Command entry: 
Modify panel
Select a NURBS object.
Modifier stack display
Curve sub-object level
Select an independent CV curve sub-object.
CV Curve rollout
Rebuild button
The Rebuild button for CV curves displays this dialog. It lets you specify how to rebuild the curve. Rebuilding the curve
can change its appearance.
Interface
- Tolerance
-
Rebuilds the curve according to accuracy. The lower the Tolerance value, the more accurate the rebuild. Increasing Tolerance
enables the curve to be rebuilt using fewer CVs.
- Number
-
(The default.) Lets you alter the number of CVs in the curve.
- Preview
-
When on (the default), your changes are previewed in viewports.
