Blender - free open source 3D content creation suite :: 3D programs

Blender is the free open source 3D content creation suite, available for all major operating systems under the GNU General Public License.

A range of 3D object types including polygon meshes, NURBS surfaces, bezier and B-spline curves, metaballs, vector fonts (TrueType, PostScript, OpenType)
Very fast Catmull-Clark subdivision surfaces with optimal iso-lines display and sharpness editing
Full multiresolution sculpting capabilities with 2D bitmap/3D procedural brushes (Paint, Smooth, Pinch, Inflate, Grab) supporting symmetry
Modifier stack deformers such as Lattice, Curve, Armature or Displace
Mirror modifier with middle vertices clipping and automatic deletion of inner faces
Non destructive real time Boolean and Array modifiers
Mesh modeling based on vertex, edge and/or face selection
Smooth soft selection editing tools for organic modeling
Python scripting access for custom tools

Website for Download: http://www.blender.org/