maya programming for 3d graphicsgraphics.snu.ac.kr/~wano/data/maya programming for 3d... ·...

Maya ProgrammingMaya Programmingfor 3D Graphicsfor 3D Graphics

made bymade by

Wano ChoiWano Choi([email protected])

([email protected]) Last Update : 2007.08.17Last Update : 2007.08.17

Maya Programming for 3D Graphics 작성자 : 최완호

Before StartBefore Start

This document introduces Maya software and its architecture to

programmers who may be unfamiliar with the Maya API.

The goal of this document is to help programmers understand

the extensible nature of the architecture of Maya.

Before reading this document, you need to be familiar with 3D

computer graphics and C++ object oriented programming.

This document can be distributed without permission.

But, please give me credit or mention my web site somewhere.

(http://graphics.snu.ac.kr/~wano)


We would like toWe would like to

study Maya programmingto develop our own in-house plug-in

to visualize our demonstration

cMuscleQualoth

FXHair

Real Flow Syflex


UnfortunatelyUnfortunately……

There are a few references about Maya programming.

Among them, the first and most important thing is..

Maya Help file ( Help > Maya Help )

Always consult with it!

However, It’s not kind for beginners.


Two Books of RecommendationTwo Books of Recommendation

Maya MEL programming


Two Books of RecommendationTwo Books of Recommendation

Maya API programming


And there are some example codesAnd there are some example codes

C:\Program Files\Alias\Maya7.0\devkit\plug-ins.


IntroductionIntroductiontoto

MayaMaya


Maya in MoviesMaya in Movies

Ice Age, Lord of the Rings, Final Fantasy, Star Wars Episode, The Mummy,

Signs, Artificial Intelligence, Perfect Storm, Monster Inc., Stuart Little,

Spider-Man, Hollow Man, Blade, Harry Potter, Gladiator, Matrix, etc.


What is Maya?What is Maya?One of the greatest and most complex computer program ever made

It is based on OpenGL.First released in 1998

Commercial total solution for 3D animation & visual effectsModelingTexturingAnimationRenderingSpecial Effects (dynamics, particle, etc.)

Maya is everywhere, especially in game / film / animation.

Rumor has it thatImplemented by over 200 PhDs.Too big s.t. no one knows it entirely well.

Maya expert = Artist + Computer Scientist


Maya VersionMaya VersionMaya 1.0 (1998)

Maya 1.5 (1998)Maya 2.0 (1999)

Maya 2.5 (1999)Maya 3.0 (2000)

Maya 3.5 (2001)Maya 4.0 (2001)

Maya 4.5 (2002)Maya 5.0 (2003)

Maya 5.5 (2003)Maya 6.0 (2004)

Maya 6.5 (2005)Maya 7.0 (2005)Maya 8.0 (2006)Maya 8.5 (2007)Maya 2008 (2007)


About VendorAbout Vendor

Alias Research, 1983

Wavefront Technologies, 1984

Alias|Wavefront under SGI, 1995

Alias@, 2003

Integrated into Autodesk, 2006


Main CompetitorsMain Competitors

Softimage | XSI (http://www.softimage.com)

3D Studio max (http://www.discreet.com)

LightWave 3D (http://www.newtek.com)

Cinema 4D (http://www.maxon.net)

ZBrush (http://pixologic.com)

Houdini (http://www.sidefx.com)

etc.


Maya as a 3D Animation PackageMaya as a 3D Animation Package

Maya has many features as default.


Maya ArchitectureMaya Architecture

Maya := MELs + MLLsMLL = DLL(Dynamic Link Library) in Maya

GUI

command (MEL)

node (MLL)


Interfaces between User and MayaInterfaces between User and Maya

GUI (Graphical User Interface)

Menus, dialog boxes, buttons, etc.

Most artists complete their work in Maya by using GUI.

Easy to use, but hard to extend Maya functionalities

Programming interface (Plug-in)

A program plugs into Maya

Additional functionality that isn’t available in Maya


Why Programming Interface?Why Programming Interface?

Maya is very powerful tool, but cannot do everything.

Programming interface is needed.

You can “bend” Maya in your own direction.

Develop your own features using programming interface.

Automate and simplify tasks

Advanced macros and your own GUI

Add new features that are not incorporated

New file formats, object types and behaviors

New dynamics and animation components

Two programming interfaces

MEL script

C++ API


MEL or C++?MEL or C++?

Two possible options for programming Maya

They are not mutually exclusive.They are complementary each other.

There are some features available in one, but not in the other.Creation of a new type of node : API

Creation of a new GUI : MEL

Some problems can be solved only by a combination of the two.

When the C++ programming interface is used, it is typically forspecific functionality that can’t be found in the MEL interface.


MEL ScriptMEL Script

MEL : Maya Embedded Language

Interpreted languageIt can be executed immediately without compile & link.

PowerfulIt provides all Maya’s built-in functionality.You can create new functionality by combining them.

Similar to pseudocodeIt can be easy to read and written quickly.It can result in subtle bugs which may be hard to find.


C++ APIC++ API

API : Application Programmer Interface

Machine language (C++)It is better performance than MEL. (approxi. 10× faster)

C++ librariesEnormous classes, but designed in a consistent manner

Most powerful means of extending MayaIt provides low level access to Maya.


Class Name PrefixesClass Name Prefixes

M

MPx

MIt

MFn

Prefix

Maya class

Proxy object

Iterator class

Function set

Logical Grouping

MObject, MPoint, M3dView

MPxNode

MItDag, MItMeshEdge

MFnMesh, MFnDagNode

Examples


Dependency Graph Node PlugDependency Graph Node Plug--insins

Twelve parent classes for dependency graph node plug-insMPxNode

MPxLocatorNode

MPxIkSolverNode

MPxDeformerNode

MPxFieldNode

MPxEmitterNode

MPxSpringNode

MPxManipContainer

MPxSurfaceShape

MPxObjectSet

MPxTransform

MPxHwShaderNode

You can subclass new nodes from these!


BriefBriefExplorationExploration

intointoMayaMaya


Open Script EditorOpen Script Editor

Window > General Editors > Script Editor


Make a CubeMake a Cube

polyCube; [crtl+enter]


HypergraphHypergraph

Windows > Hypergraph


Check Node TypeCheck Node Type

nodeType pCube1; [crtl+enter]

nodeType pCubeShape1; [crtl+enter]

TransformNode

ShapeNode


Check AttributesCheck Attributes

listAttr pCube1; [crtl+enter]


Check AttributesCheck Attributes

listAttr time1; [crtl+enter]

nodeType time1; [crtl+enter]


Connect AttributesConnect Attributes

connectAttr time1.outTime pCube1.tx; [crtl+enter]



Windows > Hypergraph


ResultResult

Press


AboutAbout

MayaMaya

NodeNode


NodeNode--based Architecturebased Architecture

DAG node

DG node

time1 timeToUnitConversion1 transform

transform

shape

DG nodes

DAG nodesnode

input output


DAG (Directed Acyclic Graph)DAG (Directed Acyclic Graph)

DAG pathThe complete path to a given node in DAG

You can get from the root node to the specific node

by traveling down through the intervening nodes in the tree.

DAG path for rightArmShape: |head|toroso|rightArm|rightArmShape

head

headShape

torso

torsoShape

leftArm

leftArmShape

rightArm

rightArmShape


DAG nodesDAG nodes

DAG nodes form parent-child relationship (hierarchy)Transform node-shape node

DAG nodes are in DG - they are DG nodesSome DAG nodes connect to non-DAG DG nodes

Some DAG nodes may not be connected to any non-DAG nodes.

Maya shows either DAG hierarchy or connected DG nodes,

not both simultaneously.


Shape NodesShape Nodes

All shape nodes must have a parent transform node.Meshes

NURBS curves and surfaces

Springs

Camera

Lights

Particles

Etc.


Transform NodesTransform Nodes

Shape node can’t exist without a transform node.

Shape node holds the data.

Transform node holds translation, rotation, scale, etc.

Transform node transforms from objects space to world space.

nurbsSphere1

nurbsSphereShape1


DG (Dependency Graph)DG (Dependency Graph)

Data flow modelData manipulated by series of operations

Pipeline

Push-pull model

DG(Dependency Graph) - heart of MayaData and operations represented as nodes

Network of nodes to perform task

Add functionality by defining new node


DG Node MechanismDG Node MechanismThe fundamental building blocks of MayaMain purpose is to store data and modify it in some way.

Attributes - properties of a nodeParticular properties of a nodeInput/output of a node

Compute()A function to produce one or more output attributes from one ormore input attributes

When an attribute changes, recomputation propagates through the graph until all affected values have been updated.

input outputcompute()

NodeThe output ofother node

The input ofother node



A window that allows you to see the nodes in their DAG hierarchical form or as the DG nodes

It doesn’t allow you to see them both at the same time.

Default existing nodes in Maya through Hypergraph



The connection lines are color-coded to indicate the type of attribute that is connecting the nodes.

You can change these default colors in the Colors window (Window > Settings/Preferences > Colors).

A dotted line in the scene hierarchy indicates a connection to an underworld node or an instanced object.

blue

cyan

green

magenta

Color

single

double

triple

data

Typetransform.translateX

makeNurbsSphere.radiusfile.repeatUV

cameraShape.cameraAperaturetransform.translate

lambert.colornurbsSurface.create

makeNurbsSphere.outputSurface

Examples

red array particleShape.positionparticleShape.velocity


““time1time1”” nodenode

It is the instance of “time” node.

It is globally exists from when Maya started.

It is a trigger node for animation & simulation.


IntroductionIntroduction

toto

MEL scriptMEL script


Where to type MEL scriptWhere to type MEL script

Command ShellWindow > General Editors > Command Shell …

Script EditorWindow > General Editors > Script Editor …

Command Line


Variable Naming ConventionVariable Naming Convention

All variables in MEL begin with ‘$’.int $a = 1;

double $b = 1.1;

string $c = “1.1”;

Variables can’t contain whitespace (spaces, tabs, …)

Variables can’t have names that start with a number.

Variable names are also case sensitive.

Reserved wordsbreak, case, continue, default, do, else, false, float, for, global, if, in, int, matrix, no, off, on, proc, return, string, switch, true, vector, while, yes, global, source, catch, alias, proc, …etc.

MEL commands


Variable TypesVariable Types

intint $i = 1;

floatfloat $f = 1.1;

stringstring $s = “myName”;

vectorvector $v = << 1.0, 2.0, 3.0 >>;

matrixmatrix $m[3][3] = << 11, 12, 13; 21, 22, 23; 31, 32, 33 >>;

※ There are not “bool” & “double” type in MEL.


Caution!Caution!

Integer division truncationfloat $a = 3 / 2; // result : 1

float $a = 3.0 / 2; // result : 1.5

float $a = (float)3 / 2; // result : 1.5

float $a = 3 / (float)2; // result : 1.5

Precision rangeint $a = 2147483647 + 1; // result : -2147483648

int $a = -2147483648 – 1; // result : 2147483647

int $a = 2147483648; // result : -2147483648

int $a = 2147483647 + 2; // result : -2147483647

※ It depends on machine.


ArrayArrayint $intArray[2] = { 1, 2 };intArray[0] = 3;intArray[1] = 4;

float $floatArray[3] = { 1.1, 2.1, 3.1 };floatArray[2] = 0.1;

string $stringArray[3] = { “abc”, “def”, “ghi” };print $stringArray[0]; print “\n”print $stringArray[1]; print “\n”print $stringArray[2]; print “\n”

vector $vectorArray[2] = { <<1,2,3>>, <<4,5,6>> };

matrix $m[3][3] = << 11, 12, 13; 21, 22, 23; 31, 32, 33 >>;


ProcedureProcedure

It is same as function of C / C++.

Procedure = function = command

global proc [return value] aaa( [parameters] ) {…

}

Example

global proc string helloValue( int $number, string $name ) {string $result;$result = “Your name : ” + $name + “, your number : ” + $number;return $result;

}


Others are similar to C / C++Others are similar to C / C++Data-type conversions

float $f = (float)4 / (float)3;

Comparison operators<, >, >=, <=, ==, !=

Logical operators&&, ||, !

Conditional statementif( 1 > 2 ) { … } else { … }switch( int i ) { case 1: … }

Loop statementfor( int $i=0; $i<100; i++ ) { … }while( … ) { … }

Comment///* … */


Global & LocalGlobal & Local

Local variablesThey are accessible only within their block.

Global variablesOnce a variable is defined as global,

it is accessible anytime and anywhere throughout Maya.

// Block 1{

int $a = 1;

// Inner Block 2{

int $b = 2;print $a;

}

print $b; // error!}


MEL scriptMEL script

ExamplesExamples


MEL Command ModeMEL Command Mode

Creation modewith no flagA command generates a new object.

Query modewith -query flagA command retrieves the value of the parameter specified.

Edit modewith –edit flagA Command changes a given property of an object.


MEL Command Mode (Example)MEL Command Mode (Example)

Create modesphere –name Sphere01;

Query modesphere –query –radius Sphere01;

Edit modesphere –edit -radius 2 Sphere01;


helphelp


print / tokenizeListprint / tokenizeList

$i=10;print $i;

$f=3.1415926535;print $f;

$s = “Hello Everyone”;print $s;

vector $v = << 1.1, 2.2, 3.3 >>;print $v;

matrix $m[2][3] = << 1, 2, 3; 4, 5, 6; 7, 8, 9 >>;print $m;

string $a = “1 , 3 4, 67”;string $b[];tokenizeList( $a, $b );print $b;


ls / Back Quote(`) / evalls / Back Quote(`) / eval

$objs = `ls -selection`;for( $obj in $objs ) {

print($obj + " ");};

ls –selection;

ls;

ls –type surfaceShape;

ls –showType;

ls -sl;

string $s[] = `sphere`;print $s[0];print $s[1];

string $cmdName = “sphere”;eval( $cmdName + “ –r 5” );eval( $cmdName + “ –r 10” );


pickWalk / listRelativespickWalk / listRelatives

string $Shape = `createNode nurbsSurface`;select $Shape;string $Transform[] = `pickWalk -d up`;

string $Shape = `createNode nurbsSurface`;string $Transform[] = `listRelatives -p $Shape`;

string $Shape = `createNode nurbsSurface`;string $Transform[] = `listRelatives -p $Shape`;

string $Shape = `createNode nurbsSurface`;select $Shape;string $Transform[] = `pickWalk -d up`;string $again[] = `listRelatives –c $Transform[0]`;print $again[0];print “\n”;


More on More on ““lsls”” commandcommand

global proc testMEL() {string $selected[] = `ls -sl -type transform`;for( $obj in $selected ) {

print $obj;}

}


string $meshShape[];$meshShape = `listRelatives -c $obj`;print $meshShape;

}}


string $meshShape[];$meshShape = `listRelatives -c $obj`;string $type = `nodeType $meshShape[0]`;if( $type == "mesh" )

print $meshShape;}

}


listAttr / getAttr / setAttrlistAttr / getAttr / setAttr

polySphere;listAttr pSphere1;getAttr pSphere1.tx;setAttr pSphere1.tx 10;

string $inSurfaceTransform[] = `sphere`;string $inSurfaceShape[] = `listRelatives -c $inSurfaceTransform`;eval( "setAttr " + $inSurfaceTransform[0] + ".tx -5" );eval( "setAttr " + $inSurfaceTransform[0] + ".ty 0" );eval( "setAttr " + $inSurfaceTransform[0] + ".tz -3" );


pluginInfopluginInfo

int $isLoaded = `pluginInfo -q -l “testNode.mll"`;if(!$isLoaded) {

loadPlugin “testNode.mll";}


playbackOptionsplaybackOptions

This command sets/queries certain values associated with playback.playbackOptions -q -ast;

0

playbackOptions -q -min;10

playbackOptions -q -max;90

playbackOptions -q -aet;100

playbackOptions -e -ast 1;playbackOptions -e -min 1;playbackOptions -e -max 1000;playbackOptions -e -aet 1000;


createNode / connectAttrcreateNode / connectAttr

global proc testMEL() {int $isLoaded = `pluginInfo -q -l “testNode.mll"`;if (!$isLoaded) {

loadPlugin "testNode.mll";}

string $selected[] = `ls -sl -type transform`;for( $obj in $selected ) {

string $inMesh[] = `listRelatives -c $obj`;string $outMesh[] = `polySphere`;string $testNode = `createNode testNode`;connectAttr ($inMesh[0] + ".worldMesh") ($testNode + ".inputMesh");connectAttr ($testNode + ".output") ($outMesh[0] + ".tx" );

}};


createNode / connectAttr (poly)createNode / connectAttr (poly)

global proc test() {

// inputstring $inMeshTransform[] = `polySphere`;string $inMeshShape[] = `listRelatives -c $inMeshTransform[0]`;

// outputstring $outMeshTransform = `createNode transform`;string $outMeshShape = `createNode mesh –p $outMeshTransform`;sets -add initialShadingGroup $outMeshShape;

// intermediatestring $testNode = `createNode testNode`;

connectAttr ( $inMeshShape[0] + “.worldMesh”) ( $testNode + “.inputMesh” );connectAttr ( $testNode + “.outputMesh” ) ( $outMeshShape + “.inMesh” );

};


createNode / connectAttr (NURBS)createNode / connectAttr (NURBS)

global proc test() {

// inputstring $inSurfaceTransform[] = `sphere`;string $inSurfaceShape[] = `listRelatives -c $inSurfaceTransform[0]`;

// outputstring $outSurfaceShape = `createNode nurbsSurface`;string $outSurfaceTransform[] = `listRelatives -p $outSurfaceShape`;sets -add initialShadingGroup $outSurfaceShape;

// intermediatestring $testNode = `createNode testNode`;

connectAttr ( $inSurfaceShape[0] + “.worldSpace” ) ( $testNode + “.inSurface” );connectAttr ( $testNode + “.outSurface” ) ( $outSurfaceShape + “.create” );

};


IntroductionIntroduction

toto

ExpressionExpression


ExpressionExpression

Expressions can be used to create complex animations with little or no manual intervention.

Generally, any attribute can be controlled by an expression.Ex.) nurbsSphere1.translateX = frame;


GUIGUI

usingusing

MELMEL


ELFELF

ELF (Extended Layer Framework)


MayaMayaEnvironmentEnvironment

VariableVariablePathPath


Two Environment VariablesTwo Environment Variables

MAYA_PLUG_IN_PATH

MAYA_SCRIPT_PATH


Two Environment VariablesTwo Environment Variables

MAYA_PLUG_IN_PATHIts order is the order of plug-ins in Maya “Plug-in Manager”.

MAYA_SCRIPT_PATHThe .mel files in the folder of this path can be executed in the Maya.


Visual C++Visual C++DevelopmentDevelopmentEnvironmentEnvironment

SettingsSettings


Maya PlugMaya Plug--in Wizardin Wizard

Maya 6.0Wizard will be installed automatically.

Maya 6.5 & 7.0

At this time the Maya install process will not copy the wizard files into the appropriate .NET directories. This process should be done manually.

Alternative way

After installing Maya 6.0 & 6.5, create VC 6.0 project using MayaPluginWizard for Maya 6.0.

And then, change the path of libraries to be linked into ones of Maya 6.5 or 7.0.


How to install Wizard (MS VS.NET)How to install Wizard (MS VS.NET)Please, go to following folder.“C:\Program Files\Alias\Maya7.0\devkit\pluginwizard”

MayaPluginWizard2.0.zipOne folder

Maya PlugIn WizardThree files

MayaPlugInWizard.icoMayaPlugInWizard.vsdirMayaPlugInWizard.vsz

Copy the three files to Visual Studio.NET 2003

“C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\vcprojects”Visual Studio.NET 2005

“C:\Program Files\Microsoft Visual Studio 8\VC\vcprojects”

Copy the folder toVisual Studio.NET 2003

“C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\VCWizards”Visual Studio.NET 2005

“C:\Program Files\Microsoft Visual Studio 8\VC\VCWizards”


How to create ProjectHow to create Project

File > New > ProjectVS.NET 2003

VS.NET 2005


Directories Setting (VS.NET 2003)Directories Setting (VS.NET 2003)

Tools > Options



or set in “project properties”.



Tools > Options



or set in “project properties”.


Libraries to be linkedLibraries to be linked

OpenGL32.lib- Classes for using OpenGL

Foundation.lib- Fundamental classes for MAYA

OpenMaya.lib- Classes for defining nodes and commands

OpenMayaUI.lib- Classes for creating new user interface elements

OpenMayaAnim.lib- Classes for deformers and inverse kinematics

OpenMayaRender.lib- Classes for rendering

OpenMayaFX.lib- Classes for dynamics


Link Libraries (VS.NET 2003)Link Libraries (VS.NET 2003)

Set in “project properties”.

or set in source code. #pragma comment( lib, "Foundation.lib" )#pragma comment( lib, "OpenMaya.lib" )


Link Libraries (VS.NET 2005)Link Libraries (VS.NET 2005)

Set in “project properties”.

or set in source code. #pragma comment( lib, "Foundation.lib" )#pragma comment( lib, "OpenMaya.lib" )


BasicBasicFrameworkFramework

ofofMayaMaya

plugplug--inin


Common Code of Maya plugCommon Code of Maya plug--inin

#pragma comment( lib, "Foundation.lib" )#pragma comment( lib, "OpenMaya.lib" )

#include <maya/MFnPlugin.h>

MStatus initializePlugin( MObject obj ) { MStatus status;MFnPlugin plugin( obj, “FXGear Inc.”, “1.0”, “Any” );

return status;}

MStatus uninitializePlugin( MObject obj ) {MStatus status;MFnPlugin plugin( obj );

return status;}

Create “empty” project & type following code.


initializePlugin(), uninitializePlugin()initializePlugin(), uninitializePlugin()

initializePlugin()

It is called immediately after the plug-in is loaded.

It registers command, node, and so on.

uninitializePlugin()

It is called before the plug-in is unloaded.

It deregisters what were registered in initializePlugin().


Load plugLoad plug--ininWindow > Settings/Preferences > Plug-in ManagerBrowse & select “testPlugIn.mll” file in “Debug” or “Release” folder.

“testPlugIn” is loaded, but it doesn’t do anything because it is empty.※ You must ensure that your plugin is unloaded before linking.


CommandCommandplugplug--inin


Minimal Code for Command PlugMinimal Code for Command Plug--inin

#include <maya/MPxCommand.h>

class testCmd : public MPxCommand {public:

MStatus doIt( const MArgList& args );static void* creator() { return new testCmd; };

};

#include "testCmd.h"

MStatus testCmd::doIt( const MArgList& args ) {MStatus stat;return MS::kSuccess;

}

testCmd.h

testCmd.cpp


Minimal Code for Command PlugMinimal Code for Command Plug--inin

#include <maya/MFnPlugin.h>#include "testCmd.h"

MStatus initializePlugin( MObject obj ) {MStatus stat;MFnPlugin plugin( obj, “FXGear Inc.”, “1.0”, “Any” );

stat = plugin.registerCommand( “testCmd”, testCmd::creator );if( !stat ) {

stat.perror( “Register Command Failure!” );return stat;

}return stat;

}

MStatus uninitializePlugin( MObject obj ) {MStatus stat;MFnPlugin plugin( obj );

stat = plugin.deregisterCommand( “testCmd” );if( !stat ) {

stat.perror( “Deregister Command Failure!” );return stat;

}return stat;

}

pluginMain.cpp


Load plugLoad plug--in & execute it.in & execute it.

Load through “Plug-in Manager”.

Execute it.

Nothing happened, but it is successively executed.


MPxCommandMPxCommand

It provides all the functionalities necessary for maya to use the command as if it were built in.


doIt()doIt()

It does the real work of the command.

It is called when the command is executed


Print outPrint out&&

StringStringin Mayain Maya


MGlobal::displayInfoMGlobal::displayInfo

#include "testCmd.h"#include <maya/MGlobal.h>#include <maya/MString.h>

MStatus testCmd::doIt( const MArgList& args ) {MStatus stat;

char buffer[256];sprintf( buffer, "%s", "Hi~" );MGlobal::displayInfo( buffer );MGlobal::displayInfo( "friends.\n" );MGlobal::displayInfo( MString("Goodbye") + "\n" );MGlobal::displayInfo( "..." );

return MS::kSuccess;}


Methods for Printing OutMethods for Printing Out

printf( “…”);#include <stdio.h>

Print out in “Output Window”

Caution : It will not be printed immediately.

MGlobal::displayInfo( MString( “…” ) );#include <maya/MGlobal.h>

Print out in “Script Editor” & “Command Feedback Line”


Other Printing Out for Error MessageOther Printing Out for Error Message

displayError#include <maya/MGlobal.h>

MGlobal::displayError( “Error!” );

Print out in “Command Feedback” & “Script Editor”

perror#include <maya/MStatus.h> or none

MStatus stat = MS::kFailure;

stat.perror( “Error!” );



MStringMString

#include <maya/MString.h>

String class to be used in Maya

Examples

MString txt( “Position : ” );float pos = 10.f;MGlobal::displayInfo( txt + pos );

unsigned int num = 10;MGlobal::displayInfo( Mstring(“num:”) + num );

MString str( “3.14159” );float pi = str.asFloat();


Other Printing Out for Error MessageOther Printing Out for Error Message

displayError#include <maya/MGlobal.h>

MGlobal::displayError( “Error!” );

Print out in “Command Feedback” & “Script Editor”

perror#include <maya/MStatus.h> or none

MStatus stat = MS::kFailure;

stat.perror( “Error!” );



MObject & Function SetsMObject & Function Sets

MObjectMaya owns the actual data and never gives you direct access to it.

It is the generic class for accessing all Maya internal objects.curve, surface, mesh, node, plug, light, shader, texture, etc.

It is just a handle to an object inside the core.It can be thought of as a pointer to some internal data.

Function setIt is C++ classes which operate on objects.

MFn prefix indicates this.


DependencyDependencyNodeNode

plugplug--inin


DG Node PlugDG Node Plug--ininYou can define your own type of node in Maya.

User-defined nodes are derived from the MPxNode class.

It is the base class for user defined DG node.

When an input changes, the compute() method is called.

User-defined nodes must have both input & output attributes.

If there are neither input or output connection to other nodes,

this node will do nothing.

All input & output attributes must be the type of MObject.All variables for input & output attributes must be type of static.

They must be initialized at the outside of the class.


An Example of Simple DG Node (1/6)An Example of Simple DG Node (1/6)

testNode.h#ifndef _TESTNODE_H_#define _TESTNODE_H_

#include <maya/MPxNode.h>

class testNode : public MPxNode {

public: // member variablesstatic MTypeId typeID; // node IDstatic MString typeName; // node namestatic MObject input; // input attributestatic MObject output; // output attribute

public: // member functionsstatic void* creator() { return new testNode(); };virtual MStatus compute( const MPlug& plug, MDataBlock& data );static MStatus initialize();

};

#endif



testNode.cpp#include "testNode.h"#include <maya/MFnNumericAttribute.h>

// unique dependency node ID & NameMTypeId testNode::typeID( 0x00001 );MString testNode::typeName( "testNode" );

// initialization for 'static' member variables as NULLMObject testNode::input;MObject testNode::output;

MStatus testNode::initialize() {…

}

MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {…

}

Don’t use the existing ID & name in Maya.



MStatus testNode::initialize() {

MStatus stat;

MFnNumericAttribute nAttr;

// 1/3) create & set attributesinput = nAttr.create( "input", "in", MFnNumericData::kDouble, 1.0, &stat );nAttr.setConnectable( true );output = nAttr.create( "output", "out", MFnNumericData::kDouble, 1.0, &stat );nAttr.setConnectable( true );

// 2/3) add attributesaddAttribute( input );addAttribute( output );

// 3/3) set causalityattributeAffects( input, output );

return stat;}

Don’t use the existing long name or short name in Maya.



MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {

MStatus stat;

if( plug == output ) { // which output attribute is requested to be recomputed?

MDataHandle inputHnd = data.inputValue( input, &stat );double inputValue = inputHnd.asDouble();

MDataHandle outputHnd = data.outputValue( output );outputHnd.set( 2*inputValue );

data.setClean( plug ); // inform the DG that the given plug has been updated} else {

return MS::kUnknownParameter; // other attributes to be treated in parent node}

return stat;}



#include "testNode.h"#include <maya/MFnPlugin.h>

MStatus initializePlugin( MObject obj ) { MStatus stat;MFnPlugin plugin( obj, "FXGear Inc.", "1.0", "Any" );// Register testNodestat = plugin.registerNode( testNode::typeName, testNode::typeID,

testNode::creator, testNode::initialize );if( !stat ) { stat.perror( "registerNode" ); return stat; }return stat;

}

MStatus uninitializePlugin( MObject obj) {MStatus stat;MFnPlugin plugin( obj );// Deregister testNodestat = plugin.deregisterNode( testNode::typeID );if( !stat ) { stat.perror( "deregisterNode" ); return stat; }return stat;

}

pluginMain.cpp


DG Node IDDG Node ID

Identifier in the binary file format

32bit value (0x00000000 ~ 0x0007ffff)

It must be unique in your work of Maya.

For any node for permanent purposes, you should get a universally unique ID from Alias|Wavefront Assist.


Member FunctionsMember Functions

creator()It is called every time a new instance of the node is requested by either the createNode MEL command or MFnDependencyNode::create() method.

It allows Maya to instantiate instances of this node.

initialize()It is called by the registration mechanism for DG nodes.

It is used to define the inputs and ouputs of the node.

compute(…)It is called whenever outputs should be newly calculated.

It does the actual work of the node.

It uses the inputs in the node to generate its outputs.


PlugsPlugs

Which output attribute the recompute is being requested for?

if( plug == output1 ) {…}

else if( plug == output2 ) {…}

else if( plug == output3 ) {…}

else return MS::kUnknownParameter;

It lets Maya know that the recomputing is done and it holds thenow correct value.

data.setClean( plug );


Data BlocksData Blocks

It contains all the data for this instance of the node.

For efficiency this data is kept as a single block.

You need to specify which of the attributes you want to retrieve.

The data is retrieved from the data handle thru. as*().It must matches the declared type of the attribute.


Attribute PropertiesAttribute Properties

ReadableProperty

Can be the source of connectionsDescription

trueDefault

Writable Can be the destination of connections trueConnectable Can be connected (superior to ‘readable’ & ‘writable’) trueStorable Is stored to scene files trueKeyable Can be animated falseHidden Is hidden falseUsedAsColor Treat values as colors falseCached Value is cached trueArray Is an array falseIndexMatter Index shouldn’t change trueArrayDataBuilder Uses array data builder to set value falseIndeterminant Determines if it can be used in an evaluation falseDisconnectBehavior Behavior after disconnection kNothingInternal Is internal to the node falseRenderSource Overrides rendering sampling information false


Compound AttributeCompound Attribute

A compound attribute is used to group other attributes.

Children : the grouped attributes

Parent : itself

Representative of compound attribute : boundingBox


DeformerDeformerNodeNode

plugplug--inin


DeformerDeformer

It takes a series of points and moves them to new location.

It cannot create or remove points.

It can modify the location of

Lattice points

Control vertices

Polygonal vertices

It is created by deriving from the MPxDeformerNode class.

The major difference from other node

deform() instead of compute()


DeformerDeformer Node Example (1/3)Node Example (1/3)

#include <maya/MPxDeformerNode.h>

#ifndef __TESTDEFORMER_H_#define __TESTDEFORMER_H_

class testDeformer : public MPxDeformerNode {public:

static void *creator() {return new testDeformer(); };static MStatus initialize() { return MS::kSuccess; };virtual MStatus deform( MDataBlock &block,

MItGeometry &iter,const MMatrix &mat,unsigned int multiIndex );

};

#endif

testDeformer.h


DeformerDeformer Node Example (2/3)Node Example (2/3)

#include <maya/MFnMatrixAttribute.h>#include <maya/MMatrix.h>#include <maya/MItGeometry.h>#include <maya/MDagModifier.h>#include <maya/MPoint.h>#include "testDeformer.h"

MTypeId testDeformer::typeId( 0x00111 );MString testDeformer::typeName( "testDeformer" );

MStatus testDeformer::deform( MDataBlock& block, MItGeometry &iter,const MMatrix &localToWorld, unsigned int geomIndex ) {

MStatus stat;MDataHandle envData = block.inputValue( envelope );float env = envData.asFloat();if( env == 0.0 ) // Deformer has no effect

return MS::kSuccess;MPoint pt;for( iter.reset(); !iter.isDone(); iter.next() ) { // per each point to be deformed

pt = iter.position(); pt = pt * 1.5;iter.setPosition( pt );

}return stat;

}

testDeformer.cpp


DeformerDeformer Node Example (3/3)Node Example (3/3)#include <maya/MFnPlugin.h>#include "testDeformer.h"

#pragma comment( lib, "Foundation.lib" )#pragma comment( lib, "OpenMaya.lib" )#pragma comment( lib, "OpenMayaAnim.lib" )

MStatus initializePlugin( MObject obj ) { MStatus status;MFnPlugin plugin( obj, "FXGear Inc.", “1.0", "Any");

plugin.registerNode( testDeformer::typeName, testDeformer::typeId, testDeformer::creator, testDeformer::initialize, MPxNode::kDeformerNode );

return status;}

MStatus uninitializePlugin( MObject obj ) {MStatus status;MFnPlugin plugin( obj );stat = plugin.deregisterNode( testDeformer::typeId );return status;

}

pluginMain.h


deform()deform()

The major function to implement in a deformer node

1) MDataBlock &blockIt holds the datablock for the deformer node.

It is the same datablock as one passed into compute().

2) MItGeometry &iterAn iterator for traversing all the points int the geometric object.

Control vertices, lattice points, mesh vertices, etc.

3) MMatrix &matLocal to world transformation

When points are given to the deformer, their positions are in the local space.

If you want to deform in world space, transform the points using this matrix.

However, return them to local space by using the inverse of this matrix.

4) unsigned int geomIndexIt is possible for a deformer to deform

multiple geometry nodes

multiple components of a single geometry node.


Changes in HypergraphChanges in Hypergraph

polySphere;



deformer -type testDeformer



“pSphereShape1Org” nodeExact duplication of the input mesh shape

( “pSphereShape1” before the deformer was applied )

“testDeformer1” nodeAn instance of the “testDeformer” deformer node

“pSphereSpahe1” nodeThe final geometry shape node


LocatorLocatorNodeNode

plugplug--inin


LocatorLocator

It provides users with a 3D visual handle.

Manipulation

Control

It won’t appear in the final rendered image.

It is similar to general DG node. (OpenGL drawable DG node.)

It is derived from “MPxNode” class.

Main difference : draw()

compute() is also available

Other additional member functions

draw(), isBounded(), boundingBox(), color(), colorRGB()


draw()draw()

You are free to draw the locator in any way you like.

Almost all OpenGL functions are available for drawing.

1) M3dView &view

Current Maya viewport in which the locator will be drawn.

2) const MDagPath &path

Complete DAG path to this locator node

3) M3dView::DisplayStyle styleDrawing mode definitions

4) M3dView::DisplayStatus statusThe current state of the node in the viewport


isBounded(), boundingBox()isBounded(), boundingBox()

isBounded()It is called when Maya needs to determine if the node knows its own

bounding extents.

If it returns ‘false’, you don’t need to implement boundingBox().

boundingBox()It is called to retrieve the actual extents of the locator shape.

It is highly recommended to implement these function.

Without them, Maya has difficulty determining the exact size of the locator,

so the Frame All and Frame Selection operations will result in incorrect

zooming.


Locator Node Example (1/3)Locator Node Example (1/3)

#include <maya/MPxLocatorNode.h>#include <maya/M3dView.h>#include <maya/MString.h>#include <maya/MTypeId.h>

#ifndef __TESTLOCATOR_H_#define __TESTLOCATOR_H_

class testLocator : public MPxLocatorNode {public:

virtual void draw( M3dView &view, const MDagPath &path,M3dView::DisplayStyle style,M3dView::DisplayStatus status );

virtual bool isBounded() const { return false; };virtual MBoundingBox boundingBox() const;static void *creator() {return new testDeformer(); };static MStatus initialize() { return MS::kSuccess; };

public:static MTypeId typeId;static MString typeName;

};#endif

testLocator.h



#include "testLocator.h"

MTypeId testLocator::typeId( 0x00111 );MString testLocator::typeName( "testLocator" );

void BasicLocator::draw( M3dView & view, const MDagPath & path,M3dView::DisplayStyle style, M3dView::DisplayStatus status ) {

view.beginGL(); glPushAttrib( GL_CURRENT_BIT );

glBegin(GL_LINES);glVertex3f( -0.5f, 0.0f, 0.0f );glVertex3f( 0.5f, 0.0f, 0.0f );

glVertex3f( 0.0f, 0.0f, -0.5f );glVertex3f( 0.0f, 0.0f, 0.5f );

glEnd();

glPopAttrib();view.endGL();

}

testLocator.cpp



#include <maya/MFnPlugin.h>#include "testLocator.h"

#pragma comment( lib, "Foundation.lib" )#pragma comment( lib, "OpenMaya.lib" )#pragma comment( lib, “OpenMayaUI.lib” ) #pragma comment( lib, “opengl32.lib” )

MStatus initializePlugin( MObject obj ) { MStatus status;MFnPlugin plugin( obj, "FXGear Inc.", "7.0", "Any");

plugin.registerNode( testLocator::typeName, testLocator::typeId, testLocator::creator, testLocator::initialize, MPxNode::kLocatorNode );

return status;}

MStatus uninitializePlugin( MObject obj ) {MStatus status;MFnPlugin plugin( obj );plugin.deregisterNode( testDeformer::typeId );return status;

}

pluginMain.h


MayaMayaStandStand--AloneAloneApplicationApplication


StandStand--alone Applicationalone Application

It contains the main routine for the application and makes API calls to access Maya in batch mode.


ExampleExample

#include <maya/MLibrary.h>#include <maya/MIOStream.h>#include <maya/MGlobal.h>

int main(int argc, char **argv) {MStatus status;

status = MLibrary::initialize (true, argv[0], true);if ( !status ) {

status.perror("MLibrary::initialize");return (1);

}// Write the text out in 3 different ways.cout << "Hello World! (cout)\n";MGlobal::displayInfo("Hello world! (script output)" );MGlobal::executeCommand(

"print \"Hello world! (command script output)\\n\"", true );MLibrary::cleanup();

return (0);}


UserUserDefinedDefinedAttributeAttribute


User Defined Attribute (1/4)User Defined Attribute (1/4)

#include <maya/MPxData.h>

class definedType : public MPxData {public:

static const MString typeName;static const MTypeId id;…

public:static void *creator() {return new definedType; };…

};

definedType.h

All user defined connectable attribute of node

that is to be passed between nodes in the dependency graph

must be derived from MPxData.

#include “definedType.h”

const MTypeId definedType::id( 0xF1000 );const MString definedType::typeName( “definedType” );…

definedType.cpp



#include <maya/MPxNode.h>#include <maya/MTypeId.h>#include <maya/MString.h>

class testNode : public MPxNode {public:

static MTypeId id;static MString typeName;MObject input;MObject output;

public:virtual MStatus compute( const MPlug& plug, MDataBlock& data );static void* creator() { return new testNode; };static MStatus initialize();void Modifier( definedType *in, definedType *out );

};

testNode.h



#include “testNode.h”#include <maya/MFnTypedAttribute.h>#include <maya/MFnPluginData.h>

const MTypeId testNode::id( 0xF1100 );const MString testNode::typeName( “testNode” );

MObject testNode::input;MObject testNode::output;

MStatus testNode::initialize() {MFnTypedAttribute tAttr;

input = tAttr.create( "input", "in", definedType::id, MObject::kNullObj );output = tAttr.create( "output", "out", definedType::id, MObject::kNullObj );

addAttribute( input );addAttribute( output );

attributeAffects( input, output );}

testNode.cpp




if( plug == output ) {MDataHandle inputDataHnd = data.inputValue( input );definedType *dType = (defineType*)inputDataHnd.asPluginData();

MDataHandle outputDataHnd = data.outputValue( output );MFnPluginData dataCreator;MObject newDataObject = dataCreator.create( definedType::id );definedType *newData = (definedType*)dataCreator.data();Modifier( dType, newData );outputDataHnd.set( newData );

}}

void testNode::Modifier( definedType *in, definedType *out ) {…

}

testNode.cpp


MayaMayaplugplug--inin

TipsTips


How to execute MEL commandHow to execute MEL command

MGlobal::executeCommand( “sphere –p 0 0 0 –r 1” );

MStringArray Locator;MGlobal::executeCommand( MString( "spaceLocator -p " )

+ p0.x + " " + p0.y + " " + p0.z, Locator );MGlobal::displayInfo( MString( “Locator Name : ” + Locator[0] );


How to retrieve selected meshesHow to retrieve selected meshes

#include <maya/MSelectinList.h>#include <maya/MItSelectinList.h>#include <maya/MDagPath.h>#include <maya/MFnMesh.h>

MSelectionList selection;MGlobal::getActiveSelectionList( selection );MDagPath dagPath;MFnMesh meshFn;

MItSelectionList iter( selection, MFn::kMesh );

for( ; !iter.isDone(); iter.next() ) {iter.getDagPath( dagPath );meshFn.setObject( dagPath );…

}


How to input How to input timetime attributeattribute

class testNode : public MPxNode {…static MObject inTime;…

};

#include <maya/MTime.h>#include <maya/MFnUnitAttribute.h>

MObject testNode::inTime;


MFnUnitAttribute uAttr;inTime = uAttr.create( "inTime", "it", MFnUnitAttribute::kTime );…

}


MDataHandle inTimeHnd = data.inputValue( inTime );MTime time = inTimeHnd.asTime();…

}


How to input How to input boolbool attributeattribute

class testNode : public MPxNode {…static MObject inValue;…

};

#include <maya/MFnNumericAttribute.h>

MObject testNode::inValue;


MFnNumericAttribute nAttr;inValue = nAttr.create( "inVal", "iv", MFnNumericData::kBoolean, true );…

}


MDataHandle inValueHnd = data.inputValue( inValue );bool inVal = inValueHnd.asBool();…

}


How to input How to input intint attributeattribute


};




MFnNumericAttribute nAttr;inValue = nAttr.create( "inVal", "iv", MFnNumericData::kInt, 1 );…

}


MDataHandle inValueHnd = data.inputValue( inValue );int inVal = inValueHnd.asInt();…

}


How to input How to input doubledouble attributeattribute


};




MFnNumericAttribute nAttr;inValue = nAttr.create( "inVal", "iv", MFnNumericData::kDouble, 1.0 );…

}


MDataHandle inValueHnd = data.inputValue( inValue );double inVal = inValueHnd.asDouble();…

}


How to input How to input NURBS curveNURBS curve

class testNode : public MPxNode {…static MObject inCurve;…

};

#include <maya/MFnNurbsCurve.h>#include <maya/MFnTypedAttribute.h>

MObject testNode::inCurve;


MFnTypedAttribut tAttr;inCurve = tAttr.create( "inCurve", "ic", MFnData::kNurbsCurve );…

}


MDataHandle inCurveHnd = data.inputValue( inCurve );MObject inCurveObj = inCurveHnd.asNurbsCurve();MFnNurbsCurve inCurveFn( inCurveObj );…

}


How to input How to input NURBS surfaceNURBS surface

class testNode : public MPxNode {…static MObject inSurface;…

};

#include <maya/MFnNurbsSurface.h>#include <maya/MFnTypedAttribute.h>

MObject testNode::inSurface;


MFnTypedAttribut tAttr;inSurface = tAttr.create( "inSurface", "ic", MFnData::kNurbsSurface );…

}


MDataHandle inSurfaceHnd = data.inputValue( inSurface );MObject inSurfaceObj = inCurveHnd.asNurbsSurface();MFnNurbsSurface inSurfaceFn( inSurfaceObj );…

}


How to input How to input MeshMesh attributeattribute

class testNode : public MPxNode {…static MObject inMesh;…

};

#include <maya/MFnMeshData.h>#include <maya/MFnMesh.h>

MObject testNode::inMesh;


MFnTypedAttribut tAttr;inMesh = tAttr.create( "inMesh", "im", MFnMeshData::kMesh );…

}


MDataHandle inMeshHnd = data.inputValue( inMesh );MObject inMeshObj = inMeshHnd.asMesh();MFnMesh inMeshFn( inMeshObj );…

}

“inMesh” & “im” is reserved keyword

tAttr.create( "inputMesh", "inM", MFnMeshData::kMesh );


How to output How to output MeshMesh

class testNode : public MPxNode {…static MObject outMesh;…

};

#include <maya/MFnMeshData.h>#include <maya/MFnMesh.h>#include <maya/MFnTypedAttribute.h>

MObject testNode::outMesh;

MStatus testNode::initialize() { MFnTypedAttribut tAttr;outMesh = tAttr.create( “outputMesh", “outM", MFnMeshData::kMesh );…

}

MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {…MFnMeshData dataCreator;MObject newData = dataCreator.create();MFnMesh mesh;mesh.create( nVerts, nPolys, vertsArray, … , newData );MDataHandle outMeshHnd = data.outputValue( outMesh );outMeshHnd.set( newData );data.setClean( plug );

}


How to output How to output NURBS surfaceNURBS surface

class testNode : public MPxNode {…static MObject outSurface;…

};

#include <maya/MFnNurbsSurface.h>#include <maya/MFnNurbsSurfaceData.h>#include <maya/MFnTypedAttribute.h>

MObject testNode::outSurface;

MStatus testNode::initialize() { MFnTypedAttribut tAttr;outSurface = tAttr.create( “outSurface", “os", MFnData::kNurbsSurface );…

}

MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {…MFnNurbsSurfaceData dataCreator;MObject newOutSurface = dataCreator.create();MFnNurbsSurface nurbsFS;MObject newNurbs = nurbsFS.create( ctrlVerts, …, newOutSurface );MDataHandle outSurfaceHnd = data.outputValue( outSurface );outMeshHnd.set( newOutSurface );data.setClean( plug );

}


How to copy NURBS surfaceHow to copy NURBS surfaceclass testNode : public MPxNode {

static MObject inSurface;static MObject outSurface;

};

#include <maya/MFnNurbsSurfaceData.h>#include <maya/MFnTypedAttribute.h>

MObject testNode::inSurface;MObject testNode::outSurface

MStatus testNode::initialize() {MFnTypedAttribute tAttr;inSurface = tAttr.create( “inSurface", “is", MFnData::kNurbsSurface );outSurface = tAttr.creat( “outSurface”, “os”, MFnData::kNurbsSurface );addAttribute( inSurface);addAttribute( outSurface );attributeAffects( inSuface, outSurface );

}

MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {if( plug == outSurface ) {

MDataHandle inSurfaceHnd = data.inValue( inSurface );MObject inSurfaceObj = inSurfaceHnd.asNurbsSurface();MFnNurbsSurfaceData surfaceData( inSurfaceObj );MObject outSurfaceObj = surfaceData.object();MDataHandle outSurfaceHnd = data.inValue( outSurface );outSurfaceHnd.set( outSurfaceObj );data.setClean( plug );

}}


How to limit numeric attribute valueHow to limit numeric attribute value


MFnNumericAttribute nAttr;

inValue1 = nAttr.create( "inVal1", "iv1", MFnNumericData::kDouble, 1.0 );

inValue2 = nAttr.create( "inVal2", "iv2", MFnNumericData::kDouble, 1.0 );nAttr.setMin(0.0);nAttr.setMax(10.0);

inValue3 = nAttr.create( "inVal3", "iv3", MFnNumericData::kDouble, 1.0 );nAttr.setMin(0.0);nAttr.setSoftMax(10.0);

inValue4 = nAttr.create( "inVal4", "iv4", MFnNumericData::kDouble, 1.0 );nAttr.setSoftMin(0.0);nAttr.setSoftMax(10.0);…

}


How to limit numeric attribute valueHow to limit numeric attribute value

createNode testNode;Attribute Editor : testNode1


How to input How to input compoundcompound attributeattributeclass testNode : public MPxNode {

…static MObject output;static MObject iboundingBox;static MObject iboundingBoxMin;static MObject iboundingBoxMax;static MObject iboundingBoxSize;…

};

#include <maya/MFnCompoundAttribute.h>#include <maya/MFnNumericAttribute.h>

MObject testNode::input;MObject testNode::iboundingBox;MObject testNode::iboundingBoxMin;MObject testNode::iboundingBoxMax;MObject testNode::iboundingBoxSize;


MFnCompoundAttribute cAttr;MFnNumericAttribute nAttr;

output = nAttr.create( “output”, “out” );

iboundingBox = cAttr.create( “iboundingBox", “ibbox" );iboundingBoxMin = nAttr.create( “iboundingBoxMin”, “ibbmin”, MFnNumericData::k3Double );iboundingBoxMax = nAttr.create( “iboundingBoxMax”, “ibbmax”, MFnNumericData::k3Double );iboundingBoxSize = nAttr.create( “iboundingBoxSize”, “ibbsize”, MFnNumericData::k3Double );

testNode.h

testNode.cpp


How to input How to input compoundcompound attributeattribute

cAttr.addChild( iboundingBoxMin );cAttr.addChild( iboundingBoxMax );cAttr.addChild( iboundingBoxSize );

addAttribute( iboundingBox );addAttribute( output );

attributeAffects( iboundingBoxMin, output );attributeAffects( iboundingBoxMax, output );attributeAffects( iboundingBoxSize, output );…

}

MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {…MDataHandle iboundingBoxMinHnd = data.inputValue( iboundingBoxMin );MVector minPosition = iboundingBoxMinHnd.asDouble3();

MDataHandle iboundingBoxMaxHnd = data.inputValue( iboundingBoxMax );MVector maxPosition = iboundingBoxMaxHnd.asDouble3();

MDataHandle iboundingBoxSizeHnd = data.inputValue( iboundingBoxSize );MVector bBoxSize = iboundingBoxSizeHnd.asDouble3();…

}


How to get node its own self How to get node its own self

MPxNode::thisMObject()It returns the MObject associated with this user defined node.

#include <maya/MFnDependencyNode.h>


…

if( plug == output ) {…MFnDependencyNode dependNodeFn( thisMObject() );…

}

…}


How to get object by nodeHow to get object by node’’s name s name

#include <maya/MGlobal.h>#include <maya/MDagPath.h>#include <maya/MStringArray.h>#include <maya/MSelectionList.h>#include <maya/MFnDependencyNode.h>

MStringArray testNodes;MGlobal::executeCommand( MString( "ls -type testNode" ), testNodes );for( int i=0; i<testNodes.length(); i++ ) {

MSelectionList sel;MGlobal::getSelectionListByName( testNodes[0], sel );MObject testNodeObj;sel.getDependNode( i, testNodeObj );

MFnDependencyNode depFn( testNodeObj );MString nodeName = depFn.name();MGlobal::displayInfo( nodeName );

}


How to input How to input arrayarray attributeattribute

class testNode : public MPxNode {static MObject inValues;

};

#include <maya/MPlug.h>#include <maya/MIntArray.h>#include <maya/MFnNumericAttribute.h>MObject testNode::inValues;

MStatus testNode::initialize() {MFnNumericAttribute nAttr;inValues = nAttr.create( “inValues", "iv", MFnNumericData::kDouble );nAttr.setArray( true );

}

MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {MFnDependencyNode depFn( thisMObject() );MPlug inValuesPlg = depFn.findPlug( inValues );int nElems = inValuesPlg.numElements();MIntArray logicalIndex;inValuesPlg.getExistingArrayAttributeIndices( logicalIndex );for( int i=0; i<logicalIndex.length(); i++) {

double temp;MPlug inValue = inValuesPlg.elementByLogicalIndex( logicalIndex[i] );inValue.getValue( temp );

}}


How to output How to output arrayarray attributeattribute

class testNode : public MPxNode {static MObject outputs;

};

#include <maya/MPlug.h>#include <maya/MIntArray.h>#include <maya/MFnNumericAttribute.h>

MObject testNode::outputs;

MStatus testNode::initialize() {MFnNumericAttribute nAttr;outputs = nAttr.create( “outputs", “outs", MFnNumericData::kDouble );nAttr.setArray( true );

}

MStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {MFnDependencyNode depFn( thisMObject() );MPlug outputsPlg = depFn.findPlug( outputs );int nElems = outputsPlg.numElements();MIntArray logicalIndex;outputsPlg.getExistingArrayAttributeIndices( logicalIndex );for( int i=0; i<logicalIndex.length(); i++) {MPlug output = outputsPlg.elementByLogicalIndex( logicalIndex[i] );

output.getValue( 10.0 );}

}


How to input / output How to input / output arrayarray attributeattributeMStatus testNode::compute( const MPlug& plug, MDataBlock& data ) {

MStatus stat;if( plug == outSurfaces ) {

MArrayDataHandle inSurfacesHnd = data.inputArrayValue( inSurfaces );inSurfacesHnd.jumpToElement( plug.logicalIndex() );

MDataHandle inSurfaceHnd = inSurfacesHnd.inputValue();MObject inSurfaceObj = inSurfaceHnd.asNurbsSurface();MFnNurbsSurface inSurfaceFn( inSurfaceObj );

MObject outSurfaceObj;

GenerateSurface( inSurfaceObj, outSurfaceObj );

MArrayDataHandle outSurfacesHnd = data.outputArrayValue( outSurfaces );outSurfacesHnd.jumpToElement( plug.logicalIndex() );MDataHandle outSurfaceHnd = outSurfacesHnd.inputValue();outSurfaceHnd.set( outSurfaceObj );

data.setClean( plug );} else {

return MS::kUnknownParameter;}return stat;

}


How to input / output How to input / output arrayarray attributeattributeMStatus tetsNode::compute( const MPlug& plug, MDataBlock& data ) {

MStatus stat;if( plug == outSurfaces ) {

MObject thisNodeObj = thisMObject();MFnDependencyNode thisNodeFn( thisNodeObj );

MPlug inSurfacesPlug = thisNodeFn.findPlug( inSurfaces );MIntArray inSurfacesIndex;inSurfacesPlug.getExistingArrayAttributeIndices( inSurfacesIndex );

for( unsigned int i=0; i<inSurfacesPlug.numConnecteElements(); i++ ) {MPlug inSurfacePlug = inSurfacesPlug.elementByLogicalIndex( inSurfacesIndex[i] );MObject inSurfaceObj;inSurfacePlug.getValue( inSurfaceObj );MFnNurbsSurface inSurfaceFn( inSurfaceObj );

MObject outSurfaceObj;

GenerateSurface( inSurfaceObj, outSurfaceObj );

MArrayDataHandle outSurfacesHnd = data.outputArrayValue( outSurfaces );outSurfacesHnd.jumpToElement( plug.logicalIndex() );MDataHandle outSurfaceHnd = outSurfacesHnd.inputValue();outSurfaceHnd.set( outSurfaceObj );

}data.setClean( plug );} else {

return MS::kUnknownParameter;}return stat;

}


How to input How to input matrixmatrix attributeattribute

class testNode : public MPxNode {…static MObject inMatrix;…

};

#include <maya/MFnMatrixAttribute.h>



MFnMatrixAttribute mAttr;inMatrix1 = mAttr.create( "inMatrix", "im", MFnMatrixAttribute::kDouble );…

}


MDataHandle inMatrixHnd = data.inputValue( inMatrix );MMatrix inMat = inMatrixHnd.asMatrix();…

}


Plug Connection Test Plug Connection Test

MFnDependencyNode thisDGNode( MPxNode::thisMObject() );

MPlug inputType1 = thisDGNode.findPlug( inValue1 , &stat );

MPlug inputType2 = thisDGNode.findPlug( inValue2, &stat );

if( inputType1.isConnected( &stat ) ) {...}


Traveling in Dependency Graph Traveling in Dependency Graph

MStatus testCmd::doIt( const MArgList& ) {MStatus stat;MSelectionList selectedList;MGlobal::getActiveSelectionList( selectedList );MItSelectionList iter( selectedList );for(; !iter.isDone(); iter.next() ) {

MObject thisNodeObj; MFnDependencyNode thisNodeFn;MObject prevNodeObj; MFnDependencyNode prevNodeFn;MObject nextNodeObj; MFnDependencyNode nextNodeFn;selectedList.getDepenNode( 0, thisNodeObj );thisNodeFn.setObject( thisNodeObj );MPlug inputPlug = thisNodeFn.findPlug( "input" );MPlugArray plugs;inputPlug.connectedTo( plugs, true, false );prevNodeObj = plug[0].node();prevNodeFn.setObject( prevNodeObj );plugs.clear();MPlug outputPlug = thisNodeFn.findPlug( "output" );outputPlug.connectedTo( plugs, false, true );nextNodeObj = plug[0].node();nexeNodeFn.setObject( nextNodeObj );

}MGlobal::executeCommand( MString( "select -cl" ) );return MS::kSuccess;

}


How to get How to get ““dag pathdag path”” from from ““node namenode name””

MString nodeName( "aaa" );MString nodeName( "bbb" );

MSelectionList sList;sList.add( node1Name );sList.add( node2Name );

MDagPath dagPath1, dagPath2;sList.getDagPath( 0, dagPath1 );sList.getDagPath( 1, dagPath2 );


How to get How to get ““world meshworld mesh””

MDagPath dagPath; // transform node name

dagPath.extendToShape();

MFnMesh meshFn( dagPath );


ReferencesReferencesDavid A. D. Gould. 2003. Complete Maya Programming I. Morgan Kaufmann

David A. D. Gould. 2005. Complete Maya Programming II. Morgan Kaufmann

Alias|Wavefront. 2001. Maya Developer’s Tool Kit. Version 4. Alias|Wavefront

Hiroyuki Haga. 2003. Maya API Quick Start. Alias Entertainment

Alias Systems Corp. 2005. Maya API White Paper. Alias|Wavefront

조상범. 2002. programming with MAYA MEL & Expression. @rtisan(www.3DArtisan.com)

Mark R. Wilkins & Chris Kazmier. MEL Scripting for Maya Animators. Morgan Kaufmann

Shuen-Huei Guan, 2003, Introduction to Maya Programming (ppt), http://graphics.csie.ntu.edu.tw/~drake/data/articles/IntroductionToMayaProgramming.ppt

Min Gyu Choi, Playing with Maya thru MEL/API. KCGS 2005 Tutorial

Rafael Baptista. How to Write a Simple Maya Model Exporter. http://www.gamedev.net/

Bryan Ewert. Maya API How-to. http://www.ewertb.com/maya

http://www.robthebloke.org/

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