Tcl3D provides OpenGL bindings for TCL scripts. It's a SWIG-generated wrapper for 3D rendering using OpenGL, or alternatively SDL, OpenSceneGraph, Open Dynamics Engine or Nvidia Cg. It provides custom extensions like gauge drawing and various utility functions on top.
Blender is a free and open source 3D animation suite. It supports the entirety of the 3D pipeline—modeling, rigging, animation, simulation, rendering, compositing and motion tracking, even video editing and game creation. Advanced users employ Blender’s API for Python scripting to customize the application and write specialized tools.
OpenCSG is a library that does image-based CSG rendering using OpenGL. CSG is short for "constructive solid geometry" and represents a modeling technique for composing shapes with 3D-primitives which are combined using volumetric boolean operations. Image-based CSG rendering means rendering CSG shapes without calculating their surface in object-space. Instead, the image of a CSG shape is composed directly in the frame-buffer of the graphics hardware by rather sophisticated stenciling and z-buff
BitWrk is a peer-to-peer computation service that tightly integrates into Blender, the 3D rendering software. BitWrk greatly accelerates rendering by scaling to a swarm of computers. Fueled by Bitcoin, BitWrk creates an open marketplace where participants buy or sell computing power like stocks in a stock exchange.
appleseed is an open source, physically-based global illumination rendering engine primarily designed for animation and visual effects. It provides individuals and small studios with a complete, reliable, fully open rendering package built with modern technologies.
Titania is a X3D/VRML editor and browser. It's intended to become a fully standard-compliants X3D renderer for future Ubuntu releases. It already completely implements the Moving Worlds specification for VRML 2.0, and most parts of the X3D spec. Titania can also be used as 3D viewer for .wrl files, as 3D rendering engine, data visualization, and even as game engine. It comes with x3dtidy for beatifying X3D/VRML files.
Functy is a 3D graphics generation tool. It plots cartesian, spherical or parametric curve functions. It allows altering their parameters for immediate redraws to explore 3D function results. It utilized GPU functions entirely for visualization.
delta3d is a game and simulation engine. It integrates Open Scene Graph, Open Dynamics Engine, Character Animation Library, OpenAL, and Qt in an easy to use API.