G-EGG(1)

💅 G-EGG(1) — the BRL-CAD manual, bestie edition 🎀

okay so bestie, welcome to G-EGG(1), a page from the BRL-CAD manual set 💖. This is the one that turns your BRL-CAD geometry into a Panda3D EGG file. Let's get into it ✨

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🌸 NAME 🌸

g-egg — convert BRL-CAD geometry to a Panda3D EGG file 🦋

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✨ SYNOPSIS ✨

g-egg [-v89] [-x rt_debug] [-X nmg_debug] [-a abs_tol] [-r rel_tol] [-n norm_tol] [-D dist_tol] [-P ncpu] [-o output.egg] database.g object [object ...]

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💜 DESCRIPTION 💜

So g-egg takes the geometry object(s) you point at in a BRL-CAD database.g and converts them into a Panda3D EGG file. Iconic, honestly 👑

Here's the tea on how it works: every object gets tessellated into a triangulated NMG via the boolean evaluator, and then written out as an EGG <Group> that holds a vertex pool plus the resulting polygons. The output uses a Z-Up coordinate system. Noted, remembered, slay 📐

If you don't hand it an output file with -o, the EGG data just goes to standard output. And when it's done? It prints a count of the triangles it produced to standard error. That's your little "we did it" moment 🫶

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🎀 OPTIONS 🎀

• -a abs_tol — absolute tessellation tolerance, in mm. Heads up: setting this disables the relative tolerance 🔥
• -r rel_tol — relative tessellation tolerance, as a fraction of the bounding box. The default is 0.01 💫
• -n norm_tol — surface normal tessellation tolerance, in degrees. Setting this disables the relative tolerance 🌀
• -D dist_tol — calculational distance tolerance, in mm, used when deciding whether vertices are coincident 📏
• -P ncpu — number of CPUs to use during tessellation. parallel bestie hours 💅
• -o output.egg — write output to the named file instead of standard output 📁
• -8 — use the marching cubes algorithm for facetization 🧊
• -9 — use the experimental "bottess" algorithm for facetization. experimental, so like… be aware 👀
• -v — verbose output (printed to standard error) 🗣️
• -x rt_debug — set the librt debugging flags (a hexadecimal bit vector) 🔍
• -X nmg_debug — set the NMG debugging flags (a hexadecimal bit vector) 🔎
• -h, -? — print the usage message and exit. classic 🫡

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🌈 EXAMPLES 🌈

Example 1. Convert objects from a database to an EGG file

g-egg -r 0.005 -o havoc.egg havoc.g body wings

This tessellates the body and wings regions from havoc.g using a tighter relative tolerance of 0.005, and writes the combined Panda3D EGG model to havoc.egg — all ready to be loaded into a Panda3D scene 🎬✨

Example 2. Generate geometry on demand and pipe it onward

g-egg -a 0.5 moss.g all.g > moss.egg

Here it facetizes the all.g assembly from the moss.g sample database with a 0.5 mm absolute tolerance, and redirects the EGG output (which would otherwise go to standard output) into moss.egg. pipes? we love pipes 🫶

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🦋 SEE ALSO 🦋

brlcad(1), g-obj(1), g-stl(1), gcv(1), mged(1) — go read those next, bestie, they're all in the family 💖

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👑 AUTHOR 👑

BRL-CAD Team

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⭐ COPYRIGHT ⭐

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

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💀 BUG REPORTS 💀

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org 📧

not me telling you to email the devs, but like… if it's broken, tell them fr fr 🙈

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okay that's the whole page, you ate that 💅 this was G-EGG(1) from the BRL-CAD manual set — no cap, go tessellate something 🍓🧚