The HOOPS 3D Graphics System is a 3D Graphics API, part of The HOOPS 3D Application Framework. The HOOPS 3D Application Framework contains three main elements.
The first is the core HOOPS 3D Graphics System, a 3D scene-graph API. The second is a rendering pipeline that drives a number of lower-level API’s, including OpenGL and Direct3D.
Finally, a layer of “application-level” functionality sits atop the scene-graph.