I am having a little issue with my Comp in Motion.
Let try explain this... :o/
When you have a comp in 2D, he Group on top will cover the one underneath (in the layers) right.
But when I change the comp to 3D and move the Group in the Z space (-700 for example). the Group that is above the other but in a negative Z space still is covering other group.
Did I miss something or is just Motion Buggy again?
If your group is being rasterized (has a square around the 3D group icon) it will be composited in layer order, not z-depth. Things that can cause this are opacity changes, blend modes, and certain filters - usually the offending parameter has a blue dot next to it in the Inspector.
Freelance Producer/Editor/Motion Graphics Artist
Apple-certified Master Trainer
Author, Motion 4 from Peachpit Press http://www.applemotion.net