Crazy Eddie's GUI (CEGUI) system is a graphical user interface C++ library. It was designed particularly for the needs of videogames, but the library is usable for non-game tasks, such as any other type of applications (rendering/visualisation/virtual reality) and tools. It is designed for user flexibility in look-and-feel, as well as being adaptable to the user's choice in tools and operating systems.
Crimild Engine is an open source scene graph based engine which purpose is to fulfil the high-performance requirements of typical multi-platform two and tridimensional multimedia projects, like games, simulations and virtual reality.
Framework and set of object-oriented and/or generic libraries designed for games and virtual reality simulations. Abstracts interfaces of APIs and provides additional general and high-level functionality for rapidly creating solid applications.
MyWorld is an open virtual reality and game engine. It is written and usable in C/C++. It has own abstract layers for Graphics and Physics. Actually we use Irrlicht for 3D-Rendering and GUI, and ODE for Physics. It is smart, powerful and easy to extend.
OpenReality will be a 3D Engine Library for development of Games, Virtual Reality and 3D Visualization applications. It will be very intuitive, and strongly object oriented. Of course, performance will have a great weight on the project´s decisions.
the simple universe library aims to provide a simple (possibly game-oriented) virtual reality where real-world objects and surfaces (like terrain) can be defined and simulated. Uses OpenGL and ODE.