I have a few students with car chases in their short stories that are to be animated in AE. I know it's possible to use AE's expressions to assemble a 3D object (like a car) from 2D flat layers imported from Photoshop. Any ideas? I vaguely remember a paper airplane that someone assembled in AE from 2D layers, brought into AE's 3D component and made to float around.
Not sure what you are getting at by refering to expressions. Is the car supposed to explode in some way? Otherwise simply assembel the car in a pre-comp with clean orientations, then use the 3D switch and collapse transformations on this layer in your main comp to maintain the 3D-ishness.
Yeah, you don't really need any expressions to make a car. Precomposing is the key though. That way you can keep all your car parts together yet still animate the wheels turning and so forth. However, if you wanted the wheels of your car to roll perfectly along the ground without "slipping," you may need an expression.