Just finished letter B of the Alphabet series, with the intention of representing Jorge Luis Borges, one of the greatest writers of all times.
To build the letter I used Maya, Arnold, Substance Designer, Substance Painter, a bit of Mudbox and Nuke for the compositing.
Cryptomatte is now officially released and fully compatible with Arnold 5 and is a game changer. For those who have not used it yet, it's a tool developed by Psyop that stores an id of every object, asset or shader in a single AOV. This layer can later be used in Nuke or Fusion to extract an Alpha channel of any of the elements in the scene. It looks like this: