【笔记】【maya工具】Python For Maya（OpenMaya）（三）Structure of a Deformer

这个案例最终复现失败了，还是因为教程太老了，版本对不上，有很多api已经有了很大的变化

1. Deformer

是一个DG node

有一个或多个几何节点作为输入

通过某种算法得到结果

  • DG

    • 空结点
    • 添加属性（IO）
    • 设计circuitry
    • 添加计算函数

  • Deformer Node

    • Input（function）
      • input
        • gourpId,inputGeometry
      • weight
      • envelope
    • output
      • outputGeometry
    • Predefined Compute（）
      • deform(args) {}

  • Create Deformer Node

    • Creator()
    • initialize()
    • initializePlugin()
    • uninitializePlugin()
    • class
      • _init_()
      • compute() ==deform()==

2. Writing Deformer / DeformerNode

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import maya.cmds as cmds
cmds.loadPlugin(r'ripple.py')
cmds.deformer(type = "RippleDeformer")

2.1 attributes

Amplitude(0-1)

Displace(0-10)

maya的默认属性设置是

  • Readable
  • Writable
  • Connectable
  • Storable
  • Cached
  • Not arrays
  • Not Keyable
  • Not hidden
  • 。。。
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import math
import sys

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

nodeName = "RippleDeformer"
nodeID = OpenMaya.MTypeId(0x102fff)


class Ripple(OpenMayaMPx.MPxDeformerNode):
    '''
    Commands ----> MPxCommand
    Custom   ----> MPxNode
    Deformer ----> MPxDeformerNode
    '''

    mObj_Amplitude = OpenMaya.MObject()
    mObj_Displace =  OpenMaya.MObject()

    def __init__(self):
        OpenMayaMPx.MPxDeformerNode.__init__(self)
        
    def deform(self, dataBlock, geoIterator, matrix, geometryIndex):
    # 1.attach handle to array value
    # 2.jump to Element
    # 3.data Handle will reach to specific dataBlock
    # 4.child -> inputGeom
        input = OpenMayaMPx.cvar.MPxGeometryFilter_input
        # 1.Attach a handle to input Array Attribute
        # 理解为列表，返回头指针
        dataHandleInputArray = dataBlock.inputArrayValue(input)
        # 2.Jump to particular element
        # 查询到对应的列表元素
        dataHandleInputArray.jumpToElement(geometryIndex)
        # 3.Attach a handle to specific dataBlock
        # 取出该指针下列表元素的储存的内容
        dataHandleInputElement = dataHandleInputArray.inputValue()
        # 4.Reach to the child - inputGeom
        # 找到该顶点对应属性
        inputGeom = OpenMayaMPx.cvar.MPxGeometryFilter_inputGeom
        dataHandleInputGeom = dataHandleInputElement.child(inputGeom)
        inMesh = dataHandleInputGeom.asMesh()
        # 开始计算了
        # Envelope
        # #deform混合程度
        envelope = OpenMayaMPx.cvar.MPxGeometryFilter_envelope
        dataHandleEnvelope = dataBlock.inputValue(envelope)
        envelopeValue = dataHandleEnvelope.asFloat()
        # Amplitude
        dataHandleAmplitude = dataBlock.inputValue(Ripple.mObj_Amplitude)
        amplitudeValue = dataHandleAmplitude.asFloat()
        # Displace
        dataHandleDisplace = dataBlock.inputValue(Ripple.mObj_Displace)
        displaceValue = dataHandleDisplace.asFloat()

        mFloatVectorArray_normal = OpenMaya.MFloatVectorArray()
        mFnMesh = OpenMaya.MFnMesh(inMesh)
        mFnMesh.getVertexNormals(False, mFloatVectorArray_normal, OpenMaya.MSpace.kObject)# angleWeighted,output,物体空间法线

        # Geometry iterator遍历几何元素
        while(not geoIterator.isDone()):

            pointPosition = geoIterator.position()

            pointPosition.x = pointPosition.x + math.sin(geoIterator.index() + displaceValue) * amplitudeValue * mFloatVectorArray_normal[geoIterator.index()].x * envelopeValue
            pointPosition.y = pointPosition.y + math.sin(geoIterator.index() + displaceValue) * amplitudeValue * mFloatVectorArray_normal[geoIterator.index()].y * envelopeValue
            pointPosition.z = pointPosition.z + math.sin(geoIterator.index() + displaceValue) * amplitudeValue * mFloatVectorArray_normal[geoIterator.index()].z * envelopeValue
            
            geoIterator.setPosition(pointPosition)
            
            geoIterator.next()




def deformerCreator():
    nodePtr = OpenMayaMPx.asMPxPtr(Ripple())
    return nodePtr

def nodeInitializer():
    '''
    Create Attributes
    Attach Attributes
    Design Circuitry
    '''
    mFnAttr = OpenMaya.MFnNumericAttribute()
    Ripple.mObj_Amplitude = mFnAttr.create("AmplitudeValue", "AmpVal", OpenMaya.MFnNumericData.kFloat, 0.0)
    mFnAttr.setKeyable(1) # 可设置关键帧
    mFnAttr.setMin(0.0)
    mFnAttr.setMax(1.0)

    Ripple.mObj_Displace = mFnAttr.create("DisplaceValue", "DispVal", OpenMaya.MFnNumericData.kFloat, 0.0)
    mFnAttr.setKeyable(1)
    mFnAttr.setMin(0.0)
    mFnAttr.setMax(10.0)

    Ripple.addAttribute(Ripple.mObj_Amplitude)
    Ripple.addAttribute(Ripple.mObj_Displace)

    #Ripple.outputGeom = mFnAttr.create()
    '''
    SWIG - Simplified Wrapper Interface Generator
    '''
    outputGeom = OpenMayaMPx.cvar.MPxGeometryFilter_outputGeom
    Ripple.attributeAffects(Ripple.mObj_Amplitude, outputGeom)
    Ripple.attributeAffects(Ripple.mObj_Displace, outputGeom)



def initializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject,"XZYW","1.0")# 发布者，版本号
    try:
        mplugin.registerNode(nodeName, nodeID, deformerCreator, nodeInitializer,
        OpenMayaMPx.MPxNode.kDeformerNode)
    except:
        sys.stderr.write("Failed to register node:" + nodeName)
        
def uninitializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.deregisterNode(nodeID)
    except:
        sys.stderr.write("Failed to deregister node" + nodeName)



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import maya.cmds as cmds
cmds.loadPlugin(r'C:\Users\XZYW\文档\maya\2023\zh_CN\scripts\rippleDeformer.py')
cmds.deformer(type = "RippleDeformer")

image-20220704225851994

3. Optimizing

  • 避免使用input Value来更新网格指针-lazy loading

  • 把DeformerNode_input存在dataBlock的output节点

设置顶点数据时，用顶点array一次性设置，而不是每个顶点设置一次

4. Painting Deformation(这一段开始大失败)

  • After user painting
  • Read the weight of each vertex获取每个顶点绘制的权重
  • weight: Use weight value in calculation

大概是由于版本的问题，在添加deformer以后，绘制里面没有办法找到绘制ripple deformer的权重

5. Accessory Objects for Deformer（失败）

  • Accessory Object/Node
    • Help deriving Deformation
    • Deletion of A object should delete Deformer node

Accessory worldMatrix->DeformerNode matrixAttr

image-20220705104054032

  • Accessory Node Setup()
    • Create object
    • connect Attributes
  • Accessory Attribute()