OGRE
Open SourceOGRE (Object-Oriented Graphics Rendering Engine) is a flexible, scene-oriented, real-time 3D rendering engine. Unlike a full game engine, OGRE focuses solely on the rendering pipeline, providing a powerful abstraction layer above lower-level graphics APIs like Direct3D and OpenGL. It's a cross-platform solution ideal for developers building custom 3D applications, simulations, or games, offering extensive control over the rendering process and scene management.