HOLES                                                      Menu: (POLYG) PEDIT
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Defines a group of 2-dimensional polygons as an external positive polygon
containing negative (internal) polygons (holes).

          1.  (IND) polygon in which to make holes
          2.  (Y/N) confirm choice ?
          3.* (IND) hole polygon
          4.* (Y/N) confirm choice ?
          5.* (Y/N) define more holes?

Description
Use this command if you intend to calculate areas of polygons (using the \area
command) and an internal part of one of the polygons is to be excluded from
the area calculation, e.g., a flight of stairs.  You must create a polygon
around the area(s) to be subtracted from the external positive polygon.  You
may define a number of internal "hole" polygons for each external polygon.

When you use this command, the internal polygons are copied and form an
integral part of the external polygon, as if they were created together using
the \pjump command.  The original internal polygons remain as independent
polygons.

Polygons participating in this operation must be 2-dimensional and on the same
plane.  You may give height to the resultant polygon.  The hole polygons will
form holes in the solid.

Indicate and confirm the external polygon in which the holes are to be made.
Then indicate the first polygon that is to be a hole.  You are prompted to
define additional holes.
