Three MatteID AOVs setup to reflect material assignments
This node outputs AOVs for compositing. It should be plugged into the Utility Pattern parameter of a PxrSurface and will output MatteID AOVs.
It outputs at most eight RGB mattes (24 mattes) named MatteID0, MatteID1 ... MatteID7.
MatteID AOVs are used as per-objects/per-object groups/per-material compositing mattes. They will be properly motion-blurred or defocused to allow you to isolate objects in your compositing software.
To associate an object or a shader to a MatteIDx, you need to add a special attribute to that object or shader:
Attribute "user" "color MatteID0" [1 0 0]
In this example, the MatteID0 AOV will be red for your object, but you can use the green and blue channel for two other sets of objects.
In RenderMan for Maya (RfM), these attributes can be added via the User Attributes menu on the transform, and there is a MatteID tab in the Outputs section of the RenderMan globals.
This input can only be used to daisy-chain other nodes that don't produce any output.
Controls MatteID AOV output.
These parameters allow the assignment of colors or patterns to be output for each matte. This is multiplied against the color chosen as the user attribute mentioned above. If you choose white as the user attribute then this parameter texture is rendered as-is.
A single integer. This output only exists to trigger the execution of the pattern in the graph.