Blender

Blender is a 3D modeling application available for Linux, Windows, and Macintosh. It is a powerful, professional 3D environment, but it has a steep learning curve, and many sometimes obscure shortcut keys. It currently supports animation rendering, radiosity, particle systems, and OpenGL Realtime animation for some (but not all) platforms/OSs. Blender is an interesting program because it was originally a commercial, closed source program. The company that made it went bust, and the code was released as open source for a fee to the creditors. That fee was paid and so the once closed source program became open source.

Learning how to use Blender can be tough, but it's worth it. A good place to start is the Using Blender section of Blender3d.org. From the homepage, go to InfoCenter -> Using Blender.

Blender has a built-in python interpreter and API for 3D object manipulation. Along with the built-in script library, there are many community-created scripts and tutorials for creating your own scripts.

In 2006, an 'open' video made entirely by blender was released called Elephants Dream. This was made under the Creative Commons license which allows anyone to use it to make their own movies as long as they say they used Elephants Dream.

List of 3D movies created by Blender

 * Big Buck Bunny, watch the trailer and/or the whole thing.
 * Elephants Dream, watch the whole thing.
 * Sintel, watch the trailer. This movie is currently in production and about to be released.