OpenCSG is a library that does image-based CSG rendering using OpenGL. OpenCSG
is written in C++ and supports most modern graphics hardware.
What is CSG, anyway? CSG is short for Constructive Solid Geometry and denotes
an approach to model complex 3D-shapes using simpler ones. I.e., two shapes
can be combined by taking the union of them, by intersecting them, or by
subtracting one shape of the other. The most basic shapes, which are not
result of such a CSG operation, are called primitives. Primitives must be
solid, i.e., they must have a clearly defined interior and exterior. By
construction, a CSG shape is also solid then.