Just updated to CS4 Mac. Stupidly in mid project. But anyways...
I frequently utilize layer solids to create basic 3D objects. A box generally. You have to be very precise in getting the corners and edges all lined up so there aren't any gaps. I toss these 3D object comps into another 3D comp and collapse transformations so that they retain their 3Dness within the new comp and interact with other 3D objects much like an actual 3D animation program. But what I'm finding is that with motion blur, it goes all the way back to the original layer and blurs the original edges of each of the layers making up the box. Visually this looks good, except for where the layers seam together, because the motion blur creates a small transparent gap at the seams of the box. Seems (no pun) like it shoudn't happen, but it always does. Any real fixes out there? Often I'll create a box within the box by doubling up the walls so that the gaps only reveal a box or layer of similar color beneath. But that's just adding to the complexity of the render.
I'd love to just turn off motion blur for those elements, but that doesn't seem to be an option since they're collapsed they take on the motion blur attribute of the comp, so unless all motion blur is off, they get motion blur.
Oh, and the annoying thing about the update to CS4 is that all my 3D precomps within 3D comps, etc. are slightly out of alignment. Which I can only assume means any of my CS3 projects using nested 3D are never going to look the same again. That pretty much sucks. Is there a fix for that?