Since you're much more in touch with the Instancing voodoo, please help with this real-world case (but using the bunny):
-materials are applied to geometry groups. Unfortunately, I have rarely found that a single object-level material is realistic.
-I then want to override parameters on a per-instance basis on a specific material.
I can't get this to work
Not using Fast Point Instancing isn't an option as the real world case for this is models of millions of polygons per model. Other than the Materials override problem, this works brilliantly in Fast Point Instancing, I can do “billions” of (instanced) polygons with great results.
In the .hip file, I have a simplified example. The bunny has its ears in a group and body is everything else. Base materials applied.
Then I try to use the Material overrides, but it doesn't work