In this second part of the Mammoth rigging tutorial Nathan Vegdahl will show you how to create good looking deformations. Even the best rig and control setup won't help if you didn't setup proper deformations. Unnaturally deforming skin, weird wrinkles and intersecting faces can destroy every rig.
There are different ways how you can assign weighted vertex groups to your mesh: automatic weights, weight-painting and manual weighting, with automatic weights being the quick and dirty way and manual weighting the most precise albeit tedious way. We went for the precise way which gives you a lot of control over the weights of every vertex but takes a lot of time and is a challenge of it's own. That's why we decided to separate it from the other part of the tutorial, where we cover bones and controls, and only focus on the deformations in this one.