Realtime raytracer using SIMD on ARM, MIPS, PPC and x86
Viewer and exporter for Unreal Engine 1-4 assets
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
3D Software Renderer in 700 Lines
Pear3DEngine is a modern and modular 3D development framework
A library to create anaglyph images with Java
Bruno's RAY Tracing Engine
1st 3D game engine built in C# for .NET, Visual3D Engine's predecessor