G-IGES(1)

NAME
g-iges - IGES Translator (BRL-CAD to IGES)

SYNOPSIS
g-iges [-f|t|m] [-v] [-s] [-x flag1] [-X flag2] [-a abs_tol] [-r rel_tol] [-n norm_tol] [-o output_file_or_directory] database.g object(s)

DESCRIPTION
g-iges converts the specified objects of the BRL-CAD database, database.g, to an IGES version 5.1 file, file.iges. The -f option selects a BREP IGES file consisting of only Manifold Solid BREP Objects. All CSG solids in the specified objects are tessellated to produce facetted BREP objects, then the indicated Boolean operations are performed for each region. Individual regions are written to the IGES file as individual BREP objects. This procedure results in some approximations since curved surface solids, such as TGCs or ellipsoids, are approximated by flat facets. The accuracy of the tessellation may be controlled through the use of the -a, -r, and -n options to specify tolerances. The -t option indicates that an IGES file consisting of only trimmed NURBs should be created. The trimmed NURBs will all be planar NURBs, and they are the facets derived from the tessellation and Boolean evaluation as in the -f option. The file produced in this way is acceptable to the Pro/Engineer IGES import routine. The -m option implies the -t option, and is used to produce multiple IGES files (one for each region converted). In this case the argument to the -o option should be a directory where the IGES files will accumulate. The -s option may be used in conjunction with the -f option or without the -f or -t options to indicate that all facets in BREP objects should be output in the form of planar NURBs (Intergraph likes their IGES files this way). If neither the -f , -t , nor the -m options are selected, the default is a CSG IGES file. In this situation, all regions will be written to the IGES file as Boolean trees with all possible solids represented by their IGES CSG equivalent. In cases where there is no IGES CSG equivalent, the BRL-CAD solid is tesellated (using the provided tolerances), and a BREP object is written for that solid. The -x option allows the user to set a hex librt debug flag (see librt/debug.h for values). The -X option allows the user to set a hex NMG debug flag (see h/nmg.h for values). The -v option requests debugging information.

EXAMPLE
g-iges -f -o sample.iges sample.g object1
This command will produce an IGES BREP output file, sample.iges, from object1 of the BRL-CAD database file sample.g.

SEE ALSO
iges-g(1).
The Initial Graphics Exchange Specification (IGES) Version 5.1, IGES/PDES Organization, September 1991.

DIAGNOSTICS
Error messages are intended to be self-explanatory.

AUTHOR
John Anderson

SOURCE
SECAD/VLD Computing Consortium, Bldg 394
The U. S. Army Research Laboratory
Aberdeen Proving Ground, MD 21005

BUG REPORTS
Reports of bugs or problems should be submitted via electronic mail to <CAD@ARL.ARMY.MIL>.