This command allows you to identify closed polylines to be used as inclusion or exclusion boundaries. These boundaries are applied in Surface Menu commands such as Two Surface Volumes and Triangulate & Contour. Inclusion polylines limit processing to inside the polyline(s). For example, an inclusion polyline for volumes would be the limit of disturbed area. Exclusion polylines prevent processing inside the polyline(s). For example, a building perimeter or pond surface could be an exclusion polyline for contouring. Tag Predefined Boundaries assigns a site name to polylines and flags the polyline as either inclusion or exclusion.
Many Surface commands will prompt for inclusion and exclusion polylines. The advantage to Predefined Boundaries is that you don't have to select the boundary polylines each time that you run the Surface command. Instead, the program will recognize that the boundary is already specified and will prompt "Use predefined boundary Area 1 (<Yes>/No)?" This lets you simply press enter to use your predefined boundaries. If you want to pick different boundaries, you can type N for No and select them prior to processing. When you have more than one set of predefined boundaries, the routine lets you choose from a list of the boundary names as shown in the dialog.
Boundary name <Site 1>: Area 1
Select Inclusion perimeter polylines.
Select objects: pick the closed polylines or press Enter for
none
Select Exclusion perimeter polylines.
Select objects: pick the closed polylines or press Enter for
none
Pulldown Menu Location: Surface >> Predefined
Boundaries
Keyboard Command: plzone
Prerequisite: Closed polyline