Blender is the free open source 3D content creation suite, available for all major operating systems under the GNU General Public License.
It can be used for modeling, UV unwrapping, texturing, rigging, water simulations, skinning, animating, rendering, particle and other simulations, non-linear editing, compositing, and creating interactive 3D applications, rigid body, fluid, cloth and softbody dynamics, modifier based modeling tools, powerful character animation tools, a node based material and compositing system and Python for embedded scripting.
