What version of AE did you update from?
What OS are you using?
Can you show us a screenshot of your interface?
SOLVED well, at least for me.
very simple solve, it was a 2d layer, and the rest was 3d. so i just had to turn the layer into 3d (or the rest off) and it was fixed.
but it's still not making any sense to me. if you got a 3d layer with a clear alpha channel, it should be able to composite over a 2d background right?
well i did some tests and it seems it is not. (or is it just me) though im pretty sure this was always the case in the previous versions.
(i guess i can say im a experienced user)
okay still not completely solved... so i cannot move the 3d layers in z space anymore.. i can change the position parameters but on screen nothing happens. or at some point it just suddenly dissapears. like its going trough another 3d layer, or like the camera is on frontal instead of active. this also happens if its on solo.