ISST(1)

📦 version 7.44.0, in nixpkgs unstable

✨ ISST(1) ✨

okay so real talk — this is the isst page from the BRL-CAD manual, and bestie, it's a whole vibe. interactive ray-traced geometry viewing, like a video game but the level is your actual CAD model. let's get into it 💅

🎀 NAME 🎀

isst — an interactive ray-traced geometry viewer. yes. that's the whole name. iconic behavior honestly.

🦋 SYNOPSIS 🦋

isst [file.g [object]]

that's it. that's the whole call. two optional little guys in brackets. so chill of it.

🌸 DESCRIPTION 🌸

isst is an interactive viewer, and she's built on Tcl/Tk and OpenGL — but the real main character energy comes from the Advanced Distributed Ray Tracer (ADRT) and its tie ray-tracing engine underneath. it renders BRL-CAD geometry in real time, so you can actually inspect and navigate a model while it's being ray traced. like, literally watch it happen. no waiting around for a batch render, we live in the moment here ✨

so here's how the startup situation goes:

  • if you hand her a geometry database file.g and an object, that object gets loaded and rendered immediately. instant gratification, we love to see it 💖
  • if you only give her file.g, she pops a dialog so you can pick one or more objects out of the database to view. choose your fighter 🫶
  • if you give her nothing at all, the viewer opens up empty and you can load a database from the File menu. no pressure, no rush, she's just hanging out.

once a view is up, the geometry window is yours to control interactively — here's the whole keyboard + mouse situation, no cap:

  • 1, 2, 3 switch the render mode to phong, surface normals, and depth. three looks, all gorgeous 💅
  • 0 resets the view back to its initial orientation. the "nvm take me back" button 😭
  • w, s, a, d walk forward and backward and strafe left and right. yes bestie it's WASD, you already know how to do this 🎮
  • - and = decrease and increase render resolution. Ctrl+- and Ctrl+= jump straight to lowest and full resolution respectively — the fast lane and the pretty lane 🔥
  • dragging with the left mouse button aims the view; dragging with the right mouse button orbits the geometry. left = look, right = spin. easy 🌀
  • F5 toggles fullscreen, and Esc exits. big screen mode or bye-bye mode, your call 💀
⚠️ tiny but crucial vibe check: the keyboard navigation keys only do their thing while the pointer is over the geometry window. so if nothing's responding, just go hover over the actual geometry window, okay? don't panic 🫶

🌈 EXAMPLES 🌈

💜 Example 1. View a single object directly

isst havoc.g havoc

opens havoc.g, loads the havoc object, and starts ray tracing it in an interactive window where you can walk through it and rotate it. one command, one object, straight to the good part ⭐

🍓 Example 2. Choose objects from a database

isst moss.g

opens moss.g and presents you with a list of its objects; whatever you select gets loaded together into the interactive viewer. this is highkey convenient with the shipped sample database — you can browse what a .g file actually contains before you commit to a full rt(1) render. window shopping but for geometry 🛍️✨

🧚 SEE ALSO 🧚

brlcad(1), mged(1), rt(1), rtedge(1)

the whole friend group. go say hi 👋

👑 AUTHOR 👑

BRL-CAD Team

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 be shy about it either — if something's acting up, tell the devs fr fr 🫶

aaaaand that's the page! brought to you by the BRL-CAD crew and their ISST(1) manual entry, copyright running 1989-2026 — go forth and ray trace something pretty bestie 💅🌸✨

📦 where this page comes from