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.
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.
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.
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.
Drome Engine is a 3D game engine written in C++ using OpenGL for graphics rendering. Some of its features include dynamic lightmaps, stenciled shadow volumes, particle effects, md2 model loading, PCX and PNG image loading, TrueType font loading, simple physics, and a Quake-style console.
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.