High-efficiency minimalist C++ wrapper for OpenGL 4.3
A real-time 3D engine for DOS-talgics (see GLOBE_3D for new stuff !)
rayshade and POV for Mathematica Export + view
Cross Platform Professional Procedural Terrain Generation & Texturing
Growth-grammar related Interactive Modelling Platform
Vivid is a modern C++ 3D engine using OpenGL4+
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
Realtime 3D engine for game development
XNA based game engine completely written in c#
3D game engine for C and C++
Pear3DEngine is a modern and modular 3D development framework
Game engine supporting many 3D/2D formats and graphic effects