Blender 2.56a Beta

Blender is a free 3D graphics application used to create 3D as well as 2D Content. Blender does modeling, texturing, rigging, simulations, skinning, animating, rendering, non-linear editing, compositing, and creating interactive 3D applications, including video games, animated film, or visual effects.

Blender's features include advanced simulation tools such as rigid, realistic body, fluid, cloth and softbody dynamics.