Renderman Gi Speed

[peliosis]

Thanks Simon, but don't get me wrong, that dirtmap shader I thought of ( animus artis site )

is a fullblown occlusion shader with environment probing and bent normals output.

[sibarrick]

Sure I understand that, what I meant was that if you want to bake occlusion into a mesh, but not on a whole scene basis then this is a viable option. The reason you might want to do this is to add dirt into a shader without having to do a pixel by pixel calculation. The underlying procedure is exactly the same it's just quicker if you allow that you only do the calculation on the geometry points and just interpolate everywhere else.

I'm not suggesting this gives a better solution, it's a hack, but hacks often have there place.