Creo Interactive Surface Design (Style) > Regeneration > To Automatically Regenerate Curves
  
To Automatically Regenerate Curves
Curves automatically regenerate during editing. To set the curve regeneration options, perform the following actions:
1. Click Style > Operations > Preferences. The Style Preferences dialog box opens.
2. To automatically generate the curves, under Auto regenerate, select the Curves check box.
If the Style feature is complicated, with a large number of curves, you can choose not to select this option to avoid the impact on performance.
Automatic regeneration applies to all curve edit operations. Curves that are children of a modified curve are updated. In the case of splitting a curve, all children of the original curve, and therefore of both resulting curves, are updated.
Typically, a child curve contains a soft point on the parent, but other situations, such as curves having aligned tangents, can create the parent-child relationship.
Curves are also automatically regenerated if you edit them in the following situations:
Multiple curves.
All dependent curves that are not created as surfaces or COS by dropping curves on a surface.
 
* If a child curve fails to regenerate, the processing of other non-dependent child curves is completed. The Resolve dialog box is not displayed. The next auto-regeneration tries to update the failed entity again.