Creo Interactive Surface Design (Style) > Curves > Creating Curves > Offset Curves > About Offsetting Curves
  
About Offsetting Curves
Use the Offset Curve tool create offsets from different types of curves.
Multiple Offset Curves
Some offset values can produce cusps or self-crossing curves where the curve splits into multiple curves to retain the cusp-point. This results in more than one offset curve.
Redefining Offset Curves
Offset curves maintain history. You can redefine the offset curves and change the offset options in one of the following ways:
• Double-click the offset curve.
• Select the curve, right-click and choose Edit Definition.
Editing Offset Curves
You cannot edit the shape of an offset curve. You must convert an offset curve to an independent curve before editing it.
Use Curve > Convert to make an offset curve independent of its parent curve, and then use Curve Edit to edit the curve.
 
* The curves do not maintain history after conversion.