold to Oor 1 The silhouette threshold may be set by a surface shader witha ___toonsilhouette output variable of type float Object based Outlines Silhouette Edges AIR provides a second object based method of silhouette detection that looks for boundaries between front and back facing polygons in the rendering mesh This method disabled by default can be enabled with Attribute toon integer frontback 1 If you use the front back method of silhouette detection you may wish to disable to the image based method Note that this method may not work well with the automatic meshing method for NURBs using explicit meshing may help Face Border Edges Edges that are shared by only one face can be included in vector based outlines by enabling the following attribute Attribute toon integer nakededges 1 Angle based Edges AIR can detect edges based on the angle between adjacent faces The minimum angle in degrees 2001 2014 SiTex Graphics Inc Outlines for Toon Rendering and I

AIR User Manual - SiTex Graphics

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