Reading extra channels from EXRs generated in other programs?

Is it possible to read extra channels from EXRs generated from programs outside of Blender? I’d like to use Blender to composite my renders from Maya, but the problem is that Mental Ray’s render pass system appends the pass name to the exr channels. Instead of getting a red channel called “R,” it spits out a channel name like “(renderpass).R” which Blender does not recognize as the red channel and the image displays as pure black. Is there any way to read these miscellaneous exr channels in the compositor? Thanks.

Change your framebuffer naming (in the render settings common tab) from “automatic” to “custom” and change the custom string to this:


That should make MR write the passes with the naming convention Blender expects.

Thanks for the reply. Unfortunately, the passes are already rendered. The render times are a bit long so rerendering isn’t an option. I’ll just have to find a way to convert them if Blender can’t read those channels.