Shading, ambient occlusion, and rendering with alpha

Hi,
I’m having a problem with shading, ambient occlusion, and rendering with alpha.

I want to render an animation of a cube resting on the ground and then composite it on to a video. What I can’t figure out how to do is render just the cube, the ambient occlusion (but no shadow), and an alpha background.

Can anyone tell me how to do that?
Thanks

Anyone?

Thanks

I think you can do that this way:

1.Set your occlusion or aproximated ao, as you wish

  1. put a plane down the cube and that material´s cube must have full alpha and turn off the shadow button.

so I think the occlusion will make the contact shadows of the cube, but will not render the plane. Try it but i am not pretty sure.