Blender

Blender is a 3D animation and compositing suite with tools for modeling (advanced subdivision modeling, multiresolution sculpting), uv unwrapping, texturing (procedural node, 2D and 3D painting), animation, rendering, particles and simulation (including fluid dynamics, hard body physics, cloth and hair), post-production with node based compositing and non linear editing, integrated game engine (with graphical programming, vehicle and rag doll constraints) and python scripting including an import and export suite.

Blender runs on all major operating systems including Windows XP/Vista, OS X, Linux, BSD, Solaris and Irix. It has sculpting similar to ZBrush©, is a full animation suite similar to Maya© or 3DS Max© ; has compositing comparable to Nuke, and full video editing.