New Constraint (External)
When you click the New Constraint button, the cursor will change to allow you to begin digitising a new polygon in the design. When you click a point, the constraint polygon will begin. You can click additional points in the constraint to create the polygon. To finish the string, either double-click as you digitise the last point or press Escape (Esc). The new string will be auto-closed when you have finished. The constraint polygon is shown in Red in the design:
In Shrinking mode (Pit/Down, Dump/Up), an External constraint will place the pit build area outside of any intersection between constraint polygon and pit string. In Expanding mode (Pit/Up, Dump/Down), constraints always expand the pit build area.