About Surface Regions
You can create surfaces with multiple surface regions by creating a surface with multiple loops or by making a cut through an existing surface.
To select a surface region, set the smart filter to Surface Regions or use the Pick From List dialog box. You can use a surface region in the following ways:
• As the seed surface for rule-based surface sets. The surface set collects surface regions that satisfy the specified rule.
• To add to a surface set.
• As the boundary for a rule-based surface set.
• To add to the excluded surface set.