Game Set and Matte

Solved one more compositing/rendering issue just now, though of course it will raise its own issues...

The problem was that I really liked the dirtmap compositing technique I came up with for this project, and it's a huge part of the overall look. But the problem is that certain textures can't be composited the same way -- they get bleached out and ugly. I tried to compensate for this by adjusting the textures in Maya, but no matter how dark I made them, when the dirtmap gets overlaid they just didn't look right.

So I needed to come up with a way to easily isolate elements in the scene in such a way that I could individually pick them out in compositing and adjust them accordingly.

So that's what I did. In a variation of my dirtmap script, which applies the dirtmap to all shading groups at render time, I created an "idMatte" script for a separate matte pass. It goes through all the shading groups looking for a custom flag, and if it finds the flag it applies a surface shader with solid red, green or blue based on the value of the flag. If the flag doesn't exist, it applies a black hole matte material. In compositing, I can then use the RGB channels from that file to create 3 separate mattes for color correcting the materials in question.

This is a perfect solution, since there are only 3 materials that need adjustment -- the tubes, the characters' hair, and pupils. The only place I have to watch out is when both characters are in one shot, in which case I'll have to manually split the matte so they each get their own hair/eye treatments.