MeshToNURB converts each mesh face into a NURB surface. It’s primary use is with low density meshes.
There is no simple command that I am aware of to convert a polysurface to a single surface.
There are many ways to create a NURBS surface from a high density mesh. The “best” method depends on a number of factors including:
- Topology of the shape. Can the shape by represented by untrimmed NURBS surfaces?
- How smooth is the shape.
- How accurately does the NURBS model need to conform to the mesh.
- Density of the mesh.
- Topology of the mesh. Is the mesh quad only cells arranged in rows and columns or does it have a more random arrangement
- User knowledge.
One method I frequently use for shapes which can be represented by an untrimmed NURBS surface is Patch with a starting surface.
DupBorder on mesh
Point to create points at corners of border polycurve
Split border polycurve using corner points
EdgeSrf to create a starting surface
Patch with mesh as object to fit to. Check
Select starting surface.
Select the starting surface. Make sure
Preserve edges is checked.
Added: Experiment with values of Stiffness for the starting suface. I typically use 0.1. Patch can be run several times using the previous result as the starting surface.
The resulting surface can be simplified if desired using the usual tools.