Matte with a PRT loader

Krakatoa for 3ds Max
2

Am I understanding correctly that you are trying to use the particles from a PRT Loader as a matte object? What steps are you taking to accomplish that?

The short answer is that only geometry (ie. meshes) can be used as a matte object. I don’t think the matte material will do anything that makes sense when applied to a PRT Loader either. You could try to set the PRT Loader’s particles to full black (or whatever your background color is) to make it appear like the background is shown behind those particles.

4

Unfortunately, I don’t think what you are trying to do is going to work. Only triangle-based geometry is usable via the Matte Object selection sets. I can’t think of any way to make a specific particle object render fully opaque to the camera but not to lights.

Are you able to rethink the problem? Why do you need particle objects to act as mattes?