iges-g — IGES Translator (IGES CSG to BRL-CAD)


iges-g [-X NMG_debug_flag] [-x rt_debug_flag] [-N solid_name] [-b ] [ -n | d | 3 | t ] -o database.g file.iges


iges-g converts the specified file.iges to a BRL-CAD database.g file. The IGES file is expected to conform to IGES 5.1. The -n option specifies that all rational B-spline surfaces in the IGES file should be combined into one BRL-CAD spline solid. The -d option indicates that IGES drawings should be converted to BRL-CAD NMG objects. Theses objects will be two-dimensional drawings, not solids. The -3 option is the same as the -d option except the final projection into 2D is not performed. This may produce 3D drawings in cases where the drawings have been produced from a 3D model. The -t option requests all the trimmed surfaces in the IGES file be converted to a single BRL-CAD NMG solid. The -N option provides a name to be used for the single solid created under the -n or -t options, and is ignored for other options. The -p option indicates that BREP objects should be converted to NMG solids rather than the default BOT solids. The -X and -x options allow the setting of debug flags for the NMG routines and the rt library respectively. See nmg.h and raytrace.h for details. The absence of any of the -n , -d , or -t options results in the default behavior where all IGES CSG and planar face BREP objects are converted to BRL-CAD equivalents. Most conversions are exact, with the exceptions of the solid of revolution and the solid of linear extrusion. These solids do not exist in BRL-CAD and are therefore approximated. The solid of revolution is built from a series of truncated right cones developed by approximating the curve to be revolved with a series of straight line segments. The extrusion is similarly handled by approximating the curve to be extruded with straight line segments and using that to build a BRL-CAD polysolid. Planar faced IGES BREP objects are converted to BRL-CAD NMG structures.


$ iges-g -o -o sample.g sample.iges


The Initial Graphics Exchange Specification (IGES) Version 5.1, IGES/PDES Organization, September 1991


Error messages are intended to be self-explanatory.


John Anderson; Susanne Muuss; Phil Dykstra; Earl Weaver


This software is Copyright (c) 1991-2016 by the United States Government as represented by U.S. Army Research Laboratory.


Reports of bugs or problems should be submitted via electronic mail to <>.