fStretch is a rigging plug-in for Autodesk Maya®. It is a surprisingly versatile tool which is proficient at creating advanced deformations on polygonal geometries. Its unique work flow allows one to precisely control effects such as stretch and squash, wrinkles and fat deformations to name a few. At one end, it lets one create cartoony rig with stunning stretch and squash while at the other end, it will allow another to create very realistic fat deformations. The beauty behind this is that both of those effects result from the very same technique.
Available on Windows, Mac OSX and Linux