This question is probably as old as time, but I've been searching and trying lots of different things to try and fix the problem and would really appreciate any extra info.
I've built and lit these 3d boxes in AE CS4. The Solid layer co-ordinates match up and each box has it's own null object to control it's position. I can't seem to get rid of the gaps for love nor money! Advanced Rendering Plug-In is enabled, layers are collapsed, resolution on full and the comp pixels are square and there's no motion blur turned on.
Thanks Cassius. I've nudged the blocks 1px apart which has helped, but I need the floor for the shadows. The gaps only appear when the camera angle is such that the floor is directly behind the box, so I'm plugging the gaps with extra internal panels! A little bit hacky but it will do for now until I have time to learn a more appropriate 3d program!