Say for example I have a Particular Cloud Bank. I want to composite a rendered 3D animation of a building sticking through those clouds. The animation of the building is rendered in .RPF format so Z-Buffer is available (as well as any other parameters available with .RPF). The camera in AE is generated from the .RPF file as well. Now I want the building in the middle of the clouds so that clouds further back go behind the building. I don't believe the obscuration layer will work becuase the rendered building is not a 3D layer.
You could do 2 layers of clouds with a separation in the Z-Buffer but there would be a gap depending on the angle. Any ideas?
You can load your depth map as a custom visibility range thingy in the visibility options. Extract The Z-depth from your RPF. You would have to combine it with a matte layer representing your building and then define the clipping levels. If particular itself doesn't give you your desired result, you can always use classical matting techniques in the same fashion based on the depth channel (apply your tweaked output as a luma matte).