shadow or light updated

In after effect, we can using 3D layer and light to create 2.5D animation, but should I use photoshop to draw shadows behind images, or just use light and 3D layer (with camera) to create shadow in AE? If I use AE, what kind of light should I use? Use "point light" looks better, but the shadow come from in a different way... wrong way...

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update:
I did shadow in photoshop for each frame, and use a transparence layer as a background behind top layer.
Each frame has it's own "frames" around the animation, in order to create a 'movie effect'. People will see images move toward by frames exchange.
5 frames per second, gives people time to think how animation work.