8.2.7} Region data

 The various regions are described in terms of differences, intersections
 and unions of bodies. As in the case of body description, the user has the
 choice between free format and two kinds of fixed format. One of the latter
 is the traditional format used by the original Combinatorial Geometry as
 implemented for example in MORSE. The other fixed format is similar to it, but
 has been extended to allow body numbers larger than 10000. Both fixed
 formats are now superseded by the more convenient free region input format,
 recently introduced. Free format is based on body mnemonic "names" instead
 of sequential numerical identifiers and allows the use of parentheses to
 perform more complex boolean operations. However, the two fixed formats are
 still available for back compatibility reasons.
 With any input format, a line having an asterisk (*) in column 1 is
 treated as a comment card.

Previous Index Next