A WebGL-based 3D engine for technical visualization
3D Software Renderer in 700 Lines
3D .NET engine for Windows, Linux, Mac
A public domain cross platform 3D game
Design and Display Happy Cube solutions
PHIGS (Programmer's Hierarchical Interactive Graphics System)
A cross-platform game framework based on OpenGL and GObject.
Gimpel3D - 2D/3D Stereo Conversion Editor
Pear3DEngine is a modern and modular 3D development framework
Minimalist 3D Scenegraph Management Framework