Rendering was done with scanline for all the layers except occlusion which was rendered in mental ray. For compositing I used After Effects (Fig .13). I divided the render into four passes for the foreground and four for the background:

1. Beauty pass
2. Direct light – since ambient occlusion should not appear in direct light, I used this layer as a mask.
3. Ambient occlusion – aah, it makes so many renders prettier!
4. Z depth channel – used for depth of field effect
5. Mist - this layer was set to be very transparent in the composite; just some mist to better tie up the foreground and the background.
6. Background trees beauty pass
7. Z background depth channel – used for fog and depth of field effect
8. Sky

Finally over all the layers I added some color correction and then popped back to Photoshop to do some small corrective repaints.