Nurb Solids


I’ve been trying to understand how exactly are solids constructed in rhino?
according to the nurbs we should have 3 knot vectors and their corresponding control points.
When building a solid on rhino it only builds multi-polisurfaces where i dont find a option to view the control points rather the only option is the meshing option.

How exactly are solids modeled?
is it possible to obtain the 3 knot vectors and the control points of a solid?
is it possible to refine the degree of the nurbs/splines and the control mesh as in a nurb surface (rebuild command)?
is it possible to extract it to a .txt file?

thanks in advance.

You are correct, solids are not constructed using the NURBS volume approach with three knot vectors. Instead, they are constructed of polysurfaces with (possibly trimmed) faces, with each face having two knot vectors. As long as these faces form a closed assembly, it is called a solid in Rhino.

If you want to see details of any object, you can use the List command, the output of which can be copy-pasted into a text file. Of course, it is also possible to write your own code to interact with objects, then you can get at all the details like controls point locations, knot vectors, etc.