I'm asking myself why you'd want to go through all the hassle of it in the first place. There is barely any difference between your two examples. Plus once it's rendered, it's all 2D anyway! If 3D and faux 3D look almost the same, what are you trying to accomplsh?
I'm trying to accomplish a completely flat animation that makes use of pre-established sprite elements. The one on the left is not true 3D. It's layers of 2D in 3D space to mimic the look of a 3D word rotating.
In the end, I can't use the one on the left. It has to be flat in 2D because the game engine sources a texture sheet and simply moves them around based on my AE animation. So even though the 2.5D looks great, it can't be rendered ingame.
This particular example is not a problem but an example. I'm working on an animation that pushes the envelope of this technique though.
Use effects. You know, there is a Transform effect and I could think of a million ways to rig up stuff using Corner Pin and Bezier Warp to simulate all kinds of perspective distortion intra-layer, including your spinning 3D layers. A simple cosine expression would take care of it.
I think perhaps I have not sufficiently explained.
There can be no effects. If I make a stroke around something I can't use the stroke effect, I have to open the file in PSD, add a stroke, save the asset out and then update it in AE.
Imagine that each layer is a cut out piece of paper (the only difference being that this paper can stretch) on a flat surface. Imagine that another program takes the instructions/animations created by me in AE and applies them to the self same assets used by AE to recreate the animation on a custom, stand-alone platform. This other rendering program can move, scale (including stretching and squashing but not skewing), rotate and affect transparency but nothing else.
The final animation has to be a simple flat moving around of the elements and that's it. It's a very strange limitation, I admit. However I think I've managed to make some very 3D like illusions within these constraints.
Well, but must you actually rotate and scale your sprites? Most people would avoid sprite transforms of that kind for performance reasons and to avoid sampling issues and just create a sprite sheet containing all animations baked in. The whole approach sounds slightly odd, though of course I don't know what game you are doing and what engine you are using. I can't even imagine what advantage there is supposed to be in trying to do the perspective stuff the way you do. Your sprite sheets and up being just as big since you need more steps for the tilted perspective and that causes just as complex traversal when looking up the rows and columns. It's really not clear to me what you are trying to achieve that you couldn't with a flat, fully baked spritesheet, given that your engine seems unable to apply vertex transforms/ deformations on your textured planes. This is nothing you can solve with all the fancy tricks in AE even if it would be completely possible to generate such vertex data.