[Luke Di rago]

I was looking for the same effect, and after thinking a while how to achieve that in AE, I’ve found a simple workaround:

If you make a white solid in 3D, and the shadows are projected with a light, you can use that as an occlusion pass; a white plane with dark shadows only, and then applied as Multiply, will do a similar effect to what a 3D OCC pass would do.

You have to set the white solid to accept shadows, but no lights (in Material Options, shortcut AA on the layer) , and then play around with the opacity, and control the sharpness/softness of the shadow with the light controls.

Hope this helps you,

Luke!