Blender is full featured application for building 3D content. It can easily be extended for new tasks with Python.

Blender is the free open source 3D content creation suite, available for all major operating systems under the GNU General Public License. Blender provides end-to-end support for the production of games and videos. This includes features such as a powerful 3D modeling tool for building objects, support for animating objects in scenes, multiple rendering options, post-production video editing, interactive playback of scenes, and a game engine.

Blender is also gaining popularity as an architecture and engineering tool.

Blender is available for all major operating systems.