Horde3D is a 3D rendering engine. It is designed to be simple and lightweight while providing the functionality for next generation graphics. While Horde3D is written in C++ and it's internals employ object-oriented design it's API is C-like allowing bindings to easily be created for most languages.
The engine has a customizable rendering pipeline and an extension system.
In the future the Horde3D engine may be simplified further by moving scene-graph-management to an extension, allowing for more flexible use which can be more naturally integrated into the application logic (for example a physics-engine).
It is licensed under the Eclipse Public License.