These topics describe how to create top-level, “starter” NURBS objects.
To create independent surfaces from top-level NURBS curve objects, use the Extrude and Lathe modifiers. Extrude adds height to the curve, creating a shape by sweeping it along the curve's local Z axis. Lathe creates a surface of rotation, revolving the shape along a specified axis. You can also use the Bevel and Bevel Profile modifiers on NURBS curves.
You can turn a spline into a NURBS object formed of CV curves. Once converted, you can no longer edit the spline shape parametrically, but you can edit it as a NURBS object, moving CVs and so on.
You can turn a standard primitive into a NURBS object formed of CV surfaces. Once converted, you can no longer edit the object parametrically, but you can edit it as a NURBS object, moving CVs and so on.
Nonrelational NURBS surfaces provide a way to improve the performance of NURBS with modifiers. These are controlled by the Relational Stack toggle on the General rollout for NURBS objects.
The check boxes on the General rollout for a NURBS curve or surface control how the object is displayed in viewports. If all check boxes are turned off, the NURBS object is invisible (except for the white bounding-box indicators displayed in shaded viewports when the object is selected).
These parameters are contained on a single rollout at the top level of a NURBS object.