First post hoping, hoping for some mental images direction!
I'm rendering out linear passes in mental ray, maya 2011, as 16bit half float exrs for compositing in nuke.
When using the pass presets beauty, diffuse, specular etc. and the compositing equations from the white paper;
Beauty = Diffuse + specular + reflection etc
I have no problem in recreating the beauty pass in nuke.
However, if I break my passes down one step further, rendering out diffuse material colour and direct irradiance and I try to recreate a the diffuse pass with the equation;
Diffuse = diffuse material colour * direct irradiance
I get an "anti aliasing/filtering" issue in my recreated diffuse pass where objects are in front/behind one another. This is not present in the normal diffuse pass.
After further experimentation I noticed that if I turn off "filtering" on all my passes they composite correctly to recreate the diffuse pass. However an unfiltered result isn't useable.
I have attached some images of a simple test scene that I set up, including a "difference" image to show the effect as it is quite subtle in this example! However for what I am doing it is quite important.
Is there a way that I should approach my render passes in maya/mental ray that would eliminate this issue??
Any guidance would be appreciated.
Thanks for your time