SoNurbsSurface(3) on Linux
The text 73178b40ab74, as Debian 4.0 (Etch) shipped it.
The SoNurbsSurface class is used to render smooth surfaces. Explaining NURBS is beyond the scope of this documentation. If you are unfamiliar with the principles of representing smooth curves and surfaces when doing 3D visualization, we recommend finding a good book on the subject.