Matte with a PRT loader

Krakatoa for 3ds Max
1

Hi everyone,

I’m working lately on Krakatoa and must admit it’s killer, good work guys.
Right now I’m trying to matte out a PRT fumefx with a PRT loader but it doesn’t seem to work. It looks like it’s not matted at all. I’m rendering in voxel mode. Any ideas?
Thanks.

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.

3

Hi Darcy,
Yes, you get it right. The way I do it is by putting the loader into a selection set and then use that set in the render matte object rollout.
I was trying to use method but I was confronted with two problems.

  1. the “matting” particles were blocking light so my render is all black (we’re inside a kind of a cylinder so there’s geometry all around).
  2. I can’t get a correct alpha with that method.
    Thanks
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?