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for version 0.6.0007 by andrew payne & rajaa issa

1. prc Fy J Meri E TE xx CEN Sub RunScriptiByVal X As Object ByVal R s Object ByVal N s Object Declare a new list of OpenNUREBS circles Dim c list s New List Of OnEllipse Declare list of lines Dim p list s New OnsdPoint rray For i s Int3zZ 1 To N Declare a new circle Dim c s New OnEllipse OnUtil On xy plane i f 2 il Rotate the circle C RoatateiR i New onsdVeceror d 1 Ol New on3sdPoint x 0 Uj idd the circle to the list c list A ddic idd center point p list ppend c cCenteri l Next Dim polyline 45 New OonPolvlineip list hssign the list to the output value A c list ssign polyline to output value B B polyline End Sub For plugin version 0 6 0007 131 15 9 OnNurbsSurface Similar to what we discussed for OnNurbsCurve class to create a OnNurbsSurface you will need to know Dimension which is typically 3 Order in u and v direction degree 1 Control points Knot vector in u and v directions Surface type clamped or periodic The following example creates a nurbs surface from a grid of control points Sub Runseript ByVal Pts s List Of OnsdPoint ByVal Go As Integer Create a grid af points Dim Grid s Mew ArrayList Call grid function Call CreatecridiPtzz Grid G5 Call create nurbs surface function Dim ns s onNurbsSurface ns CreateNS Grid G3 Assign mid point to output nsr na End Sub oub CreateGrid ByVal Pts
2. RhinaExtendLineThraughBax Y RhinaExEtrudecurvesStraight RhinoExtrudecurveToPoint w RhinaFaircurve w RhinaFibCurve RhinaFiELine ToP oinEs w RhinoInterpcurve w RhinoInterpolatePointsOnSurface RhinamakecubicBeziers Y RhinoMakeCurveclosed RhinoMakeCurveEndsMeet w RhinoMergecurves w RhinoOrrsetCurve Y RhinoOrrsetCuryvye On Stk Surface RhinachangeSeam RhinocreabeSurFaceFramcCarnerz RhinaExtendsurFace RhinaFitSurFace RhinaInterseckSurFaces Y RhinoMaked 1 Surface RhinoRailR evolve Y RhinaRebuildSurFace RhinoRepairSurFace RhinaRetrimSurFace RhinaRevalve w RhinasrFCantrolPEarid RhinaSrFPEGrid Mesh Y RhinaPeshBaoleanDifFerence Y RhinoMeshBooleanIntersection Y RhinoMeshBooleanSplit Y RhinoMeshBooleanUnion Y RhinoMeshBox RhinoMeshCone Y RhinoMeshCvlinder Y RhinoMeshObjects Y RhinoMeshOrrset RhinoMeshPlane RhinoMeshSphere Y RhinoRepairMesh Y RhinoSplitDisjointMesh RhinoUnifyMeshhormals RhinaPlanarclosedcurvecontainmentTest Y RhinoPlanarcurvecollisionTest w RhinoProjectCurvesToBreps Y RhinoPullCurveToMesh Y RhinoRebuildCurve RhinoRemoveshortSegments Y RhinoRepairCcurve w RhinaShorkPath w RhinoSimplify Curve w RhinoSimplifyCurveend For plugin version 0 6 0007 Brep RhinoBaaleanDiFFerence RhinoBooleaniIntersection Y RhinoBooleanUnion W RhinaBrepCapPlanarHales Y
3. Imports Grasshopper Kernel Types Class Grasshopper Custom script je WBE NET on MSDN B Grasshopper Custom Script Class Grasshopper Custom Script class consists of three parts ScriptEditor Class Grasshopper Custom Script Reqion members Private app s HMEhino pp Private doc s MEhinoDboc Public Ext End Region ESPECIE Object Bn EE Pll a our code gt 9 gf your code gt End Suk Region Additional methods and Type declarations End Region B VB NET on MSDN 98 For plugin version 0 6 0007 1 Members This includes two references one to the current rhino application app and the other to the active document doc Rhino application and document can also be accessed directly using RhinoUtil Members region also includes return values or the output of the script function Return is defined as a generic system type and the user cannot change that type 2 RunScript This is the main function that the user writes their code within 3 Additional methods and type declarations this is where you may put additional functions and types The following example shows two ways to access document absolute tolerance The first is through using the document reference that comes with the script component doc and the second is through RhUtil Rhino Utility Functions Notice that when printing the tolerance value to the output window both functions yield same result Also note that in this example th
4. 100 100 100 100 101 103 104 104 106 107 110 113 114 116 118 118 118 121 123 124 124 126 130 132 137 138 147 148 155 EB Getting Started Installing Grasshopper To download the Grasshopper plug in visit http grasshopper rhino3d com Click on the Download link in the upper left hand corner of the page and when prompted on the next screen enter your email address Now right click on the download link and choose Save Target As from the menu Select a location on your hard drive note the file cannot be loaded over a network connection so the file must be saved locally to your computer s hard drive and save the executable file to that address Download complete ve y Download Complete Asshopper_ wip_20081202 exe from download mcneel com o mM Downloaded 43 5KB in 5 sec Download to CA grasshopper wip 200812402 exe Transfer rate 6 1KB Sec E Close this dialog box when download completes Select Run from the download dialogue box follow the installer instructions note you must have Rhino 4 0 with SR4b or higher already installed on your computer for the plug in to install properly For plugin version 0 6 0007 EB The Interface The Main Dialog Once you have loaded the plug in type Grasshopper in the Rhino command prompt to display the main Grasshopper window Grasshopper unnamed File Edit View Arrange Solution Window Help unnamed Params Logic Scalar Ve
5. s Listiot on3dPoint ByRet Grid s ArrayList ByVal GS As Integer Dim i s Integer Dim j s Integer For i U To Ptz cCount 1 Step Gs Declare a row of points Dim Row s New List Of OnsdPoint For j i Ta i GS 1 Gert a reference od the point Dim pt s OnsdPoint pt Prst 7 Add point to the raw Row Add ipo Next Add row to the grid Grid Add Row Next End sub 132 For plugin version 0 6 0007 Function CreateNS ByVal cvpoints s ArrayList ByVal GS Integer s OnNurbssurtace Const Degree 4s Integer 3 Hake the surface Dim arderU s Integer Degree 1 Dim orderV 45 Integer Degree 1 Dim ns s New OnNurbsSurtface ns Create s False orderU orderV GS GS Add cv points Dim i 4s Integer Dim j 4s Integer Dim pt As OnsdPoint For i To Gh 1 For j 0 Ta Ga 1 pt evpoints il ij nas etC i J pt Next Next net knots for open surface ns MakeClampedUnitformEnotVecror i ns MakeClampedUnitformEnotVecrori ll CreateHNS na End Function Another common example is to divide a surface domain The following example divides surface domain into a equal number of points in both direction number of points must be greater than one to make sense and it does the following normalize surface domain set domain interval to 0 1 Calculate step value using number of points Uses a nested loop to calculate surface points using u and v parameters For
6. D im end normal is OnsdVector Find start and end points in parameter space Dim start3d Ls Mew OnsdPoint srtart3d crysd Pointa tstart ii Dim end3d 45 Mew OnidPoint endsd crv3d Point itEndi Declare parameters Dim u s Double Dim w 45 Double Cet surface closest point srf cetclosestPointi start3d u v Start normal srf Hormal t u w Output start parameters Print 3D Start u amp uj Print 3D Start v M amp x srf cetClosestPointiend3d u wi end normal srf Normal itiu w Output end parameters Printi sD End u amp uj PEAnCI 3s0 End w 2 W EndVectorss3sD Addistart normal EndVectorssb Addiend normal End Sub This is the component picture showing output of parameter value at the end points using both functions Notice that both methods yield same parameters as expected 136 For plugin version 0 6 0007 15 10 Surface Classes not Derived from OnSurface OpenNURBS provides surface classes not derived from OnSurface They are valid mathematical surface definitions and can be converted into OnSurface derived types to use in functions that take OnSurface Here is a list of surface classes and their corresponding OnSurface derived classes OnPlane OnPlaneSurface or OnNurbsSurface use OnPlane GetNurbsForm function OnShpere OnRevSurface or OnNurbsSurface use OnShpere GetNurbsForm function OnCylinder OnRevSurface or OnNurbsSurface use OnCylinder GetNurbs
7. Enter Interpolated Curves The V input is for the component is similar to the NURBS component in that it asks for a specific set of points to create the curve However with the Interpolated Curve method the For plugin version 0 6 0007 69 resultant curve will actually pass through these points regardless of the curve degree In the NURBS curve component we could only achieve this when the curve degree was set to one Also like the NURBS curve component the D input defines the degree of the resultant curve However with this method it only takes odd numbered values for the degree input so it is impossible to create a two degree Interpolated curve Again the P input determines if the curve is Periodic You will begin to see a bit of a pattern in the outputs for many of the curve components in that the C L and D outputs generally specify the resultant curve the length and the curve domain respectively C Kinky Curves Curve Spline Kinky Curve Despite its name a kinky curve is no more than a glorified Interpolated Curve It has many of the attributes of the Interpolated Curve method mentioned in subsection B with one small difference The kinky curve component allows you the ability to control a specific angle ce threshold where the curve will transition from a kinked line to a smooth interpolated curve We have connected a numeric slider to the A input of the Kinky Curve component to see the
8. go through the associated control point For plugin version 0 6 0007 119 Evaluation rule The evaluation rule uses a mathematical formula that takes a number and assigns a point The formula involves the degree control points and knots Using this formula there are SDK functions that take a curve parameter and produce the corresponding point on that curve A parameter is a number that lies within the curve domain Domains are usually increasing and they consist of two numbers minimum domain parameter m t 0 that usually the start of the curve and maximum m t 1 at the end of the curve NURBS Surfaces You can think of nurbs surfaces as a grid of nurbs curves that go in two directions The shape of a NURBS surface is defined by a number of control points and the degree of that surface in each one of the two directions u and v directions Refer to Rhino Help Glossary for more details NURBS surfaces can be trimmed or untrimmed Think of trimmed surfaces as using an underlying NURBS surface and closed curves to cut a specific shape of that surface Each surface has one closed curve that define the outer border outer loop and as many non intersecting closed inner curves to define holes nner loops A surface with outer loop that is the same as that of its underlying NURBS surface and that has no holes is what we refer to as an untrimmed surface 120 For plugin version 0 6 0007 The surface on the left is untrimmed The
9. many changes as you want within Grasshopper and after hitting Refresh All you will see the reflected changes in Excel For plugin version 0 6 0007 El vector Basics From physics we know that a vector is a geometric object that has a magnitude or length direction and sense or orientation along the given direction A vector is frequently represented by a line segment with a definite direction often represented as an arrow connecting a base point A with a terminal point B The magnitude or amplitude of the vector is the length of the segment and the direction characterizes the displacement of B relative to A how much one should move the point A to carry it to the point B Sense A Base Point Direction In Rhino vectors are indistinguishable from points Both are represented as three doubles where each double or numeric variable which can store numbers with decimals represents the X Y and Z coordinate in Cartesian space The difference is that points are treated as absolutes whereas vectors are relative When we treat and array of three doubles as a point it represents a certain coordinate in space When we treat the array as a vector it represents a certain direction Vectors are considered relative because they only indicate the difference between the start and end points of the arrow i e vectors are not actual geometrical entities they are only information This means that there is no
10. o OnPoint OnBrepVertex OnAnnotationTxtDot o OnPointGrid o OnPointCloud o OnCurve abstaract class OnLineCurve For plugin version 0 6 0007 121 O O e OnPolylineCurve OnArcCurve OnNurbsCurve OnCurveOnSurface OnCurveProxy e OnBrepTrim e OnBrepEdge OnSurface abstract classt OnPlaneSurface OnRevSurface OnSumsSurface OnNurbsSurface OnProxySurface e OnBrepFace e OnOffsetSurface OnBrep OnMesh OnAnnotation Points and Vectors not derived from OnGeometry O O O O On2dPoint good for parameter space points On3dPoint On4dPoint good for representing control points with x y z and w for weight On3dVector Curves not derived from OnGeometry O O Q O0 OO OnLine OnPolyline is actually derived from OnPointArray OnCircle OnArc OnEllipse OnBezierCurve Surfaces not derived from OnGeometry O O OOOO OnPlane OnSphere OnCylinder OnCone OnBox OnBezierSurface Miscellaneous O O O O 122 OnBoundingBox For objects bounding box calculation Onlnterval Used for curve and surface domains OnXform for transforming geometry objects move rotate scale etc OnMassProperties to calculate volume area centroid etc For plugin version 0 6 0007 15 4 Class structure A typical class which is a user defined data structure has four main parts e Constructor This is used to create an instance of the class e Public member variables This is
11. 100 so that our output list will show 101 equally spaced values between 0 0 and 10 0 We then drag and drop a Graph Mapper component Params Special Graph Mapper onto the canvas Right click on the Graph Mapper component and set the Graph Type to Linear Now connect the Range R output to the Graph Mapper input To finish the definition drag and drop a Post it Panel component onto the canvas and connect the Graph Mapper output to the Post it Panel input Since the Graph Mapper type is set to Linear the output list shown in the Post it Panel displays a set of numeric data that ascends from 0 0 to 10 0 in a linear fashion However if we right click on the Graph Mapper component and set the Graph Type to Square Root we should see a new list of data that represents a logarithmic function 48 For plugin version 0 6 0007 To export the list of data from the Post it Panel simply right click on the panel and select Stream Contents When prompted find a location on your hard drive to Save the file with a unique file name In our example we will save the file to the following location C Tutorials Exporting Data Stream_Contents csv There are a variety of file types you can use to save your data including Text Files txt Comma Separated Values csv and Data Files dat to name a few tend to use the Comma Separated Values file format because it was designed for storage of data structured in a table form although many of the file forma
12. For Each line s String In lines Tokenize line into array of strings separated by Dim parts s string line Spliti TocChar rrayi l Make sure that each line has exactly 3 values If UBoundi parts lt gt 2 Then Continue For Convert each coordinate from string to double Dim x 45 Double Convert ToDboubleirpartsai n Dim y s Double Convert ToDboublei partzasi l l Dim z 45 Double Convert ToDboublei partai z pts Add iNew OoOnsdPoint x v zl Next A pte End Sub For plugin version 0 6 0007 EEA Rhino NET SDK 15 1 Overview Rhino NET SDK provides access to OpenNURBS geometry and utility functions There is a help file that comes when you download NET SDK It is a great resource to use This is where you can get it from http en wiki mcneel com default aspx McNeel Rhino4DotNetPlugIns html In this section we will focus on the part of the SDK dealing with Rhino geometry classes and utility functions We will show examples about how to create and manipulate geometry using Grasshopper VB script component 15 2 Understanding NURBS Rhino is a NURBS modeler that defines curves and surfaces geometry using Non Uniform Rational Basis Spline or NURBS for short NURBS is an accurate mathematical representation of curves and surfaces that is highly intuitive to edit There are many books and references for those of you interested in an in depth reading about NURBS http en wikipedia org w
13. Integer to 0 Right click on the i input of the second List Item and Set the Integer to 1 Right click on the i input of the third List Item and Set the Integer to 2 Right click on the i input of the fourth List Item and Set the Integer to 3 You probably noticed that we increased the List Item index number by 1 each time Since our tree structure has been setup and Grasshopper understands that we have 144 different paths each with 4 item at the end of each path all we need to do is go into each path and retrieve the first item and then retrieve the second point and so on and so forth So the 4 List Item components are going to define each corner point of the sub For plugin version 0 6 0007 surfaces and now that we have them separated we can connect opposing points with a line to create our diagrid Curve Primitive Line Drag and drop two Line components onto the canvas Connect the first List Item E output to the first Line A input Connect the third List Item E output to the first Line B input Connect the second List Item E output to the second Line A input Connect the fourth List Item E output to the second Line B input At this point you should see a set of lines on your surface that will represent the diagrid structure e eurface Freeform Pipe Drag and drop a Pipe component onto the canvas e Connect the first Line L output to the Pipe C input e While holding the Shift key down connect the second Line L output to the Pipe C input To
14. Numeric Slider Drag and drop a numeric slider component to the canvas e Double click the slider to set o Lower limit 0 0 For plugin version 0 6 0007 21 o Upper limit 100 0 Value 50 0 note this value is arbitrary and can be modified to any value within the upper and lower limits e Select the slider and type Ctrl C copy and Ctrl V paste to create a duplicate slider e Params Primitive Integer Drag and drop two Integer components onto the canvas e Connect slider 1 to the first Integer component e Connect slider 2 to the second Integer component The slider s default value type is set to Floating Point which results in a decimal numeric value By connecting the slider to the Integer component we can convert the floating point value to an Integer or any whole number When we connect a Post It panel Params Special Panel to the output value of each Integer component we can see the conversion in real time Move the slider to the left and right and notice the floating point value be converted to a whole number Of course we could have simplified this step by just setting the slider type to Integers Scalar Operators Add Drag and drop an Add component to the canvas Connect the first Integer component to the Add A input Connect the second Integer component to the Add B input Params Special Panel Drag and drop a Post it panel to the canvas Connect the Add R output to the Post it panel input You can now see the summ
15. Pt output to the Line B input Below is a screen shot of the Unit Vector definition Note To see the finished definition of the example above Open the file Unit Vectors ghx found in the Source Files folder that accompanies this document 54 For plugin version 0 6 0007 9 1 Point Vector Manipulation Grasshopper has an entire group of Point Vector components which perform the basic operations of vector mathematics Below is a table of the most commonly used components and their functions Compute the Distance between two points A and B inputs Break down a point into its X Y and Z components Compute the angle between two vectors Output computed in Radians Add the components of vector 1 A input to the Vector Vector Summation components of vector 2 B input Vector Vector Vector2pt Creates a vector from two defined points Negate all the components of a vector to invert Vector Vector Reverse the direction The length of the vector is maintained Divide all components by the inverse of the length of the vector The resulting vector has a length of 1 0 and is called the unit vector sometimes referred to as normalizing Vector Vector Unit Vector Multiply the components of the vector by a Vector Vector Multiply specified factor For plugin version 0 6 0007 55 9 2 Using Vector Scalar Mathematics with Point Attractors Scaling Circles Now that we know some of the basics behind Scalar
16. RhinaBrepClasestPoinE Y RhinobrepGetedProjection Y RhinobrepGetedSection RhinoBrep Split RhinacreateiFaceBrepFromPoinbs RhinoCreateEdgeSrf Y RhinoIntersectBreps RhinaJoinBrepMakedEdges RhinaJoinBreps RhinoMakePlanarBreps Y RhinoMergeAdjoiningEdges Y RhinoMergebrepCoplanarFaces RhinoMergebreps RhinaR epairBrep Y RhinasplitBrepFace W RhinoStraightenbrep Y RhPlanarRegionBaalean RhPlanarRegianDifFerence Y RhPlanarRegianIntersection Y RhPlanarRegianLInian RhinaSdkLaft amp RhinaSdkLofFESurFace W RhinaSweep1 Y RhinaSweepz Utility RhinoAckivecPlane W Rhino4App RhinaFitPlaneTaPointsz Y RhinoaPlaneThroughBox RhinoProjectToPlane Y RhinoTriangulate3dPolygon 151 RhUtil Divide curve It is possible to divide a curve by number of segments or length on curve using the utility function RhUtil RhinoDivideCurve This is a breakdown of function parameters RhinoDivideCurve Function name Curve constant curve to divide Num number of segments Len Curve length to divide by False flag to reverse curve can be set to True or False True include end point can be set to True or False crv p list of divide points crv t list off divide points parameters on curve Divide curve by number of segments example ESTEE Wytt tenti Let FEE aub RunSceriptiByVal Curve ALs OnCurve ByVal Hum s Integer Dim cry p s New On3dPoint rray Dim cry t As New A
17. a new list of numeric data You can hover your mouse over the r output of each function to see the result of each equation Vector Point Point XYZ Drag and drop a Point XYZ component onto the canvas Connect the first Function r output to the X input of the Point component Connect the second Function r output to the Y input of the Point component Connect the Range R output to the Z input of the Point component Now if you look at the Rhino viewport you will see a set of points forming a spiral You can change the two numeric sliders at the beginning of the definition to change the number of points on the spiral or the length of the spiral For plugin version 0 6 0007 e Curve Spline Curve Drag and drop a Curve component onto the canvas e Connect the Point Pt output to the Curve V input We have created a single curve that passes through each point of the spiral We can right click on the Curve D input to set the Curve degree a 1 degree curve will create straight line segments between each point and will insure that the curve actually passes through each point A 3 degree curve will create a smooth Bezier curve where the points of the spiral will act as control points for the curve however the line will not actually pass through each point Perspective ar Me aer ure d F Note To see a video tutorial of this example please visit Zach Downey s blog at http www designalyze com 2008 07 07 generating a spiral in rhinos grass
18. ad to them and also assign a type If you right mouse click on any of the input parameters you will see a menu that has the following e Parameter name you can click on it and type new name For plugin version 0 6 0007 93 e Runtime message for errors and warnings e Disconnect and Disconnect All Work the same as other Grasshopper components e Flatten to flatten data In case of a nested list of data it converts it to single array of elements e List to indicate if the input is a list of data e Type hint Input parameters are set by default to the generic type object It is best to specify a type to make the code more readable and efficient Types that start with On are OpenNURBS types right mouse click y Mo Runtime messages Disconnect All Disconnect Flatten List OpenNURBS types No hint Boolean Integer Double String DateTime Color On3dPoint On3dvectar onPlane OnInterval OneForm OnLine oncircle OnArc OnCurve OnSurface OnBrep Onkesh Input parameters can also be managed from the main component menu If right mouse click in the middle of the component you get a menu that has input and output details 94 For plugin version 0 6 0007 You may use this menu to open input manager and change parameters names add new ones or delete as shown in the image Note that your scripting function signature input parameters and their types can only be
19. and we have set this to represent the value of the point farthest away from the attractor point The t input value for the Gradient component represents the list of values you would like to chart along the gradient range We have chosen to input all of our scale factor values so that the scale of each box will also be associated with a color along the gradient range e Vector Color Create Shader Drag and drop a Create Shader component onto the canvas e Connect the Gradient output to the Shader Kd input The Shader component has a number of inputs to help define how you want your preview to look Below is a brief description of how each input effect the resultant shader Kd Input defines the Diffuse Color of the shader This will define the primary color of each object The diffuse color is defined by three integer numbers that range from 0 255 and represent the Red Green and Blue values of a color Ks Input defines the color of the Specular Highlight and requires an input of three integer values to define its RGB color Ke Input defines the shader s Emmissivity or the shader s self illumination color T Input defines a shader s Transparency For plugin version 0 6 0007 65 S Input defines the Shininess of the shader where a value of 0 means the shader has no shininess and value of 100 has maximum shininess We have connected the gradient slider to the Diffuse input of the Shader component so that our box s primary color will b
20. be our first list of data but we will copy and paste this two more times so that we have three lists to weave together Add 5 strings to the collection so that your list looks like this LO A LO B LO C LO D LO E The LO prefix just tells us that these strings are in list zero and will help us be able to track the data once we weave them together Your String Manager should look like the image below string value manager L9 e P Items with warming or emor icans will not be included __ lin the final collection af because they do not e Select the String parameter and hit Ctrl C copy and Ctrl V paste to duplicate 2 more String parameters to the canvas e Right click the second String parameter and open the String Collection Manager Change your string collection so that your list now reads like this L1 A L1 B L1 C L1 D L1 E e Right click the third String parameter and open the String Collection Manager Change your string collection so that your list now reads like this L2 A L2 B L2 C L2 D L2 E e Now connect the Integer parameter the one that is going to define our weave pattern to the P input of the Weave component Connect the first String parameter to the O input of the Weave component Connect the second String parameter to the 1 input of the Weave component Connect the third String parameter to the 2 input of the Weave component Param
21. bone and create a second method from which we can control solid objects like we normally would in the Rhino interface Enter the Brep or the Boundary Representation The Brep can be thought of as a three dimensional solid or similarly to the polysurface in Rhino It is still made up of a collection of NURBS surface however they are joined together to create a solid object with thickness whereas a single NURBS surface theoretically has no thickness Since Breps are essentially made up of surfaces that are joined together some of the standard NURBS surface analysis components will still work on a Brep while others will not This happens because Grasshopper has a built in translation logic which tries to convert objects into the desired input If a component wants a BRep for the input and you give it a surface the surface will be converted into a BRep on the fly The same is true for Numbers and Integers Colors and Vectors Arcs and Circles There are even some fairly exotic translations defined for example e Curve Number gives the length of the curve e Curve Interval gives the domain of the curve e Surface Interval2D gives the uv domain of the surface e String Number will evaluate the string even if it s a complete expression e Interval2D Number gives the area of the interval There are more auto conversion translations and whenever more data types are added the list grows That should be enough back
22. circles become if they get too far away from the attractor point Scalar Utility Minimum Drag and drop a Minimum component onto the canvas Connect the Division R output to the Minimum A input Params Special Numeric Slider Drag and drop a numeric slider onto the canvas Right click the slider and set the following o Name Falloff o Slider Type Floating Point For plugin version 0 6 0007 o Lower Limit 0 0 o Upper Limit 30 0 o Value 5 0 e Connect the Falloff slider to the Minimum B inputs e Curve Primitive Circle CNR Drag and drop a Circle CNR Center Normal and Radius onto the canvas We would like the center point of each circle to be located at one of the grid points that we created at the beginning of the definition e Connect the Rectangular Point Grid G output to the Circle C input e Connect the Minimum R output to the Circle R input e Right click on the Rectangular Point Grid component and turn the Preview off RecGrd J SILL LSS Your definition should look like the image above We have now create a set of circles that scale up and down depending on how far away each circle is from a single attractor point But what if we wanted to add an additional attractor point Since we already have the definition set up we merely need to copy and paste a few of our components to make this happen e Select the following components Attractor Point parameter Distance component Pt 1 Influence slider Division compon
23. have connected a Circle component Curve Primitive Circle to the Dispatch A output so that a circle with a radius specified by the numeric slider will be created only if the boolean value passed into the Dispatch component is True Since no component has been linked to the Dispatch B output if the boolean value is False then nothing happens and a circle will not be created We can further this definition a little bit by connecting a N sided Polygon Curve Primitive Polygon curve to the Dispatch B output making sure to connect the wire to the Polygon R input to define the polygon radius Now if the numeric slider falls below 5 then a five sided polygon with a radius defined by the number slider will be created at the origin point If we take the slider value above 5 then a circle will be created By this method we can begin to create as many If Else statements as needed to feed information throughout our definition F Th B Result Note To see the finished version of the circle boolean test example Open the file If Else test ghx found in the Source Files folder that accompanies this document 28 For plugin version 0 6 0007 7 4 Functions amp Numeric Data The Function component is very flexible that is to say that it can be used in a variety of different applications We have already discussed how we can use a Function component to evaluate a conditional statement and deliver a boolean value output However we can als
24. how to get from one part o the other 3 Surface 3D Curve Edges v etices 2 Bg Trims VERTEX Loop 4 A Je 2D Curve We will spend the coming few examples showing how to create an OnBrep navigate different parts and extract brep information We will also show how to use few of the functions that come with the class as well as global functions Create OnBrep There are few ways to create a new instance of an OnBrep class Duplicate existing brep Duplicate or extract a face in an exiting brep Use Create function that takes an OnSurface as an input parameter There are 5 overloaded function using different types of surfaces o from SumSurface o from RevSurface o from PlanarSurface o from OnSurface Use global utility functions o From OnUtil such as ON BrepBox ON BrepCone etc o From RhUtil such as RhinoCreatEdgeurface or RhinoSweep1 among others For plugin version 0 6 0007 141 This is an example to create a brep box from corner points input points sub Runs iptiByvVal C 45s Listior On3dPoint T unzcriptiByva orners s List Or On ointjil Build the brep from corners Dim Brep 45 OnBrep j OnUtil OM BrepbBox cCorners To rravil A Brep End Sub Navigate OnBrep data The following example shows how to extract vertices points of a brep box Sub RunScripti ByVal Corners s List Qf OnsdPoint Build the brep from corners Dim Brep 45 On
25. is a curve then delete it This conditional statement is called an If Else statement If the object meets certain criteria do something else do something else Grasshopper has the same ability to analyze conditional statements through the use of Function components i In the example above we have connected a numeric slider to the x input of a single variable Function component Logic Script F 1 Additionally a conditional statement has been linked to the F input of the Function defining the question Is x greater than 5 If the numeric slider is set above 5 then the r output for the Function shows a True boolean value If the numeric slider drops below 5 then the r output changes to a False value Once we have determined the boolean value of the function we can feed the True False pattern information into a Dispatch component Logic List Dispatch to perform a certain For plugin version 0 6 0007 27 action The Dispatch component works by taking a list of information in our example we have connected the numeric slider information to the Dispatch L input and filters the information based on the boolean pattern result of the single variable function If the pattern shows a True value the list information will be passed to the Dispatch A output If the pattern is False it passes the list information to the Dispatch B output For this example we have decided to create a circle ONLY if the slider value is greater than 5 We
26. more polylines Input parameters which are expected to yield more than one value are called List Parameters and they are ignored during data matching 20 For plugin version 0 6 0007 Scalar Component Types Scalar Component Types are typically used for various mathematical operations and consist of A Constants Returns a constant value such as Pi Golden Ratio etc C Intervals Used to divide numeric extremes or domains into interval parts There are many components under the Intervals tab that allow you to create or decompose a number of different interval types D Operators Used in mathematical operations such as Add Subtract Multiply etc E Polynomials Used to raise a numeric value by some power F Trigonometry Returns typical trigonometric values such as Sine Cosine and Tangent etc G Utility Analysis Used to evaluate of two or more numerical values 7 1 Operators As was previously mentioned Operators are a set of components that use algebraic functions with two numeric input values which result in one output value To further understand Operators we will create a simple math definition to explore the different Operator Component Types Note To see the finished version of this definition Open the file Scalar operators ghx found in the Source Files folder that accompanies this document Below is a screen shot of the completed definition To create the definition from scratch e Params Special
27. one on the right is the same surface trimmed with an elliptical hole Note that the NURBS structure of the surface doesn t change when trimming Polysurfaces A polysurface consists of more than one usually trimmed surfaces joined together Each of the surfaces has its own parameterization and uv directions don t have to match Polysurfaces and trimmed surfaces are represented using what is called boundary representation BRep for short It basically describes surfaces edges and vertices geometry with trimming data and relationships among different parts For example it describes each face its surrounding edges and trims normal direction relative to the surface relationship with neighboring faces and so on We will describe BReps member variable and how they are hooked together in some detail later OnBrep is probably the most complex data structures in OpenNURBS and it might not be easily digested but luckily there are plenty of tools and global functions that come with Rhino SDK to help create and manipulate BReps 15 3 OpenNURBS Objects Hierarchy The SDK help file show all classes hierarchy Here is a dissected subset of classes related to geometry creation and manipulation that you will likely use when writing scripts have to warn you this list is very incomplete Please refer to the help file for more details OnObject all Rhino classes are derived from OnObject OnGeometry class is derived from or inherits OnObject
28. plugin version 0 6 0007 133 oub Runseript byVal Brep 45 OnBrep ByVal Num 4s Integer Find step Num must be gt 1 Dim StepValue is Double 1 Num 1 Dim noart ls New OnNurbzSurface nart Brep Face OU Nurbssurtace Mormalize domain in u and w directions nort 2etbomainrimil 1 nort 2oetbomainri U 1 Dim Points 45 New Listi Of on3dPoint Dim i s Double U Dim j s Double U For i U To 1 Step StepValue For j U To 1 Step StepValue Dim Pt New OnsdPoint Pr nSrf Point ti i 7 Points 4 ddiPt Next Next 4 Points End Sub OnSurface class has many functions that are very useful to manipulate and work with surfaces The following example shows how to pull a curve to a surface There are 2 outputs in the Grasshopper scripting component The first is the parameter space curve flat representation of the 3d curve in world xy plane relative to surface domain The second is the curve in 3d space We got the 3d curve through pushing the 2d parameter space curve to the surface Input curve Input surface 134 For plugin version 0 6 0007 oub RunScriptiByvVal Cry As OnCurve ByVal Sri s OnBrep Get pulled curve in 2D parameter sp Dim pull cry 45 Oncurve pull cry Srf m S 0 Pullback Cry doc A bsoluteTolerancer IT Ge the pulled Curve ain oD Spas Dim push cry As OnCurve push cry art m S 0 Pushup pull cry doc bsoluteTolerance t IT Cutput both curves CEvZd pull c
29. still transferred Recerver Wire Display Disconnect All Disconnect e Help For plugin version 0 6 0007 17 EB Data Stream Matching Data matching Data matching is a problem without a clean solution It occurs when a component has access to differently sized inputs Imagine a component which creates line segments between points It will have two input parameters which both supply point coordinates Stream A and Stream B It is irrelevant where these parameters collect their data from a component cannot see beyond its in and output parameters Stream A x x Stream B Xx x x x x As you can see there are different ways in which we can draw lines between these sets of points The Grasshopper plug in currently supports three matching algorithms but many more are possible The simplest way is to connect the inputs one on one until one of the streams runs dry This is called the Shortest List algorithm Stream A Stream B x x The Longest List algorithm keeps connecting inputs until all streams run dry This is the default behavior for components Stream A Stream B Finally the Cross Reference method makes all possible connections Stream A Stream B This is potentially dangerous since the amount of output can be humongous The problem becomes more intricate as more input parameters are involved and when the volatile data inheritance starts to multiply da
30. that Donde literal decomposes the interval into 4 numbers onto the RT canvas Connect the Divide Interval S output to the Interval nds Components l input Interval Components e Params Special Graph Mapper Drag and drop a Interval Graph Mapper component onto the canvas TENE e Connect the UO output to the input of the Graph Mapper Interval Components Holding the shift key connect the U1 output to the sj _ Interval Components input of the Graph Mapper e Right click on the Graph Mapper and choose a graph type I think the bezier graph type works best in this situation but to each their own You can adjust the graph by moving the bezier handles around the Graph Mapper component Your probably asking yourself why we re doing all of this Well essentially what we ve done is decompose our evenly spaced interval into a list where we can access each of our U and V values We ve fed our U list data into the Graph Mapper which will reorganize the list according to a specific graph type Ultimately we re going to take this reorganized data and reassemble it back into a new interval that we can feed back into the Isotrim component e Logic List List Length Drag and drop a List Length component onto the canvas e Connect the U1 output to the List Length L input e Logic List Split List Drag and Drop a Split List component onto the canvas e Connect the output of the Graph Mapper to the L input of the Split List component e Connect the Lis
31. the y output of the Sin component to the Multiplication B input Connect the Multiplication r output to the Y input of the Point XYZ component This connection should replace your existing connection which had been previously connected to the Sine component output The Amplitude slider is just multiplying the Sine values by a scale factor Since the slider is driving the Y value of our Sine curve when you increase the Amplitude value you will in turn be increasing the amplitude of the curve Vector Point Point XYZ Drag and drop another Point XYZ component onto the canvas Connect the first Range R output to the X input of the new Point XYZ component Curve Primitive Line Drag and drop a Line component onto the canvas Connect the first Point Pt output to the Line B input Connect the second Point Pt output to the Line A input In the last part of definition we have created a second set of evenly spaced points along the X axis which correspond to the same x coordinates of the Sine curve The Line component creates a line segment between the first list of points the ones that create the sine curve and the second list of points which define the X axis The new lines give you a visual reference of the vertical displacement in the wave form pattern Your definition should look like the image below O O O O For plugin version 0 6 0007 Wave Length g avum mnn Amplitude 491 5000 2 ZZ ZZ Num Pts on Curve OO Frequency
32. then it is even better Check the following page to help you get set up http en wiki mcneel com default aspx McNeel Rhino4DotNetPluglns html Grasshopper Scripting Samples Grasshopper Gallery and discussion forum has many examples of scripted components that you will probably find useful For plugin version 0 6 0007 155 Notes 156 For plugin version 0 6 0007 For plugin version 0 6 0007 157
33. there are a potentially large number of these it only shows the N most recently used items In order to see the entire collection you have to click on the bar at the bottom of the Panel e AG M E r4 Is ru G Lan Lr Uana ooog Fix Fixy F x y z Fia be d Logarithm Natural logarithm This will pop up the category panel which provides access to all objects You can either click on the objects in the popup list or you can drag directly from the list onto the canvas Clicking on items in the category panel will place them on the toolbar for easy future reference Clicking on buttons will not add them to the Canvas You must drag them onto the Canvas in order to add them D JE d s 1 pem LT l Ae Maximum I I x A sfe us m a m on You can also find components by name by double clicking anywhere on the canvas launching a pop up search box Type in the name of the component you are looking for and you will see a list of parameters or components that match your request The Window Title Bar D The Editor Window title bar behaves different from most other dialogs in Microsoft Windows If the window is not minimized or maximized double clicking the title bar will For plugin version 0 6 0007 3 fold or unfold the dialog This is a great way to switch between the plug in and Rhino because it minimizes the Editor without moving it to the bot
34. they make life so much easier for us Grasshopper handles NURBS surfaces similarly to the way that Rhino does because it is built on the same core of operations needed to generate the surface However because Grasshopper is displaying the surface on top of the Rhino viewport which is why you can t really select any of the geometry created through Grasshopper in the viewport until you bake the results into the scene some of the mesh settings are slightly lower in order to keep the speed of the Grasshopper results fairly high You may notice some faceting in your surface meshes but this is to be expected and is only a result of Grasshopper s drawing settings Any baked geometry will still use the higher mesh settings Source Rhinoscript 101 by David Rutten http en wiki mcneel com default aspx McNeel RhinoScript1 01 74 For plugin version 0 6 0007 Grasshopper chooses to handle surface in two ways The first as we have already discussed is through the use of NURBS surfaces Generally all of the Surface Analysis components can be used on NURBS surfaces like finding the area or surface curvature of a particular surface While there is a fair amount of complicated math involved this would still be fairly easy to solve because the computer doesn t have to take into account the third dimension of a volume like depth or thickness But how does Grasshopper interpret three dimensional surfaces Well the developers at McNeel decided to throw us a
35. vs Series vs Interval Functions amp Booleans Functions amp Numeric Data Trigonometric Curves The Garden of Forking Paths Lists amp Data Management Weaving Data Shifting Data Exporting Data to Excel Vector Basics Point Vector Manipulation Using Vector Scalar Mathematics with Point Attractors Scaling Circles Using Vector Scalar Mathematics with Point Attractors Scaling Boxes Curve Types Curve Analytics Surface Types Surface Connect Paneling Tools Surface Diagrid Uneven Surface Diagrid An Introduction to Scripting The Scripting Interface Where to find the script components Input Parameters Output Parameters Out Window and Debug Information Inside the Script Component 14 14 1 14 2 14 3 14 4 14 5 14 6 14 7 14 8 14 9 Visual Basic DotNET Introduction Comments Variables Arrays and Lists Operators Conditional Statements Loops Nested Loops Subs and Functions 14 10 Recursion 14 11 Processing Lists in Grasshopper 14 12 Processing Trees in Grasshopper 14 13 File I O 15 15 1 15 2 15 3 15 4 15 5 15 6 15 7 15 8 15 9 Rhino NET SDK Overview Understanding NURBS OpenNURBS Objects Hierarchy Class Structure Constant vs Non constant Instances Points and Vectors OnNurbsCurve Curve Classes not derived from OnCurve OnNurbsSurface 15 10 Surface Classes not derived from OnSurface 15 11 OnBrep 15 12 Geometry Transformation 15 13 Global Utility Functions 16 Help
36. where class data is stores ODenNURBS member variables usually start with m to quickly isolate e Public member functions This includes all class functions to create update and manipulate class member variable or perform certain functionality e Private members these are class utility functions and variables for internal use Once you insatiate a class you will be able to see all class member functions and member variable through the auto complete feature Note that when you roll over any of the function or variables the signature of that function is shown Once you start filling function parameters the auto complete will show you which parameter you are at and its type This is a great way to navigate available function for each class Here is an example from On3dPoint class Dim point 4s New OnsdPoint point member functions member variables y CompareTao w Dispose w DiskanceTo Equals Fuzz GekHashCade M GelT ype A InternalPointer TsValid Maximumtcaordinate MaximumcaardinateIndex t MinimumcCaardinate i MinimurmcaardinateIndex y Rotate w Sel A ToString Transform public 4 as Double Copying data from an exiting class to a new one can be done in one or more ways depending on the class For example let s create a new On3dPoint and copy the content of an existing point into it This is how we may do it Dim new pt as New On3dPoint input pt D
37. window of the canvas allows you to quickly move around the canvas without having to scroll and pan This feature is similar to the Navigator window in Photoshop Zoom Extents will adjust the zoom factor if the definition is too large to fit on the screen Focus corners these 4 buttons will focus on the 4 corners of the definition Named views exposes a menu to store and recall named views Rebuild solution forces a complete rebuild of the history definition Rebuild events by default Grasshopper responds to changes in Rhino and on the Canvas You can disable these responses though this menu 10 Cluster compactor turn all selected objects into a Cluster object Cluster objects are not finished yet and are more than likely going to be completely re worked in the future Caution using these in your current files Pp Ro BON On 4 For plugin version 0 6 0007 11 Cluster exploder turn all selected clusters into loose objects Cluster objects are not finished yet and are more than likely going to be completely re worked in the future Caution using these in your current files 12 Bake tool turns all selected components into actual Rhino objects 13 Preview settings Grasshopper geometry is previewed by default You can disable the preview on a per object basis but you can also override the preview for all objects Switching off Shaded preview will vastly speed up some scenes that have curved or trimmed surfaces 14 Hide but
38. 205 6 91325 0 ica ey ON 907 I ger um l E o1 E Drv t Double Number of segments E d tn l X s Parameter values at division points Local Integer list 1 values 8 10 ni Local Double list 11 values SS m 2 3 Aud o i ER PERI es 0 088025 IJ S Dry K Boolean T ocammar 0 558983 Split segments at kinks 4 0 861135 m S 1 16784 1 518264 Local Boolean list 1 values 1 361531 False 2 42381 A ES ee eee 2 184346 1 Using Context Popup Menus All objects on the Canvas have their own context menus that expose most of the features for that particular component Components are a bit trickier since they also expose in a cascading style all the menus of the sub objects they contain For example if a component turns orange it means that it or some parameter affiliated with the component generated a warning If you want to find out what went wrong you need to use the component context menu Cir Preview Shortest list Longest list Cross reference Input P Input R Output C p Runtime warnings L Input parameter R failed to collect data Set Double Set multiple Doubles it Ana n ac Fr Vall 1p Make volatile Expression F X Here you see the main component menu with the cascading menu for the R input parameter The menu usually starts with an editable text field that lists the name of the object in question You can change the name to something more de
39. 7 81 82 Name V Interval Slider Type Integers Lower Limit 5 0 Upper Limit 30 0 o Malue 10 0 Connect the U Interval slider to the Divide Interval U input Connect the V Interval slider to the Divide Interval V input Xform Morph Surface Box Drag and drop a Surface Box component onto the canvas Connect the Surface component output to the Surface Box S input Connect the Divide Interval S output to the Surface Box D input Right click on the Curve Loft and Surface components and turn their Preview off We have now subdivided our z EX surface into 100 areas based on our U and V interval sliders What is happening is that we originally created an interval that Mullion ranged from zero to one which did correspond to the same interval value of our surface Glazing Then we divided that interval 10 O O O O Spandrel Panel times in the U direction and 10 times in the V direction which ultimately created 100 unique interval combinations You can change the U and V values on the sliders to control the amount 7 of subdivision in each direction of your surface Now let s take a step back and create a geometric pattern that we can propagate across each new subdivision In the scene you will find some a window system consisting of a spandrel panel a window mullion and a glazing panel We will use these three geometric instances to create a facade system
40. Brep OnUtil ON BrepBox Ccorners To rravil Dim myCorners 4s New Listi Of OnsdPoint Dim w 45 OnBrepVertex Dim i s Integer For i O To Brep m V cCount 1 get reference to OnBrepVertex v Brep m Vii Ger vertex point locrion Dim pt s New OnsdPoint pt v point idd point to array InyCornerza amp kddi pt Next bes Il Brep InyCornera End Sub Hi Il 142 For plugin version 0 6 0007 The following example shows how to get the number of geometry and topology parts in a brep box faces edges trims vertices etc Transform OnBreps All classes derived from OnGeometry inherit four transformation functions The first three are probably the most commonly used which are Rotate Scale and Transform But there is also a generic Trabsform function that takes a 4x4 transformation matrix defined with OnXform class We will discuss OnXform in the next section brep Rotate w Scale Transform Translate Edit OnBrep Most of OnBrep class member functions are expert user tools to create and edit breps There are however many global function to Boolean intersect or split breps as we will illustrate in a separate section There is an excellent detailed example available in McNeel s wiki DotNET samples that creates a brep from scratch and should give you a good idea about what it takes to create a valid OnBrep from scratch Here is an example that extracts OnBrep faces and move them away from
41. Column data format General 7 Text General converts numeric values to numbers date values to dates and all remaining values to text Date MDY I Advanced Bo not import column skip Data preview You will now be prompted as to which cell you would like to use to begin importing your data We will use the default cell value of A1 You will now see all 101 values in the A column that correspond to the values within the Grasshopper Post it Panel The Grasshopper definition is constantly streaming the data so any change we make to the list data will automatically update the CSV file Go back to Grasshopper and change the Graph Mapper type to Sine Note the list data change in the Post it Panel For plugin version 0 6 0007 51 owitch back to Microsoft Excel and under the Data Tab you will see another button that says Refresh All Select this button and when prompted select the CSV file that you previously loaded into Excel The list data in column A will now be updated Now select cells A1 through A101 select A1 and while holding the shift button select A101 and click on the Insert Tab at the top Choose the Line Chart type and select the first 2D line chart icon Area Scatter Other ki k Charts fa aig All Chart Types 52 Sine Seriesl You will see a Line Chart that reflects the same shape shown in the Graph Mapper component in Grasshopper You can make as
42. Form function OnCone OnRevSurface or OnNurbsSurface use OnCone GetNurbsForm function OnBezierSurface OnNurbsSurface use GetNurbsForm member function Here is an example that uses OnPlane and OnCone classes aub Runscript BbyVal radius s Double Create a plane from origin and normal Dim plane s New OnPlane Dim origin s New On3dPoint 1 1 0 Dim normal s New On3dVectori ili 1 3 plane cCreatreFromMormal oridgin normal Define height value Dim height 45 Double 5 Create cone Dim cone s New OnCone plane height radius hsslgn output parameter E cone E plane End Sub For plugin version 0 6 0007 137 15 11 OnBrep Boundary representation B Rep is used to unambiguously represent objects in terms of their boundary surfaces You can think of OnBrep as having three distinct parts Geometry 3d geometry of nurbs curves and surfaces Also 2D curves of parametric space or trim curves 3D Topology faces edges and vertices Each face references one nurbs surface The face also knows all loops that belong to that face Edges reference 3d curves Each edge has a list of trims that use that edge and also the two end vertices Vertices reference 3d points in space Each vertex also have a list of edges they lie on one of their ends 2D Topology 2d parametric space representation of faces and edges In parameter space 2d trim curves go either clockwise or anti clockwise depending on whether they
43. Manifald IsMorphable IsPnintInside IsSolid IsSurface IsValid Q IsValidFor 2 IsValidGeometry IsValidTolerances4ndFlags IsValidTopology x Following example checks if a given point is inside a brep Here is the code to check if a point is inside oub RunScripti ByVal brep s onBrep ByVal point s On3dPoint Test if input point is inside brep Dim tol s Double dac bsoluteTolerancer Dim stricktly inside As Boolean True Dim is inside s Boolean Call brep function to test the point is inside brep IsPointInside point tol stricktly inside Print is inside End Sub 146 For plugin version 0 6 0007 15 12 Geometry Transformation OnXform is a class for storing and manipulating transformation matrix This includes but not limited to defining a matrix to move rotate scale or shear objects OnXform s m xform is a 4x4 matrix of double precision numbers The class also has functions that support matrix operations such as inverse and transpose Here is few of the member functions related to creating different transformations Dim xform As New OnXform xtorim w ChangeBasis Mirror W PlanarProjection Rotation w Scale Se Shear W Translation One nice auto complete feature available to all functions is that once a function is selected the auto complete shows all overloaded functions For example Translation accepts either three numbers or a vector as shown in t
44. Rhino file found in the same folder called Curve Paths base file 3dm For plugin version 0 6 0007 39 8 1 Lists amp Data Management Its helpful to think of Grasshopper in terms of flow since the graphical interface is designed to have information flow into and out of specific types of components However it is the DATA such as lists of points curves surfaces strings booleans and numbers etc that define the information flowing in and out of the components such that understanding how to manipulate list data is critical to understanding the Grasshopper plug in Below is an example of how you can control a list of numeric data using a variety of list components found under the Lists subcategory of the Logics tab Note To see the finished definition seen below Open the file List Management ghx found in the Source Files folder that accompanies this document 40 For plugin version 0 6 0007 To start we have created a Series component with a starting value of 0 0 a step value of 1 0 and a count of 10 Thus the Post it panel connected to the Series S output shows the following list of numbers 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 and 9 0 Note The Post it panel s default setting is to show the list index number before the numeric data so that each panel entry actually looks like this TITLE AREA gt ENTRY NUMBER gt LIST DATA These can be toggled on off by right clicking on the Post it panel and chan
45. Sphere lOnPlane with lOnSphere Line parameters tO amp t1 and Arc points pO amp p1 Line parameters tO amp t1 and circle points pO amp p1 Line parameters Onlnterval 2 points On3dPoint 2 points On3dPoint lOnPlane with lOnPlane with lOnPlane On3dPoint For plugin version 0 6 0007 149 Parameter t Double Parameters a amp b on first and second line as Double t oub Runscript byVal L s OnLine ByVal P 4s OnPlane ByVal E 4s Double Dim point New OnsdPoint Dim pointi s New On3sdPoint Dim circle s New oncircle Declare the sphere Dim sphere s New Onophere OnUtil On origin E Intersect line with sphere Onltil ocNM IntersectiL sphere pointo pointi Intersect plane with sphere QnULil GN IntersectiP sphere circled ssiudgn output PeO point Pel pointi Circle circle End Sub Rhutil Rhino Utility RhUtil has many more geometry related functions The list expands with each new release based on user s requests This is snapshot of functions related to geometry 150 For plugin version 0 6 0007 EhUtil Foints w Rhina amp rePoinEscoplanar RhinoPointInPlanarClosedCurve RhinoPrajeckPointsTaBreps W RhinaIsPointInBrep RhinolsPointOnFace Curve y RhinaconverkCcurveTaoPalvline Y RhinacurveBrepInterseck W RhinaCurveFaceInterseck Y RhinaDividecurve y RhinoDoCurveDirectionsMatch RhinaExtendCrv on5 rF RhinoExtendCurve
46. Translation dir Dim m circle 45 Mew OnCircle circle m circle Transform move circles Addim circle Assign output A circles End Sub 15 13 Global utility functions Aside from member functions that come within each class Rhino NET SDK provides global functions under OnUtil and RhUtil name spaces We will give examples using few of these functions 148 For plugin version 0 6 0007 OnUtil Here a summary of functions available under OnUtil that is related to geometry onlntil oS ON BrepBox oS ON BrepCone Y OM BrepConeEdge oS ORL BrepConeFace w OR BrepConeLoop w OM BrepCylinder Y OM BrepExkrude w OM BrepExtrudeEdge Y OM BrepExtrudeFace w OM BrepExtrudeLoop SOR BrepExtrudevertex SOR BrepFramPesh SON BrepRey Surface SON BrepSphere w OM BrepTorus w OM BrepTrimmedPlane w OM BrepWedge w ON Intersect i On xaxis i On xv plane ri Qn axis t On vz plane rim ion axis rin On zERO TOLERANCE rem On zx plane OnUtil intersections Create and edit breps Intersect simple qeometry World coordinate system ON_ Intersect utility function has 11 overloaded functions Here is a list of intersected geometry and the return values the preceding I like in IlOnLine means a constant instance is passed lOnLine with lOnArc lOnLine with lOnCircle lOnSphere with lOnShere lOnBoundingBoc with lOnLine lOnLine with lOnCylinder lOnLine with lOn
47. VYSSI VVFVa 8 SANAVd MAYCNV Ad 400090 NOISHYSA J04 YdaddOHSsvVad The Grasshopper Primer Second Edition for version 0 6 0007 Copyright 2009 All Rights Reserved Introduction Welcome to the wonderful new world of Grasshopper This is the second edition of this primer and it wouldn t have been possible without the tremendous contribution from Rajaa Issa Rajaa is a developer at Robert McNeel and Associates and is the author of several other Rhino plugins including ArchCut and the ever popular PanelingTools This revision provides a much more comprehensive guide than the first edition with over 70 new pages dedicated to creating your own customized scripting components The release of this manual coincides with two events the first being the new release of Grasshopper version 0 6 0007 which proves to be a giant upgrade to the already robust Grasshopper platform Existing users will find subtle and some not so subtle changes to how data is stored in the current version making some previous definitions outdated or even unusable It is the hope that this primer will help new and existing users navigate many of the changes to the software system The second event that overlaps with this publication is the conference titled FLUX Architecture in a Parametric Landscape that is being held at the California College of the Arts The event explores contemporary architecture and design through its relationship with changes in design technologies
48. We have shown how to create a sine wave curve however you can generate other sinusoidal curves like a Cosine or Tangent wave forms by replacing the Sine component with a Cosine or Tangent component found under the Scalar Trigonometry tab Note To see a video tutorial of this example please visit David Fano s blog at http designreform net 2008 06 01 rhino 3d sine curve explicit history For plugin version 0 6 0007 35 EN The Garden of Forking Paths In all versions of Grasshopper released prior to version 0 6 00xx data inside a parameter was stored in a single list and as such did not need a list index However there has been a complete overhaul of how data is stored in Grasshopper and now its possible to have multiple lists of data inside a single parameter Since multiple lists are available there needed to be a way to identify each individual list Below is an image created by David Rutten that represents a reasonably complex yet well structured tree diagram Branch with S Data List yD Empty Branch Grasshopper Data Tree In the image above there is a single master branch you could call this a trunk but since it s possible to have multiple master branches it might be a bit of a misnomer at path 0 This path contains no data but does have 3 sub branches Each of these sub branches inherit the index of the parent branch 0 and add their own sub index 0 1 and 2 respectively It would be wro
49. YZ component If you look at the Rhino viewport you should see a series of points in the shape of a sine wave Since the first Range output is being fed directly into the X input of the Point component without first being fed into a trigonometric function component our x value of the points are constant and evenly spaced However our sine component is being fed into the Y input of the Point component so we see a change in the y value of our points which ultimately form a wave pattern You can now change any of the numeric sliders to change the shape of the wave pattern Curve Spline Interpolate Drag and drop an Interpolated Curve component onto the canvas Connect the Point Pt output to the Curve V input At this point your definition should look like the screen shot below We have set up our definition to use the Num Pts on Curve Wave Length and Frequency sliders but we can set up one last slider to control the amplitude of the sine curve For plugin version 0 6 0007 33 Num Pts on Curve 34 M Wave Length Frequency e 43412 7 Params Special Slider Drag and drop another number slider onto the canvas Right click on this new slider and set the following Name Amplitude Slider Type Floating Point Lower Limit O 1 Upper Limit 5 0 o Value 2 0 Scalar Operators Multiplication Drag and drop a Multiplication component onto the canvas Connect the Amplitude slider to the Multiplication A input Connect
50. _value gt Step lt step_value gt For loop body starts here statements code to be executed inside the loop Exit For Optional to exit the loop at any point other statements 104 For plugin version 0 6 0007 Continue For optional to skip executing the remaining of the loop statements other statements For loop body ends here just before the Next Next means go back to the start of the for loop to check if index has passed end value Tf index passed end value then exit loop and execute statements following Next Otherwise increment the index by step value Next statements following the For Loop The following example uses a loop to iterate through an array of places Dim places list As New List of String places list Add Paris places list Add NY places list Add Beijing Dim i As Integer Dim place As String Dim count As Integer places list Count For i 0 To count 1 place places_list i Print place Next If looping through objects in an array you can also use the For Next loop to iterate through elements of the array without using an index The above example can be rewritten as follows Dim places_list As New List of String places list Add Paris places list Add NY places list Add Beijing For Each place As String In places list Print place Next While End While Loop This is also a widely used loop The struc
51. and Vector mathematics lets take a look at an example that scales a grid of circles according to the distance from the center of the circle to a point Note To see the finished definition of this example Open the file Attractor 2pt circles ghx found in the Source Files folder that accompanies this document Above is a look at the finished definition needed to generate the series of scaled circles below 56 For plugin version 0 6 0007 To create the definition from scratch Params Special Numeric Slider Start by dragging and dropping three numeric sliders onto the canvas Right click all three sliders to set the following o Slider Type Integers o Lower Limit 0 0 o Upper Limit 10 0 o Value 10 0 Vector Point Grid Rectangular Drag and drop a Rectangular Point Grid component onto the canvas Connect the first slider to the Pt Grid X input Connect the second slider to the Pt Grid Y input Connect the third slider to the Pt Grid S input The Rectangular Point Grid component create a grid of points where the P input is the origin of the grid in our case we ll use 0 0 0 The Grid component creates a number of points in both the X and Y direction specified by the numeric sliders However notice that we have set both of these to 10 0 If you actually count the number of rows and columns you ll find that there are 20 in each direction This is because it creates the grid from a center point and offsets the number of
52. are part of an outer or inner loop of the face Each valid face will have to have exactly one outer loop but can have as many inner loops as it needs holes Each trim reference one edge 2 end vertices one loop and the 2D curve The following diagram shows the three parts and how they relate to each other The top part shows the underlying 3d nurbs surface and curves geometry that defines a single face brep face with a hole The middle is the 3d topology which includes brep face outer edges inner edges bounding a hole and vertices Then there is the parameter space with trims and loops 138 Nurbs surfaces and curves in 3d space sat I I l Surface Marmal l l 2d parameter space Loop WA o For plugin version 0 6 0007 OnBrep member variables OnBrep Class member variables include all 3d and 2d geometry and topology information Once you create an instance of a brep class you can view all member functions and variables The following image shows member functions in the auto complete The table lists data types with description Dim brep s Mew OnBrep brep OnBrepVertexArray m V Array of brep vertices OnBrepVertex OnCurveArray m C2 Array of trim curves 2D curves CnCurveArray m C3 Array of edge curve 3D curves ONSurfaceArray m S Array of surfaces Notice that each of the OnBrep member functions is basically an array of other classes For example m F is an array of references
53. ariable in the name of that container Once a variable is defined the rest of the code can retrieve the content of the container using the name of that variable Let s define a container or variable called x of type Int32 and initialize it to 10 After that let s assign the new integer value 20 to x This is how it will looks in VB DotNET Dim x as Int32 10 x 20 Here are other examples of commonly used types Dim x as Double 20 4 Dim b as Boolean True Dim name as String Joe The following Grasshopper example uses three variables X is an integer variable that is defined inside the code y is an integer variable passed to the function as an input A is the output variable The example prints variable values to the output window throughout the code As mentioned before this is a good way to see what is happening inside your code and debugging to hopefully minimize the need to an external editor 100 For plugin version 0 6 0007 aub RunSceriptiByvVal y s Integer Print variables values Print Following are y and x values Print input value Yv Print y amp y Declare x as an integer variable Dim x s int3z2 10 Print x initial value Prinrt x amp x aer x value to be whatever was there plus input y x X Printi amp X Assign x to output L x End Sub Assigning meaningful variable names that you can quickly recognize will make the code much m
54. ation value of the two integers in the Post it panel e Drag and drop the other remaining Scalar Operators onto the Canvas Subtraction Multiplication Division Modulus o Power e Connect the first Integer component to each of the Operator s A input value e Connect the second Integer component to each of the Operator s B input value e Drag and drop a five more Post it panels onto the canvas and connect one panel to each Operator s output value O O O O The definition is complete and now when you change each of the slider s values you will see the result of each Operator s action in the Post it panel area 22 For plugin version 0 6 0007 7 2 Conditional Statements You probably noticed that there were a few components under the Operators subcategory of the Scalar tab that we didn t cover in the last section That s because there are 4 components new to version 0 6 0007 that act somewhat differently than the mathematical operators in that they compare two lists of data instead of performing a algebraic expression The four components are Equality Similarity Larger Than and Smaller Than and are explained in further detail below Note To see the finished version of this definition Open the file Conditional Statements ghx found in the Source Files folder that accompanies this document Below is a screen shot of the completed definition List A A Equality component takes two lists and compares the first item of Lis
55. c Slider Drag and drop 2 sliders onto the canvas Right click on the first slider and set the following o Slider Type Integers o Lower Limit 0 0 o Upper Limit 10 0 o Value 3 0 Right click on the second slider and set the following o Slider Type Integers o Lower Limit 0 0 o Upper Limit 25 0 o Value 25 0 Vector Point Grid Rectangular Drag and drop a rectangular Point Grid component onto the canvas Connect the first slider to BOTH the Point Grid X amp Y input components Connect the second slider to the Point Grid S input You should see a grid of point in your scene where the first slider controls the number of points in both the X and Y axis remember because if offsets the points from a center point there are always double the amount of rows and columns as the numeric slider input The point spacing will be controlled by the second slider We now need to copy this point grid in the Z axis to form a three dimensional volume Logic Sets Series Drag and drop a Series component onto the canvas Connect the second slider to the Series N input Connect the first numeric slider to the Series C input Our Series component will count the number of copies of the point grid we will make in the Z direction however you may have already noticed we have a small error in our math As was previously mentioned our point grid was created from a center point so even though we have set the number of points in both the X amp Y axis to 3 we act
56. ch will be the boundaries of our lofted surface Note To see the finished definition of this example in Grasshopper Open the file Surface Diagrid ghx found in the Source Files folder that accompanies this document SECUS RV NAS AS SRNL BIN Be b 84 For plugin version 0 6 0007 Let s start the definition from scratch Params Geometry Curve Drag and drop two Curve components onto the canvas Right click the first Curve component and rename it to Input Crv1 Right click the Input Crv1 component and select Set One Curve When prompted select one of the curves in the Rhino scene Right click the second Curve component and rename it to Input Crv2 Right click the Input Crv2 component and select Set One Curve When prompted select the other curve in the Rhino scene eurface Freeform Loft Drag and drop a Loft component onto the canvas Connect the Input Crv1 component to the Loft S input While holding the Shift key connect the Input Crv2 component to the Loft S input You should now see a lofted surface between the two input curves inside your Rhino scene Params Geometry Surface Drag and drop a Surface component onto the canvas Connect the Loft L output to the Surface component input Scalar Interval Divide Interval Drag and drop a Divide Two Dimensional Interval component onto the canvas Just like in the last example we are going to subdivide our surface into smaller surfaces To
57. changed through this menu Once you start editing the source only function body can be changed and not the parameters change parameters names Variable Parameters Edit Source delete parameter Input Manager iuEpul Manager add new parameter Input x Input y iuEput out QucpuE 13 3 Output Parameters You can also define as many outputs or returns as you wish using the main component menu Unlike input parameters there are no types associated with output They are defined as the generic system type object and the function may assign any type array or not to any of the outputs Following picture shows how to set outputs using the output manager Note that the out parameter cannot be deleted It has debugging string and user debugging strings For plugin version 0 6 0007 95 up locked parameter Preview change parameters names c Runtime warnings Shortest list Ve riable Parameters Longest list WO cross reference Edit Source delete parameter Input Manager iuEpul Manager Input x add new parameter Input s iuEput aut OuEpub 13 4 Out Window and Debug Information Output window which is called out by default is there to provide debug information It lists all compiling errors and warnings The user can also print values to it from within the code to help debug It is very useful to read compiling messages carefully wh
58. component The Smaller Than component determines if list A is less than list B and returns a list of boolean values Similarly the two outputs let you determine if you would like to evaluate each list according to a less than lt or less than and equal to lt condition 24 For plugin version 0 6 0007 7 2 Range vs Series vs Interval The Range Series and Interval components all create a set of values between two numeric extremes however the components operate in different ways Note To see the finished version of the following examples Open the file Scalar intervals ghx found in the Source Files folder that accompanies this document The Range component creates a list of evenly spaced numbers between a low and a high value called the domain of numeric range In the example above two numeric sliders are connected to the input values of the Range component The first slider defines the numeric domain for the range of values In this example the domain has been defined from zero to one since the slider is set to 1 The second slider defines the number of steps to divide the domain which in this case has been set to 10 Thus the output is a list of 11 numbers evenly divided between 0 and 1 note The second slider set to 10 is defining the number of divisions between 0 and 1 which ultimately creates 11 numbers not 10 The Series component creates a set of discreet numbers based on a start value step size and the number
59. create a variable structural thickness we will use a slider to control the Pipe radius e Params Special Number Slider Drag and drop a numeric slider onto the canvas e Right click on the slider and set the following o Name Pipe Radius o Slider Type Floating Point o Lower Limit 0 0 o Upper Limit 1 0 o Value 0 05 e Connect the Pipe Radius slider to the Pipe R input Lastly we will create a flat surface between each of the 4 corner points We are doing this because the sub surfaces we originally created are curved and for this exercise we would like to create a faceted surface with a diagrid structural system e Surface Freeform 4Point Surface Drag and drop a 4 Point Surface component onto the canvas Connect the first List Item E output to the 4 Point Surface A input Connect the second List Item E output to the 4 Point Surface B input Connect the third List Item E output to the 4 Point Surface C input Connect the fourth List Item E output to the 4 Point Surface D input Make sure you turn the Preview off for all components except for the 4 Point Surface component and the Pipe component For plugin version 0 6 0007 87 Structure Paths 144 path 0 0 0 N 4 aie Lt 1 TS ri Ds Ul d Fipe Radius La ur iun o1 WEISE ERES The last part of your definition should look like the image above This definition will work on any type of single surface and you can replace the Loft part of the definition at the be
60. ctor Curve Surface Mesh Intersect Form ASIa NRA SHO akk weBKGAY gt 5g REC 5 F At w B Sets APRo E This interface contains a number of different elements most of which will be very familiar to Rhino users A The Main Menu Bar The menu is similar to typical Windows menus except for the file browser control on the right B You can quickly switch between different loaded files by selecting them through this drop down box Be careful when using shortcuts since they are handled by the active window This could either be Rhino the Grasshopper plug in or any other window inside Rhino Since there is no undo available yet you should be cautious with the Ctrl X Ctrl S and Del shortcuts B File Browser Control As discussed in the previous section this drop down menu can be used to switch between different loaded files Source RhinoWiki http en wiki mcneel com default aspx McNeel ExplicitHistoryPluginInterfaceExplained html 2 For plugin version 0 6 0007 C Component Panels This area exposes all component categories All components belong to a certain category such as Params for all primitive data types or Curves for all curve related tools and all categories are available as unique toolbar panels The height and width of the toolbars can be adjusted allowing for more or fewer on screen buttons per category The toolbar panels themselves contain all the components that belong to that category Since
61. der Drag and drop two numeric sliders onto the canvas Right click the first slider and set the following Name U Divisions Slider Type Integers Lower Limit 0 0 Upper Limit 100 0 Value 15 0 Right click the second slider and set the following Name V Divisions Slider Type Integers Lower Limit 0 0 Upper Limit 100 0 o Value 25 0 Connect the U Divisions slider to both Divide Surface U inputs Connect the V Divisions slider to both Divide Surface V inputs The two sliders now control the number of divisions in each direction on both surfaces Since both surfaces have the exact same number of points and thus each point has the same index number we will easily be able to connect the inner surface to the outer surface with a simple line Curve Primitive Line Drag and drop a Line component onto the canvas Connect the first Divide Surface P output to the Line A input Connect the second Divide Surface P output to the Line B input It s as easy as that You should now see a series of lines connecting each point of the inner surface to the corresponding point on the outer surface We can take the definition a step further by giving each line some thickness Surface Freeform Pipe Drag and drop a Pipe component onto the canvas Connect the Line L output to the Pipe C input Params Special Slider Drag and drop a Numeric Slider onto the canvas Right click the slider and set the following o Name Pipe Radius o Slider Type Fl
62. do this we must create an interval in both the U and V direction from which to subdivide our surface Connect the Surface component output to the Divide Interval l input Params Special Numeric Slider Drag and drop a slider onto the canvas Right click the slider and set the following Name Surface Division Number Slider Type Integers Lower Limit 0 0 Upper Limit 20 0 o Value 12 0 Connect the Slider to both the U and the V inputs of the Divide Interval component Surface Utility Isotrim Drag and drop an Isotrim component onto the canvas Connect the Surface component output to the Isotrim S input Connect the Divide Interval S output to the Isotrim D input Right click the Loft and Surface component and turn the Preview off You should now see a set of subdivided surface corresponding to the subdivision value you set in the numeric slider Because we have connected only one slider to both of the U and V inputs for the interval you should see the subdivisions change equally as you move the number slider to the right and left You can add an additional slider here if you would like to control the divisions separately Surface Analysis Brep Components Drag and drop a Brep Components onto the canvas This component will break down a series of Breps into their component elements such as Faces Edges and Vertices In this case we want to know the positions of each corner point so that we can begin to make diagonal connect
63. e Dim new line 45 New OnLine Line Dim end pt s New On3dPoint end pt new line Point tiD 95 new line To end pt Rotate new line Rotate langle OnUtil On zaxis Line frori AllLines dd new line Call self Call DividedndRotate new line AllLines angle HMinLendth End Sub HEnd Region For plugin version 0 6 0007 111 This is the same functionality using iterative solution using a while loop aub RunSceriptiByvVal C s OnLine ByVal A s Double ByVal L 4s Double Declare all lines Dim llLines s New Listi of OnLine Find current length Dim current L s Double C Lengthi Dim new line s OnLine new line C Loop until length is less than min length While current L gt L Generate rhe new line new line Divide indEotate new line Aj Add to list AllLines A ddinew line natopping condition current L new line Lengdthi End While hssign return value Lines AllLines End Sub Reqion Additional methods and Type declarations Function DividedndRotate ByVal L s OnLine ByVal s Double as OnLine Take a portion of the line Dim new line 45 New OnLine Lb Dim end pt s New OnsdPoint end pt new line Point iti0 95 new line To end pt Rotate new line Eotateij OnUtil On zaxis L from Function return Divide ndBotate new line End Function End Region 112 For plugin version 0 6 0007 14 11 Processing Lists in Grasshopper Grasshopper script co
64. e precision On3dPoint x as Double Most commonly used to represent points in three y as Double dimensional coordinate space On4dPoint x as Double Used for grip points Grips have weight information y as Double in addition to the three coordinates z as Double w as Double Points and vectors operations include Vector Addition Dim add v As New On3dVector vO v1 124 For plugin version 0 6 0007 Vector Subtraction Dim subtract vector As New On3dVector vO v1 Vector between two points Dim dir vector As New On3dVector p1 pO Vector dot product if result is positive number then vectors are in the same direction Dim dot product As Double vO v1 Vector cross product result is a vector normal to the 2 input vectors Dim normal v As New On3dVector OnUtil ON CrossProduct vO v1 Scale a vector Dim scaled v As New On3dVector factor vO Move a point by a vector Dim moved point As New On3dPoint org point dir vector Distance between 2 points Dim distance As Double ptO DistanceTo pt1 Get unit vector set vector length to 1 vO Unitize Get vector length Dim length As Double vO Length Following example show how to calculate the angle between two vectors oub Runseript byVal vO 45 On3dVector ByVal vil s OnsdVector Ci Unitize the input vector WO Uniticze vi Unitizeil Dim dot s Double OnUtil ON DotProduct vo wl Force the dot product of the two input vect
65. e represented by the gradient pattern You can change the colors of the gradient by selecting one of the small white dots in the Gradient pattern and defining the Color In and the Color Out values You can also drag the dot up and down the length of the gradient to control the location of where you would like the color to change values Additionally there are a number of preset gradient patterns loaded into the Gradient component and you can set them by right clicking on the gradient pattern and choosing one of the four preset patterns Our example has the gradient pattern set to Spectrum e Params Special Custom Preview Drag and drop a Custom Preview component onto the canvas e Connect the Scale G output to the Custom Preview G input e Connect the Shader S output to the Custom Preview S input e Right click and turn the preview off for the Scale component Below is a screen shot of how we have set up the third step of this definition If you move the attractor point around in your Rhino scene the scaled boxes and color information will automatically update 66 For plugin version 0 6 0007 ET Curve Types Since curves are geometric objects they possess a number of properties or characteristics which can be used to describe or analyze them For example every curve has a starting coordinate and every curve has an ending coordinate When the distance between these two coordinates is zero the curve is closed Also every curve has a number o
66. ect the attractor point output to the Distance A input Connect the rectangular Grid Point G output to the Distance B input For plugin version 0 6 0007 of 58 UO o m o as The first step of our definition should look like the screenshot above If we hover our mouse over each Distance D output we will see a list of numbers which correspond to how far each grid point is from the attractor point We will use these values to determine each circle s radius but first we must scale these numbers down to give us more appropriate radius dimensions Scalar Operators Division Drag and drop a Division operator onto the canvas Connect the Distance D output to the Division A input Params Special Numeric Slider Drag and drop a numeric slider onto the canvas Right click the slider and set the following o Name Pt1 Influence o Slider Type Floating Point o Lower Limit 0 0 o Upper Limit 100 0 o Value 25 0 Connect the Pt1 Influence slider to the Division B input Since the distance values were quite large we needed a scale factor to bring the numbers down to a more manageable value We have used the numeric slider as division factor to give us a new set of output values that we can use for our circle radius We could directly input these values into a Circle component but to make our definition a little more robust we can use some scalar math to determine a falloff distance What this means is that we can limit how large our
67. en the code is not running correctly our Mo Runtime messages Help It is a good idea to connect the output string to a text component to see compiling messages and debug information directly 96 For plugin version 0 6 0007 13 5 Inside the Script Component To open your script component double click on the middle of the script component or select Edit Source from the component menu The script component consists of two parts Those are A Imports B Grasshopper Custom Script class C Link to Microsoft developer network help on VB NET D Check box to activate the out of focus feature of scripting component double click ScriptEditor Class Grasshopper Custom Script aub Bunscripti iByvVal x 45 object ByVal y 45 Object LT RUE code gf your code gt End Sub End Class ye VB NET on MSDN C D A Imports Imports are external dlls that you might use in your code Most of them are DotNET system imports but there is also the two Rhino dlls RMA openNURBS and RMA Rhino These include all rhino geometry and utility functions There are also the Grasshopper specific types For plugin version 0 6 0007 97 ScriptEditor Imports System Imports system I0 Imports system Drawing Imports System Drawing Drawings D Imports system Reftlection Imports System cCollections Imports System Collections Generic Imports Microsoft VisualBazsic Imports RMA OpenNURBS Imports RMA Rhino
68. ent Falloff slider and the Minimum component and hit Ctrl c copy and Ctrl v paste to duplicate these components o LU T Tem 9 D Uu e Move the duplicated components down the canvas slightly so that your component don t overlap each other For plugin version 0 6 0007 59 We need to assign another point attractor to our definition but of course to do this we need to make another point in our Rhino scene first e Inthe Rhino scene type Point in the dialogue box and place a Point object anywhere in your scene As we did before place the point in the Top viewport so that the point is in the XY plane e Right click the duplicated Point parameter and select Set One Point e When prompted select the attractor point object that you just created in the Rhino scene We now have 2 rows of components that are evaluating the distance from the rectangular Point Grid and giving us information that we can use to control the radius of a circle However we need to combine the two lists that are the result of the Minimum component into a single list To do this we will use the scalar Addition component e Scalar Operators Addition Drag and drop and Addition component onto the canvas e Connect the first Minimum R output to the Addition A input e Connect the second Minimum R output to the Addition B input e Now connect the Addition R to the Circle R input Note This will replace the existing connection wire If comple
69. ent will be created to close the loop The output for the Polyline component is slightly different than that of the previous examples in that the only resultant is the curve itself You would have to use one of the other analytic curve components within Grasshopper to determine the other attributes of the curve E Poly Arc Curve Spline Poly Arc nz A poly arc is almost re identical in nature to the polyline except that instead of straight line segments the poly arc uses a series of arcs connect each point The poly arc is unique in that it computes the required tangency at each control point in order to create one fluid curve where the transition between each arc is continuous There are no other inputs other than the initial point array and the only output is the resultant curve For plugin version 0 6 0007 Pt6 10 1 Curve Analytics It would be quite difficult to create a tutorial that would utilize all of the analytic tools available in Grasshopper so have included a table to explain many of the most commonly used components Find the center point and radius of arcs and circles Curve Analysis Center Curve Analysis Closed Test if a curve is closed or periodic Curve Analysis Closest Find the closest point on a curve to any Point sample point in space Extract the end points of a curve Decompose a curve into its component parts Join as many curve segments together as possible Curve Analys
70. ere are two outputs MyOutput1 and myOutput2 They are listed in the members region of the script class Class Grasshopper Custom Script HRegion members Private app s HMEhino pp Private doc s HREhinobaoc Public MyOutpul Hyoutputz As System oh ject End Region oub RunSceriptiByVal MyInputl s object ByVal HyInpute s object Zevour code gt Dim tol s Double tol doc bsoluteTolerancer Printi doc bsoluteTolerance amp tal tol Rnoutil Rhino ppl ctiveDoc bsoluteTolerance j Printi Rhoutil Rhino ppl ctiveDboc bsoluteTolerance j amp tol gf your code gt End Suk For plugin version 0 6 0007 99 EY visual Basic DotNET 14 1 Introduction There are plenty of references about VB NET available over the Internet and in print The following is meant to be a quick review of the essentials that you will need to use in your code 14 2 Comments It is a very good practice to comment your code as much as possible You ll be surprised how fast you will forget what you did In VB NET you can use an apostrophe to signal that the rest of the line is a comment and the compiler should ignore In Grasshopper comments are grey color For example 14 3 Variables You can think of variables as containers of data Different variables have different sizes depending on the type of the data they accommodate For example an int32 variable reserves 32 bits in memory and the name of the v
71. f control points if all these points are located in the same plane the curve as a whole is planar Some properties apply to the curve as a whole while others only apply to specific points on the curve For example planarity is a global property while tangent vectors are a local property Also some properties only apply to some curve types So far we ve discussed some of Grasshopper s Primitive Curve Components such as lines circles ellipses and arcs SSOS d ng axe Line Polyline Circle Ellipse Arc Nurbs curve Poly curve Grasshopper also has a set of tools to express Rhino s more advanced curve types like nurbs curves and poly curves Below is an example that will walk us through some of Grasshopper s Spline Components but first we will need to create a set of points that will define how our curves will act In the Source Files folder that accompanies this manual Open the Curve Types 3dm file In the scene you will find 6 points placed on the X Y plane have labeled them from left to right like the image on the right as this will be the order from which will pick them from within Grasshopper For plugin version 0 6 0007 67 Now in Grasshopper Open the file Curve Types ghx in the Source Files folder that accompanies this document You will see a Point component connected to several Curve components each defining a curve using a different method We will go through each component individually but fir
72. f the Divide Curve component This is because all of the points are stored in 1 list with no branches or paths so the component is programmed to draw a Polyline through all of the points in the list If we were using Grasshopper version 0 5 the point index and the resulting Polyline would have looked like this Curve 2 gt B Y f 4 s 24 T ha 35 10 i Agi 7 i a o A d i _ f8 2 20 i4 j 2 Ugo 30 a i a Bee Tr For plugin version 0 6 0007 37 However since we now know that Grasshopper has the capabilities to incorporate paths and branches we can now use that index to control how the Polyline component behaves If we follow the exact same steps as before only using Grasshopper version 0 6 00xx or higher our Polyline component will create 2 polylines because it recognizes that there are 2 paths that have each been divided into 20 segments We can check out the tree structure by using the Parameter Viewer Params Special Param Viewer Below is a screenshot of this example which shows that our structure has 2 paths 0 0 and 0 1 which each have 1 resultant curve at their terminus path 0 1 N i QRa GU B x 5 j d ii og 3 a 10 a 11 E 5 18 E 12 T5 s 20 13 1 19 15 T i i 14 ET 8 14 B U4Ag cU Pa 3 14 18 44 12 We now know that our definition has 2 paths but what if we really only wanted 1 path and thus 1 resultant polyline Grasshopper has a numbe
73. geometry in the scene Let s start the definition by creating a lofted surface 80 Params Geometry Curve Drag and drop a Curve component onto the canvas Right click the curve component and select Set Multiple Curves When prompted select the 4 ellipses in the scene one by one starting from the bottom most curve and working your way up to the top Hit enter after you have selected the last ellipse As we have done in some of our previous examples we have now implicitly defined some Rhino geometry within Grasshopper eurface Freeform Loft Drag and drop a Loft component onto the canvas Connect the Curve output to the Loft S input If you right click on the Loft O input you will find the typical loft options associated with the Rhino command In our case the default settings will suffice but there might be a time when these setting would need to be adjusted to fit your particular need Optional Step It is almost impossible to tell whether or not your lofted surface is facing the right direction However through trial and error in setting up this tutorial noticed that my default lofted surface happened to face inward thus causing all of my panels to face inward as well So we can use the Flip component to reverse the normals of our surface to face outward We will put the component in our definition but if you find that when we get to the end of the definition that all of your panels are facing the opposite directio
74. ging the Entry Numbers preview to either on or off However we will leave the Entry Numbers turned on for this example as it will allow us to see exactly what list index number is assigned to each value A The numeric data is then fed into a List Item component Logic List List Item which is used to retrieve a specific entry within the list When accessing individual items in a list one has to use an index value The first item in any list is always stored at location zero the second item at location 1 and so on and so forth Typically if you start to access a list at index 5 an error will occur since no such location exists We have connected the Series S output into the List Item L input Additionally we fed an integer into the List Item i input which defines which list index number we would like to retrieve Since we have set this value to 5 0 the List Item output will show the numeric data associated with the 5th entry number which in this case is also 5 0 B The List Length component Logic List List Length essentially evaluates the number of entries in the list and outputs the last entry number or the length of the List In this example we have connected the Series S output to the List Length L input showing that there are 10 values in the list C We can invert the order of the list by using a Reverse List component Logic List Reverse List We have input an ascending list of numbers into the Reverse List component whereby
75. ginning with more complicated surface generation methods 88 For plugin version 0 6 0007 11 4 Uneven Surface Diagrid We showed in the last example how we can subdivide a surface to create a uniformly spaced diagrid structure The diagrid was uniformly spaced because we created an evenly spaced interval however we can use a few new components and a Graph Mapper to control our interval collection and also the diagrid spacing This tutorial will build off of the previous one so am assuming that you have already built the evenly spaced diagrid definition Below is a screenshot of the finished definition for the un evenly spaced diagrid and the components we are going to add to the existing definition are shown in green Note To see the finished definition of this example in Grasshopper Open the file Uneven Surface Diagrid ghx found in the Source Files folder that accompanies this document For plugin version 0 6 0007 89 In the last definition we connected the Divide Interval component to the Isotrim component We will start our definition by disconnecting that connection 90 e Right click on the Isotrim D input and select Disconnect All Because we are going to be inserting a number of new components its probably a good idea to select everything downstream of the Isotrim component and move it farther to the right side of the canvas e ocalar Interval Interval Components Drag and drop an Interval Components the one
76. ground on surface types to begin looking at a few different examples For plugin version 0 6 0007 15 11 1 Surface Connect The following example created by David Fano from Design Reform is an excellent tutorial that shows a range of surface manipulation techniques In this example we ll cover the Sweep2Rail Surface Offset and Surface Division components by creating the model displayed below To start in Rhino Open the SurfaceConnect 3dm file found in the Source Files folder that accompanies this manual In this file you ll find 3 curves 2 rails and a section curve which will provide the framework needed for this example Note To see the finished definition of this example Open in Grasshopper the file SurfaceConnect ghx also found in the Source Files folder 76 For plugin version 0 6 0007 SectionCurve To create the definition from scratch Surface Freeform Sweep2Rail Drag and drop a Sweep 2 Rails component onto the canvas Right click on the Sweep2Rail R1 input and select Set one Curve When prompted select the first rail curve in the scene see image above Right click on the Sweep2Rail R2 input and select Set one Curve When prompted select the second rail curve in the scene to state the obvious see the image above Right click on the Sweep2Rail S input and select Set one Curve Again when prompted select the section curve in the scene no need to belabor the point here If all curves were p
77. he picture Dim xform s Mew Onktftorr xtform Translationi 4 of zZ Void Direstorm Translation dx As Double dy amp s Double dz 4s Double 4 2 of 2 Void Onstorm Translation d As RMA OpenNURES l n3dYector Here are few more OnXform functions Dim xform 4s Mew Oonzxform xtform PlanarProjectionr Void reform FlanarPraepection plane As RHA OpenNURES IOnPlane Get transformation that projects to a plane Dim xform As New Oonxform xtoarm sheari Vaid Oretom Shear plane As RMA D penNUHBS IDnPlane 1 s AMA OpenMNLU RBS n3dvectar yl As AMA OpenNURBS lOnadVector z1 s AMA OpenNURES ID n3dvectar Create shear transformation The following example takes an input circle and outputs three circles The first is scaled copy of the original circle the second is rotated circle and the third is translated one For plugin version 0 6 0007 147 GUA RUS eee tative circle nCircle ByVal factor s Double ByVal angle s Double ByVal dir s OnsdVector Dim circles s New Listi Of OncCircle 5caled circle Dim Scale s Mew Oonxform scale ScaleionDUtil on origin factor Dim s circle 45 Mew Oncircleicircle s circle Transtormiscale circles A ddi s circle Rotated circle Dim rotate s New Onxform roatate Rotationiangle OnUtil On vaxis OnUtil On origin Dim r circle 45 Mew Oncirele circle r circle Transtorm rotate circles Addir circle Hoved circle Dim move s New Onxtform move
78. hopper plugin For plugin version 0 6 0007 31 7 5 Trigonometric Curves We have already shown that we can use Function components to evaluate complex formulas to create spirals and other mathematical curves however Grasshopper also has a set of trigonometric components built into the scalar component family Trigonometric functions like sine cosine and tangent are important tools for mathematicians scientists and engineers because they define a ratio between two sides of a right triangle containing a specific angle called Theta These functions are important in Vector analysis which we will cover in later chapters However we can also use these functions to define periodic phenomena like sinusoidal wave functions often found in nature in the form of ocean waves sound waves and light waves In 1822 Joseph Fourier a French mathematician discovered that sinusoidal waves can be used as simple building blocks to make up and describe nearly any periodic waveform The process is called Fourier analysis In the following example we will create a sinusoidal wave form where the number of points on the curve the wavelength frequency and amplitude can be controlled by a set of numeric sliders Note To see the finished definition used to create the sine curve below Open the file Trigonometric curves ghx found in the Souce Files folder that accompanies this document To create the definition from scratch e Params Special Slider D
79. iki NURBS A basic understanding of NURBS is necessary to help you use the SDK classes and functions more effectively There are four things that define a nurbs curve Degree control points Knots and evaluation rules Degree It is a whole positive number that is usually equal to 1 2 3 or 5 Rhino allows working with degrees 1 11 Following are few examples of curves and their degree Lines and polylines are degree 1 nurbs curves Order 2 order degree 1 Circles and ellipses are examples of degree 2 nurbs curves They are also rational or non uniform curves Order 3 Free form curves are usually represented as degree 3 nurbs curves Order 4 Degree 5 is also common but the rest are pretty much hypothetical 118 For plugin version 0 6 0007 Control points Control points of a NURBS curve is a list of at least degree 1 points The most common way to change the shape of a nurbs curve is through moving its control points Control points have an associated number called a weight With a few exceptions weights are positive numbers When a curve s control points all have the same weight usually 1 the curve is called non rational and We will have an example showing how to change the weights of control points interactively in Grasshopper Knots or knot vector Each NURBS curve has a list of numbers associated with it that is called a knot vector Knots are a little harder to understand and set but luckily there a
80. im new pt as New On3dPoint new pt input pt For plugin version 0 6 0007 123 Dim new pt as New On3dPoint new pt New input pt Dim new pt as New On3dPoint new pt Set input pt Dim new pt as New On3dPoint new_pt x input pt x new pt y input pt y new ptz input pt z Dim new crv as New OnNurbsCurve new crv input crv DuplicateCurve 15 5 Constant vs Non constant Instances Rhino NET SDK provide two sets of classes The first is constant and it classes names are preceded by an I for example On3dPoint The corresponding non constant class which is what you will mostly need to use has same name without the I for example On3dPoint You can duplicate a constant class or see its member variables and some of the functions but you cannot change its variables Rhino NET SDK is based on Rhino C SDK C programming language offers the ability to pass constant instants of classes and is used allover the SDK functions On the other hand DotNET doesn t have such concept and hence the two versions for each class 15 6 Points and Vectors There are many classes that could be used to store and manipulate points and vectors Take for example double precision points There are three types of points On2dPoint x as Double Mainly used for parameter space points y as Double The d in the class name stand for double precision floating point number There are other points classes that has f in the name that use singl
81. ime and money Therefore all parameters when freshly added are orange to indicate they do not contain any data and have thus no functional effect on the outcome of the History Solution Once a parameter inherits or defines data it will become black C A selected component All selected objects have a green sheen to them D A regular component E A component containing warnings Since a component is likely to contain a number of input and output parameters it is never clear which particular object generated the warning by just looking at the component There may even be multiple sources of warnings You ll have to use the context menu see below in order to track down the problems Note that warnings do not necessarily have to be fixed They may be completely legit Source RhinoWiki http en wiki mcneel com default aspx McNeel ExplicitHistoryPluginObjectsExplained html 8 For plugin version 0 6 0007 F A component containing errors Similar to warnings it is not possible to see where the error was generated in a component You ll need to use the context menu see below Note that a component which contains both warnings and errors will appear red the error color takes precedence over the warning color G A connection Connections always appear between an output and an input parameter There is no limit to how many connections any particular parameter may contain but it is not allowed to create a setup with cyclical recursive c
82. ion to find grid mid points 72 3ub FindMidPoints ByVal Grid s ArrayList mid points s List End Region EM Here is how each of the two subs looks when expanded Region Additional methods and Type declarations Funetion to convert id array to zd array aub Createcridi ByVal Pta s List Of On3dPoint ByRet Grid s ArrayList Byval GS s Integer Dim i 4s Integer Dim j s Integer For i O To Pts Count 1 Step Ga Declare a row of points Dim Row s Mew Listi Of Oon3dPoint For j i To i Ga 1 Get a reference od the point Dim pt s On3dPoint pt Ptsi j idd point to the row Row Add pt Next idd row to the grid Grid 4dd Row Next End Sub For plugin version 0 6 0007 109 Function to find grid mid points sub FindMidPointsiByVal Grid As ArrayList mid points As List Of On3dPoint Dim i s Integer Dim j 4s Integer For i 1 To Grid count 1 Get first and second rows Dim Raw s Listi Of On3sdPoint Row Gridi i 1 Dim Rowl s Listi Of OnsdPoint Rowl Gridiil For j 1 To RowO Countlf 1 Dim mid pt s New OnsdPoint mid pt Row0 j 1 RowO 4 Rowl j 1 Rowlij E mid points ddimid pt Next Next End Sub End Region 14 10 Recursion Recursive functions are special type functions that call themselves until some stopping condition is met Recursion is commonly used for data search subdividing and generative systems We will discuss a
83. ions between each subdivision Connect the Isotrim S output to the Brep Components B input O O O O For plugin version 0 6 0007 85 Our definition so far should look like the image above We have essentially subdivided our surface into smaller sub surfaces and exploded each sub surface to get the position of each surface corner point In our next step we will look at our tree structure an index each of the corner points 86 Param Special Parameter Viewer Drag and drop a Parameter Viewer component onto the canvas Connect the Brep Components V output to the Parameter Viewer input The Parameter Viewer will help us examine our tree structure The structure for this particular example tells us that we have 144 paths with each terminus branch containing 4 data entries in our case these are the four corner points of each subdivided surface We can use the List Item component to go into each path or sub path and retrieve a specific data entry To create our diagrid we want to know where the first second third and fourth point of each subdivided surface is in Cartesian space Structure Paths 144 path 0 0 0 N 4 eye Pa m a sel i LI 4 path 02022 BI 4 Pata ce Que ELI 4 P uds Logic List List Item Drag and drop four List Item component onto the canvas Connect the Brep Components V output to all four of the List Item L inputs Right click on the i input of the first List Item and Set the
84. is Length Measure the length of a curve Curve Division Divide Curve Divide a curve into a equal length segments Curve Division Divide Divide a curve with a preset distance between Distance points Curve Division Divide Divide a curve with a segments with a preset Length length 72 For plugin version 0 6 0007 Curve Utility Flip Flip the an an optional Curve Utility Offset Offset a curve with a specified distance Curve Utility Fillet Fillets the sharp corners of a curve with an input radius m l Project a curve onto a Brep a Brep is a set of CrV AGEGE joined surfaces like a polysurface in Rhino Intersect Region Split with Split a curve with one or more Breps Trim a curve with one or more Breps The Ci Intersect Region Trim with Curves Inside and Co Curves Outside outputs indicate the direction in which you would like the trim to occur Trim a curve with one or more Regions The Ci Intersect Region Trim with Curves Inside and Co Curves Outside Region s outputs indicate the direction in which you would like the trim to occur Intersect Boolean Region Finds the outline or union of two planar Union closed curves Intersect Boolean Region Finds the intersection of two planar closed Intersection curves Intersect Boolean Region Finds the difference between two planar Difference closed curves For plugin version 0 6 0007 13 ELE Surface Types Apart from a few primitive surface types such as sphere
85. k on the Circle C input and click Set One Point In the Rhino dialogue box type 0 0 0 and hit enter Right click on the Circle R input and Set Number to 10 0 Vector Constants Unit Z Drag and drop a Unit Z vector component onto the canvas Right click on the F input of the Unit Z component and Set Number to 10 0 X Form Euclidean Move Drag and drop a Move component onto the canvas Connect the Unit Z V output to the Move T input Connect the Circle C output to the Move G input We have just created a circle whose center point is at 0 0 0 and has a radius of 10 0 units We then used the move component to copy this circle and move the duplicated circle in the Z axis 10 0 units Curve Division Divide Curve Drag and drop two Divide Curve components onto the canvas Connect the Circle C output to the first Divide C input Connect the Move G output to the second Divide C input Params Special Slider Drag and drop a numeric slider onto the canvas Select the slider and set the following parameters o Slider Type Integers o Lower Limit 1 0 o Upper Limit 30 0 o Malue 30 0 Connect the numeric slider to both Divide Curve N input components You should now see 30 points evenly spaced along each circle Logic List Shift List Drag and drop a Shift List component onto the canvas Connect the second Divide Curve P output to the Shift List L input Params Special Slider Drag and drop a numeric slider onto the canvas Select the new slider and set the following pa
86. ld A Startimportatrow 1 File origin 437 OEM United States Preview of file M Grasshopper 101 Primer Definitions Stream Contents csv 0 0 316227766 ap 4472135955 lap 5477225575 In p 6aza45s5a2 otep 2 of the Text Import Wizard allows you to set the which types of Delimiters will define how your data is separated A Delimiter is some character such as a semi colon comma or space stored in the CSV file that indicates where the data should be split into another column Since we only have numeric data stored in each line of the CSV file we do not need to select any the specific delimiter characters Select Next to proceed to Step 3 Text Import Wizard Step 2 of 3 2 x This screen lets you set the delimiters your data contains You can see how your text is affected in the preview below Delimiters 7 Tab Semicolon Treat consecutive delimiters as one oo Textguaifer M Other 9 0 316227766 4472135955 D 5477225575 632455532 4l 50 For plugin version 0 6 0007 otep 3 of the Text Import Wizard allows you to tell Excel how you would like to format your data within Excel General converts numeric data to numbers Date converts all values to Dates Day Month Year and all remaining values are formatted as Text data For our example select General and hit Finish Text Import Wizard Step 3 of 3 OU mim This screen lets you select each column and set the Data Format
87. llow you to return one result You basically assign a value to that function name For example Function AddFunction ByVal x As Double ByVal y As Double AddFunction x y End Function That is said you don t have to have a function to return a value Subs can do it through input parameters that are passed ByRef In the following rc is used to return result Sub AddSub ByVal x As Double ByVal y As Double ByRef re As Double r xty End Sub Here is how the caller function looks like using the Function and the Sub Dim x As Double 5 34 Dim y As Double 3 20 Dim rc As Double 0 0 rc AddFunction x y AddSub x y rc In the nested loops section we illustrated and example that created a grid from a list of points then calculated mid points Each of these two functionalities is distinct enough to 108 For plugin version 0 6 0007 separate in an external sub and probably reuse in future code Here is a re write of the grid example using external functions ub RunScripti ByVal Pts s List Of OnsdPoint ByVal Go As Integer Create a grid of points Dim Grid s New ArrayList Call grid function Call CreateGrid Pts Grid G3 Call mid points function Dim mid points s New Listi of On3dPoint 2 Assign mid point to output MP mid points End Sub Region Additional methods and Type declarations Function to convert id array to zd array oub CreateGrid ByVal Pts s Listi Funct
88. lononaBooeanexpresson Or Performs a logical disjunction on two Boolean expressions For plugin version 0 6 0007 103 14 6 Conditional Statements You can think of conditional statements as blocks of code with gates that get executed only when the gate condition is met The conditional statement that is mostly used is the If statement with the following format IF condition Then lt code gt End IF Single line if statement doesn t need End If condition x lt y code x x y Ifx y Thenx xty Multiple line needs End If to close the block of code If x y Then X xt y End If It is also possible to use an Else If Then and Else to choose n alternative code block to execute For example If x y Then X xt y Else If x gt y Then X xX y Else X 2 x End If There is also the Select Case statement It is used to execute different blocks of code based on the value of an expression index in the example For example Select Case index Case 0 X x xX Case 1 X7x 2 Case 2 x x 0 5 End Select 14 7 Loops Loops allow repeating the execution of the code block inside the body of the loop again and again as long as the loop condition is met There are different kinds of loops We will explain two of them that are most commonly used For Next Loop This is the most common way of looping The structure of the loop looks like For lt index start_value gt To lt end
89. ls Input Manager Input F i Input 0 k Input 1 i Output W i 7 Help e Open the Input Manager and select the green plus button to add an additional list to the component Your Input Manager should look like the image above e Params Primitive Integer Drag and drop an Integer parameter onto the canvas e Right click the Integer parameter and select Manage Integer Collection e By clicking on the green plus button at the top you can add an integer into the collection Add three numbers to the collection and change each value so that your list looks like this O 1 2 Your manager should look like the image below Integer value manager I Format Bin 00000000 Dec 0 Hex HI Ort eu Misc TypeDescrption A 32bit signed integer TypeName Integer Valid True El Number Sign no sign tems with warming or eror Bin icons will not be included in Binary notation the final collection because F they do not represent valid This integer collection will determine our weaving pattern By changing the order of these numbers we can quickly change the order of our data set 44 For plugin version 0 6 0007 e Params Primitive String Drag and drop a String component onto the canvas e Right click on the String component and select Manage String Collection Just like we did with the integer collection we re going to add a list of strings that we want to weave together This will
90. matching algorithm is set to Longest List If you right click on the component you can change the algorithm to Cross Reference Now when you look at your scene you should see a three dimensional cube of points See Chapter 6 for more information about Data Stream Matching Surface Primitive Center Box Drag and drop a Center Box component onto the canvas Connect the Move G output to the Center Box B input Right click on the Point Grid and the Move component and set the Preview to off Below is a screen shot of how our first step of the definition should be set up 2 m o Q Br Step 2 Solve the Scalar and Vector Math Params Geometry Point Drag and drop a Point component onto the canvas Right click on the Point component and rename it to Attractor Pt Just like in the scaling circles example we will need to assign the Attractor Pt component to a point pre defined in the Rhino scene To do this we will first need to create a point In the Rhino scene type Point in the dialogue box and place a point anywhere in your scene Go back into Grasshopper and right click on the Attractor Pt component and select Set One Point When prompted select the point that you just created in the Rhino scene You should now see a small red X over the point indicating that the Attractor Pt component has been assigned that point value in your scene If you move the point anywhere in your scene the Grasshopper com
91. ming language It includes three sections The first is about the script component interface The second includes a quick review of VB DotNET language The next section talks about Rhino DotNET SDK geometry classes and utility functions At the end there is a listing of where you can go for further help 92 For plugin version 0 6 0007 The Scripting Interface 13 1 Where to find the Script Components VB DotNet Script component is found under logic tab Currently there are two script components One is for writing Visual Basic code and the other for C There will no doubt be other scripting languages supported in the future To add a script component to the canvas drag and drop the component icon Ed Logic Scalar Vector Curve Surface Mesh LV 8s SEU c t8 6 Ce HL fF x dnm Ma AE A M conpt F gt b Output string for debugging and compiling messages Output parameters script return vilue s eee 6 Eg pA Al p j views Input parameters The default script component has two inputs and two outputs The user can change names types and number of inputs and outputs X first input of a generic type object Y second input of a generic type object Out output string with compiling messages A Returned output of type object 13 2 Input Parameters By default there are two input parameters x and y It is possible to edit parameters names delete or
92. mponent can process list of input in two ways 1 Process one input value at a time component is called number of times equal to number of values in the input array 2 Process all input values together component is called once If you need to process each element in a list independently from the rest of the elements then using first approach is easier For example if you have a list of numbers that you like to increment each one of them by say 10 then you can use the first approach But if you need a sum function to add all elements then you will need to use the second approach and pass the whole list as an input The following example shows how to process a list of data using the first methods possessing one input value at a time In this case the RunScript function is called 10 times once for each number Key thing to note is the Number input parameter is passed as a Double as opposed to List of Double as we will see in the next example oub RunocriptiByval Number s Double ByVal Value s Double Humber Value End sub For plugin version 0 6 0007 113 In the following we input the list of numbers You can do that by right mouse click on the input parameter and check List The RunScript function is called only once NList s List Of Doublel T oub BunSceriptiBy Vval Dim Sum s Double O Dim i s Integer For i O To HList cCount 1 Sum Sum NListii Nex
93. n example that shows how recursion works For more recursive examples check Grasshopper wiki and the Gallery page The following example takes smaller part of an input line and rotates it by a given angle It keeps doing it until line length becomes less than a minimum length Input parameters are e Staring line C e Angle in radians A Slider shows angle in degrees but converts it to radians e Minimum length L As a stopping condition Output is e Array of lines We will solve same example iteratively as well as recursively for the sake of comparison 110 For plugin version 0 6 0007 Recursive solution Note that inside the DivideAndRotate sub there are e Stopping condition to exit the sub e Acalltothe same function recursive function call themselves e AllLines array of lines is passed by reference to keep adding new lines to the list aub RunSceriptiByvVal C s OnLine ByVal 4 4s Double ByVal L s Double Declare all lines Dim llLines s New Listi Of OnLine Call recursive function Call DividedndRotate Line AllLines Li Assign return value Lines llLines End Sub Reqion Additional methods and Type declarations oub Divide ndBotate Byval Line s OnLine ByRef llLines s ListioOf OnLine ByVal angle s Double ByVal MinLength s Double Check the stopping condition If Line Length lt MinLength Then Exit Sub Take a portion of the lin
94. n than what you intended all you will need to do is delete the Flip component and reconnect the appropriate wires eurface Utility Flip Drag and drop a Flip component onto the canvas Connect the Loft L output to the Flip S input Params Geometry Surface Drag and drop a Surface component onto the canvas Connect the Flip S output to the Surface component s input Right click on the Surface component and select the check box next to the word Reparameterize Currently our surface has a domain interval that ranges from zero at the base of the surface to some number representing the top of the surface We really don t know care what that upper limit is because we can reparameterize the surface Meaning we will reset the domain of the surface to be an interval from zero to one where zero represents the base of the surface and one represents the upper limit of the surface This is a crucial step because our Srf Preview No Runtime messages Disconnect All Disconnect Clear values Help For plugin version 0 6 0007 surface will not subdivide correctly if it is not reparameterized into an interval between zero and one e Scalar Interval Divide Interval Drag and drop a Divide Two Dimensional Interval what a mouth full component onto the canvas We ll first need to set up our interval range before we subdivide our surface e Right click the l input
95. ng to call this an index because that implies just a single number It is probably better to refer to this as a path since it resembles a folder structure on the disk Each of these sub branches are again host to 2 sub sub branches and they again contain no data themselves The same is true for the sub sub branches Once we reach nesting level 4 we finally encounter some data lists are represented as colorful thick lines data items are bright circles Every sub sub sub 36 For plugin version 0 6 0007 branch or level 4 branch is a terminus branch meaning they don t subdivide any further Each data item is thus part of one and only one branch in the tree and each item has an index that specifies its location within the branch Each branch has a path that specifies its location within the tree To further examine tree structures let s take a look at a very simple example We ll start with two Curves which we reference into Grasshopper We ll then use a single Divide Curve Curve Division Divide Curve component to divide both curves into 20 individual segments ultimately giving us 21 points on each curve but a list of 42 points Let s now feed all of those points into a Polyline component Curve Spline Polyline which will create a new line through the division points If we had been using Grasshopper version 0 5 or before the Polyline curve would draw only 1 line through our entire point list which has 42 points as a result o
96. nts and two parameters At this stage all the objects are unconnected and we need to start hooking them up It doesn t matter in what order we do this but lets go from left to right If you start dragging near the little circle of a parameter what us hip people call a grip a connecting wire will be attached to the mouse Once the mouse with the Left Button still firmly pressed hovers over a potential target Parameter the wire will attach and become solid This is not a permanent connection until you release the mouse button Source RhinoWiki http en wiki mcneel com default aspx McNeel ExplicitHistoryVolatileDatalnheritance htm For plugin version 0 6 0007 13 We can do the same for the Y parameter of the PtGrid component and the A and B parameters of the Line component Click Drag Release 14 For plugin version 0 6 0007 Note that we can make connections both ways But be careful by default a new connection will erase existing connections Since we assumed that you will most often only use single connections you have to do something special in order to define multiple sources If you hold Shift while dragging connection wires the mouse pointer will change to indicate addition behavior If the ADD cursor is active when you release the mouse button over a source parameter that parameter will be added to the source list If you specify a source parameter which is already defined as a source no
97. o increase the amount of structure needed to support your surface The middle portion of your definition should now look like the image below For plugin version 0 6 0007 91 EPA An Introduction to Scripting Grasshopper functionality can be extended using scripting components to write code using VB DotNET or CZ programming languages There will probably be support for more languages in the future User code is placed inside a dynamically generated class template which is then compiled into an assembly using the CLR compiler that ships with the DotNET framework This assembly exists purely in the memory of the computer and will not be unloaded until Rhino exits The script component in Grasshopper has access to Rhino DotNET SDK classes and functions which are what plugin developers use to build their plug ins for Rhino As a matter of fact Grasshopper is a Rhino plugin that is completely written as a DotNET plugin using the very same SDK that accessible to these scripting components But why bother using the script components to start with Indeed you may never need to use one but there are some cases when you might need to One would be if you like to achieve a functionality that is otherwise not supported by other Grasshopper components Or if you are writing a generative system that uses recursive functions such as fractals This Primer gives a general overview of how to use the scripting component in Grasshopper using VB DotNET program
98. o longer empty and it turns from orange to black At this point you can use this parameter to seed as many objects as you like with identical vectors 12 For plugin version 0 6 0007 EB volatile Data Inheritance Data Inheritance Data is stored in parameters either in Volatile or Persistent form and used in components When data is not stored in the permanent record set of a parameter it must be inherited from elsewhere Every parameter except output parameters defines where it gets its data from and most parameters are not very particular You can plug a double parameter which just means that it is a number with some decimal number into an integer source and it will take care of the conversion The plug in defines many conversion schemes but if there is no translation procedure defined the parameter on the receiving end will generate a conversion error For example if you supply a Surface when a Point is needed the Point parameter will generate an error message accessible through the menu of the parameter in question and turn red If the parameter belongs to a component this state of red ness will propagate up the hierarchy and the component will become red too even though it may not contain errors of itself Connection management Since Parameters are in charge of their own data sources you can get access to these settings through the parameter in question Let s assume we have a small definition containing three compone
99. o use Function components to solve complex mathematical algorithms and display the numeric data as the output In the following example we will create a mathematical spiral similar to the example David Rutten provided in his Rhinoscript 101 manual For more information about Rhinoscript or to download a copy of the manual visit http en wiki mcneel com default aspx McNeel RhinoScript101 html Note To see the finished version of the mathematical spiral example Open the file Function_spiral ghx found in the Source Files folder that accompanies this document Below is a screen shot of the completed definition To create the definition from scratch e Logic Sets Range Drag and drop a Range component onto the canvas e Params Special Slider Drag and drop two numeric sliders onto the canvas e Right click the first slider and set the following Name Crv Length Slider Type Floating Point this is set by defualt Lower Limit O 1 Upper Limit 10 0 Value 2 5 ow right click on the second slider and set the following Name Num Pts on Crv Slider Type Integers Lower Limit 1 0 Upper Limit 100 0 o Value 100 0 e Connect the Crv Length slider to the Range D input e Connect the Num Pts on Crv slider to the Range N input We have just created a range of 101 numbers that are evenly spaced that range from 0 0 to 2 5 which we can feed into our Function components e O O O O Zo O O O For plugin version 0 6 0007 29 30 Logic Scrip
100. o values 2 0 and 3 0 The component continued this pattern until reaching the end of the list 42 For plugin version 0 6 0007 8 2 Weaving Data In the last section we explained how we can use a number of different components to control how lists are managed in Grasshopper but we can also use the Weave Component to control the order of a list The Weave component can be found under the Lists subcategory of the Logics Tab Logics Lists Weave Note To see the finished definition seen below Open the file Weave Pattern ghx found in the Source Files folder that accompanies this document Litl To create the definition from scratch e Logic List Weave Drag and drop a Weave component onto the canvas You should immediately see 3 input items The first or the P input is the weaving pattern and this will determine the order in which we weave our data The next two input items label 0 and 1 respectively will allow us to input two lists to weave together But what if we want to weave more than two lists Well if you right click on the middle of the Weave component you can open the Input Manager and add as many lists as needed When the Input Manager opens click on the green plus button to add another list Similarly the red X next to each list number will remove that list from the component For plugin version 0 6 0007 43 Variable Parameters Shortest list Longest list Cross reference Insert nul
101. oating Point o Lower Limit 0 0 o Upper Limit 2 0 o Value 0 75 Connect the Pipe Radius slider to the Pipe R input O O O O O O O O O For plugin version 0 6 0007 11 2 Paneling Tools McNeel recently released an excellent free plug in for Rhino called Paneling Tools The plug in among other things allows you the ability to propagate specific geometric modules over a given surface Grasshopper also has some components that can be used to re create the Paneling Tools method and in the following tutorial we ll cover how to subdivide a surface through the use of an Interval component and we ll cover some of the Morphing components included in Grasshopper To find out more about the Paneling Tools plug in please visit http en wiki mcneel com default aspx McNeel Paneling Tools html Below is a screen shot of the definition needed to copy a geometric pattern such as a window mullion system across the surface of a high rise tower Note To see the finished definition of this example in Grasshopper Open the file Paneling Tool ghx found in the Source Files folder that accompanies this document For plugin version 0 6 0007 79 To create the definition from scratch we ll first need a set of curves in which to Loft the tower surface In Rhino Open the file Panel Tool base 3dm also found in the Source Files folder You should find 4 ellipses which we will use to help us define our surface and some preset pattern
102. ode End Sub For plugin version 0 6 0007 107 Sub End Sub Are keywords that enclose function block of code RunScript is the name of the sub Parentheses after the sub name enclose the input parameters ByVal x As Object Are what is called input parameters Each input parameter needs to define the following e ByRef or ByVal Specify if a parameter is passed by value or by reference e Name of the parameter e Parameter type preceded by As keyword Notice that input parameters in Grasshopper RunScript sub are all passed by value ByVal key word That means they are copies of the original input and any change of these parameters inside the script will not affect the original input However if you define additional subs functions inside your script component you can pass parameters by reference ByRef Passing parameters by reference means that any change of these parameter inside the function will change the original value that was passed when the function exits You maybe able to include all your code inside the body of RunScript however you can to define external subs and functions if needed But why use external functions e To simplify the main function code To make the code more readable To isolate and reuse common functionality To define specialized functions such as recursion What is the difference between a Sub and Function anyway You define a Sub if you don t need a return value Functions a
103. of the Divide Interval component and select Manage Interval Collection e Click the green plus button to add an interval to the collection By default the interval is set to u 0 0 To 0 0 v 0 0 To 0 0 but we need the interval to range from 0 to 1 in both the U and V direction e Change the value of U End to 1 0 e Change the value of V End to 1 0 i Interval value manager W u 0 0 To 1 0 v 0 0 To p tems with warming or emor icons will not be included in the final collection a because they do not represent valid x values El Misc Type Description Ml AA Type Nan E valid O Properties E U Domain UEnd LStart El U Properties lsincreasing ls Mormalized E V Domain VEnd VStart El V Properties lsincreasing Is Mormalized emet E IL nine Vv JL JI Area Signed area of 2D domain Your Interval Collection Manager should look like the image above Click OK to accept the interval Now if you hover your mouse over the Divide Interval input you will now see that both our U and V base intervals range from zero to one which also corresponds to our reparameterized surface e Params Special Slider Drag and drop two numeric sliders onto the canvas e Right click on the first slider and set the following o Name U Interval Slider Type Integers Lower Limit 5 0 Upper Limit 30 0 Value 10 0 e Right click on the second slider and set the following For plugin version 0 6 000
104. of the higher degree control points have a larger range of influence D and D are pretty much hypothetical degrees Rhino goes all the way up to D but these high degree splines bear so little resemblance to the shape of the control polygon that they are unlikely to be of use in typical modeling applications In our example we have connected a numeric slider to the Curve D input to define the degree of our NURBS curve By dragging our slider to the left and right we can visually see the change in influence of each control point The NURBS Curve P input uses a boolean value to define whether or not the curve should be periodic or not A False input will create an open NURBS curve whereas a True value will create a closed NURBS curve The three output values for the NURBS Curve component are fairly self explanatory where the C output defines the resultant curve the L output provides a numeric value for the length of the curve and the D output defines the domain of the curve or the interval from O to the numeric value of the curve degree B Interpolated Curves Curve Spline Interpolate xb Interpolated curves behave slightly differently than NURBS curves in that the curve passes through the control points You see it is very difficult to make NURBS curves go through specific coordinates Even if we were to tweak individual control points it would be an incredibly arduous task to make the curve pass through a specific point
105. of values in the Series The series example shows three numeric sliders connected to the Series component The first slider when connected to the Series S input defines the starting point for the series of numbers The second slider set to 10 defines the step value for the series Since the start value has been set to 1 and the step size has been set to 10 the next value in the series will be 11 Finally the third slider defines the number of values in the series Since this value has also been For plugin version 0 6 0007 25 set to 10 the final output values defined in the series shows 10 numbers that start at 1 and increase by 10 at each step The Interval component creates a range of all possible numbers between a low and high number The Interval component is similar to the numeric domain which we defined for the Range component The main difference is that the Range component creates a defualt numeric domain between 0 and whatever input value has been defined In the Interval component the low and the high value can be defined by the A and B input values In the example below we have defined a range of all possible values between 10 and 20 set by the two numeric sliders The output value for the Interval component now shows 10 0 To 20 0 which reflects our new numeric domain If we now connect the Interval Il output to a Range D input we can create a range of numbers between the Interval values As was the case in the previous Range e
106. ols You can enable the panel through the View menu of the Main window or through the GrasshopperPanel command 6 For plugin version 0 6 0007 Viewport Preview Feedback Pe rspective A Blue feedback geometry means you are currently picking it with the mouse B Green geometry in the viewport belongs to a component which is currently selected C Red geometry in the viewport belongs to a component which is currently unselected D Point geometry is drawn as a cross rather than a rectangle to distinguish it from Rhino point objects For plugin version 0 6 0007 Grasshopper Objects Grasshopper Definition Objects A Grasshopper definition can consist of many different kinds of objects but in order to get started you only need to familiarize yourself with two of them e Parameters e Components Parameters contain data meaning that they store stuff Components contain actions meaning that they do stuff The following image shows some of the possible objects you are likely to encounter in a Grasshopper definition A A parameter which contains data Since there is no wire coming out the left side of the object it does not inherit its data from elsewhere Parameters which do not contain errors or warnings are thin black blocks with horizontal text B A parameter which contains no data Any object which fails to collect data is considered suspect in an Explicit History Definition since it appears to be wasting everyone s t
107. on our surface Params Geometry Geometry Drag and drop a Geometry component onto the canvas Right click on the Geometry component and select Set Multiple Geometries When prompted select the spandrel panel mullion and the glazing panel from the scene Hit enter after selecting all three Breps Surface Primitive Bounding Box Drag and drop a Bounding Box component onto the canvas Connect the Geometry component output to the Bounding Box C input We re using the Bounding Box component for two reasons First the Bounding Box component will help us determine the height of our geometric pattern Since we have only used rectangular boxes as our pattern the height would be pretty easy to determine However if you had chosen a more organic shape to copy across your surface the height would be much more difficult to resolve We ll use this height information as an input value for our Surface Box component Secondly we ll use For plugin version 0 6 0007 the Bounding Box as a reference Brep for the BoxMorph component which we will discuss in a moment e Right click on the U input of the Bounding Box component and set the boolean value to True This is an important step as this will tell our bounding box to create a single box for all 3 Brep objects e eurface Analysis Box Components Drag and drop a Box Components onto the canvas e Connect the Bounding Box B output to the Box Components B input e Connect the Box Components Z
108. oncatenation Operators Logical Operators Raises a number to the power of another number Multiplies two numbers Divides two numbers and returns a floating point result Divides two numbers and returns an integer result Divides two numbers and returns only the remainder Adds two numbers or returns the positive value of a numeric expression Returns the difference between two numeric expressions or the negative value of a numeric expression Assigns a value to a variable Raises the value of a variable to the power of an expression and assigns the result back to the variable Multiplies the value of a variable by the value of an expression and assigns the result to the variable E i Divides the value of a variable by the value of an expression and assigns the floating point result to the variable Divides the value of a variable by the value of an expression and assigns the integer result to the variable Adds the value of a numeric expression to the value of a numeric variable and assigns the result to the variable Can also be used to concatenate a String expression to a String variable and assign the result to the variable Subtracts the value of an expression from the value of a variable and assigns the result to the variable E sesensmeresurtodetaabeorpe PE assigns the result to the variable or property s fea 010 amp Generates a string concatenation of two expressions Not Peromslogialnega
109. onnections Such a recursion is detected and the entire Solution is short circuited when it occurs resulting in an error message in the first component or parameter that was detected to be recursive For more information on connections see chapter about Data Inheritance Component Parts A component usually requires data in order to perform its actions and it usually comes up with a result That is why most components have a set of nested parameters referred to as Input and Output parameters respectively Input parameters are positioned along the left side output parameters along the right side A The three input parameters of the Division component By default parameter names are always extremely short You can rename each parameter as you please B The Division component area usually contains the name of the component C The three output parameters of the Division component When you hover your mouse over the individual parts of a Component object you ll see different tooltips that indicate the particular type of the sub object currently under the mouse Tooltips are quite informative since they tell you both the type and the data of individual parameters I a Div P Point 2 S Div C Curva gt Point Curve to divide Division points ota i Local Curve list 1 values EN Local Point list 11 values Referenced Curve i 2 11376 10 388907 0 5 036074 3 015571 0 H RE I 7 44T7
110. ore readable and easier to debug We will try to stick to some good coding practices throughout the examples in this chapter 14 4 Arrays and Lists There are many ways to define arrays in VB NET There are single or multi dimensional arrays You can define size of arrays or use dynamic arrays If you know up front the number of elements in the array you can declare defined size arrays this way Dim myArray 1 As Integer Dim my2DArray 1 2 As Integer myArray 0 10 my2DArray 0 0 10 myArray 1 20 my2DArray 0 1 20 my2DArray 0 2 30 my2DArray 1 0 50 my2DArray 1 1 60 my2DArray 1 2 70 C SNIN Y Dim myArray As Integer 10 20 Dim my2DArray As Integer 10 20 30 40 50 60 For plugin version 0 6 0007 101 Keep in mind that arrays in VB NET are zero based so when you declare an array size to be 9 that means that the array has 10 elements Same goes for multi dimentional arrays For single dimension dynamic arrays you can declare a new List as shown in the following example and start adding elements to it Dim myList As Hew List Of Integer For ji As Integer 21 Ta 10 myList dau i Print Element amp i 1 amp 2 amp myList 111 Mext You can use nested List or ArrayList to declare dynamic multi dimensional arrays of same or mixed types Check the following example Dim myList As Hew ArrayList Dim myFow160 As Double 120 1 21 1 22 1 25 1 Dim myRow20 As Intege
111. ors to fall within the domain for inverse cosine which is 1 lt x lt 1 This will prevent runtime domain error math exceptions If dot lt 1 0 Then dot 1 0 If dot gt 1 0 Then dot 1 0 ho System Math Acos dot End sub For plugin version 0 6 0007 125 15 7 OnNurbsCurve In order to create a nurbs curve you will need to provide the following Dimension which is typically 3 Order Curve degree 1 Control points array of points Knot vector array of numbers Curve type clamped or periodic There are functions to help create the knot vector as we will see shortly so basically you need to decide on the degree and have a list of control points and you are good to go The following example creates a clamped curve x Sub Runseript ByVal CPoints s List QE OnsdPoint Create nurbs curve Dim dimension 4s Integer 3 Dim order 4s Integer 4 Dim nc s New OnNurhsCurve Create open iClamped Nurhs Curve nc CreatecClampedUniformNurbasidimension order cCPointzs To rray l l Assign curve to the output value nc IsValid Then For smooth closed curves you should create periodic curves Using same input control points and curve degree the following example shows how to create a periodic curve 126 For plugin version 0 6 0007 Sub RunScriptiByVal CPoints s List ot OnsdPoint j Create nurbs curve Dim dimension s Integer 3 Dim order ds In
112. ouble cCurve Dbomainr MHMini j Dim max 45 Double Curve bomainr MHMaxi l Find the step value Dim step value s Double max min Num 1 Dim Points s New Listi Of on3dPoint Dim t list Num s Double For i s Integer UO To Num t list i i Num Hext If Curve cGetNHormalized rcLengthPointsi t list t list Then For i s Integer UO To Num Dim pt s Oon5dPoint Curve Point t t listi il Points A ddipt Hext End If Points t list Ed te lH oll End Sub 15 8 Curve Classes not Derived from OnCurve Although all curves can be represented as NURBS curves it is useful sometimes to work with other types of curve geometry One reason is because they mathematical 130 For plugin version 0 6 0007 representation hat is easier to understand than NURBS and are typically more light weighted It is relatively easy to get the NURBS form of those curves not derived from OnCurve when you need one Basically you need to convert to a corresponding class The following table shows the correspondence OnLine OnLineCurve OnPolyline OnPolylineCurve OnCircle OnArcCurve or OnNurbsCurve use GetNurbsForm member function OnArc OnArcCurve or OnNurbsCurve use GetNurbsForm member function OnEllipse OnNurbsCurve use GetNurbsForm member function OnBezierCurve OnNurbsCurve use GetNurbsForm member function Here is an example that uses OnEllipse and OnPolyline classes rr
113. output to the Surface Box H input We re on the home stretch now e Xform Morph Box Morph Drag and drop a Box Morph component onto the canvas Connect the Pattern Geometry output to the Box Morph G input Connect the Bounding Box B output to the Box Morph R input Connect the Surface Box B output to the Box Morph T input Right click on the Morph Box component and set the data matching algorithm to Cross Reference e Right click on the Surface Box component and turn the Preview off Phew If your brain isn t about to explode I ll try to explain the last part of the definition We ve input the pattern geometry into the Morph Box component which replicates that pattern over each subdivision We ve used the Bounding Box of our window system as our reference geometry and we input the 100 box subdivisions as our target boxes to replicate our geometry If you followed all of the steps correctly you should be able to change your base surface pattern geometry and the U and V subdivisions to control any number of panels on a surface For plugin version 0 6 0007 83 11 3 Surface Diagrid We ve already shown how we can use the Paneling Tools definition to create facade elements on a surface but the next example will really show how we can manipulate the information flow to create a structural diamond grid or diagrid on any surface To begin lets Open the Surface Diagrid 3dm file in Rhino In the scene you will find two mirrored cosine curves whi
114. point We can take our definition one step further by adding color to our boxes to give us a visual representation of the scale factor O O O O Scale Factor iz i 25 9 otep 3 Assign a color value to each scaled box 64 Logic List Sort List Drag and drop a Sort List component onto the canvas In order to assign a color value based on each box s distance from the attractor point we will need to know two numeric values the closest point and the point that is furthest away To do this we must sort our list of distance value and retrieve the first and last entry from the list Logic List List Item Drag and drop a List Item component onto the canvas Connect the Sort List L output to the List Item L input Right click on the List Item i input and Set the Integer value to 0 0 This will retrieve the first entry in our list which will be the smallest distance value Logic List List Length Drag and drop a List Length component onto the canvas Connect the Sort List L output to the List Length L input For plugin version 0 6 0007 The List Length component will tell us how many entries are in our list We can input this information into another List Item component to retrieve the last value in the list e Logic List List Item Drag and drop another List Item component onto the canvas e Connect the Sort List L output to the second List Item L input e Connect the List Length L output to the second List Item i input If you hover you
115. ponent will automatically update its position Vector Point Distance Drag and drop a Distance component onto the canvas Connect the Attractor Pt output to the Distance A input Connect the Move G output to the Distance B input If we were to hover our mouse over the Distance D output we would see a list of numeric values indicating each points distance away from the Attractor Pt In order to use these values as a scale factor for our boxes we will need to divide them by some number to bring the values down to the appropriate levels for our example For plugin version 0 6 0007 63 Scalar Operators Division Drag and drop a Division component onto the canvas Connect the Distance D output to the Division A input Params Special Numeric Slider Drag and drop a slider onto the canvas Right click on the slider and set the following Name Scale Factor Slider Type Integers Lower Limit 0 0 Upper Limit 25 0 o Value 25 0 Connect the Scale Factor slider to the Division B input X Form Affine Scale Drag and drop a Scale component onto the canvas Connect the Center Box B output to the Scale G input Connect the Division R output to the Scale F input Right click the Center Box component and turn the Preview off Below is a screen shot of how the definition has been set up so far If you look at the Rhino scene now you should notice that all of your boxes have been scaled according to their distance away from the attractor
116. ponents The NURBS Curve D input sets the degree of the curve The degree of a curve is always a positive integer between and including 1 and 11 Basically the degree of the curve determines the range of influence the control points have on a curve where the higher the degree the larger the range The table on the following page is from David Rutten s manual Rhinoscript 101 and illustrates how the varying degrees define a resultant NURBS curve 68 For plugin version 0 6 0007 NURBS curve knot vectors as a result of varying degree A D nurbs curve behaves the same as a polyline It follows from the knotcount formula that a D curve has a knot for every control point Thus there is a one to one relationship AD nurbs curve is in fact a rare sighting It always looks like it is over stressed but the knots are at least in straightforward locations The spline intersects with the control polygon halfway each segment D nurbs curves are typically only used to approximate arcs and circles D is the most common type of nurbs curve and indeed the default in Rhino You are probably very familiar with the visual progression of the spline eventhough the knots appear to be in odd locations D is technically possible in Rhino but the math for nurbs curves doesn t work as well with even degrees Odd numbers are usually preferred D is also quite a common degree Like the D curves it has a natural but smoother appearance Because
117. r 30 31 32 353 354 Dim myRows0 As String ABC DEF Dim myList As New ArrayList Dim myFowl As Mev Listi of Double 1 hy Fon A dai20 1Y MyFRovwd Addit 1 MyRowd Add 22 1 MyRowd Add 23 13 Dim myFow2 Az Mev Listi Of Integer 3 MyFow Addo MyRow Addai MyRow2 Add s27 MyRow 2 Adda MyRow Adda Dim myRow3 As Mew List Of String My Rows Addi ABC Mykow3 Addi DEF Dim myList As New List Of Object Dim myRow 4s Mew Listi Of Double 3 MyFiowr1 Addt20 1 Mykow Addt21 13 Mykew Sdd 22 1 MyRowd Add 23 13 Dim imyvFow Az Mew Listi Of Integer 3 MyFow Addts0y MyRow Addai MyRow z Addar MyRow2 Addi3sy MyRow Addit Dim myRows3 As Mew Listl Of String MyRows Add ABC hMyRows Addi DEF Dim myList As New List Of List Of Integer Dim myRaow1 4s Mew Listi Of Integer 3 dy Fior Addo MyRowd Addii ygove Adad 22y Mybkow1 dd 23 Dim myRow2 As Mew Listi Of Integer MyFROwz2 2Sddi30 MyRow2 Addis MyRow2 Add 32 MyRow2 Addi33y MyRovez Sdd 341 Add Lists and Print myL ist Add imyRow t myList Add nyRow nvyList Add nyRow 3 Print Element 0 1 amp myList 0 1 Print Element 1 4 amp myList 1 4 Print Element 2 0 amp myList 240 102 For plugin version 0 6 0007 14 5 Operators There are many built in operators in VB NET They operate on one or more operands Here is a table of the common operators for quick reference Arithmetic Operators Assignment Operators Comparison Operators C
118. r mouse over the second List Item E output you will see that the component has not retrieved the last value in the list This is because list data in Grasshopper always stores the first value as entry number 0 So if our list length is showing that there are 100 values in the list and our first number starts at 0 our last entry number will actually be number 99 We must add an expression to the second List Item i input to subtract 1 value from the list length to actually retrieve the last item e Right click on the second List Item i input and select the Expression Editor e Inthe editor dialogue box enter the following equation i 1 Now if you hover your mouse over the second List Item E output you should see a numeric value which corresponds to the distance value that is farthest away from the attractor point e Params Special Gradient Drag and drop a Gradient component onto the canvas e Connect the first List Item E output the one associated with our closest distance value to the Gradient LO input e Connect the second List Item E output the one associated with our farthest distance value to the Gradient L 1 input e Connect the Division R output to the Gradient t input The LO input defines what numeric value will represent the left side of the gradient and in our example the left side of the gradient will indicate the closest box to the attractor point The L1 input defines what numeric value will represent the right side of the gradient
119. r of new tree structure components found under the Tree subcategory of the Logics tab which can help you control your tree structure We can use a Flatten Tree component Logic Tree Flatten Tree to collapse an entire tree structure into 1 list much like the data would have been displayed in version 0 5 or before You can see in the image below that when we flatten our tree our structure now only has 1 path with 1 resultant curve stored in the terminus ultimately giving us the same single polyline curve that we would have gotten if we had used an earlier version of Grasshopper 38 For plugin version 0 6 0007 Structure Paths 1 You can also simplify this definition by flattening your structure inside the Polyline component and by passing the Flatten component To do this simply right click on the V input of the Polyline component and select the Flatten toggle By doing this you should notice that your tree structure which we can view through the Parameter Viewer changes from 2 paths back to 1 NoRuntime messages Disconnect All Disconnect gt S fetes O Set one Point Set multiple Points Manage Point collection Clear values Extract parameter Expression gt e Help Note To see the finished definition used to create this example Open the file Curve Paths ghx found in the Source Files folder that accompanies this document You will also need to open the corresponding
120. rag and drop 3 numeric sliders onto the canvas e Select the first slider and set the following parameters o Name Num Pts on Curve Slider Type Integers Lower Limit 1 Upper Limit 50 Value 40 elect the second slider and set the following parameters Name Wave Length Slider Type Integers Lower Limit O Upper Limit 30 Value 10 e O O O O O U O O O 32 For plugin version 0 6 0007 Num Pts on Curve e Select the third slider and set the following parameters Name Frequency Slider Type Integers Lower Limit O Upper Limit 30 o Value 12 Logic Sets Range Drag and drop 2 Range components onto the canvas Connect the Wave Length slider to the first Range D input Connect the Frequency slider to the second Range D input Connect the Num Pts on Curve slider to both Range N inputs O O O O Wave Length m ioi Frequency mal Your definition should look like the image above We have now created two lists of data the first is a range of evenly divided numbers from O0 to 10 and the second is a list of evenly divided numbers ranging from O to 12 Scalar Trigonometry Sine Drag and drop a Sine component onto the canvas Connect the second Range R output to the x input of the Sine component Vector Point Point XYZ Drag and drop a Point XYZ component onto the canvas Connect the first Range R output to the X input of the Point XYZ component Connect the y output of the Sine component to the Y input of the Point X
121. rameters o Slider Type Integers o Lower Limit 10 0 o Upper Limit 10 0 o Malue 10 0 Connect the numeric slider output to the Shift List S input Right click the Shift List W input and set the boolean value to True We have shifted the points on the upper circle up the index list by 10 entries By setting the wrap value to True we have created a closed loop of data entries Curve Primitive Line Drag and drop a Line component onto the canvas Connect the first Divide Curve P output to the Line A input Connect the Shift L output to the Line B input We have created a series of line segments that connect the un shifted list of points on the bottom circle to the shifted set of points on the upper circle We can change the value of the numeric slider that controls the Shift Offset to see the line segments change between the un shifted and shifted list of points For plugin version 0 6 0007 47 8 4 Exporting Data to Excel There are many instances where you may need to export data from Grasshopper in order to import the information into another software package for further analysis Note To see the finished definition of the following example Open the file Stream Contents Excel ghx found in the Source Files folder that accompanies this document To start we have dropped a Range component Logic Sets Range onto the canvas and set the numeric domain from 0 0 to 10 0 By right clicking on the Range N input we have set the number of steps to
122. re SDK functions that do the job for you Nevertheless there are few things that will be useful to learn about the knot vector Knot multiplicity Number of times a knot value is duplicated is called the knot s multiplicity Any knot value can not be duplicated more than the curve degree Here are few things that would be good to know about knots Full multiplicity knot is a knot duplicated number of times equal to curve degree Clamped curves have knots with full multiplicity at the two ends of the curve and this is why end control points coincide with curve end points If there were full multiplicity knot in the middle of the knot vector then the curve will go through the control point and there would be a kink Simple knot is a knot with value appearing only once Uniform knot vector satisfies 2 conditions 1 Number of knots number of control points degree 1 2 Knots start with a full multiplicity knot is followed by simple knots terminates with a full multiplicity knot and the values are increasing and equally spaced This is typical of clamped curves Periodic curves work differently as we will see later Here are two curves with identical control points but different knot vectors Degree 3 Number of control points 7 knot vector 0 0 0 1 2 3 5 5 5 Degree 3 Number of control points 7 knot vector 0 0 0 1 1 1 4 4 4 Note Full knot multiplicity in the middle creates a kink and the curve is forced to
123. rep s OnbBrep Find brep hounding Hox Dim bhox 45 New OnBoundingBax bhox brep BboundingBox i Find bounding box ceneter Dim center s New On3dPoint center bhox Center Print bounding box diagonal length Dim length s Double bhox Diagonal Length i Printi BRox diagonal length amp length 4 b pox B center End Sub Another area that is useful to know about is the mass properties OnMassProperties class and few of its functions is illustrated in the following example aub RunScript ByVal myBrep s Object Find and print brep area Dim a mass s New OnMassProperties myBrep reaMassProperties a mass Dim area s Double a mass rea Printi Brep Area amp area Find and print brep volume Dim v mass s New OonMassProperties myBrep VolumneMassPropertiesiwv mass Dim vol 45 Double v mass Volumei Print Brep Volume amp vol End sub For plugin version 0 6 0007 145 There are few functions that start with Is that usually retunes a Boolean true or false They inquire about the brep instance you are working with For example if you like to know whether the brep is closed polysurface then use OnBrep IsSolid function It is also useful to check if the brep is valid or has valid geometry Here is a list of these inquiring functions in OnBrep class Dim brep 4s New OnBrep brep Is E IDeformable IsDuplicate IskindOf Is
124. roperly selected you should now see a surface Spanning between each rail curve Surface Freeform Offset Drag and drop a Surface Offset component onto the canvas Connect the Sweep2Rail S output to the Offset S input Params Special Slider Drag and drop a Numeric Slider onto the canvas Right click on the slider and set the following o Name Surface Offset o Slider Type Floating Point o Lower Limit 0 0 o Upper Limit 10 0 o Value 10 0 Connect the slider to the Surface Offset D input For plugin version 0 6 0007 TT 78 You should now see a new surface that is offset 10 units or whatever value you have set for your Surface Offset slider from the original surface Surface Utility Divide Surface Drag and drop two Divide Surface components onto the canvas Connect the Sweep2Rail S output to the first Divide Surface S input You should immediately see a set of points show up on your first Sweep2Rail surface This is because the default U and V values for the Divide Surface component is set to 10 Basically the Divide Surface component is creating 10 divisions in each direction on the surface ultimately creating a grid of points on your surface If you were to connect the points along each division line you would get the isocurves that form the internal framework of the surface Connect the Surface Offset S output to the Divide Surface S input Again a new set of grid points have been created on the offset surface Params Special Sli
125. rows and column in each direction from this point So essentially you get double the number of X and Y points The S input specifies the spacing between each point Params Geometry Point Drag and drop a Point component onto the canvas This component is considered an implicit component because it uses persistent data as its input value See Chapter 4 for more information about persistent data types This component is different than the other Point XYZ component that we have used before in that it does not create a point until you actually assign it a point from the scene To do this of course there must already be a point object in your Rhino scene These Will be our attractor point In the Rhino scene type Point in the dialogue box and place a Point object anywhere in your scene In our case we ll place the point in the Top viewport so that the point is in the XY plane Now that we have created an attractor point in the scene we can assign them to the Point component we just created inside Grasshopper Right click the Point component and select Set One Point When prompted select the attractor point object that you created in the Rhino scene We have now created a Grid of points and we have also referenced in an attractor point from our scene We can use a bit of vector mathematics to determine the distance from each grid point to the attractor point Vector Point Distance Drag and drop a Distance component onto the canvas Conn
126. rraydouble ho utility function to divide by number or curve length EhUtil REhinoDividecurveicCurwve Num O False True cry p cry tj A cry p B crv t End sub Divide curve by arc length example 152 For plugin version 0 6 0007 aub Runscript tbyVal Curve s oncurve ByVal Len s Double Dim cry p s New OnidPointa rray Dim cry t 45 New Arraydouble ho utility function to divide by number or curve length RhUtil REhinoDividecurve iCurve D Len False True cry p cry tJ A cry p B cry t End Sub RhUtil Curve through points interpolate curve RhinolnterpCurve Function name 3 curve degree pt array points to create a curve through Nothing Start tangent Nothng End tangent 0 Uniform knots The following example takes as an input a list of On3dPoints and outputs a nurbs curve that goes through these points Sub RunScript ByVal Points s List f OnsdPoint Dim pt array 45 Mew ArrayOnsdPoint Dim i s Integer For i To Points cCount 1 pr array ppendiPoints i il Next Create an interpolated nurbs curve Dim cry s New OonNurhbscCurve cry BhUtil RhinoInterpCurvei3 pt array Nothing Wothing 0 Ii crv IsValidi i Then uet return vlue to list ery End If End Sub For plugin version 0 6 0007 153 RhUtil Create edge surface The input in the following example is a list of four curves and the output is an edge surface Sub RunSscriptiByVal Curves
127. rt is in relation to the extents of the entire definition The Widgets can be enabled disabled through the View menu H The Status Bar The status bar provides feedback on the selection set and the major events that have occurred in the plug in Key information about whether or not you have any errors or warnings in your definition will be displayed here The square orange icon on the bottom left of the Status Bar is a live RSS reader of the Grasshopper forum By clicking on this icon a list of the most recent threads linked to the Grasshopper user group website will be displayed Selecting any one of the threads will take you directly to the discussion posted by one of the user group members You can visit the Grasshopper user group website at http grasshopper rhino3d com The Remote Control Panel Since the Grasshopper window is quite large you may not want it on the screen all the time Of course you can minimize or collapse it but then you can t tweak the values anymore If you want a minimal interface to the values inside the currently active definition you can enable the Remote Panel This is a docking dialog that keeps track of all sliders and boolean switches and possibly other values as well in future releases Explicit History Variable B AS 0 706 E v Cycle values Toggle 1 Variable A 0 250 Offset amount 15 656 The Remote panel also provides basic preview event and file switching contr
128. rv CEv3d push cry End sub Using the previous example we will calculate normal vector of the start and end points of the pulled curve Here are 2 ways to do that Use pulled 2D curve start and end 2D points and this would be start and end points on surface in parameter space Oruse pushes 3D curve end points find closest point to surface and use resulting parameters to find surface normal aub cetrEndNormalszDiByVvVal crvzd s OntCurve ByVal sri As onSurface BbyvERer EndVectorszb s List OE OnsdVector Dim start normal is On3adwvector D iim end normal is On3dvector find start and end points in parameter spac Dim Started 48s New OnedPoint started cerved Poaintatstart i Dim ended is New OnedPoint endzd crvzd PointitEndi IT Cutput parameters aurface parameters are the x and y of the zd curve end points Print 2D Start u amp tartzd x Print 2D Start v amp started w Prinr 2zb End u amp endzd x Prinrt zb End w amp endzd y Printi Call surface normal function start normal srrf Mormal t startzd x startzd Y end normal srf Hormal ti endzd x ended EndVectorszD amp Addistart normal EndVectorszDb amp ddiend normal End Sub For plugin version 0 6 0007 135 aub cetrEndNormals3DiByVvVal crvad s OntCurve ByVal sri is onSurface ByRet EndVectrors3b s ListiOf OnsdVector 1 Declare start and end normal D im start normal is OnsdVector
129. s List A 0 0 1 0 2 0 3 0 4 0 List B 5 0 6 0 7 0 8 0 9 0 F The Cull Nth component Logic Sets Cull Nth will remove every Nth data entry from the list where N is defined by a numeric integer In this example we have connected a numeric slider to the Cull Nth N input We have set our slider to 2 0 such that the Cull Nth component will remove every other entry from the list The Cull Nth L output reveals a new culled list where every odd entry has been deleted 0 0 2 0 4 0 6 0 and 8 0 If we change the numeric slider to 3 0 the Cull Nth component will remove every third number from the list so that the output would be 0 0 1 0 3 0 4 0 6 0 7 0 and 9 0 G The Cull Pattern component Logic Sets Cull Pattern is similar to the Cull Nth component in that it removes items from a list based on a defined value However in this case it uses a set of boolean values that form a pattern instead of numeric values If the boolean value is set to True the data entry will remain in the list whereas a false value will remove the data entry from the set In this example we have set the boolean pattern to True True False False Since there are only 4 boolean values and our list has 10 entries the pattern will be repeated until it reaches the end of the list With this pattern the output list will look like 0 0 1 0 4 0 5 0 8 0 and 9 0 The Cull Pattern component kept the first two entries 0 0 and 1 0 and then removed the next tw
130. s cones planes and cylinders Rhino supports three kinds of freeform surface types the most useful of which is the NURBS surface Similar to curves all possible surface shapes can be represented by a NURBS surface and this is the default fall back in Rhino It is also by far the most useful surface definition and the one we will be focusing on Sphere primitive Cylinder primitive Plane primitive Cone primitive Plane Radius fPlane Radius Height Plane Width Height Plane Radius Height NURBS surfaces are very similar to NURBS curves The same algorithms are used to Norma calculate shape normals tangents curvatures and other properties but there are some Q distinct differences For example curves have CI tangent vectors and normal planes whereas surfaces have normal vectors and tangent planes This means that curves lack orientation while surfaces lack direction This is of course true for all curve and surface types and it is something you ll have to learn to live with Often when writing code that involves curves or surfaces you ll have to make assumptions about direction and orientation and these assumptions will sometimes be wrong Ng o In the case of NURBS surfaces there are in fact two directions implied by the geometry because NURBS surfaces are rectangular grids of u and v curves And even though these directions are often arbitrary we end up using them anyway because
131. s nor define a set of sources Output parameters are fully under the control of the component that owns them Persistent data is accessed through the menu and depending on the kind of parameter has a different manager Vector parameters for example allow you to set both single and multiple vectors through the menu But let s back up a few steps and see how a default Vector parameter behaves Once you drag drop it from the Params Panel onto the canvas you will see the following The parameter is orange indicating it generated a warning It s nothing serious the warning is simply there to inform you that the parameter is empty it contains no persistent records and it failed to collect volatile data and thus has no effect on the outcome of a history solution The context menu of the Parameter offers 2 ways of setting persistent data single and multiple Vector parameter rS Runtime warnings pcc ILI LT s Extract parameter Expression Help Ue Source RhinoWiki http en wiki mcneel com default aspx McNeel ExplicitHistoryPersistentDataRecordManagement html For plugin version 0 6 0007 11 Once you click on either of these menu items the Grasshopper window will disappear and you will be asked to pick a vector in one of the Rhino viewports Once you have defined all the vectors you want you can press Enter and they will become part of the Parameters Persistent Data Record This means the Parameter is now n
132. s List ot Oncurwvelj Dim nc listi3 s OnNurbscurve For i s Integer O To 3 nc list i New OnNurbscurve i Next Get nurb form of each curve For i s Integer O To 3 Curvesiij GetHurbForminc listi il Hext Create the edgesurface Dim Brep 45 Onbrep RhHtil REhinoCreateEdgesrtinc list ho Brep End Sub 154 For plugin version 0 6 0007 KA Help Where to find more information about Rhino DotNET SDK There is a lot of information and samples in McNeel Wiki Developers actively add new material and examples to it all the time This is great resource and you can find it here http en wiki mcneel com default aspx McNeel Rhino4DotNetPluglns html Forums and discussion groups Rhino community is very active and supportive Grasshopper discussion forum is a great place to start http grasshopper rhino3d com You can also post questions to the Rhino Developer Newsgroup You can access the developer newsgroup from McNeel s developer s page http www rhino3d com developer htm Debugging with Visual Studio For more complex code that is hard to debug from within Grasshopper script component you can use Visual Studio Express that Microsoft provides for free or the full version of developer studio Details of where to get the express visual studio and how to use it are found here http en wiki mcneel com default aspx McNeel DotNetExpressEditions If you have access to the full version of Visual Studio
133. s Special Post it Panel Drag and drop a Post it Panel onto the canvas Connect the Weave W output to the Post it Panel so that we can look at the data The Post it Panel should now show a list of data that has been weaved together according to our Integer collection The first item in the list should be the first item from list 0 Accordingly the second item in the list will be the first item of list 1 And so on so forth until it reaches the end of the list Try changing the order of the Integer collection to change the order of your weaved list For plugin version 0 6 0007 45 8 3 Shifting Data We discussed in section 8 1 how we can use the Shift component to move all values in a list up or down depending on a shift offset value Below is an example created by David Rutten to demonstrate how we can use the shift component on two sets of point lists of a circle You can find more information on this example here http en wiki mcneel com default aspx McNeel ExplicitHistoryShiftExample html Note To see the finished definition of the following example Open the file Shift Circle ghx found in the Source Files folder that accompanies this document Below is a look at the finished definition needed to generate the shifted circle example Perspective 46 For plugin version 0 6 0007 To create the definition from scratch Curve Primitive Circle CNR Drag and drop a Circle CNR Center Normal and Radius onto the canvas Right clic
134. scriptive but by default all names are extremely short to minimize screen real estate usage The second item in the menu Preview flag indicates whether or not the geometry produced defined by this object will be visible in the Rhino viewports Switching off preview for components that do not contain vital information will speed up both the Rhino viewport framerate and the time taken for a History Solution in case meshing is involved If the preview for a parameter or a component is disabled it will be drawn with a faint white hatch Not all parameters components can be drawn in viewports numbers for example and in these cases the Preview item is usually missing The context menu for the R input parameter contains the orange warning icon which in turn contains a list just 1 warning in this case of all the warnings that were generated by this parameter 10 For plugin version 0 6 0007 EB Persistent Data Management Types of Data Parameters are only used to store information but most parameters can store two different kinds Volatile and Persistent data Volatile data is inherited from one or more source parameters and is destroyed i e recollected whenever a new solution starts Persistent data is data which has been specifically set by the user Whenever a parameter is hooked up to a source object the persistent data is ignored but not destroyed The exception here are output parameters which can neither store permanent record
135. st we must assign the points in the Rhino scene to the Point component within Grasshopper To do this right click on the point component and select Set Multiple Points When prompted select each of the 6 points making sure to select the points in the correct order from left to right As you are selecting the points an implied connection line will be drawn on the screen in Blue to indicate your selections When you ve selected all 6 points hit enter to return to Grasshopper All 6 points should now have a small Red X on top of them indicating that this particular point has been assigned to the Grasshopper Point component NURBS Curves Curve Spline Curve Non Uniform Rational Basic Splines or NURBS curves are one of many curve definition types that are available in Rhino In addition to the control points that help define the curves location these are the 6 points we just selected in Rhino NURBS curves also have specific properties like degree knot vectors and weights Entire books or at least very lengthy papers have been written about the mathematics behind NURBS curves and will not cover that here However if you would like a little more information about this topic please visit http en wikipedia org wiki NURBS The NURBS Curve V input defines the curve control points and these can be described implicitly by selecting points from within the Rhino scene or by inheriting volatile data from other com
136. such as parametric modeling digital fabrication and scripting Among other things the event will consist of an exhibition and a series of workshops dedicated to parametric software systems am honored to be teaching an Introduction to Grasshopper modeling while Rajaa Issa and Gil Akos will be handling the Advanced Grasshopper modeling and VB Net Scripting workshop We have included a lot of new information in this primer and we hope that it will continue to be a great resource for those wanting to learn more about the plugin However one of the greatest assets this software has going for it is you the user because when more people begin to explore and understand parametric modeling it helps the entire group would encourage each person who reads this primer to join the growing online community and post your questions to the forum as there is almost always someone willing to share a solution to your problem To learn more visit http www grashopper rhino3d com Thanks and good luck Andrew Payne LIFT architects www liftarchitects com Rajaa Issa Robert McNeel and Associates http www rhino3d com Table of Contents Introduction Table of Contents oO01 amp cGocN N 11 2 11 3 11 4 12 13 13 1 13 2 13 3 13 4 13 5 Getting Started The Interface Grasshopper Objects Persistent Data Management Volatile Data Inheritance Data Stream Matching Scalar Component Types Operators Conditional Statements Range
137. t Lat End Sub 14 12 Processing Trees in Grasshopper Trees or multi dimensional data can be processed one element at a time or one branch path at a time or all paths at ones For example if we divide three of curves into ten segments each then we get a structure of three braches or paths each with a eleven points If we use this as an input then we get the following A If both Flatten and List are checked then the component is called once and flat list of all points is passed Paths Mo Runtime messages Disconnect All Disconnect Flatten List Type hint Help 114 For plugin version 0 6 0007 B If List only is checked then the component is called three times in each time a list of divide points of one curve is passed Paths Mo Runtime messages Disconnect All Disconnect Flatten List Type hint Help C When nothing is checked then the function is called once for each divide points the function is called 33 in this case The same thing happens if only Flatten is checked Paths Mo Runtime messages Disconnect All Disconnect Flatten List Type hint Help This is the code inside the VB component Basically just print the word inside to indicate that the component was called oub RunScriptiByVal Paths s Object Print inside End Sub For plugin version 0 6 0007 115 14 13 File I O There are many wa
138. t A and compares it to the first item of List B If the two values are the same then a True boolean value is created conversely if the two values are not equal then a False boolean value is created The component cycles through the lists according to the set data matching algorithm default is set to Longest List There are two outputs for this component The first returns a list of boolean values that shows which of the values in the list were equal to one another The second output returns a list that shows which values were not equal to one another or a list that is inverted from the first output B Similarity component evaluates two lists of data and tests for similarity between two numbers It is almost identical to the way the Equality component compares the two lists with one exception in that it has a percentage input that defines the ratio of list A that list B is allowed to deviate before inequality is assumed The Similarity component For plugin version 0 6 0007 23 also has an output that determines the absolute value distance between the two input lists C Larger Than component will take two lists of data and determine if the first item of List A is greater than the first item of List B The two outputs allows you determine if you would like to evaluate the two lists according to a greater than gt or greater than and equal to gt condition D Smaller Than component performs the opposite action of the Larger Than
139. t F 1 Drag and drop a single variable Function component onto the canvas Right click the F input of the Function component and open the Expression Editor In the Expression Editor dialogue box type the following equation o X sin 5 x If you have entered the algorithm into the editor correctly you should see a statement that says No syntax errors detected in expression under the errors rollout o Click OK to accept the algorithm Expression Designer Ww p Structurals X Ry Rz Po Px Py Pz 9 lal xyz Constants Aihame x a Comparison 2 2 iol Ier zm mun ut uh kh ni uox s dus nm Iu m oS N Ary symbols E E x of bead poor EE 3 zx x x x dE x Display function list Expression x sin 5 x x As Double Variables Eo Mo syntax emors detected in expression Preview Select the Function component and hit Ctrl C copy and Ctrl V paste to create a duplicate of this Function Right click the F input of the duplicated Function component and open the Expression Editor In the Expression Editor dialogue box type the following equation o X cos 5 x Note the only difference in this equation is that we have replaced the sine function with the cosine function o Click OK to accept the algorithm Connect the Range R output to the x input to both Function components We have now fed the 101 numbers created by the Range component into the Function component which solves a mathematical algorithm and outputs
140. t Length L output to the Split List i input e Scalar Interval Interval 2d Drag and drop a two dimensional Interval component onto the canvas e Connect the Split List A output to the UO input of the two dimensional Interval component e Connect the Split List B output to the U1 input of the two dimensional Interval component e Connect the VO and V1 outputs of the decomposed interval to the VO and V1 inputs respectively of the two dimensional Interval component Since we connect two lists into the input of the Graph Mapper we needed to split the list in two so that we could feed the correct list data back into the two dimensional interval We ve connect all of the U values into the Graph Mapper so our U subdivision will be controlled by the bezier curve Since we ve connect the VO and V1 directly from the decomposed interval to the two dimensional interval no change will happen in that direction However you could follow the same steps and connect another Graph For plugin version 0 6 0007 Mapper component to the VO and V1 lists and control the V subdivisions in the same manner Now all we need to do is to connect our newly created interval collection to the Isotrim component Connect the two dimensional Interval I output to the Isotrim D input Since the end portion of the definition is the same our graph type will now control the spacing of our subdivisions subsequently driving the diagrid You can adjust the bezier curve t
141. t convert a single dimension array to 2 dimension array we call Grid Second process the grid to find cells mid points In both parts we used nested loops Here is the script definition in Grasshopper 106 For plugin version 0 6 0007 aub Runacript ByVal Pts s List Of OnadPoint Byval Go As Integer Creare a grid or points Dim Grid 435 New ArrayList i Dim i s Integer Dim j s Integer Wested loop to covert 1D array to zDb grid For i To Ptz cCounti i 1 Step Gs Declare a row of points Dim Row s Mew List Of OnsdPoint For j i Ta i GS 1 Gert a reference od the point Dim pt z OnsdPoint pt Ptsi j L1 idd point to the row Row 4dd pt Wext idd row to the grid Grid Add Rot Next Process the grid to find mid points of cells Dim mid points s New List Of OnsdPoint L1 For i 1 To Grid Count 1 Get first and second rows Dim Row s Listi Of OnsdPoint RowO Gridfi 1 Dim Rowi s Listi Of OnsdPoint Rowi Gridi i For j 1 To RowO Countti 1 L Dim mid pt s New On3dPoint mid pt RowO j 1 RowD0 j Rowl j 1 Rouwl j 4 mid points Add mid pt Next Hext Assign mid point to output HP mid points End Sub 14 9 Subs and Functions RunScript is the main function that all script components use This is what you see when you open a default script component in Grasshopper Sub RunScript ByVal x As Object ByVal y As Object your c
142. ta but the logic remains the same Source RhinoWiki http en wiki mcneel com default aspx McNeel ExplicitHistoryDataStreamMatchingAlgorithms html 18 For plugin version 0 6 0007 Imagine we have a point component which inherits its x y and z values from remote parameters which contain the following data X coordinate 0 0 1 0 Y coordinate 0 0 1 0 Z coordinate 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 03 0 3 0 4 03 If we combine this data in the Shortest List fashion we get only two points since the Z coordinate contains only two values Since this is the shortest list it defines the extent of the solution Rhino Viewport Perspective e The Longest List algorithm will create ten points recycling the highest possible values of the Y and Z streams For plugin version 0 6 0007 19 Rhino Viewport Perspective Cross Reference will connect all values in X with all values in Y and Z thus resulting in 10x5x2 a hundred points Rhino Viewport XJ Perspective Every component can be set to obey one of these rules the setting is available in the menu by right clicking the component icon Note the one big exception to this behavior Some components EXPECT to get a list of data in one or more of their input fields The polyline component for example creates a polyline curve through an array of input points More points in the input parameter will result in a longer polyline not in
143. ted correctly your definition should look like the screenshot above You may notice that I ve deleted one of the Falloff sliders and am controlling both of the Minimum components with a single slider Try playing around with the Pt Influence and Falloff sliders to adjust how your circles scale according to the distance information Note To see a video tutorial of this example please visit David Fano s blog at http designreform net 2008 07 08 grasshopper patterning with 2 attractor points 60 For plugin version 0 6 0007 9 3 Using Vector Scalar Mathematics with Point Attractors Scaling Boxes We ve already shown how we can use vector and scalar mathematics to determine a circles radius based on distances away from other point objects but we can also use the same core components to scale objects and determine object coloring with Grasshopper s shader components The following example definition has been used to generate the screen shot below but let s start from the beginning and work through the definition step by step Note To see the finished definition of this example Open the file Color Boxes ghx found in the Source Files folder that accompanies this document EIKAI ry HH 959 e S 907 Em us cgi B S t i Pa o9 29 il 9 9 OT gS gt gi T 61 For plugin version 0 6 0007 Step 1 Begin by creating a three dimensional point grid 62 Params Special Numeri
144. teger 4 Dim nc s New OnNurbscurve Create closed Periodic Murba Curve ne CreatePeriodicUnitformiurhs dimension order CPoints To rravy l hssign curve to the output value A Ifi nc IsValid Then A nc End If End Sub Clamped vs periodic NURBS curves Clamped curves are usually open curves where curve ends coincide with end control points Periodic curves are smooth closed curves The best way to understand the differences between the two is through comparing control points The following component creates clamped NURBS curve and outputs For plugin version 0 6 0007 127 Note that the periodic curve turned the four input points into seven control points 4 degree and while the clamped curve used four control points only The knot vector of the periodic curve used only simple knots while the clamped curve start and end knots have full multiplicity Here are same examples but with degree 2 curves As you may have guessed number of control points and knots of periodic curves change when degree changes This is the code used to navigate through CV points and knots in the previous examples Output control points Dim count s Double ne cY Count ii Dim i s Integer Dim cvs s New Listi Of On3dPoint For i O To count 1 Dim cw As New OnsdPointiO 0 0 nc GcGetoVvii cv evs 4dd ew Next Output knots Dim knots s New Listi Of Double count nc Enotcount l For i U To co
145. the brep center The example uses bounding box center For plugin version 0 6 0007 143 oub RunsSceripti ByvVal brep s OnBrep ByVal dis s Double Dim faces s New List of OnbBrepn Loop through brep faces to extract them For fi s Integer O To brep m F Counti i 1 Decalre new brep Dim face Lsa New Onbrep face brep DuplicateFace fi False dd to faces array faces Rhddiface Next Find brep bounding box center Dim center As New OnsdPoint center prep Bounding Boxi Center i Loop through faces and mowe away from center by dis Dim dir 4s New OnsdVector For i s Integer D To faces Count 1 Dim face s OnBrep face facesii Find ceneter of each extracted face Dim face center is On3sdPoint face center face BoundingBox i Center i Find translation vector dir face center center dir Unitizeril dir dis Hove face away from center face Translate dir Next hssign output A faces End Sub Other OnBrep member functions OnBrep class has many other functions that are either inherited from a parent class or are specific to OnBrep class All geometry classes including OnBrep have a member function called BoundingBox One of OpenNURBS classes is OnBoundingBox which gives useful geometry bounding information See the following example that finds a brep bounding box its center and diagonal length 144 For plugin version 0 6 0007 El oub BunscriptiByvVal b
146. the output shows a descending list from 9 0 to 0 0 D The Shift component Logic List Shift List will either move the list up or down a number of increments dependent on the value of the shift offset We have connected the Series S output into the Shift L input while also connecting a numeric slider to the For plugin version 0 6 0007 41 Shift S input We have set the numeric slider type to integers so that the shift offset will occur in whole numbers If we set the slider to 1 all values of the list will move down by one entry number Likewise if we change the slider value to 1 all values of the list will move up by one entry number We can also set the wrap value or the Shift W input to either True or False by right clicking the input and choosing Set Boolean In this example we have a shift offset value set to 1 so we have a decision to make on how we would like to treat the first value If we set the wrap value to True the first entry will be moved to the bottom of the list However if we set the wrap value to False the first entry will be shifted up and out of the list essentially removing this value from the data set E The Split List component does just what you think it might do it splits a list into two smaller lists It has a splitting index which is just an integer where it will split the list In this case we have told the Split List component to split it after the 5th entry item thus our output will look like thi
147. thing will happen You cannot inherit from the same source more than once By the same token if you hold down Control the REM cursor will become visible and the targeted source will be removed from the source list If the target isn t referenced nothing will happen For plugin version 0 6 0007 1 ai e No Runtime messages Disconnect All 16 For plugin version 0 6 0007 Grasshopper also has the capability to transfer information wirelessly through the use of a receiver found under the Special subcategory of the Params tab You can make connections to the receiver just as you would with any other component However as soon as you release the left mouse button from the connection the wire automatically disappears This happens because the receivers default setting is set to only shows its dashed connection wires when the receiver is selected You can right click on the receiver and set the wire connections to show only when the receiver is selected or to always or never show the connection wires You can connect the output of the receiver to as many other components as needed ENDE 8S Here the dashed connection wire is shown because the receiver component is selected The number 1 before the input of the receiver component indicates that there is one connection being fed into its input However since the receiver component is not selected the connection wire no longer appears but the information is
148. threshold change in real time It should be noted that the A input requires an input in radians In our example there is an expression in the A input to convert our numeric slider which specifies an angle in degrees into radians D Polyline Curves Curve Spline Polyline A polyline just may be one of the most flexible curve types available in H Rhino This is because a polyline curve can be made up of line segments a polyline segments degree 1 NURBS curves or any combination of the above But let s start with the basics behind the polyline Essentially a polyline is the same as a point array The only difference is that we treat the points of a polyline as a series which enables us to draw a sequential line between them As was previously mentioned a one degree NURBS curve acts for all intents and purposes identically to a polyline Since a polyline is a collection of line segments connecting two or more points the resultant line will always pass through its control points making it similar in some respects to an Interpolated Curve Like the curve types mentioned above the V input of the Polyline component specifies a set of points that 70 For plugin version 0 6 0007 will define the boundaries of each line segment that make up the polyline The C input of the component defines whether or not the polyline is an open or closed curve If the first point location does not coincide with the last point location a line segm
149. to OnBrepFace OnBrepFace is a class derived from OnSurfaceProxy and has variable and member functions of its own Here are the member variables of OnBrepFace OnBrepEdge OnBrepVertex OnBrepTrim and OnBrepLoop classes Dim brep face s Hew OnBrepFace brep face eer m bRev Eg m Face index E m Face material channel E m Face uuid rm om i eh m si For plugin version 0 6 0007 139 Dim brep edge 4s New OnbrepEdge brep edge E m c3i m m edge index gn A mti AA m tolerance E E m vi d Dim brep vertex s New OnBrepVertex brep vertex m ei SA m tolerance p m vertex index iss io e Dim brep trim 45 New OnBrepTrirm brep trim A m bRev3d m m cei J i m ei m m isa i m li m pbox i m pline AA m Falerance ih m Lrim index ih m Lvpe ih mwi 4 Dim brep loop s New OnbrepLoop brep loop rn m f E m loop index ng S m pbax er m Fi rm m type bul The following diagram shows OnBrep member variables and how they reference each other You can use this information to get to any particular part of the brep For example each face knows its loops and each loop has a list of the trims and from a trim you can get to the edge it is hooked to and the 2 end vertices and so on outer loop P face innerloopts timis RN start and end vertices edge 140 For plugin version 0 6 0007 Here is another more detailed diagram of how brep parts are hooked together and
150. tom of the screen or behind other windows Note that if you close the Editor the Grasshopper geometry previews in the viewports will disappear but the files won t actually be closed The next time you run the Grasshopper command the window will come back in the same state with the same files loaded The Canvas Toolbar E The canvas toolbar provides quick access to a number of frequently used features All the tools are available through the menu as well and you can hide the toolbar if you like It can be re enabled from the View menu bb ARO Store current view 10 2556 No named views The canvas toolbar exposes the following tools from left to right 1 Definition properties editor 2 Sketch tool The sketch tool works like most pencil type tools of Photoshop or Window s Paint Default controls of the sketch tools allow changes of line weight line type and color However it can be quite difficult to draw straight lines or pre defined shapes In order to solve this problem draw out any sketch line onto the canvas Right click on the line and select Load from Rhino and select any pre defined shape in your Rhino scene This can be any 2d shape like a rectangle circle star etc Once you have selected your referenced shape hit Enter and your previously drawn sketch line will be reconfigured to your Rhino reference shape 3 Zoom defaults 4 Navigation Map pops open a smaller diagrammatic
151. ton This button hides the canvas toolbar you can switch it back on through the View menu F The Canvas This is the actual editor where you define and edit the history network The Canvas hosts both the objects that make up the definition and some UI widgets G Objects on the canvas are usually color coded to provide feedback about their state A Parameter A parameter which contains warnings is displayed as an orange box Most parameters are orange when you drop them onto the canvas since the lack of data is considered to be a warning B Parameter A parameter which contains neither warnings nor errors C Component A component is always a more involved object since it contains input and output parameters This particular component has at least 1 warning associated with it You can find warning and errors through the context menu of objects D Component A component which contains neither warnings nor errors E Component A component which contains at least 1 error The error can come either from the component itself or from one of its input output parameters We will learn more about Component Structures in the following chapters All selected objects are drawn with a green overlay not shown For plugin version 0 6 0007 5 G UI Widgets Currently the only UI widget available is the Compass shown in the bottom right corner of the Canvas The Compass widget gives a graphic navigation device to show where your current viewpo
152. ts can be imported into Excel Each line in the CSV file corresponds to a row in the table Within a line fields are separated by commas each field belonging to one table column Our example only has one value per line so we will not utilize the mutli column aspect available with this file format but it is possible to create complex spreadsheets by exporting the data correctly Edit Notes Entry numbers Stream contents Stream filepath A Script A Monospace A Serif A Sans Serif A Sans Serif humanist Custom Font Disconnect All Disconnect F Help We can now import the data into Microsoft Excel 2007 First launch the application and select the Data tab Select the Get External Data from Text under this tab and find the otream Contents csv file you saved on your hard drive You will now be guided through the Text Import Wizard where you will be asked a few questions on how you would like to import the data Make sure that the Delimited radial button is marked and select Next to proceed to Step 2 For plugin version 0 6 0007 49 Cats STA Sn SE Gm e LU amm The Text Wizard has determined that your data is Delimited If this is correct choose Mext or choose the data type that best describes your data Original data type Choose the file type that best describes your data JE i Characters such as commas or tabs separate each field 0 Fixed width Fields are aligned in columns with spaces between each fie
153. ture of the loop looks like While some condition is True While loop body starts here statements to be executed inside the loop Exit While Optional to exit the loop other statements Continue While optional to skip executing the remaining of the loop statements For plugin version 0 6 0007 105 other statements While loop body ends here Go back to the start of the loop to check if the condition is still true then execute the body If condition not true then exit loop and execute statements following End While End While statements following the While Loop Here is the previous places example re written using while loop Dim places list As New List of String places list Add Paris places list Add NY places list Add Beijing Dim i As Integer Dim place As String Dim count As Integer places list Count i 0 While i lt count i lt count evaluat place places_list i Print place i i 1 End While Laa od beri a deum fev OC FIIO Or Talca es to true or false O 14 8 Nested Loops Nested loops are a loop that encloses another loop in its body For example if we have a grid of points then in order to get to each point in the list we need to use a nested loop The following example shows how to turn a single dimensional array of points into a 2 dimensional grid It then processes the grid to find cells mid points The script has two parts Firs
154. ually have 7 points in each direction Since we ultimately would like to have a three dimensional cube of points we need to create 7 copies in the Z axis to be consistent In order to keep the count uniform we will need to write a simple expression to double the Series Count Right click on the Series C input and scroll down to the Expression Tab In the Expression editor type in the following equation C 2 1 We have now told the component to multiply Series C input by a factor of two and then add 1 Since our original input was set to 3 our new Series Count will be 7 0 Vector Constants Unit Z Drag and drop a Unit Z vector component onto the canvas Connect the Series S output to the Unit Z F input If you hover your mouse over the Unit Z V output you should see that we have defined 7 locally defined values where the Z value of each entry increases by 25 0 or the value of the second numeric slider We will use this vector value to define the distance we would like to space each copy of our point grid X Form Euclidean Move Drag and drop a Move component onto the canvas Connect the Point Grid G output to the Move G input Connect the Unit Z V output to the Move T input For plugin version 0 6 0007 If you look at the Rhino scene you will notice that our points don t necessarily look much like a three dimensional cube of points If anything it looks like a ramp leading up to a plane of rectangular points This is because the default data
155. unt 1 knota iddinc Enot il Next 128 For plugin version 0 6 0007 Weights Weights of control points in a uniform nurbs curve are set to 1 but this number can vary in rational nurbs curves The following example shows how to modify weights of control points interactively in Grasshopper Sub RunScript ByVal CPoints s Listior OnsdPoint ByVal W s Double Dim i s Integer Create nurhs curve Dim dimension s Integer 3 Dim order 4s Integer 4 Dim cy count s Integer CPoints Count Dim nc s New OnNurbscurve nc CreatePeriodicUniformMHurbsi dimension order CPoints To rrayi il nc MakeRationalil Assign weights Dim cv As New Oon3dPoint For i O To cv count 1 nc etC ii cw cy oy W nc SetovVii cw nc setlHeidghr i W Hext AS3ign curve to the output value A If nc IsValid Then A nc End If End Sub For plugin version 0 6 0007 129 Divide NURBS curve Dividing a curve into a number of segments involves the following steps Find curve domain which is the parameter space interval Make alist of parameters that divide the curve into equal segments Find points on the 3d curve The following example shows how to achieve that Note that there is a global function under RhUtil name space that divides a curve by number of segments or arc length that you can use directly as we will illustrate later oub RunScriptiByVal Curve s Oncurve ByVal Num s Integer Dim min 45 D
156. visual indicator of the vector in Rhino however we can use the vector information to inform specific geometric actions like translation rotation and orientation For plugin version 0 6 0007 53 In the example above we start by creating a point at the origin 0 0 0 using the Point XYZ component Vector Point Point XYZ We then connect the Point Pt output to a Move G input component to translate a copy of the point in some vector direction To do this we drag and drop a Unit X Unit Y and Unit Z component onto the canvas Vector Constants These components specify a vector direction in one of the Orthagonal directions of the X Y or Z axes We can specify the magnitude of the vector by connecting a numeric slider to the input of each Unit Vector component By holding down the Shift button while connecting the Unit Vector outputs to the Move T input we are able to connect more than one component Now if you look at the Rhino viewport you will see a point at the Origin point and three new points that have been moved in each of the X Y and Z axes Feel free to change the value of any of the numeric sliders to see the magnitude of each vector change To get a visual indicator of the vector similarly to drawing an arrow we can create a line segment from the Origin point to each of the translated points To do this drag and drop a Line component Curve Primitive Line onto the canvas Connect the Move G output to the Line A input and the Point
157. xample if we set the number of steps for the Range to 10 we will now see 11 values evenly divided between the lower Interval value of 10 0 and the upper Interval value of 20 0 Note There are multiple ways to define an interval and you can see several other methods listed under the Scalar Interval tab We have merely defined a simple Interval component but we will discuss some of the other interval methods in the coming chapters 26 For plugin version 0 6 0007 7 3 Functions amp Booleans Almost every programming language has a method for evaluating conditional statements In most cases the programmer creates a piece of code to ask a simple question of what if What if the 9 11 terrorist attacks had never happened What if gas cost 10 gallon These are important questions that represent a higher level of abstract thought Computer programs also have the ability to analyze what if questions and take actions depending on the answer to the question Let s take a look at a very simple conditional statement that a program might interpret If the object is a curve delete it The piece of code first looks at an object and determines a single boolean value for whether or not it is a curve There is no middle ground The boolean value is True if the object is a curve or False if the object is not a curve The second part of the statement performs an action dependant on the outcome of the conditional statement in this case if the object
158. ys to read from and write to files in VB NET and many tutorials and documents are available in the internet and printed material In general reading a file involves the following Open the file Generally you need a path to point to Read the string whole string or line by line Tokenize the string using some delimiter character s Cast each token to double in this case Store result We will illustrate a simple example that parses points from a text file Using the following text file format we will read each line as a single point and use the first value as x coordinate the second as y and the third as z of the point We will then use these points as curve control points coordinates txt Notepad Sele File Edit Format View Help The VB component accepts as an input a string which is the path of the file to read and output On3dPoints Here is the code inside the script component There are few error trapping code to make sure that the file exits and has content 116 For plugin version 0 6 0007 oub Runseript byVal path 4s String Check if file exists If Not IO File Existsi path Then Prinrt Exit without readincg Return End If Read the file Dim lines s Stringi IO File BRead illLines path Check that file is not empty If lines Is Nothing Then Printi i File has no contenr Return End If Declare list of points Dim pts s New ListiOf OnsdPoint Loop through lines

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for version 0.6.0007 by andrew payne & rajaa issa