The MaterialID, ObjectID and TriangleID channels output multicolored material, object or triangle silhouettes. This is useful for easier selections in a 2D image editor when you want to edit only specific materials in the rendered image. In the case of the Triangle ID channel, it can be used to generate something similar to a wireframe render using a find edge filter in an image editor.
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Render followed by Object ID, Material ID and Triangle ID channels.
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