Antimony: the CAD tool from a parallel universe where Lisp machines beat drafting tables
Antimony: CAD Software Evolved from Lisp Machines and Not Drafting Tables
Antimony is a node-based CAD tool built on directed acyclic graphs, a CSG geometry engine using functional representations, and a Python-driven standard library of shapes and transforms. Each node is a customizable Python 3 script with input and output ports; changes propagate downstream automatically, and UI widgets hook back into the graph. It exports heightmaps and STL files, runs at beta stability, and grew out of MIT Center for Bits and Atoms work on personal-scale CAD/CAM.
Antimony is a computer-aided design (CAD) tool from a parallel universe in which CAD software evolved from Lisp machines rather than drafting tables.
- mkeeter
This could use a (2015) label :)
I've been tapering off maintenance since 2016 or so, but it has a more actively-maintained fork over at https://github.com/nsfm/stibium (albeit with heavy LLM assistance, because it's 2026!)
YMMV – I haven't used it or closely inspected the changes, but have corresponded with the author, who seems genuinely dedicated in the success of the project.
- WillAdams
This probably merits noting that the whole Code CAD thing is getting pushed very hard lately with many new AI-driven projects.
I will note the following projects which have made recent advancements:
- OpenSCAD --- the hopefully final Release Candidate for the long-awaited update is now available: https://openscad.org/downloads.html#rc
- PythonSCAD --- for folks who want variables which change and so forth: https://www.pythonscad.org/
- CADquery --- https://cadquery.github.io/
- Build123D --- https://github.com/gumyr/build123d
Longer list/discussion at: https://github.com/Irev-Dev/curated-code-cad
Also, a more recent project by Matt Keeter, Halfspace was announced recently but didn't get much discussion here:
- seemaze
>Antimony is a computer-aided design (CAD) tool from a parallel universe in which CAD software evolved from Lisp machines rather than drafting tables
That's an ironic take in that the most prolific CAD software in use, AutoCAD, has supported a a lisp dialect, named AutoLISP[0], natively as an alternative runtime for more than four decades. It is so prolific in the CAD industry, that other vendors have even adopted compatibility with the language.
It is heartening to see CAD referenced in relation to drafting tables. I spend much of my time trying to educate new CAD users about the different solutions offered between the 'drafting table' metaphor and the 'world model' metaphor present in most CAD applications.
- sjia
I've been using AI to create CAD models. Results often are close to my intent, but I also have to spend much effort on tweaking parameters and features to fit parts in the real word. AI does help, but doesn't solve CAD modeling problems, unlike GenAI image/video for entertainment.
- badlibrarian
To anyone else who had to parse early KiCad file formats, where the parentheses and quoting on S-expressions was more of a guideline than a rule, I salute you.