Sculptris

Sculptris is a virtual sculpting software program, with a primary focus on the concept of modeling clay. It has been actively developed since early December 2009.
Users can pull, push, pinch, and twist, similar to modeling clay. It is geared toward character sculpting and "organic" models.
3D meshes (.obj) can be imported into the program for further detailing, generating normal and displacement maps.
Tomas Pettersson joined the Pixologic team (creators of ZBrush) in late July 2010, causing Sculptris to be developed by Pixologic.

 ^{http://pixologic.com/sculptris/features/}