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.
How would one apply a fillet to an edge, in this model?
I haven't really used the constructive geometry approaches to CAD, but I've been learning CAD recently through OnShape, and really appreciated how easy were all the operations I wanted to do with it. I've heard that the purely constructive geometry approaches of the OpenSCAD type can make certain operations more complicated to implement.
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.
It's not really useless though. Yes, in some dimensions it is terrible compared to GUI parametric CAD. But in other dimensions it is far more powerful and lets you build really complex stuff quickly and easily.
do you know of a traditional CAD program which could be used to drive such designs/projects in a useful fashion? I'm currently contemplating a re-write to use a Domain Specific Language....
Would you be interested in evaluating (or having your LLMs check out) my geometry kernel Aetheris for your project? I already have DSL (called Firmament) parser/lexer/AST part down, and it is designed to be easy to extend, so you don't have to write everything from scratch.
One of my goals when I built the kernel is I want to make building a pro grade CAD software as easy as wrapping a web frontend around the Aetheris libraries. It's still very much an aspirational goal though.
I love OpenSCAD and code-based CAD, but even I must admit it's really only good for simple things and is more of a toy than a tool to solve real world problems. The main issue is fundamental, which is that CSG operations change topology in unpredictable ways, and there is no reliable way to refer to the components of the result. This is already bad for a few operations, but becomes exponentially problematic for more complicated models. Even in 2D, suppose I want to make a C-shaped thing out of a box and subtracting a different box out of it. You don't know how many edges the result will have, or even how many connected components the result will have, so how do you go on to perform the next step "on that one part that I want" if it even exists? Of course for a single concrete instantiation this is not really a problem, but the whole point is to have the shape tunable based on parameters, and once you allow that all hell breaks loose.
You might also like FluidCAD (I'm the author). It uses js as scripting, but all features can be done through the UI. It has a constraint based 2D sketcher, timeline and assemblies.
20 comments:
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.
What are you working on these days?
Are there any CAD system that combine code-CAD and more traditional sketch based CAD, like OnShape, Solidworks etc?
Try out https://cadrs.net/ its in rust and opensource
Fluidcad does this very nicely. Still in early development but very promising.
How would one apply a fillet to an edge, in this model?
I haven't really used the constructive geometry approaches to CAD, but I've been learning CAD recently through OnShape, and really appreciated how easy were all the operations I wanted to do with it. I've heard that the purely constructive geometry approaches of the OpenSCAD type can make certain operations more complicated to implement.
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:
https://news.ycombinator.com/item?id=49881890
I would like to add FluidCad to this list. A very interesting combination of Code Cad and GUI cad.
> Also, a more recent project by Matt Keeter, Halfspace was announced recently but didn't get much discussion here:
there is (was?) also libfive (and its "studio") from Keeter in-between: https://news.ycombinator.com/item?id=26930822
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.
I was all ready to say how useless code-based CAD usually is (like OpenSCAD), but this actually looks pretty sick.
If you could add support for SolveSpace's 2D sketcher, and also bevels/fillets, then this might actually be useful.
It's not really useless though. Yes, in some dimensions it is terrible compared to GUI parametric CAD. But in other dimensions it is far more powerful and lets you build really complex stuff quickly and easily.
I am currently trying to apply code-based CAD principles to my current project:
https://studio.flet.dev/run/bicQWc3Aul
do you know of a traditional CAD program which could be used to drive such designs/projects in a useful fashion? I'm currently contemplating a re-write to use a Domain Specific Language....
Would you be interested in evaluating (or having your LLMs check out) my geometry kernel Aetheris for your project? I already have DSL (called Firmament) parser/lexer/AST part down, and it is designed to be easy to extend, so you don't have to write everything from scratch.
https://github.com/yuechen-li-dev/Aetheris
One of my goals when I built the kernel is I want to make building a pro grade CAD software as easy as wrapping a web frontend around the Aetheris libraries. It's still very much an aspirational goal though.
Interesting. I'll have to try to look into what the integration of flet.dev/Python w/ that code looks like.
What is your beef with code based, parametric CAD? It's pretty neat.
I love OpenSCAD and code-based CAD, but even I must admit it's really only good for simple things and is more of a toy than a tool to solve real world problems. The main issue is fundamental, which is that CSG operations change topology in unpredictable ways, and there is no reliable way to refer to the components of the result. This is already bad for a few operations, but becomes exponentially problematic for more complicated models. Even in 2D, suppose I want to make a C-shaped thing out of a box and subtracting a different box out of it. You don't know how many edges the result will have, or even how many connected components the result will have, so how do you go on to perform the next step "on that one part that I want" if it even exists? Of course for a single concrete instantiation this is not really a problem, but the whole point is to have the shape tunable based on parameters, and once you allow that all hell breaks loose.
You might also like FluidCAD (I'm the author). It uses js as scripting, but all features can be done through the UI. It has a constraint based 2D sketcher, timeline and assemblies.