Wiley Maya Professional Tips and Techniques
Contents
1. Customization and MEL Scripting MAYA TAKES THE lion s share of high end 3D work in the feature film and visual effects industry You can trace this fact to one particular trait the software is infinitely customizable The customization is not restricted to multimillion dollar productions however You can customize Maya to your own tastes and thereby work faster more intelligently and most important more comfortably The most thorough and powerful method of customization is the application of MEL scripting MEL is the underlying language on which the entire program is built Every single tool and function within Maya has one or more lines of MEL code associated with it This chapter s topics are organized into the following techniques Resetting to Factory Swapping Prefs Files Creating Custom Shelf Icons Building a Simple MEL Window Building an Intermediate MEL Window Creating an Autosave MEL Script Creating Your Own Paint Effects Brushes Creating Notes for Your Fellow Animators Passing Information to Files Industry Tip Creating an Expert Mode MEL Script 2 Chapter 1 Customization and MEL Scripting B Resetting to Factory Swapping Prefs Files There comes a time in every animator s life when it d be nice to return to the past That is it s sometimes necessary to return Maya to either its factory default or to a state that is known to be productive To return the Maya user interface UI and glob2. _ FREEZE NEG YJ SUB D BFCOFF _ BESET NEG 2 DELETE HISTORY Top Maya interface with all UI elements hidden appears in monitor 1 Bottom MDMwindow mel window fills monitor 2 aide Oead il Deady bo J a top Oamony 7_topt korit Demonlend_haads_top1 Danondlerd_heads torr Panavfinice NS B disonaLghi iestionduight2 Ry diosiowalLight3 O Zg ow mj a gapi 20 Chapter 1 Customization and MEL Scripting Imbedded shelf buttons Shelf buttons are freed from shelves and integrated directly into the layout To create a single shelf button with a custom icon that creates a NURBS circle the following line is used shelfButton imagel MDMcircleY bmp width 32 height 32 c CreateNURBSCircle Maya assumes that the custom icon BMP file is in the default icons folder For example the path might be as follows C Program Files Alias Maya8 0 icons Tab layout To maximize the number of buttons and windows six tabs are included Tabs are defined by the tabLayout command string tabs tabLayout innerMarginWidth 3 innerMarginHeight 3 The contents of each tab are preceded by the line similar to the following string child1 columnLayout adjustableColumn true The tabs are finally constructed with the following code tabLayout edit tabLabel child1 Modeling tabLabel child2 Dynamics tabLabel child3 Animation tabLabel child4 Rendering tabLabel child5 Mel Sc
3. readText A Delete History on head B Create blends C Dagpose neck and head bones D Skin head with selected head joints A custom note window With this example the script reads a binary file established by the filename variable You can create your own custom Maya binary files with the fopen command which is dis cussed in the next section 16 Chapter 1 Customization and MEL Scripting Passing Information to Files Maya allows you to write and read custom binary files This is useful when a MEL script needs to call on a list or if the script needs to permanently record events for example a dynamic simulation To write to a file you can use this code fileName internalVar userWorkspaceDir note tmp fileWrite fopen fileName w forint fileWrite Maya Rules fclose fileWrite In this example the written file named note tmp is one line long and contains the text Maya Rules The fprint command undertakes the writing The fclose command frees the written file if fclose is skipped note tmp will remain inaccessible to future fprint commands The intenalVar variable which is a permanent and global establishes the directory to which the file is written userWorkspaceDir represents the current project directory Other inter nalVar flags represent other default locations for example userTmpDir represents the Maya temp directory and userScriptDir represents the user script director
4. 0 prefs Mac OS X Users username Library Preferences Alias maya 8 0 prefs Linux username maya 8 0 prefs The prefs folder contains a series of subfolders and text files that store user settings If you have Maya configured the way you like it it s advisable to copy the entire prefs folder to a safe location Should Maya wind up in a state you don t like you can simply exit the pro gram delete the current prefs folder and return your backup copy to its place Saving and replacing the prefs folder is the perfect way to carry your preferences to machines that you are forced to share such as those in a classroom A description of default subfolders follows icons A folder that is available for user icon storage markingMenus A folder that contains custom marking menus Each marking menu is saved as a separate file for example menu_ChangePanelLayout mel Resetting to Factory Swapping Prefs Files 3 shelves A folder that contains default and custom shelves Each shelf is saved as a file for example shelf_Animation mel This folder is empty until a custom shelf is saved or Maya is exited for the first time The following files are created or updated when Maya is exited or the Save button is clicked in the Preferences window userHotkeys mel Lists user defined hot keys userNamedCommands mel Lists commands that have user defined hot keys assigned to them userRunTimeCommands mel Stores user defined commands You can create
5. command any time any object in Maya is selected or deselected The following list includes other events SelectTypeChanged Triggered when the selection type is changed for example Select Surface Objects to Select Point Components ToolChanged Triggered when a new tool is selected for example switching from the Move tool to the Scale tool timeChanged Triggered when the Timeline moves to a new frame When scriptiJob triggers the command it outputs a job number You can use the job number to kill the triggered scriptJob This is often necessary to avoid multiple iterations of scriptJob running simultaneously In order to capture the job number you can use the following line jobNumber scriptJob event SelectionChanged SaveScene In this example Maya saves the scene file each time there is a selection change To kill the job you can use the following line at a different point in the script scriptjJob kill jobNumber One way to avoid killing the job is to add the runOnce flag to the scriptJob command which allows the job to be triggered only one time Timing with timerX and Killing with scripUob Obviously saving with every selection change is overkill A second important element of an autosave script is thus an ability to track time timerX provides that ability by serving as an internal stopwatch You can note the current time then derive elapsed time with the follow ing lines int sta
6. t affect protected jobs To see what jobs exist and which ones are protected use the listJobs flag The Script Editor lists all jobs with the job number to the left 27 protected event SelectionChanged objectDetailsSmoothness 4167 event SelectionChanged SaveScene If youre feeling adventurous you can kill all the protected script jobs by adding the force flag Caution should be used however since Maya supplies a number of jobs that control the UI You can also protect your own jobs by adding the protected flag B Creating Your Own Paint Effects Brushes Paint Effects is a powerful system that allows you to paint geometry and other specialized strokes With a few simple steps you can create an entire forest a raging fire or a scruffy beard Paint Effects brushes are in reality short MEL scripts that live in the brushes folder in the Maya program directory for example C Program Files Alias Maya8 0 brushes Two basic brush styles exist tube and sprite Tube brushes grow primitive tube geometry into complex shapes Sprite brushes paste bitmaps onto short tube segments To swap out a default sprite brush bitmap for your own 1 Switch to the Rendering menu set choose Paint Effects gt Get Brush and a select a brush that uses sprites such a hands mel in the flesh brush folder Paint a stroke 12 Chapter 1 Customization and MEL Scripting 2 Select the stroke curve and open its Attribute Editor
7. your own commands with runTimeCommand For example you can create a command that displays the internal Maya time in a confirm dialog window by executing the following line in the Script Editor runTimeCommand command confirmDialog message timerX WhatTime From that point forward executing WhatTime in the Script Editor pops up a confirm dia log window with the system time Many of the MEL commands discussed in this book are extremely long and thus must be printed on mul tiple lines In reality the Script Editor is indifferent to line breaks so long as the end of each command is indicated by a semicolon You can open the Script Editor by choosing Window gt General Editors gt Script Editor To execute a command in the Script Editor you must press Ctrl Enter after typing the command userPrefs mel Stores global user preferences including working units performance settings and Timeline options windowPrefs mel Determines the default size and position of non workspace windows Hypergraph options windows and so on pluginPrefs mel Lists all autoloaded plug ins The following files are created or updated when custom UI colors are saved through the Colors window userColors mel paletteColors mel and userRGBColors userColors mel stores user defined colors defined in the Active and Inactive tabs of the Colors window user RGBColors mel stores colors defined in the General tab of the Colors window paletteColors mel defin
8. Graph Editor simply choose a Panels menu option The following MEL code is used to imbed the Outliner panel at the script s start up outlinerPanel setParent In order to arrange the panels the paneLayout command is needed in the script paneLayout configuration right3 right3 signifies that there are three panes in the panel layout with two stacked on the right side The panes are divided by moveable separator lines A total of 16 pane layouts are avail able You can find descriptions of each in the paneLayout Maya help file Industry Tip Creating an Expert Mode MEL Script 19 Puya 73k C wurk yetect mel Fie Edt Medy Cene Daday Windsw Annae Defen Seem Skin Contain Chware HED MAYA DUAL MONITOR WINDOW written by Mike Stohworthy x Fie Modes Editors Interface Modeling Dynamics Arimation Rendering Mel Scaptng Channe Box Display Show Panels i OO aoa GFE curves OUT CURVES INSERT KNOT J SMOOTH ADD POINTS j OPEN CLOSE REVERSE CURVE nunes DUPLICATE PATCHES INTERSECT SURFACES ALIGN SURFACE REVERSE SURFACE f INSERT ISOPARMS REBUILD j PROJECT CURVE TRIM SURFACE j BOUNDARY SCULPT SURFACE Z SURFACES Revove EXTRUDE J LOFT BOUNDARY j PLANAR BEVEL PLUS J x PoLycons SUBDIVIDE SMOOTH PRD f SMOOTH OUT FACES j COMBINE BOOLEAN j HIDE TOGGLE PvoTS DUPLICATE QURVES WIRE __ ADJUST REGULA SURFACES XRAY __CENTER NEG J POLYGONS BFCON
9. al preferences to the factory default choose Window gt Settings Preferences gt Preferences In the Preferences window choose Edit gt Restore Default Settings from the upper left drop down menu This returns all the options in the Preferences window to default and redisplays any UI elements that were previ ously hidden Restore Default Settings will not however restore individual tools to their default settings Every options window that is provided by a tool has an Edit gt Reset Settings option in the upper left drop down menu Unfortunately Reset Settings does not provide a universal way to reset every tool You can force Maya to return to its original installation configuration by exiting the pro gram deleting the prefs folder and restarting the program If Maya discovers that the prefs folder is missing but detects an older installation of the program it displays a message win dow with two buttons Choosing the Create Default Preferences button returns Maya to its installation configuration Choosing the Copy Old Preferences button retrieves a copy of the prefs folder from the The Maya startup preferences window older installation If the prefs folder is missing and no other installation exists Maya automatically supplies a new factory default prefs folder You can find the prefs folder in the following default locations with Maya 8 0 Windows drive Documents and Settings username My Documents maya 8
10. der on the CD To use video mel choose File gt Source Script in the Script Editor This script randomly retrieves phrases from two text files and creates humorous video rental titles B Industry Tip Creating an Expert Mode MEL Script Some animators really enjoy creating custom MEL GUIs so much so that they forgo the standard Maya UI elements in favor of their own custom windows One example comes from Michael Stolworthy an exhibit designer at GES Michael has written MDMwindow mel which is designed to maximize the efficiency of a dual monitor setup The custom MEL window fills one monitor while the Maya interface with hidden UI elements fills the other ey The script is included in the Chapter 1 mel folder on the CD To run the script see the MDMReadMe txt file in the MDMwindow subfolder The script works equally well on a single monitor setup MDMwindow mel is not a short script In fact at 19 pages and 27 000 characters it can not be pasted into the Script Editor but can only be sourced Nevertheless like many MEL scripts many of its components are fairly basic and are simply repeated numerous times In terms of functionality MDMWindow mel carries several unique features a few of which are dis cussed with their matching piece of MEL code Imbedded panels The right half of the MEL window is dedicated to standard Maya panels You can set the panels to workspace views or windows such as the Hypergraph Hypershade and
11. e true label frame name width 250 rowLayout numberOfColumns 3 columnWidth3 100 100 100 text buttons or fields go here setParent setParent The two setParent commands are necessary for the frame to function You can place as many frames as you like in a window so long as each frameLayout command has two match ing setParent commands In addition each frame must have its own layout command in this example rowLayout is used The numberOfColumns flag indicates the number of columns within the frame The columnWidth3 flag indicates the pixel width of each column a pixel width of 100 is set by including 100 100 100 after the flag Although these are optional flags they make the results much cleaner Retrieving Values from Fields lt 3 One of the trickier aspects of MEL scripting is the creation of numeric fields in which users can enter new values newcam mel creates two of these one in the Lens frame and one in the Clip frame The following line creates the Lens field and establishes the size of the camera lens string holdera intField width 45 value 25 minValue 25 maxValue 250 changeCommand int cam_lens intField query value enteredValuea enteredValuea Creating an Autosave MEL Script 9 The intField command creates an integer field The width flag sets the field width in pixels The value flag sets a default value that appears in the field minValue and maxValue flags se
12. ering text SS ae ee eee 3 model the effects of riction and viscosity of the water into the Annotate Node window The text appears and aiz on the object s motion in all the workspace views with an arrow pointing The Notes area for the Make Notor to the objects pivot point Boats tool Creating Notes for Your Fellow Animators 15 An annotation note and its position within the Hypergraph Hierarchy window The annotation node is parented to a locator which in turn is parented to the object In reality the arrow has a desire to point toward the locator The annotation and locator nodes can be unparented and freed from the object or simply deleted if no longer needed You can update the text at any time by opening the annotation node s Attribute Editor tab You can also use MEL scripting to create a note window that a user can launch from a shelf icon For example you can MMB drag the following text from the Script Editor work area to a shelf window title Notes noteWin rowColumnLayout text label Note A Try this text label Note B Then this showWindow noteWin When the new shelf icon is clicked the note window opens If you have the patience you can make the window quite detailed In another variation the text of the confirm dialog win dow is provided by an external file fileRead fopen fileName r string readText fgetline fileRead confirmDialog message
13. es the colors that create the index palettes in the Active and Inactive tabs You can change an existing palette by double clicking on a palette swatch and choosing a new color through the Color Chooser window The colors are written as RGB values with a 0 to 1 range If custom colors are never selected these files are not created You can open the Colors window by choosing Window gt Settings Preferences gt Color Settings 4 Chapter 1 Customization and MEL Scripting If need be you can edit any of the files in the prefs folder with a text editor Perhaps the most useful file to edit by hand is userRunTimeCommands mel in which it s easy to delete cus tom commands that are no longer needed You can force Maya to update the files in the prefs folder by executing the savePrefs com mand in the Script Editor The savePrefs command offers various flags such as uiLayout that allow you to update specific files In addition on each exit Maya forces all tools that are not on a shelf to save their custom settings as optionVars optionVars are specialized variables that survive multiple invocations of Maya That is if you exit Maya and open it later the optionVars with their correct values remain accessible and readable optionVars are written out to the disk Aside from the option Vars created by the Preferences window however optionVars are not accessible outside Maya Nevertheless you can create your own custom optionVars at any ti
14. es within quotes If the escapes are not present Maya becomes confused To see what the 1 node camera command normally looks like in the Script Editor choose Create gt Cameras gt Camera As demonstrated with this example variables are often necessary in MEL scripting Three simple types of variables exist int float and string While int rounds off a number to a whole value float maintains all the decimal places string on the other hand stores words and phrases such as hello there A variable is always signified by the initial sign For more com plex examples of variables and variable use within expressions and MEL scripts see Chapter 3 B Creating an Autosave MEL Script One of the first features that users of Autodesk 3ds Max miss when switching to Maya is the autosave function Although Maya has no autosave feature at this point you can write one with a MEL script This requires a MEL command that can sit in the background and wait for an opportune moment to save the file or to remind the user to save scriptJob does just that 10 Chapter 1 Customization and MEL Scripting scriptJob triggers a command when a particular event occurs If the event does not occur no action is taken The easiest way to apply scriptJob is with the following line scriptjJob event event_name command The event flag offers a long list of events to choose from Perhaps the most useful is SelectionChanged which triggers the
15. he Command line Bottom A MEL error message in the Script Editor In this example a quotation mark is missing before the ending semicolon If Maya has an issue with a specific part of the script it will add a brief explanation to the Script Editor Usually broken MEL scripts are a result of a mistyping a misspelling or a missing semicolon which needs to appear at the end of each command except for those with an opening or closing curly bracket Building an Intermediate MEL Window MEL scripting provides numerous ways to organize the look of a window and to control the ey way in which it operates As an example an intermediate MEL script named newcam mel is included in the Chapter 1 mel folder on the CD newcam mel allows the user to create a 1 2 or 3 node camera with the click of a button To use newcam mel open the Script Editor choose File gt Source Script and browse for the file newcam mel is loaded into memory but will not run instantly You must type newcam in the Script Editor work area and press Ctrl Enter for the window New Cam 15 x to appear To create a new camera type a new value into the Focal Length field press Enter type a new value into the Far Clipping Plane field press Enter and click either the 1 Node 2 Node or 3 Node button Ctrl Entering newcam in the work area is required by newcam mel allows users the proc command The script starts like this to create camera with the click of a bu
16. ll the lines that were MMB dragged regardless of what they were The shelf icon may be as simple as a single MEL line such as performPlayblast true which opens the Play blast options window The icon may be as complex as the 200 lines necessary to create an entire skeleton Once a shelf icon exists you can edit the contained script lines in the Shelf Building a Simple MEL Window 55 Editor To do this highlight the shelf name in the Shelves tab select the icon name in the Shelf Contents tab and make your changes in the Edit Commands tab If you want dagPose reset naxe bindPosel to save your changes press the keypad Enter key To save all ee ge the shelves click the Save All Shelves button this exits the window You can customize the look of a shelf icon by entering The Edit Commands tab of the Shelf Editor window a name into the Icon Name field The name is superim posed over the icon You can also use your own custom icon by clicking the Change Image button Maya is able to use a 32X32 BMP XPM or DIB file XPM is a somewhat haic ASCII i fe M ili j 7 arc aig SC image ormat supported by Maya and Si i ic lien pea n ET Graphics machines DIB Device Independent Bitmap isa amp custom shelf The custom icons Windows variation of the standard BMP format You can are included in the Chapter 1 images folder on the CD x store your icon files in the icons folder found within the program directory or the
17. me and then retrieve the values with the query or q flag as in this example optionVar intValue WorkOrderNumber 57235 optionVar query WorkOrderNumber Last you can force Maya to save tool settings and update corresponding optionVars by executing the saveToolSettings command in the Script Editor B Creating Custom Shelf Icons Many Maya books have touched on the customization of shelves inside Maya Nevertheless they are so amazingly flexible that they are worth an additional look Maya comes from the factory with a set of ready made shelves full of shelf icons also referred to as shelf buttons You can delete any of these by choosing Window gt Settings Preferences gt Shelf Editor selecting the Shelves tab highlighting the shelf that is undesired and clicking the Delete Shelf button To make a new empty shelf click the New Shelf button There are several ways to populate a shelf with shelf icons Pressing Ctrl Alt Shift and selecting a menu item such as a tool adds an icon to whichever shelf is visible at the time Pressing Ctrl Alt Shift and selecting the options box of a tool also adds a shelf icon in this case clicking the icon opens the tool options window instead of applying the tool immedi ately with its prior settings You can also highlight and MMB drag any script lines you find in the Script Editor and drop them onto a shelf A generic mel icon is created When the icon is clicked Maya runs through a
18. ommand is used fprint writes all the information to the disk at one time You can force fprint to write to the disk at any time by inserting the fflush command To read and print the contents of a file one line at a time you can use this code fileRead fopen fileName r string readLine fgetline fileRead while size readLine gt 0 print readLine readLine fgetline fileRead fclose fileRead Reading Text Files GO As an alternative to fopen the popen command allows you to read regular text files by piping a system function For example you can use the following code to read and print each line of a 50 line text file int count 0 int lineNumber 50 pipe popen type note txt r if count lt lineNumber string readLine fgetline pipe string line readLine print line count count 1 pclose pipe 18 Chapter 1 Customization and MEL Scripting With this code the Windows command type prints out the contents of note txt which is found in the same folder as the script The contents are captured by the popen command and made available for fgetline to read 1ineNumber establishes how many lines the text file contains Each line is temporarily stored by the line variable allowing it to be printed with the print command ey As an additional working example a MEL script named video me is included in the Chapter 1 mel fol
19. ons and menus are not limited to tools and such operations as file save and quit You can also launch Maya windows For example HypergraphWindow opens the Hypergraph window and GraphEditor opens the Graph Editor To see the MEL lines associated with windows choose History gt Echo All Commands in the Script Editor Note that MEL scripting is case sensitive Returning to the simple mel script the columnLayout command allows you to add as many buttons as you d like to the layout By default they stack vertically A layout command is mandatory for basic MEL windows You have the choice of rowColumnLayout rowLayout or columnLayout each of which organizes the window according to its name You can add extra menu items by inserting additional menuItem lines If you d like more than one drop down menu add additional menu commands The text command offers a simple way to add a message to a window Whatever message you would like to appear should be inserted between the quotation marks after the label flag Building an Intermediate MEL Window 7 On the first line of the script the window command describes the GUI window On the last line showWindow newWindow launches the described window A variation of the window command is mandatory if a pop up window is desired If you write a new MEL script or adapt an example and the script fails to run a red error message appears on the Command line A Script Editor Top A red MEL error on t
20. prefs folder You can load a previously saved shelf by choosing Load Shelves from the Menu Of Items To Modify The Shelf shortcut arrow to the left of the shelves B Building a Simple MEL Window One of the most satisfying elements of MEL scripting is the creation of custom windows or GUIs If youre relatively new to the world of scripting however the MEL code can be very intimidating With that in mind this section boils down MEL windows into their most basic components The following MEL script makes a simple window with two drop down menu options two buttons and a short text message window title Simple Window menuBar true newWindow menu label Options menuItem label Save File command file f save menultem label Exit Maya command quit columnLayout button label Scale Up command scale r 2 2 2 button label Scale Down command scale r 5 5 5 text label Click me showWindow newWindow 6 Chapter 1 Customization and MEL Scripting This script is saved as simple mel in the Chapter 1 mel folder on the CD To use it open the Script Editor choose File gt Source Script and browse for the file The MEL window pops up immediately You can also paste the text into the work area of the Script Editor highlight it and MMB drag it onto a shelf to create a shelf icon Youre free to use any command within the quotes after each command flag whether it is used for a menu item or a bu
21. re sponds to the Flowers check box in the Growth section A 0 after Flowers signifies that Flowers is unchecked Obviously you would not want to write a tube brush from scratch However it s fairly easy to copy an existing brush and adapt it If you re not sure what each attribute does a detailed list can be found in the brush node Maya help file B Creating Notes for Your Fellow Animators Communication is important to professional animators so there are a number of techniques available for making notes within Maya Every single node that can be loaded in the Attribute Editor has a Notes section Any thing you type into these sections is saved with the Maya scene file On occasion Maye uses these areas to add documentation notes that have 3 This node asi expression expressionl to simulate buoyancy effects Several attributes on this node under Zztra not been included in the regular Maya help files ee ee ee default buoyancy of 0 5 will float the object half in and For example the Make Motor Boats tool adds such pap eg de age gg red gre dng peer longing center at the locator position The bortom of the cbject a note will then sit on top of the water if the buoyancy is near 1 0 like a beachbell N and hover Jose belon the water You can create a 3D note by selecting an object Si teescy ac ane stan zezo For aes morion relative to the water set the Scene Scale on the locator choosing Create gt Annotation and ent
22. ripting tabLabel child6 Channel Box tabs Industry Tip Creating an Expert Mode MEL Script 21 MICHAEL STOLWORTHY After graduating with a degree in Media Arts and Animation Michael served as creative director at Concept Design Productions Inc in Pasadena California Concept Design Productions specializes in the creation of retail store space stage sets trade show exhibits and themed environments for public relations events He has recently joined GES in Las Vegas Nevada as an exhibit designer GES also special izes in trade show and event exhibition and has over two dozen offices in North America and Canada To learn more about Michael s work visit www ges com Of www iaoy com
23. rtTime timerX gt int totalTime timerX startTime startTime If these two lines of code are placed within two different areas or procedures of a script totalTime becomes a value that represents the number of seconds Maya has been running In actuality timerX measures time in 10ths of a second using an int variable however ensures that the value is rounded off to a whole second Creating Your Own Paint Effects Brushes 11 A working autosave script named as mel is included in the Chapter 1 mel folder on the ey CD To use as mel choose File Source Script in the Script Editor By default it will pop ip a save reminder window every 5 minutes EE ici With this script you have the option to save the file with an incremen tal name as 1 mb as 2 mb and so on skip the save and exit the window or kill the autosave job completely You ll find additional customization TE sgt The save notes at the top of the file Keep in mind that this script is meant to demon r mind r strate various MEL concepts and should not be considered a perfect exam window of the ple of MEL coding That is there are numerous ways to make the script as mel script tighter and take up fewer lines The scriptJob command has other uses beyond the creation of an autosave script For instance you can kill all MEL jobs currently running regardless of their number with the following line scriptJob killA11 The ki11A11 flag won
24. t lower and upper field limits The changeCommand flag executes a command when the value in the field is changed and the Enter key is pressed The command appearing between quotes is the declaration of a variable int cam_lens intField query value enteredValuea A variable named cam_lens is created It s defined as an integer a whole number with no decimal places by including the int option The variable is equal to everything within the single back facing quotes In this case intField is used again this time however the query flag forces it to output whatever the user entered into the field Thus if you enter 50 cam_lens becomes 50 The cam_lens variable is used again in each of the button com mands as in this example button label 1 Node command camera focalLength cam_lens farClipPlane far_clip objectMoveCommand cameraMakeNode 1 When the 1 Node button is clicked it creates a camera with the camera command The focal length of the camera is determined by the focalLength flag The focal length value is provided by the cam_lens variable objectMoveCommand is normally provided by Maya in order to keep the new camera selected and is necessary in this situation Note that it is possible to have multiple commands within the button command quotation marks so long as they re separated by semicolons The two backslashes at the end of the line are known as escapes and are necessary when there are quot
25. tab Switch to the Paint Effects tab to the immediate right of the stroke tab The Paint Effects tab is named after the brush type In the Texturing section click the file browse button beside the Image Name attri bute and load your own bitmap IFF TIF and BMP formats work If you d like transpar ency choose an IFF file with an alpha channel For a sprite to work the Map Method attribute must be set to Tube 2D Tube 3D will work but will cause the image to disap pear when the back side of the tube faces the camera Render a test Your bitmap image appears along the painted stroke If you d like to permanently create a custom sprite brush it s fairly easy to adapt an existing MEL file 1 Open the Maya brushes folder Open the flesh subfolder Duplicate the hands mel file Rename the duplicated file custom mel Create a new subfolder and call it custom as in this example C Program Files Alias Maya8 0 brushes custom Move custom mel into the custom folder Open custom mel with a text editor Windows WordPad provides the proper formatting Change the second line to the following bPsetName imageName custom iff custom iff is your custom bitmap Maya assumes that all brush images are in the brushImages folder C Program Files Alias Maya8 0 brushImages Change the last line of the brush script to this rename getDefaultBrush custom Save the file Make sure that the file has the mel extension or the brush
26. tton global proc newcam proc stands for procedure A procedure is a group of MEL statements that can be used multiple times in a script The start of a procedure is defined by an opening curly bracket which appears after the procedure name and double parentheses The end of a procedure is 8 Chapter 1 Customization and MEL Scripting determined by a closing curly bracket In the case of newcam mel the closing curly bracket is on the last line of the script A procedure is not activated until it is called Executing the procedure name in the Script Editor work area is one way to call a procedure This assumes that the procedure is global which is determined by the inclusion of the word global Once a procedure is global you can call it from any part of a script that is not part of the procedure That is you can call global procedures from non procedure parts of the script from other pro cedures or as a command listed by a button or menu item If variables symbolic names that hold values are set up correctly within the script the global option is not necessary and procedures become local For a deeper discussion of global and local variables and when to use them see Chapter 3 Another feature of the newcam mel script is the use of three collapsible frames indicated by the down pointing arrows on the left side of the window To create a collapsible frame code similar to the following is needed frameLayout collapsabl
27. tton If youre wondering what commands are available look no further than the Script Editor Every single transform operation and tool within Maya has a MEL line associated with it For example if you transform a sphere a line similar to this appears move r 16 289322 8 110931 10 206124 If you create a default sphere this line appears sphere p 0 0 O ax 0 1 0 ssw 0 esw 360 r 1 d 3 ut tol 0 01 s 8 nsp 4 ch 1 objectMoveCommand Even though the sphere command has a huge number of option flags a flag has a dash and several letters such as p or ax you do not have to use them all sphere by itself will suffice The same holds true for tools For example the Rebuild Surfaces tool prints out this rebuildSurface ch 1 rpo 1 rt 0 end 1 kr 0 kcp 0 kc 0 su 4 du 3 sv 4 dv 3 tol 0 01 fr 0 dir 2 nurbsSphere With any tool you can pick and choose the flags you need For example rebuildSurface su 12 will rebuild the surface with 12 spans in U direction with all the other settings left at default Rest assured memorizing what each and every flag does is close to impossible Luckily you can look up the flags and their functions by choosing Help gt MEL Command Reference in the Script Editor All Maya commands including all tools are listed with a detailed explanation of all possible flags Keep in mind that flags have a short form and a long form For instance su is the same as spansU Commands used by butt
28. w remains open choose Paint Effects gt Save Brush Preset The Save Brush Preset window opens Select a Label name this will be the brush s filename and an Overlay Label the text that appears on the icon Choose a Save Preset option The To Shelf option saves to the brush to the currently active shelf The To Visor option permanently writes the brush to the disk in the folder determined by the Visor Directory field Click the Save Brush Preset button 14 Chapter 1 Customization and MEL Scripting It s possible to adapt the MEL script of a tube brush although it s a bit more tricky As an example the first line of the willow mel brush found in the trees brush folder looks like this brushPresetSetup bPset time 1 bPset globalScale 0 3186736972 bPset depth 1 bPset modifyDepth 1 This is only a small portion of the first line If printed out in full it would fill an entire page Fortunately you can decipher it Each item in quotes such as depth is an attribute The number after the attribute is the attribute setting Each attribute corresponds with an attribute in the Paint Effects Attribute Editor tab For example depth corresponds to the Depth check box in the Channels section Digging deeper color1G corresponds to the Color G channel of the Colorl attribute in the Shading section The following number 0 6470588446 is the color value written for the 0 to 1 color range As a third example flowers cor
29. will not work Start or restart Maya Choose Window gt General Editors gt Visor Switch to the Paint Effects tab The new custom folder is listed with all the original brush folders Click the custom folder icon The custom mel brush appears with a generic Maya icon Click the icon The Paint Effects brush is activated Click drag the mouse in a workspace view The Paint Effects stroke appears Render a test frame Your custom image is rendered along the stroke path Creating Your Own Paint Effects Brushes 13 The result of a custom Paint Effects sprite brush The brush is included as MayaBrush mel in the ey Chapter 1 mel folder Customizing a Tube Brush zi The main disadvantage of sprite brushes is the two dimensionality of the resulting stroke In addition sprite strokes tend to create poor shadows Tube strokes on the other hand can be quite realistic Tube brushes are easily adapted with the Paint Effects Brush Settings window To adapt an existing tube brush and save it out as a new brush 1 Select a brush by choosing Paint Effects gt Get Brush Paint a stroke Choose Paint Effects gt Template Brush Settings The Paint Effects Brush Settings window opens The window contains all the settings of the brush that was last employed Change as many attributes as is necessary to create a custom variation of the brush Paint addi tional strokes to test your custom settings 2 While the Paint Effects Brush Settings windo
30. y To read and print the line contained within note tmp use the following lines fileName internalVar userWorkspaceDir note tmp fileRead fopen fileName r string readText fgetline fileRead print readText fclose fileRead To write a longer file you can create a script that contains these commands proc appendFile string valueToWrite test n fileWrite fopen note tmp a fprint fileWrite valueToWrite fclose fileWrite In this example fopen fprint and fclose commands are contained within a procedure named appendFile To append the file fopen uses the a option instead of the w option Each time appendFile is called it writes valueToWrite to a binary file named note tmp Since no Passing Information to Files 17 directory path is declared Maya assumes that note tmp resides in the project directory The valueToWrite string is constructed from the variable test which is defined outside the pro cedure and n The n instructs fprint to include an end of line code This forces fprint to create a brand new line the next time the procedure is called If n is not used fprint will continually append to the same line You can also use n when creating the original file like so fprint fileWrite Maya Rules n fprint does not write to the disk each time it s called Instead it writes to a temporary software buffer When the buffer is full or the fclose c
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