G-VRML(1)

📦
version 7.44.0 · 2 versions
, in nixpkgs unstable

💅 g-vrml — your girl's guide to yeeting BRL-CAD geometry into VRML 2.0

okay so first things first: this is page one of the BRL-CAD manual, section 1, and it's literally called g-vrml. she converts stuff. she slays. let's get into it 💖

✨ NAME ✨

g-vrml — convert a BRL-CAD geometry database to a VRML 2.0 file 🦋

🌸 SYNOPSIS 🌸

g-vrml [-b | -e] [-v] [-d calc_dist_tol] [-a abs_tess_tol] [-r rel_tess_tol] [-n norm_tess_tol] [-u units] [-x librt_debug_flag] [-X NMG_debug_flag] [-o output.wrl] database.g object [object ...]

like, that's the whole mood. database.g in, object(s) named, VRML out. periodt 💅

🎀 DESCRIPTION 🎀

so g-vrml takes the objects you name from a BRL-CAD geometry database (database.g) and turns them into a faceted Virtual Reality Modeling Language (VRML) version 2.0 file. iconic behavior honestly.

by default, each region gets tessellated and its Boolean operations get evaluated through the NMG routines, which produces a triangulated IndexedFaceSet per region. region colors and shaders — plastic, glass, texture — get translated into VRML material and texture nodes, and regions using the light shader get emitted as VRML light sources. the way that all just… works 🫶

the result goes to the file you name with -o, or to standard output if you don't give -o. output units default to millimeters; peep -u if you want a different unit. and ngl, this conversion is the inverse direction of what importers like vrml-g would be — it complements other geometry exporters like g-stl(1) and g-obj(1). bestie squad of converters fr fr 💜

🔥 OPTIONS 🔥

  • -b — dump BOT (Bag of Triangles) primitives straight to the VRML file with zero Boolean evaluation happening; non-BOT (CSG) primitives just get skipped. heads up: this is mutually exclusive with -e 🚫
  • -e — evaluate all the geometry, tessellating and doing the Boolean evaluation of both CSG and BOT primitives. also mutually exclusive with -b, pick a lane bestie 💀
  • -v — verbose mode; reports conversion progress on standard error. she's chatty, we love her 🙈
  • -d calc_dist_tol — calculational distance tolerance in millimeters, used to tell neighboring vertices apart. the default is 0.005 📏
  • -a abs_tess_tol — absolute tessellation tolerance in millimeters (that's the maximum chord error). setting this disables the relative tolerance ⚠️
  • -r rel_tess_tol — relative tessellation tolerance, expressed as a fraction of the bounding box of each primitive. the default is 0.01 ✨
  • -n norm_tess_tol — surface normal tessellation tolerance in degrees (the maximum allowed angle between approximated and true surface normals). setting this disables the relative tolerance too ⚠️
  • -u units — units for the resulting VRML file. default is mm. literally any unit name BRL-CAD accepts works (for example m, cm, in, ft) 🌈
  • -x librt_debug_flag — set the librt debug flag (hexadecimal). see raytrace.h for the bit values 🔍
  • -X NMG_debug_flag — set the NMG debug flag (hexadecimal). see nmg.h for the bit values 🔍
  • -o output.wrl — write output to the named file. if you omit it, output goes to standard output 🎯
  • -h, -? — print a usage message and exit. the classic escape hatch 😌

🧚 EXAMPLES 🧚

Example 1. Convert specific tops objects to a VRML file

g-vrml -o havoc.wrl -u m havoc.g havoc

tessellates and Boolean-evaluates the havoc object from havoc.g and writes a VRML 2.0 model in meters to havoc.wrl — ready to load in a web or desktop VRML viewer. chef's kiss, no notes 👑

Example 2. Export only the triangle meshes from a model

g-vrml -b -o meshes.wrl model.g body wheels

dumps the BOT meshes contained under the body and wheels objects directly, skipping CSG primitives and the comparatively slow Boolean evaluation. this is the move when a model is already mostly faceted and you just want a fast export ⚡

🦋 SEE ALSO 🦋

brlcad(1), mged(1), g-stl(1), g-obj(1), g-dxf(1)

(the whole friend group, go say hi 💕)

👑 AUTHOR 👑

BRL-CAD Team — icons, legends, the whole vibe 🫶

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

🌺 BUG REPORTS 🌺

found a bug? a problem? a little oopsie? reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org 📬 — they wanna hear it, fr fr.

and that's the whole page bestie!! this was page G-VRML(1) from the BRL-CAD manual set, dated at the bottom like a little signature — same version, same date, same energy. mwah 💋✨

📦 where this page comes from