VFX - Maya render pass

After getting back into using maya my tutor asked us to place a animation into a picture. Like this;

However were told to change the image on the cube. So basically he gave us the assets to use and then change them round and add the passes.

So first pass was shadow, this one is self explaintory in that we create shadows from the lamp for the cube to look more realistic.

Second pass was reflection. we did this because in the picture there is a glass mat therefore as the cube lands on it, a reflection would be created. I found this didn't work on my first try, the reasons are unknown but they were fixed for the second attempt.

The last pass was the occlusion, this was about creating shadows on it self. I found this made little difference to the cube however on bigger and more complex objects I can see this being very useful.