conversion of a NURBS surface to analytical form

I have seen an interesting method of ShapeCustom_Surface, but I have found no call to it under "ros" and it was never mentioned in the forum.
Does anyone use it?

Handle_Geom_Surface ConvertToAnalytical (const Standard_Real tol, const Standard_Boolean substitute)
Tries to convert the Surface to an Analytic form
Returns the result
Works only if the Surface is BSpline or Bezier.
Else, or in case of failure, returns a Null Handle

If is True, the new surface replaces the actual
one in

It works by analysing the case which can apply, creating the
corresponding analytic surface, then checking coincidence
Warning: Parameter laws are not kept, hence PCurves should be redone


Forum supervisor's picture

Hello Mauro,

This functionality is obsolete and is not supported.
The complete and up-to-date functionality to convert NURBS geometry (surfaces and also curves) in shapes is provided by our advanced component - Canonical Recognition (

Best regards,
Forum Supervisor

jiang jing's picture


I need to get a line (not polyline) by some points,can you give any idea?I consider the method of least square  to sovle it,but I don't know how to do it.