So I watched some digital tutors tutorials on the environment fog for maya 2011, and I have a basic understanding of how it should work. I just plugged the EnvironmentFog shader directly in the environment volume in the render globals. Problem is, is keeps rendering black no matter what I do. I have a huge scene, and I set the fog height pretty high so that it will cover my scene. I tried setting the fog distance to something like 9999999 so that it should be pretty transparent, and i set the fog density to .1 with no luck. Plus, I raised the fog emission color a little bit but it still renders completely black. Any ideas what I am doing wrong?
Maybe you set the Fog height pretty high.
Try to lower the Fog height value until you start getting any result different than black.
Like Zdravko said, it might be that the fog is too dense and simply blocks all light.
Best regards,
Vlado