In theory the Pixel Velocities from the Max scan-line renderer should work. In practice it’s something no app currently interprets correctly on input except perhaps Digital Fusion at least for getting it in (although the Y seems transposed and you need a pixel scripting custom tool to remap it). The Motion out Max via Mental Ray is broken in Max7,7.5 , we filed a bug report… So what to do?
Things to try:
search: RPF channel
The President of Boboland seems to have such a script (not sure it it works)
If you can extract images out of it, I will certainly look at it.
Why don’t you ask the people that do Brazil? If they do the renderer, they can actually do multi-pass for cheaper. Else if you know someone that can write a Brazil shader, I can give instructions.