NURBS surfaces

NURBS surfaces are based on splines and are mainly used for free-form surfaces such as those used in the automotive industry. There are two processes for creating NURBS surfaces and several commands to edit them, which are presented next.

Creating NURBS surfaces

We can create NURBS surfaces by previously specifying a value 1 for the SURFACEMODELINGMODE system variable and applying surface creation commands, or by converting existing objects with the CONVTONURBS command.

The SURFACEMODELINGMODE variable

When creating surfaces, the SURFACEMODELINGMODE variable controls if NURBS or procedural surfaces are created:

• 0: With this value, a procedural surface is created when creating surfaces.

• 1: With this value, a NURBS surface is created when creating surfaces. It is applied to all surface creation commands, with the exception of PLANESURF.

This variable is not saved and by default is set to 0.

The CONVTONURBS command

The CONVTONURBS command (no alias) allows you to convert procedural...