Compositing passes..

[rohanshinde]

Hi,

i am new to this Forum. Wish to interact with lots of MR fanatics..newayz.. i was wondering if anyone could help in rendering out passes..AO,diffuse,refelction,shadow refraction..etc..and compositing them..is there a standard method that anyone follows..i am talking abt MR passes in passes tab..

[2bitfxprod]

It really depends on what shaders you are using and what version of Maya.

I use the mental ray x_passes shaders with maya 2009/2010. Watch out though there is a bug with the cutout opacity. One solution to that is to clamp the low end of your grayscale image. It crashes if pixels have a value of 0, so clamp it at .001 and it will give you the same visual result with no crashes.

Setting up the passes is as simple as using the presets in the render globals pain. If you don't understand how that works holler.

As for compositing... Most passes should just be plus-ed together. The AO I times/multiply in. If your diffuse/specular/sss are all raw passes (no shadows baked in) you will want to multiply those passes by the shadow pass. I don't typically feel the need to have self-shadowing on a separate layer but to each his own. If you are rendering your passes as premultiplied be sure to unpremultiply them before color correcting and combining. Then after all that is done swap in the original alpha to your combine passes and premultiply.

Hope this helps.

Rob