3DM-G(1)

📦
version 7.44.0 · 2 versions
, in nixpkgs unstable

💅 3DM-G(1) — or, how to turn your Rhino3D model into a BRL-CAD database, bestie

Okay so real quick, this page lives in the BRL-CAD manual section, and it's about one tiny iconic little tool called 3dm-g. Buckle up 🎀

✨ NAME ✨

3dm-g — converts a Rhino3D (.3dm) model into a BRL-CAD database. that's it. that's the whole vibe. 💖

🌸 SYNOPSIS 🌸

3dm-g [-r] [-v] [-h] [-o output_file.g] input_file.3dm [output_file.g]

🦋 DESCRIPTION 🦋

So 3dm-g takes your Rhino3D file input_file.3dm and turns it into a BRL-CAD geometry database, output_file.g. And like, you've got options for naming that output file — you can use the -o option or you can just drop it as the final positional argument. pick your fighter, both slay. 💅

Now here's the part that's genuinely so cool — BRL-CAD uses the OpenNURBS library both to read .3dm files and as the foundation of its own NURBS support. so the conversion is typically direct and reliable. no cap, it just works. ✨

The translation itself happens through the libgcv geometry conversion library, which means the exact same import behavior is available from other BRL-CAD tools too — like mged(1) and gcv. same energy across the whole friend group fr fr 🫶

💖 OPTIONS 💖

  • -r — randomizes the colors assigned to imported objects. lowkey this is the move when you've got a bunch of distinct components and you need to tell them apart visually. it's giving rainbow realness 🌈
  • -v, --verbosity — turns up the verbosity of conversion progress reporting. and yes bestie, it may be repeated to raise the verbosity level even further. stack 'em. go off. 🔥
  • -o, --output _output_file.g_ — sets the output BRL-CAD database filename. this one's required if you're not passing the output file as the final positional argument. so like, pick one, don't leave it hanging 😭
  • -h, --help, -? — prints a usage message and exits. the classic. the icon. the "help me help you" 🎀

⭐ EXAMPLES ⭐

Example 1. Basic conversion

3dm-g model.3dm model.g

This converts the Rhino3D file model.3dm into a BRL-CAD database named model.g. simple. clean. no notes. 💅

Example 2. Verbose conversion with randomized colors and a follow-on render

3dm-g -r -v -o nist.g NIST_MBE_PMI_7-10.3dm
rt -o nist.png nist.g NIST_MBE_PMI_7-10

So here we're importing the NIST MBE PMI sample model into nist.g, with randomized object colors and detailed progress output — like, we're watching it happen, main character energy 👑

Then it uses rt(1) to ray trace the resulting top-level assembly out to a PNG image, so you get a quick visual check of the conversion. genuinely obsessed, ngl 🧚

💀 DIAGNOSTICS 💀

OpenNURBS diagnostic messages may be emitted while the .3dm file is being read. so like, if you see chatter while it's reading, that's just what's happening. don't panic 💜

🌟 SEE ALSO 🌟

brlcad(1), mged(1), rt(1), g-stl(1), stl-g(1)

go read those too, they're all in the group chat 🫶

👑 AUTHOR 👑

BRL-CAD Team — icons only.

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

fr fr if something's broken, tell them — they want to know 💖

okay and finally, this whole page is from the BRL-CAD family, dated 3DM-G(1) energy through and through — go convert something gorgeous, bestie. slay. periodt. ✨🎀💅

📦 where this page comes from