I have an animated sequence in Premiere Pro like this:
I would like to make the same in AE to get better animation results, using 3D layers and camera movement. The first problem is I can't get blending as shown above since the text layer was changed into 3d layer. Second question - what would be the best way to edit letter A to make inner triangle transparent (like in this example)? I've tried to add triangle shape but then I couldnt get uniform blending of shape and text (when they were 2d layers yet).
I don't follow. If you were able to do it in Premiere (of all things), then this would/ should be easy as pie, but honestly, your description is confusing and it seems you don't have any experience in AE. None of this is any issue with a bit of masking and pre-composing, but obviously it might be difficult explaining the color of the sky to a blind man, so I strongly urge you to read the help and watch som basic tutorials.