Python 如何使用pymel（或Maya.cmds）将自定义UV集中的UV链接到Maya中的纹理

我正在编写一个工具，它将帮助我在一个模型上创建自定义UV集，该模型将链接到将发送到vray_extraTex渲染元素的渐变（无插值）。这些将成为蒙版，并以与vRay multi-mattes相同的方式使用。但是，我无法使用pymel将作为vray_extraTex纹理的渐变链接到自定义UV集

我可以在Maya中手动执行所有这些操作，但由于某些原因，我缺少pymel将UV链接到渐变的功能。我正在Maya场景中测试一个pSphere，它有两个UV集，第二个UV集处于活动状态。此代码已被精简了一点：

def main():
    inclusiveSet = None
    renderElements =[]
    ramps = []
    newChannels = ['TestA','TestB','TestC','TestD'] 
    for i, channel in enumerate(newChannels):
        modIndex = i % 3 # 0:Red, 1:Green, 2:Blue
        shapeNode=pm.PyNode('pSphereShape1')
        transformNode=shapeNode.getTransform()

        if modIndex == 0: # the first channel in the new Render Element
            # make an etex render element
            eTexElement = pm.PyNode(pm.mel.eval('vrayAddRenderElement("ExtraTexElement")'))
            eTexElement.vray_name_extratex.set('')
            eTexElement.vray_explicit_name_extratex.set('empty_empty_empy')            
            renderElements.append(eTexElement)
            # make a ramp
            ramp = pm.shadingNode('ramp', asTexture=True, name='eTex_{}_ramp'.format(transformNode.name()))
            ramps.append(ramp)
            ramp.outColor.connect(eTexElement.vray_texture_extratex)
            # make a place2dtexture
            place2d = pm.shadingNode('place2dTexture', asUtility=True)
            place2d.outUV.connect(ramp.uv)
            place2d.translateFrameU.set(len(renderElements) - 1)
            # link UVs to ramp
            # NOT WORKING
            indices = pm.polyUVSet(shapeNode.name(), query=True, allUVSetsIndices=True)
            currentUVSet = pm.polyUVSet(shapeNode, query=True, currentUVSet=True )
            for i in indices:
                if currentUVSet == pm.getAttr("{}.uvSet[{}].uvSetName".format(shapeNode.name(), i)):
                    pm.uvLink(uvSet='{}.uvSet[{}].uvSetName'.format(shapeNode.name(), i) , texture=ramp)

        explicit_name = eTexElement.vray_explicit_name_extratex.get()
        nameTokens = explicit_name.split('_')
        nameTokens[modIndex] = channel
        explicit_name = '_'.join(nameTokens)
        eTexElement.vray_explicit_name_extratex.set(explicit_name)

main()

我没有得到任何错误，但是当我检查UV链接时，渐变仍然设置为map1 UV集，而不是第二个激活的集

我希望看到连接到UV选择器节点并链接到第二个UV集的渐变

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我在写这篇文章时意识到，在我可以用python链接渐变之前，可能需要将渐变附加到指定给geo的着色器。下一步我将尝试测试它，因此在经过更多测试后，我能够在将渐变指定给对象着色器上的新属性后使其工作，并对我之前发布的代码进行了一些小的修复。固定的：

def connectTexture(layeredTex, shapeNode):
    shadingGrps = pm.listConnections(shapeNode,type='shadingEngine')
    shaders = pm.ls(pm.listConnections(shadingGrps),materials=1)
    shader = shaders[0]
    pm.addAttr(shader, longName='eTexLayeredTex', usedAsColor=True, attributeType='float3' )
    pm.addAttr(shader, longName='eTexLayeredTexR', attributeType='float', parent='eTexLayeredTex' )
    pm.addAttr(shader, longName='eTexLayeredTexG', attributeType='float', parent='eTexLayeredTex' )
    pm.addAttr(shader, longName='eTexLayeredTexB', attributeType='float', parent='eTexLayeredTex' )
    layeredTex.outColor.connect(shader.eTexLayeredTex)


def main():
    inclusiveSet=None
    renderElements=[]
    ramps=[]
    newChannels = ['TestA','TestB','TestC','TestD']
    shapeNode=pm.PyNode('pSphereShape1')
    transformNode=shapeNode.getTransform()

    # make a layeredTexture
    layeredTexture = pm.shadingNode('layeredTexture', asTexture=True, name='eTex_{}_layeredTexture'.format(transformNode.name()))
    layeredTexture.attr('inputs')[0].color.set(0,0,0)
    layeredTexture.attr('inputs')[0].alpha.set(1)
    layeredTexture.attr('inputs')[0].blendMode.set(1)
    connectTexture(layeredTexture, shapeNode)
    for i, channel in enumerate(newChannels):
        modIndex = i % 3 # 0:Red, 1:Green, 2:Blue
        if modIndex == 0: # the first channel in the new Render Element

            # make an etex render element
            eTexElement = pm.PyNode(pm.mel.eval('vrayAddRenderElement("ExtraTexElement")'))
            eTexElement.vray_name_extratex.set('')
            eTexElement.vray_explicit_name_extratex.set('empty_empty_empy')            
            renderElements.append(eTexElement)

            # make a ramp
            ramp = pm.shadingNode('ramp', asTexture=True, name='eTex_{}_ramp'.format(transformNode.name()))
            ramps.append(ramp)
            ramp.interpolation.set(0)
            ramp.colorEntryList[0].position.set(0.0)
            ramp.colorEntryList[1].position.set((1.0 / 3.0))
            ramp.colorEntryList[2].position.set((2.0 / 3.0))
            ramp.colorEntryList[0].color.set(1,0,0)
            ramp.colorEntryList[1].color.set(0,1,0)
            ramp.colorEntryList[2].color.set(0,0,1)
            ramp.defaultColor.set(0,0,0)            
            ramp.outColor.connect(eTexElement.vray_texture_extratex)
            ramp.outColor.connect( layeredTexture.attr( 'inputs[{}].color'.format( 1 + i // 3)))

            # make a place2dtexture
            place2d = pm.shadingNode('place2dTexture', asUtility=True)
            place2d.outUV.connect(ramp.uv)
            place2d.outUvFilterSize.connect(ramp.uvFilterSize)
            place2d.wrapU.set(0)
            place2d.wrapV.set(0)
            place2d.translateFrameU.set(len(renderElements) - 1)

            # link UVs to ramp
            indices = pm.polyUVSet(shapeNode.name(), query=True, allUVSetsIndices=True)
            currentUVSet = pm.polyUVSet(shapeNode, query=True, currentUVSet=True )[0]
            for index in indices:
                if currentUVSet == pm.getAttr('{}.uvSet[{}].uvSetName'.format(shapeNode.name(), index)):
                    pm.uvLink(uvSet='{}.uvSet[{}].uvSetName'.format(shapeNode.name(), index) , texture=ramp)

        explicit_name = eTexElement.vray_explicit_name_extratex.get()
        nameTokens = explicit_name.split('_')
        nameTokens[modIndex] = channel
        explicit_name = '_'.join(nameTokens)
        eTexElement.vray_explicit_name_extratex.set(explicit_name)

main()

关键点是将坡道连接到指定给对象的材质。奇怪的是，在创建UV链接后，可以删除渐变和材质之间的连接，并且UV链接仍然可以正常工作。我发布了这篇文章，以防有人遇到类似的问题