Quesa is a 3D rendering and scene graph library for macOS and Windows, with a BSD license. It was begun way back in the year 2000 as a re-implementation of Apple's QuickDraw 3D APIs, using OpenGL 2. Rendering was recently upgraded to OpenGL 3.2. One can still get a pretty good understanding of how it works, such as the use of reference counted objects and the 3DMF object file format, in Apple's QuickDraw 3D manual.
The Quesa project was begun by Dair Grant. At its period of maximum activity, it was also administered by José Cruanyes, Roger Holmes, Kevin Matthews, Joe Strout, and James W. Walker, with contributions from a few others. Now it is solely maintained by James W. Walker.
Most recently, I have added all-seeing and fisheye cameras. See the API documentation, or the documentation comments in QuesaCamera.h.
I have added a Mac example project called FilamentViewer that illustrates how to do rendering, cameras, and lighting using Filament while using Quesa as a file format and scene graph. Not only Quesa geometries and materials, but also many Quesa style and transform objects, are converted to Filament information.