I'm doing some research into render passes and the mia_material_x_passes in particular.
I made several 32-bitfloat custom color passes, with writetoPassBuffers added to a single standard mia_material_x_passes material as an excersize. I made as many passes and buffers as were mentioned in the mentla ray docs as needed for compositing the mia_material back together.
Complete with a mia_exposure_simple to enforce a linear colorspace (the render is done with gamma in it set to 1, with a gamma color correct on the mia_material x's midlevel gray).
But after doing this and adding them back together, to see if I would end up with exactly the same as the MasterBeauty I noticed the shadows don't quite match. On the left of this image if the original master beauty and on the right the acculmination of the render passes as layed out in the mental ray docs.
I'm assuming that I'm missing a special pass to comp;letely match the result, does anyone know what pass is missing from the mental ray docs?