Creo Reverse Engineering (Restyle) > Creating Curves in Restyle > To Create a Free Curve that Snaps to Geometry
  
To Create a Free Curve that Snaps to Geometry
1. Click Restyle > Curve > Through Snap Points.
2. Select points on the existing geometry for the free curve to pass through and middle-click. Restyle creates a curve that passes through the selected points. This free curve snaps to the existing geometry.
 
* Snapping does not create constraints. The curve does not change if the existing geometry on which it lies changes.