Just wanted to share with you a strange bug I encountered (in Mental Ray for Maya 2009), and propose a solution.
While rendering in MR from the front view - a simple plane with a simple texture showed up black.
After an hour of fighting and a small nervous breakdown, the solution I found, was to change the texture projection method - from "normal", to "projection" (my UVs were fine). When I did that, the texture rendered fine.
Kinda strange, huh?
Well, I hope this info will help someone in the future.
If anybody knows the real reason for that behavior - I'd be more than happy to know...