BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.
view3dscene is a browser for VRML (1.0 and 2.0) and X3D, and a viewer for other 3D model formats (3DS, MD3, Wavefront OBJ, and Collada are handled). It supports viewing the scene in the "Examine" mode and walking in the virtual world with features such as collision detection and gravity. Rendering is done using OpenGL. Many advanced 3D graphic effects are available, like mirrors (flat and through cube environment mapping), shadows (shadow maps and shadow volumes), GLSL shaders and more. The program can also convert files from 3DS, MD3, Collada and other formats to X3D and pretty-print VRML and X3D files.
PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
Drqueue is a distributed rendering queue. It helps manage jobs on a render farm. It works under Linux, Mac OS X, FreeBSD, IRIX, and Windows, supports Maya, Blender, Lightwave, Mental Ray, Bmrt (Renderman), 3Delight, and Pixie out of the box, and can support any other renderer or computing task that can be handled via scripting.
G3D is a C++ library for game developers, researchers, and students. It is a base of robust and high performance code common to most 3D projects. It is not a stand-alone graphics or game engine, but is a set of pieces to jump start your own engine or graphics project. The library has two parts: G3D for pure math, and GLG3D for interacting with hardware acceleration via OpenGL. You can use G3D without GLG3D if you want to use another 3D API (like DirectX) or don't like the OpenGL abstraction.
NUI is a GUI ToolKit intended to work with SGI's OpenGL API. It is similar in many ways to GTK+, Qt and even Win32, but with many enhancements in order to make it an easy and yet powerful tool for cross- platform GUI programming. It is currently developed on platforms supported by the NGL framework.
ManiWheel is a GL hack for xscreensaver. It draws the spinning Tibetan mantra, "OM MANI PEME HUNG" for the blessing of all beings. It features transparent and no-transparent modes, two internal textures, the option to enable or disable a specular image. The height, radius, shininess, distance, and speed of rotation may be changed. It can also be used to draw any texture in the .rgb format.
Octaviz is a visualization system for Octave. It is a wrapper that makes all VTK classes accessible from within Octave using the same object-oriented syntax as in C++ or Python. It also provides high-level functions for 2D and 3D visualization. Using those functions, most common visualization tasks (3D surface plots, contour plots, meshes, etc.) can be accomplished without any knowledge about VTK.