How can I mask 3d text?

[Darby Edelen]

[Shaun Carollo] “when placed into the comp, the alpha layer is not lined up as seen above”

If these are image sequences make sure that they are interpreted with the same frame rate. You can check this by selecting them in the project panel and looking at the footage information at the top of the panel. You can change the frame rate interpretation by pressing ctrl-alt-g (cmd-opt-g on mac) with the footage item selected.

Otherwise make sure that the layers in points are, in fact, aligned on the timeline. One way to do this would be to duplicate the RGB footage and the duplicate selected holding alt and dragging the alpha footage from the project panel to the timeline. This will replace the selected layer with the new footage source while keeping all other layer properties (in point, out point, transforms, all effects and properties) the same.

Also, since these are 3D renders it would generally be much cleaner to import the camera from your 3D package into After Effects instead of using the Camera Tracker. The workflow for doing this varies depending on your 3D package but there’s always a way to get that data in there.

Darby Edelen