Creo Reverse Engineering (Restyle) > Managing Domains in Restyle > To Add a Loop to a Domain
  
To Add a Loop to a Domain
1. Click Restyle > Curve > On Facet.
2. Select points on the faceted surface such that the resulting curve forms a closed loop inside the existing domain or intersects the existing domain.
3. Click Restyle > Add Loop and click inside the original domain. Select a point in the region for adding a loop. Adding a loop limits the domain by excluding the points that lie inside your selected region.