G-ACAD(1)

NAME

g-acad - BRL-CAD to Lockheed Martin ACAD facet file converter

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SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

g-acad [-vi] [-x lvl] [-X lvl] [-a abs_tol] [-r rel_tol] [-n norm_tol] [-D dist_tol] [-P ncpus] [-e error_file] [-o output_file] database.g object(s)

g-acad converts the specified object(s) from a BRL-CAD database.g file to the Lockheed Martin "Advanced Computer-Aided Design" (ACAD) facet file format (formerly from General Dynamics). Each region is tessellated into a triangulated mesh using the NMG boolean evaluator and written as a separate part. Note that this format has nothing to do with the Autodesk AutoCAD software.

If no output file is specified with -o, the result is written to standard output.

OPTIONS

-v: Enable verbose output, reporting each region as it is processed.
-i: Output vertex coordinates in inches (the default is millimeters).
-x lvl: Set the librt debug flag to the given hexadecimal value.
-X lvl: Set the NMG debug flag to the given hexadecimal value.
-a abs_tol: Absolute tessellation tolerance (mm). The maximum permitted distance between a surface and its tessellated approximation. Setting this clears the relative tolerance.
-r rel_tol: Relative tessellation tolerance, expressed as a fraction of the bounding box of each object (default is 0.01).
-n norm_tol: Surface normal tolerance (degrees), the maximum angle between adjoining facet normals. Setting this clears the relative tolerance.
-D dist_tol: Calculational distance tolerance (mm). Vertices closer together than this are considered identical.
-P ncpus: Number of processors to request (currently informational only; tessellation runs single-threaded).
-e error_file: Write error and diagnostic messages to error_file instead of standard error.
-o output_file: Write the ACAD output to output_file instead of standard output.
-h, -?: Print a usage message and exit.

EXAMPLES

Example 1. Convert a region to an ACAD facet file

g-acad -o hull.acad vehicle.g hull

Tessellates the hull region from vehicle.g and writes the result to hull.acad in millimeters.

Example 2. Convert with tighter tolerances and inch units

g-acad -i -a 0.5 -n 15 -e convert.log -o tank.acad tank.g turret hull tracks

Converts three regions to a single ACAD facet file in inches, using a 0.5 mm absolute tessellation tolerance and a 15-degree normal tolerance for finer faceting, while logging diagnostics to convert.log.