【笔记】【Maya工具】Python For Maya（OpenMaya）（一）API基础与插件

Python Programming in maya

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import maya.cmds as cmd
cmds.select(all=True)
cmds.delete()
for step in range(40):
    cmds.polyCube(w=10,d=3,h=0.5)
    cmds.move(3,step*0.5,0)
    cmds.xform(ws = True,rotatePivot=(0,0,0))
    cmds.rotate(0,step*10,0)


1. DAG——描述Maya中的功能节点：

DAG（Directed Acyclic Graph有向无环图）

  • Dag Node:Transform
  • Dag Node:Shape

DG:Dependency Graph依赖图

DAG path，某个对象的DAG path描述从根节点到物体的完整查找路径

MObject（Model Object）

  • maya.OpenMaya.MObject

MSelectionList（选择的模型对象列表）

  • maya.OpenMaya.MSelectionList
    • 创建一个选择列表
    • 在选择列表中添加、移除对象
    • 可遍历
    • etc
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import maya.OpenMaya as OpenMaya
mSelectionList = OpenMaya.MSelectionList()
mSelectionList.add("<something_Name>")

mDagPath = OpenMaya.MDagPath()
mSelectionList.getDagPath(0,mDagPath)#返回0位置的path
print(mDagPath.fullPathName())

mObj = OpenMaya.MObject()
mSelectionList.getDependNode(0,mObj)
print(mObj.apiTypeStr())#kTransform

2. Traversing Hyper Graph in Maya Scene

MFn = Model Function Set

MFnMesh表示接收Mesh类型的函数集

  • create
  • modify
  • retrave
  • add Edge\face,subdivision

MFnDependencyNode：一组函数需要Dependency Node Type的数据，提供函数

  • create（dependency graph）
  • modify（dependency graph）
  • retrave（dependency graph）

可以通过MObj和MDagpath来提供到函数集的接口

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import maya.OpenMaya as OpenMaya
# Create a Selection List
mSel = OpenMaya.MSelectionList()
mSel.add("pPlane1")
# Create MObject
mObj = OpenMaya.MObject()
mDagPath = OpenMaya.MDagPath()
# Request Dependency Node and DagPath of the Obj
mSel.getDependNode(0,mObj)
mSel.getDagPath(0,mDagPath)
# Create Mesh function set
mFnMesh = OpenMaya.MFnMesh(mDagPath)#可以用mObj和mDagpath两种
print(mFnMesh.fullPathName())#|pPlane1|pPlaneShape1
#说明mFnMesh是在ShapeNode下运作的

# Dependency function set
mFnDependNode = OpenMaya.MFnDependencyNode(mObj)#只能用mObj
print(mFnDependNode.name())

MPlug提供操作功能的类（操作Plug Type）

Plug：节点属性的接口

  • create
  • modify
  • access（通过plug访问属性）

  1. Network Plug: Dependency Node Plug

  2. Non-Network Plug: User Defined Plug

MPlugArray

image-20220627211430302 
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# Get all the connections of a Shape node
mPlugArray = OpenMaya.MPlugArray()
mFnMesh.getConnections(mPlugArray)

print(mPlugArray.length())#2
print(mPlugArray[0].name())#pPlaneShape1.instObjGroups[0]
print(mPlugArray[1].name())#pPlaneShape1.inMesh
image-20220627212637049 image-20220627212705325

image-20220627213320170

看看这个就知道是在干嘛了，我们的最终目的是操纵polyPlane1进行细分

通过pPlaneShape1的plug接口，就可以完成

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mPlugArray2 = OpenMaya.MPlugArray()
mPlugArray[1].connectedTo(mPlugArray2,True,False)#后面这两个bool值不太明白

print(mPlugArray2.length())#1
#len()不能用在这个对象上
print(mPlugArray2[0].name())#polyPlane1.output

image-20220627214040508

完整代码

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import maya.OpenMaya as OpenMaya
# Create a Selection List
mSel = OpenMaya.MSelectionList()
mSel.add("pPlane1")
# Create MObject
mObj = OpenMaya.MObject()
mDagPath = OpenMaya.MDagPath()
# Request Dependency Node and DagPath of the Obj
mSel.getDependNode(0,mObj)
mSel.getDagPath(0,mDagPath)
# Create Mesh function set
mFnMesh = OpenMaya.MFnMesh(mDagPath)#可以用mObj和mDagpath两种
print(mFnMesh.fullPathName())#|pPlane1|pPlaneShape1
#说明mFnMesh是在ShapeNode下运作的

# Dependency function set
mFnDependNode = OpenMaya.MFnDependencyNode(mObj)#只能用mObj
print(mFnDependNode.name())

# Get all the connections of a Shape node
mPlugArray = OpenMaya.MPlugArray()
mFnMesh.getConnections(mPlugArray)

print(mPlugArray.length())
print(mPlugArray[0].name())
print(mPlugArray[1].name())

mPlugArray2 = OpenMaya.MPlugArray()
mPlugArray[1].connectedTo(mPlugArray2,True,False)#后面这两个bool值不太明白

print(mPlugArray2.length())#len()不能用在这个对象上
print(mPlugArray2[0].name())

mObj2 = mPlugArray2[0].node()
mFnDependNode2 = OpenMaya.MFnDependencyNode(mObj2)
print(mFnDependNode2.name())

mPlug_width = mFnDependNode2.findPlug("width")
mPlug_height = mFnDependNode2.findPlug("height")
print(mPlug_width.asInt(),mPlug_height.asInt())

mPlug_subWidth = mFnDependNode2.findPlug("subdivisionsWidth")
mPlug_subHeight = mFnDependNode2.findPlug("subdivisionsHeight")

mPlug_subWidth.setInt(20)
mPlug_subHeight.setInt(20)


3. Command Communication Flow

image-20220627220119395
  • Command Plugin
    • 函数
    • 初始化/注册Initialization，Registration
    • Uninitialization/De-registration

把东西注入到Maya core，就是注册

  • 命令插件编写基本流程
    • 定义一个类
    • 创建一个实例
    • 用一个指针指向这个实例
    • Maya获取这个指针

4. Writing command plugin

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import maya.OpenMaya as OpenMaya
import maya.OpenMayaMPx as OpenMayaMPx
import sys

commandName = "pluginCommand"

class pluginCommand(OpenMayaMPx.MPxCommand):
    def __init__(self):
        OpenMayaMPx.MPxCommand.__init__(self)
        
    def doIt(self,argList):
        print("doIt")
#创建实例并添加指针
def cmdCreator():
    return OpenMayaMPx.asMPxPtr(pluginCommand())

#初始化
def initializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.registerCommand(commandName,cmdCreator)#mayaCore handle
    except:
        sys.stderr.write("Failed to register command:" + commandName)
        
def uninitializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.deregisterCommand(commandName)
    except:
        sys.stderr.write("Failed to deregister command" + commandName)

保存脚本后，在maya中加载插件

Mel，python，mayaUI三种方法

window-setting preferences-pluginManager

image-20220627222747095

image-20220627222850467

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cmds.loadPlugin("./pluginCommand.py")

5. Maya API Iterators

Iterator是一个对象，对数据结构进行遍历

  • MItDag
    • Dag上的iterator
    • 深度优先
    • 广度优先
image-20220627230758404
  • MItDependencyGraph
image-20220627230836150
  • MItMeshEdge
image-20220627230927076
  • MItMeshVertex
image-20220627231006974
  • MItMeshPolygon(face)
image-20220627231033010
  • MItSurfaceCV(CVs of Nurbs)
image-20220627231104357 
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import maya.OpenMaya as OpenMaya

dagIterator = OpenMaya.MItDag(OpenMaya.MItDag.kDepthFirst, OpenMaya.MFn.kInvalid)#arg1=树搜索算法,arg2 = Filtering
dagNodeFn = OpenMaya.MFnDagNode()

while (not dagIterator.isDone()):
    currentObj = dagIterator.currentItem()#return dagNode
    depth = dagIterator.depth()
    dagNodeFn.setObject(currentObj)
    
    name = dagNodeFn.name()
    type = currentObj.apiTypeStr()
    path = dagNodeFn.fullPathName()
    
    printOut = ""
    for i in range(0,depth):
        printOut += "----->"
    printOut += name + " : " + type
    print(printOut)
    dagIterator.next()
    
===========
World : kWorld
----->persp : kTransform
----->----->perspShape : kCamera
----->top : kTransform
----->----->topShape : kCamera
----->front : kTransform
----->----->frontShape : kCamera
----->side : kTransform
----->----->sideShape : kCamera
----->pCube1 : kTransform
----->----->pCubeShape1 : kMesh
----->----->pCylinder1 : kTransform
----->----->----->pCylinderShape1 : kMesh
----->----->----->pCone1 : kTransform
----->----->----->----->pConeShape1 : kMesh
----->----->----->----->pPlane1 : kTransform
----->----->----->----->----->pPlaneShape1 : kMesh
----->----->----->----->----->pPipe1 : kTransform
----->----->----->----->----->----->pPipeShape1 : kMesh

放到插件的doIt方法里面

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import maya.OpenMaya as OpenMaya
import maya.OpenMayaMPx as OpenMayaMPx
import sys

commandName = "printHierarchy"

class pluginCommand(OpenMayaMPx.MPxCommand):
    def __init__(self):
        OpenMayaMPx.MPxCommand.__init__(self)
        
    def doIt(self,argList):
        print("Scene Heirarchy")
        dagIterator = OpenMaya.MItDag(OpenMaya.MItDag.kDepthFirst, OpenMaya.MFn.kInvalid)#arg1=树搜索算法,arg2 = Filtering
        dagNodeFn = OpenMaya.MFnDagNode()
        
        while (not dagIterator.isDone()):
            currentObj = dagIterator.currentItem()#return dagNode
            depth = dagIterator.depth()
            dagNodeFn.setObject(currentObj)
            
            name = dagNodeFn.name()
            type = currentObj.apiTypeStr()
            path = dagNodeFn.fullPathName()
            
            printOut = ""
            for i in range(0,depth):
                printOut += "----->"
            printOut += name + " : " + type
            print(printOut)
            dagIterator.next()
#创建实例并添加指针
def cmdCreator():
    return OpenMayaMPx.asMPxPtr(pluginCommand())

#初始化
def initializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.registerCommand(commandName,cmdCreator)
    except:
        sys.stderr.write("Failed to register command:" + commandName)
        
def uninitializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.deregisterCommand(commandName)
    except:
        sys.stderr.write("Failed to deregister command" + commandName)

保存脚本然后

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import maya.cmds as cmds
cmds.loadPlugin("c:\\Users\\XZYW\\Desktop\\printHierarchy.py")
cmds.printHierarchy()

插件就可用了，这就是编写插件的方式。

6. Command with Arguments

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cmds.polySphere("mySphere",q = True,sx = True)

image-20220628205624179

  • MSyntax
    • flags
    • Args
    • Object
  • MArgDatabase
    • 是MArgParser的派生类
    • Parsing
    • Storing
    • Retreving
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import maya.OpenMaya as OpenMaya
import maya.OpenMayaMPx as OpenMayaMPx
import sys
import maya.OpenMayaFX as OpenMayaFX
#使用粒子系统

commandName = "vertexParticle"
kHelpFlag = "-h"
kHelpLongFlag = "-help"
kSparseFlag = "-s"
kSparseLongFlag = "-sparse"
helpMessage = "This command is used to attach a particle on each Vertex of a poly mesh"

class pluginCommand(OpenMayaMPx.MPxCommand):
    sparse = None
    def __init__(self):
        OpenMayaMPx.MPxCommand.__init__(self)
    
    
    def argumentParser(self,argList):
        syntax = self.syntax()#MSyntax Object
        parsedArguments = OpenMaya.MArgDatabase(syntax,argList)
        if parsedArguments.isFlagSet(kSparseFlag):
            self.sparse = parsedArguments.flagArgumentDouble(kSparseFlag,0)
            return
        if parsedArguments.isFlagSet(kSparseLongFlag):
            self.sparse = parsedArguments.flagArgumentDouble(kSparseLongFlag,0)
            return
        if parsedArguments.isFlagSet(kHelpFlag):
            self.setResult(helpMessage)
            return
        if parsedArguments.isFlagSet(kHelpLongFlag):
            self.setResult(helpMessage)
            return# OpenMaya.MStatus.kSuccess这个方法已经被取消了，其实不用返回任何东西
    def isUndoable(self):
        return True
    def undoIt(self):
    	print("Undo")
        mFnDagNode = OpenMaya.MFnDagNode(self.mObj_particle)
        
        mDagMod = OpenMaya.MDagModifier()
        mDagMod.deleteNode(mFnDagNode.parent(0))#粒子系统创建是带有Transform的
        
        mDagMod.doIt()
        return
    
    def redoIt(self):
        mSel = OpenMaya.MSelectionList()
        mDagPath = OpenMaya.MDagPath()
        mFnMesh = OpenMaya.MFnMesh()
        OpenMaya.MGlobal.getActiveSelectionList(mSel)#处理所有主动选择的对象，并添加到提供的选择列表中
        if mSel.length() >=1:
            try:
                mSel.getDagPath(0,mDagPath)
                mFnMesh.setObject(mDagPath)
            except:#如果选中的不是polymesh
                print("Select a poly mesh")
                
                return
        else:#如果没选东西
            print("Select a poly mesh")
            return
        mPointArray = OpenMaya.MPointArray()
        mFnMesh.getPoints(mPointArray, OpenMaya.MSpace.kWorld)#提供所有顶点世界坐标
        
        # create a particle system
        mFnParticle = OpenMayaFX.MFnParticleSystem()
        self.mObj_particle = mFnParticle.create()
        
        # Fix Maya Bug
        mFnParticle = OpenMayaFX.MFnParticleSystem(self.mObj_particle)
        
        counter = 0
        # attach particle to vertex
        for i in range(mPointArray.length()):
            if i%self.sparse == 0:
                mFnParticle.emit(mPointArray[i])
                counter += 1
        print("Total Points:" + str(counter))
        mFnParticle.saveInitialState()#如果应用动力学，确保粒子在原来位置上去应用
        return
    
    def doIt(self,argList):
        print("doIt")
        self.argumentParser(argList)
        if self.sparse != None:
            self.redoIt()
        return
        
#创建实例并添加指针
def cmdCreator():
    return OpenMayaMPx.asMPxPtr(pluginCommand())
#创建命令语法
def syntaxCreator():
    # create MSyntax object
    syntax = OpenMaya.MSyntax()
    # collect/add the flags
    syntax.addFlag(kHelpFlag,kHelpLongFlag)#short name,long name,data type
    syntax.addFlag(kSparseFlag,kSparseLongFlag,OpenMaya.MSyntax.kDouble)
    # return MSyntax
    return syntax


#初始化
def initializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.registerCommand(commandName,cmdCreator,syntaxCreator)#同时注册语法
    except:
        sys.stderr.write("Failed to register command:" + commandName)
        
def uninitializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.deregisterCommand(commandName)
    except:
        sys.stderr.write("Failed to deregister command" + commandName)


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range 是生成一个列表
xrange用法与range完全相同，不同的是生成的不是一个list对象，而是一个生成器
在生成很大的数字序列时候，用xrange会比range性能优很多，因为不需要一上来就开辟一块很大的内存空间
xrange和range都在循环的时候使用。
  • Command Execution
  • Undo
  • Redo

每执行一个Command Execution，都会把对应的命令添加到Undo队列

如果Command Execution使用Undo命令，就会把Undo队列中最后面的移到Redo队列上

如果Command Execution使用Redo命令，就会把Redo队列中最后面的移到Undo队列上

image-20220628211342017

image-20220628213019559

好了，写完了这个脚本，看完这集教程，终于发现，它是过时的版本，作者用的还是maya2013，非常恐怖