No comprehensive NURBS surfaces lib available?

I am surprised not to find open and free comprehensive C++ libraries related to NURBS curves and surfaces. These are very much used in the CAD, CG, or robotics industries. Hence I was expecting to find a few comprehensive libraries available to developers on the Internet but all I can find are pay-for libraries (check SMS here), or old libraries which are no longer maintained and not really comprehensive as old nurbs++ here.

Most Internet NURBS libraries offer a few evaluation methods for curves and surfaces and that's it... when I am expecting advanced functions such as approximation of points by curves and surfaces, trimmed surface tessellation, fillets computation, swung, skinned, swept, Gordon, Coons surfaces and more.

I currently especially need code for advanced surface approximation from cloud points.

Am I missing something?