Dark Matter is a 3D game engine and sandbox I worked early in XNA beta. It includes collision systems, tile-based height maps, full culling systems, in-game authoring and placement controls, basic physics, particle systems, atmosphere control, HUD alignment system, and even day and night.
Its been a fun project to work on but I haven’t been able to get back to it. It was built with Microsoft XNA and C#. It compiles for the PC, and eventually I might get it working on XBOX.Quick video demo of the overall system.
Check out the new game authoring tools from MicrosoftXNA