Blender is a free 3D animation studio. It includes tools for modeling, sculpting, texturing (painting, node-based shader materials, or UV mapped), UV mapping, rigging and constraints, weight painting, particle systems, simulation (fluids, physics, and soft body dynamics and an external crowd simulator), rendering, node-based compositing, and non linear video editing, as well as an integrated game engine for real-time interactive 3D, and game creation and playback with cross-platform compatibility.
Moonlight|3D is a modeling and animation tool for three-dimensional art. It currently supports mesh-based modeling. It's a redesign of Moonlight Atelier, formed after Moonlight Atelier/Creator died in 1999/2000. Rendering is done through pluggable backends. It currently supports Sunflow, with support for RenderMan and others in planning.
LiquidMaya is a Maya to Renderman plug-in that handles full Renderman output support with a focus on speed, efficiency, and extensibility. Its features include procedural rib generation, full network rendering support, segmented rib files, a shader assignment interface, and much more. Along with the ability to write full C++ plug-ins, it is incredibly easy to script Liquid with Mel. Liquid was used for the visual effects of the "Lord of the Rings" movie.
The glAppGrapher is an interactive OpenGL-based debugging "watch window" that communicates with your program via Berkeley sockets. Its purpose is to simplify mondain tasks of debugging a physics engine or other 3D application. The program may work over the Internet or your LAN, and is supported in both Windows and Linux environments.
Fandango is a GL-rendered, Python-scripted CAD program. The low-level functionality is programmed in C++, and then the relevant functions are exposed to Python and used as building blocks for more functions. Currently the memory core allows lines, triangles, line strips, and triangle strips. Texture, blending, and lighting can be switched on and off from a command line.