No light inside sphere
 

Did you have "Use shadow maps" turn on on your dir light?
I think this is why no light was lighting the scene when inside a sphere.

wow, i ahve mental ray and i was thinking that what the heck was it useful for

I LOVE Mental Ray, ever since it came out I don't think I've used Maya's renderer once!

I'm making a hotel hallway at the moment (just for fun), it's still in the very early stages but there's a render attached.

It's totally lit by the rectangle lights (they're just planes) using FG and GI, there's depth of field too just for fun.

It got a bit artifacty from the jpeg compression, but nevermind.

How long did that take to render?

Gulp, 2 hours!

I may have gone a bit overboard on the FG settings though. It was rendered on my Athlon XP 1800+ with 768meg of DDR ram.