Gmsh(1)

🌸 Gmsh — the manual page, but make it a group chat 💅

Okay bestie, sit down, hydrate, because you're about to meet Gmsh: a 3D finite element mesh generator with a built-in CAD engine and a post-processor. This whole thing is the official Gmsh manual page, rewritten by me for you, with zero facts lost and maximum vibe. Let's go. ✨

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🎀 NAME 🎀

Gmsh — 3D finite element mesh generator with built-in CAD engine and post-processor.

Like. That's the whole identity. Meshes, CAD, post-processing, one girl. 👑

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💖 SYNOPSIS 💖

gmsh [file(s)] [option(s)]

That's it. Files in, options in, magic out. Simple as. 🦋

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✨ DESCRIPTION ✨

So Gmsh is a 3D finite element mesh generator with a build-in CAD engine and post-processor. (Yes, "build-in", that's literally what the original says, we don't fix, we respect. 💀)

Its design goal? Providing a fast, light and user-friendly meshing tool with parametric input and flexible visualization capabilities. It's giving "I'm not like other meshers". Because it isn't. 🫶

Now the structure, and this is the part that matters: Gmsh is built around four modules — geometry, mesh, solver and post-processing. And the way you can control them? Literally so many ways:

• the graphical user interface 👀
• the command line (what this page is about, periodt)
• text files written in Gmsh's own scripting language (.geo files) 📝
• the C++, C, Python, Julia and Fortran application programming interface 🔥

Pick your fighter. Or all of them. No one's stopping you.

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🌈 GEOMETRY OPTIONS 🌈

The "shape first, chaos later" section. 🧚

• -0 — Output model, then exit. Model out, door out. 🚪
• -tol float — set geometrical tolerance. Tiny number, big consequences. ✨

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🦋 MESH OPTIONS 🦋

Where the actual mesh happens. Bestie, this is the main character section. 👑

• -1, -2, -3 — perform 1D, 2D or 3D mesh generation, then exit. Pick your dimension, then dip. 💫
• -o file — specify output file name. Name your baby. 🍼
• -format string — set output mesh format (auto, msh, msh1, msh2, msh4, unv, vrml, stl, mesh, bdf, med, ...). The ... is doing a lot of work there and I respect it. 🙈
• -bin — use binary format when available. Binary when we can, okay? 💾
• -saveall — save all elements (discard physical group definitions). Heads up: this one discards your physical group definitions, so know that going in. 😭
• -algo string — select mesh algorithm (meshadapt, del2d, front2d, del3d, front3d, hxt, ...). So many algorithms, so little time. 🔥
• -parametric — save nodes with their parametric coordinates. Extra coordinates, extra slay. 📐
• -part int — partition the mesh after batch mesh generation. Dividing the work, queen behavior. 👯
• -smooth int — set number of mesh smoothing steps. Glow-up, but for elements. ✨
• -order int — set mesh order. Level up. 📈
• -clscale float — set global mesh element size scaling factor. Everything, scaled. 🌍
• -clmin float — set minimum mesh element size. The floor. 🧊
• -clmax float — set maximum mesh element size. The ceiling. ☁️
• -rand float — set random perturbation factor. A lil chaos, as a treat. 🎲
• -bgm file — load the post-processing view in file as the current background mesh. Background mesh? Loaded. 🖼️
• -check — perform various consistency checks on mesh. Bestie check-in, but for your mesh. 🔍

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💜 POST-PROCESSING OPTIONS 💜

• -combine — combine input views into multi-time-step ones. Multiple views walking in as one. Fusion dance. 🕺

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🌸 DISPLAY OPTIONS 🌸

The aesthetic section. Obviously my favorite. 💅

• -n — hide all meshes and post-processing views on startup. Minimalism on launch. 🫧
• -fontsize int — specify the font size for the GUI. Typography is a personality trait. 🔤
• -display string — specify display. You pick the screen, bestie. 🖥️

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⭐ OTHER OPTIONS ⭐

The everything-else drawer. It's full. We love it. 🎁

• - — parse input files, then exit. Just a lil dash. Mighty though. 🥢
• -new — create new model before merge next file. Fresh start, new model, new me. 🌱
• -merge — merge next files. Bringing the files together like a friend group. 🫂
• -open — open next files. 🚪✨
• -a, -g, -m, -s, -p — start in automatic, geometry, mesh, solver or post-processing mode. Choose your starting era. 👑
• -pid — print pid on stdout. Numbers on the screen, very demure. 🔢
• -listen string — always listen to incoming connection requests on the given socket (a default socket is used if not specified). She's listening. She's always listening. 👂
• -v int — set verbosity level. How much do you want her to talk? 🗣️
• -nopopup — don't popup dialog windows in scripts. No popups, no jumpscares. 🙅
• -setnumber name value — set constant number name=value. 🧮
• -setstring name value — set constant string name=value. 🔤
• -string string — parse option string at startup. 🌟
• -option file — parse option file at startup. 📂
• -convert files — Convert files into latest binary formats, then exit. Glow-up to the newest binary format, then leave. 💫
• -version — show version number. Who are you? 🔖
• -info — show detailed version information. Who are you, in detail? 📋
• -help — show help message. The classic. We stan a helpful queen. 🆘

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🫶 AUTHORS 🫶

Christophe Geuzaine (cgeuzaine@uliege.be) and Jean-Francois Remacle (jean-francois.remacle@uclouvain.be).

Legends. Both of them. Building all of this. 💖

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🔗 SEE ALSO 🔗

• getdp(1)
• Gmsh examples (/usr/share/doc/gmsh)
• Gmsh homepage (https://gmsh.info)

And okay, important one, no skipping: the full documentation for Gmsh is maintained as a Texinfo manual. If the info and gmsh programs are properly installed at your site, this command

info gmsh

should give you access to the complete manual. So if you want the deep lore, that's where the deep lore lives. 📚✨

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Lowkey the most important takeaway: every flag on this page is real, every default is real, and every "discard" or "hide" actually does what it says. Don't be cute with -saveall unless you meant it. 😭

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That's the whole page, bestie — brought to you by the 4th Berkeley Distribution, dated 3 July 2025, filed under Gmsh(1). Now go mesh something iconic. 💅🎀🦋