Creo Interactive Surface Design (Style) > Surfaces > About Chains in Style
  
About Chains in Style
You can use one-by-one or rule-based edge chains as references in the Surface and Curve from Datum tools.
For the Surface tool, the chain segments require tangent continuity or greater. They can be part of the current Style feature, or they can be external Style curve segments.
For the Curve from Datum tool, the chain segments require position continuity or greater.
When you create a surface, or when you align two surfaces using the Surface Edit tool, you can adjust the edge chain length in the following ways:
Drag the drag handles.
Snap to a reference.
Specify a measurement.
You can also reorder the chains in a surface without deselecting them.