For several years now I have been working on my own 3D game engine, originally intended for the 3D version of Seed of Chaos, but although that project never got off the ground I still work on the engine for educational purposes and for other personal projects. The engine is written in C# and uses XNA, mainly for the graphics device and math library. The Scene, Model, Mesh, Material classes etc are all custom taylored for the engine. I have also recently integrated the Bullet Physics Engine.
Below is a brief list of Engine features:
-Real-time per-pixel lighting with normal mapping with several light types
-Normal mapped ambient pass with placeable ambient lights to vary color and intensity of ambient lighting in the environment, blended with ambient occlusion.
light maps for ambient and global illumination
soft shadows and projected texture effects on light sources
-Utilizes the Bullet Physics Engine for rigid body physics and ragdoll
detection and character animation
scene system allowing various game types to be made easily with the
engine (i.e. the engine is just as suited for making an RTS as it
would be for a FPS).
Click on the image below to see a brief demo video of my 3D Game engine
Below are some screenshots of the engine and the editor
2D Seed of Chaos Game in Progress