渲染设定 Python API 和命令

渲染设定 Python API

渲染设定 Python API 作为 Maya 安装的一部分提供，您可在以下文件夹中找到相关文件：..\Python\Lib\site-packages\maya\app\renderSetup。

注： 目前，渲染设定 Python API 未获得正式支持。随着时间的推移，这一状况可能会有所改变。

若要使用渲染设定 API，您应先按如下所示导入渲染设定模块： 

import maya.app.renderSetup.model.override as override
import maya.app.renderSetup.model.selector as selector
import maya.app.renderSetup.model.collection as collection
import maya.app.renderSetup.model.renderLayer as renderLayer
import maya.app.renderSetup.model.renderSetup as renderSetup

还应导入 maya.cmds (import maya.cmds)，以便能够使用本地 Maya 命令。

以下示例脚本创建了一个层和两个集合。它使用表达式 mySphere* 将球体添加到第一个集合，然后使用表达式 myCube* 将立方体添加到第二个集合。

创建一个绝对覆盖并将其应用于第一个集合，然后创建一个相对覆盖并将其应用于第二个集合。

该示例最终切换到渲染层，您将在此看到以模板显示模式显示的球体，以及平移的立方体。 

import maya.app.renderSetup.model.override as override
import maya.app.renderSetup.model.selector as selector
import maya.app.renderSetup.model.collection as collection
import maya.app.renderSetup.model.renderLayer as renderLayer
import maya.app.renderSetup.model.renderSetup as renderSetup
import maya.cmds as cmds

rs = renderSetup.instance()  
  
# Create and append the render layer
rl = rs.createRenderLayer("MyRenderSetupLayer")

# Create and append 2 collections
c1 = rl.createCollection("sphereCollection")
c2 = rl.createCollection("cubeCollection")

# Create a trivial scene with a cube, a sphere and a cylinder
cmds.polySphere(name='mySphere')
cmds.move(2, 'mySphere', y=True)
cmds.polyCube(name='myCube')
cmds.move(5, 'myCube', y=True)
cmds.polyCylinder(name='myCylinder')
cmds.move(10, 'myCylinder', y=True)

# Set up collection 1 to select all spheres using the pattern mySphere*, 
# and collection 2 to select all cubes using the pattern myCube*.
c1.getSelector().setPattern('mySphere*')
c2.getSelector().setPattern('myCube*')

# Set up an absolute override on mySphereShape.template with a value of True
ov1 = c1.createAbsoluteOverride('mySphereShape', 'template')
ov1.setAttrValue(True)

# Set up a relative override on myCube.translate with a multiply value of
# [2.0, 2.0, 2.0] and an offset of [0.1, 0.1, 0.1]
ov2 = c2.createRelativeOverride('myCube', 'translate')
ov2.setMultiply([2.0, 2.0, 2.0])
ov2.setOffset([0.1, 0.1, 0.1])

# Set the render layer as visible. 
# Only the sphere and the cube are displayed as they are collection members.
rs.switchToLayer(rl)

然后，您可以扩展此示例以创建着色器覆盖。在本示例中，将创建两个表面着色器，其中第一个着色器指定给场景层中的立方体。第一个表面着色器设置为红色，第二个着色器设置为蓝色。因此，在场景层中，立方体设置为红色。

然后，创建一个着色器覆盖，以便为立方体指定第二个表面着色器。现在，当您切换渲染层时，将看到立方体为蓝色并已平移。球体以模板显示模式显示。 

import maya.app.renderSetup.model.override as override
import maya.app.renderSetup.model.selector as selector
import maya.app.renderSetup.model.collection as collection
import maya.app.renderSetup.model.renderLayer as renderLayer
import maya.app.renderSetup.model.renderSetup as renderSetup
import maya.cmds as cmds

# Helper function for creating a shader
def createShader(shaderType):
    """ Create a shader of the given type"""
    shaderName = cmds.shadingNode(shaderType, asShader=True)
    sgName = cmds.sets(renderable=True, noSurfaceShader=True, empty=True, name=(shaderName + "SG"))
    cmds.connectAttr(shaderName + ".outColor", sgName + ".surfaceShader")
    return (shaderName, sgName)
	
# Helper function for assigning a material
def assignMaterial(shapeName, shadingGroupName):
    cmds.sets(shapeName, forceElement=shadingGroupName)
	
# Helper function for setting a color attribute to some color value
def setColor(attr, color):
    cmds.setAttr(attr, color[0], color[1], color[2], type="float3")
	
rs = renderSetup.instance()    

# Create and append the render layer
rl = rs.createRenderLayer("MyRenderSetupLayer")

# Create and append 2 collections
c1 = rl.createCollection("sphereCollection")
c2 = rl.createCollection("cubeCollection")

# Create a trivial scene with a cube, a sphere and a cylinder
cmds.polySphere(name='mySphere')
cmds.move(2, 'mySphere', y=True)
cmds.polyCube(name='myCube')
cmds.move(5, 'myCube', y=True)
cmds.polyCylinder(name='myCylinder')
cmds.move(10, 'myCylinder', y=True)

# Set up collection 1 to select all spheres using the pattern mySphere*, 
# and collection 2 to select all cubes using the pattern myCube*.
c1.getSelector().setPattern('mySphere*')
c2.getSelector().setPattern('myCube*')

# Set up an absolute override on mySphereShape.template with a value of True
ov1 = c1.createAbsoluteOverride('mySphereShape', 'template')
ov1.setAttrValue(True)

# Set up a relative override on myCube.translate with a multiply value of
# [2.0, 2.0, 2.0] and an offset of [0.1, 0.1, 0.1]
ov2 = c2.createRelativeOverride('myCube', 'translate')
ov2.setMultiply([2.0, 2.0, 2.0])
ov2.setOffset([0.1, 0.1, 0.1])

# Creates two surface shaders. Makes one red, the other blue and assigns the
# red shader to myCubeShape. Then creates a shader override with the blue
# shader.
shaderName, sgName = createShader("surfaceShader")
shaderName2, sgName2 = createShader("surfaceShader")
assignMaterial("myCubeShape", sgName)
setColor(shaderName + ".outColor", [1.0, 0.0, 0.0])
setColor(shaderName2 + ".outColor", [0.0, 0.0, 1.0])
outColorShaderOvr = c2.createAbsoluteOverride(shaderName2, 'outColor')

# Set the render layer as visible. 
# Only the sphere and the cube are displayed as they are collection members.
rs.switchToLayer(rl)
注：

调用 rs.switchToLayer() 方法可确保渲染设定与任何场景更改同步。这相当于以交互方式使用 Maya 时单击层可见性图标 更新层成员身份。

渲染设定 Python 命令

您可以使用渲染设定命令查询渲染设定成员身份。

若要了解有关以下命令的详细信息：

请使用 help() 查询文档字符串。

例如，以下 Python 命令可用于查询 renderLayerMembers 命令： 

import maya.app.renderSetup.model.modelCmds as modelCmds
help(modelCmds.RenderLayerMembersCmd)

您可以通过类似方式查询其他命令的文档字符串。

若要了解有关 renderSetupSelect 命令的详细信息，请在“脚本编辑器”(Script Editor)的“Python”选项卡中输入以下命令： 

import maya.app.renderSetup.views.viewCmds as viewCmds
help(viewCmds.RenderSetupSelectCmd)

在 Python 中导入和导出 .json 文件

您可以按如下所示定义函数，用于在场景中导入和导出渲染设定 .json 文件。 

import maya.app.renderSetup.model.renderSetup as renderSetup

import json

# Cannot name function "import", as this is a reserved Python keyword.
def importFile(filename):
    with open(filename, "r") as file:
        renderSetup.instance().decode(json.load(file), renderSetup.DECODE_AND_OVERWRITE, None)

def exportFile(filename):
    with open(filename, "w+") as file:
        json.dump(renderSetup.instance().encode(None), fp=file, indent=2, sort_keys=True)

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