Ambrose3D is a simple, but useful 3d-engine in C/C++ based on OpenGL and SDL. It does not include too many buzzword features, but it's complete enough to be useful starting point for all kinds of interesting things you can do with 3d hardware.
Being a "bare bones" engine it is possible for a mere mortal to understand everything about the engine.
Ambrose3D is free for anyone to use, extend, and learn from, and this is what it was designed for. The source code is licensed under the very liberal zlib/libpng license; the exporter is gpl.
Ambrose3d 1.0 including vs.net03 project, sources and win32 binaries
See 'installing' for install instructions, 'engine' for engine structure description, 'exporter' for exporter description, and 'project ideas' for some Ambrose3D extension project ideas and hints.