Align 3D layers perfectly in AE

Greyscale Gorilla follows up May's Pixel-Perfect Camera Move Transitions with How To align 3D layers perfectly in After Effects. The video is below but be sure to check out the lively comments for more tips and scripts:

"Sometimes, when making 3D shapes in after effects, you just can’t get two layers to line up properly. Here is a trick I learned [Alpha Add] to make sure your edges always look like they are perfect."

How To Get Rid of edge seams in After Effects from Nick Campbell on Vimeo.