G-ACAD(1)

🎀 NAME 🎀

g-acad — BRL-CAD to Lockheed Martin ACAD facet file converter. This is the G-ACAD(1) page from the BRL-CAD manual, and bestie, it’s giving “take my BRL-CAD geometry and turn it into an ACAD facet file” energy. 💅

🛠️ 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)

🌸 DESCRIPTION 🌸

okay so 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. slay. ✨

⚠️ Not me clarifying this again: this format has literally nothing to do with the Autodesk AutoCAD software. Different thing, bestie. 💀

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

✨ OPTIONS ✨

• -v — Enable verbose output, reporting each region as it is processed. she’s chatty and we love that.
• -i — Output vertex coordinates in inches (the default is millimeters). inches era. 📏
• -x lvl — Set the librt debug flag to the given hexadecimal value. hex girl debug moment.
• -X lvl — Set the NMG debug flag to the given hexadecimal value. more hex, more debug, more vibes.
• -a abs_tol — Absolute tessellation tolerance (mm). This is 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). yup, that’s the default, don’t come for me.
• -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. lowkey the “same vertex” detector.
• -P ncpus — Number of processors to request (currently informational only; tessellation runs single-threaded). she’s asking for the whole squad but actually running solo. 😭
• -e error_file — Write error and diagnostic messages to error_file instead of standard error. keep the messy tea in a file. 🍓
• -o output_file — Write the ACAD output to output_file instead of standard output. put it somewhere cute.
• -h, -? — Print a usage message and exit. help and bounce. 👋

🧪 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. iconic little conversion moment. 🔥

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. main character tessellation behavior, fr fr. 👑

👀 SEE ALSO 👀

brlcad(1), g-stl(1), g-obj(1), g-vrml(1), mged(1) — go read those next, bestie. 🫶

👑 AUTHOR 👑

BRL-CAD Team — iconic. periodt. 💜

📜 COPYRIGHT 📜

This software is Copyright (c) 1989-2026 by the United States Government as represented by U.S. Army Research Laboratory.

🐛 BUG REPORTS 🐛

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org. don’t suffer in silence, send the bug report. 🙈

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that’s the whole page, bestie 💖 source/version: BRL-CAD; page: G-ACAD(1). The footer doesn’t give a date, so we’re not inventing one — we keep it fr fr. 🫶