I used 3 area lights, one of which was a spherical lamp and the others were rectangular. You can see more in Fig.07. Note that the intensity of light is dependent on the values of the exposure controller. I used mr photographic controller which is really very good and suitable for Mental Ray scenes.
Mental Ray is a very good engine for rendering; I used simple render settings with final gather and GI for this particular work (Fig.08).
After rendering the final image I extracted the passes (Z-depth and Ambient Occlusion). You can extract the Z-depth with render elements in the render options; you just add it and then change the min and max values to achieve a suitable pass.
Mental Ray contains a specific shader for generating an Ambient Occlusion pass; you should assign it to the surface map of a new Mental Ray material and then assign this material to all objects in the scene.
After extracting the passes I took them into Photoshop to composite them (Fig.09 - 11).
You can assign Ambient Occlusion by putting it in a new layer above the original image layer and then change the blending mode to multiply.
You can assign Z-depth to a new channel in Photoshop and apply a lens blur filter and play with the values. Finally, you can add some colour correction and adjust the Levels and add some effects (such as a glow) if you want to.
And here are the final images (Fig.12 - 13). I hope this article has been helpful, thanks for reading.