Already tried that, in a normal scene, with normal vray light planes, it all looks normal. When I add lights inside, the rest of the car lights up, not the inside. and the materials aren't black.
Can you add a non-VRay light and see if that does anything?
If the mats aren't black, and u can see the interior in a different scene then you might have enabled or disabled something you shouldn't have - double check your light settings incl. any setting related to the windows and interiors, or re-create the scene. I can't be more specific about 3DS stuff
Edit: hide/delete the windows temporarily and do a render. Does that change anything? If not then u defo have messed something up.
Ok, thats some good progress. See if there is anything with the window material or the mesh settings, that could cause the light not to enter. It could be anything really and since I don't use 3DS, I can only guess - could be stuff like GI light depth being set to 0, or windows not visible to GI or anything like that.
A simple way to test the material - simply apply a default material and make it transparent.
I had you on my last msn but it was hacked, now add my new one and send me your scene, I think I can solve your problem but I don't know how to explain it here.
Sorry for offtopic, but i found something pretty interesting. I dunno where to post it, because it's not an LFS vid, but it's about rendering. And if i post somewhere deep in the offtopic, then nobody will check it . http://www.youtube.com/watch?v=qHD8Xf5Rnvo&feature=fvw
If it disturbe you, then ask a moderator to remove, replace it.
Cheers
Thats the idea with the brakelights...Exhaust on the other side? think on the chrysler Neon (old).. Original exahust is like my exhaust, when u put a Muffler the exhast change side. That´s the idea...