Blender

Blender is the open source software for 3D modeling, animation, rendering, post-production, interactive creation and playback. Available for all major operating systems under the GNU General Public License. Revolutionary non-overlapping and non-blocking UI delivers unsurpassed workflow ; Flexible and fully configurable window layout with as many screen setups as you prefer video sequence editing, character animation action editor, non-linear animation mixer, image/UV editing, file/image selection and file management ; Built-in text editor for annotations and editing Python scripts ; Consistent interface across all platforms .

Features:
· A range of 3D object types including polygon meshes, NURBS surfaces, bezier and B-spline curves, metaballs, vector fonts (TrueType, PostScript, OpenType)
· Character animation pose editor
· 'Ipo' system integrates both motion curve and traditional key-frame editing
· 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
· Armature (skeleton) deformation with forward/inverse kinematics with pole target support
· Auto IK allows posing FK chains easily
· Non-linear animation editor for mixing individual actions created in Action editor
· Automated walkcycles along paths
· 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
· Animated constraint system
· Vertex key framing for morphing, with controlling sliders
· Edit and create new blendshapes from existing targets