How can a single .exr containing all passes from a scene be created if certain passes have different shaders applied. For example the matte pass might have different color surface shaders while you need something like a lambert for the diffuse pass.
Is it possible to get all of the layers rendered even if they have different shaders into the same .exr file. If so how would it be set up?
I researched this as a Maya user looking for an alternative, only the most current version of Maya 2016 has this option or some of their more expensive renderer options like vray. (Maya 2016 .exr multi-pass option)
There is a tutorial here showing how matte passes would be handled in an older version of Maya with mental ray: Tutorial on multi-shader passes & .exr. It renders out two .exr files, one for all of the main passes and one for a matte rgb pass. With this method you would have to create a seperate .exr for every pass that uses a different shader on a seperate render layer.