Avogadro libraries provide 3D rendering, visualization, and analysis
Open Source Solid Modeling CAD
LDraw™ editor for LEGO® style digital building instructions.
Cross Platform Professional Procedural Terrain Generation & Texturing
Simple voxel raycasting engine in SFML with multithreading support
Gimpel3D - 2D/3D Stereo Conversion Editor
Pear3DEngine is a modern and modular 3D development framework
Megalui: 2D/3D OpenGL & C/C++ Library for Scientific Visualizations
povray modeler