µcad: New open source programming language that can generate 2D sketches and 3D

by todsacerdoti • 8 months ago

400 135 8 months ago

This is a neat idea and I quite like some of the syntax, but what is this for? I have a hard time seeing this gaining traction over traditional sketch-based CAD for a number of reasons, so is it just meant to be a toy?

sho_hn• 8 months ago

Hmm - are you familiar with OpenSCAD, which is highly popular? This would appear to compete there. There's a few others, e.g. CadQuery.

lovemenot• 8 months ago

Such languages can be amenable to LLM generation, reducing barriers to entry.

Normal_gaussian• 8 months ago

I'm a much more capable of designing useful models by programming than I am in using CAD software. The way I think about the construction of models is much more suited to standard programming techniques. I freely admit there is probably immense value in using the industry standard tools instead... I've printed a few projects now which I used OpenSCAD to design, and it went fairly well, and I'm confident in them. OpenSCAD is a bit of a PITA though.

I have no idea if this approach might gain traction over sketch-based CAD, I doubt it; yet this approach has a strong chance of expanding the space.

WillAdams8• 8 months ago

If there was a real possibility of folks being willing to use this sort of UI in industry, BRL-CAD would be far more popular, and writing AutoLISP scripts wouldn't be an obscure specialty.

raddan• 8 months ago

I would personally prefer to work with a language-based CAD than a strictly graphical one. Especially for parametric kinds of objects. Now that 3D printing is going mainstream, I am certain that new and interesting things are still to come in CAD.

krisoft• 8 months ago

Curious. How much experience do you have with any form of CAD? Is the preference based on that you tried graphical CAD software and you found them lacking, or is it based on imagining how they might work?

Last week at the hackspace someone asked me to quickly design a manifold which holds together a scuba mouth piece, a 48mm diameter valve and a nato 40mm screw fitting. They wanted to minimise the internal tidal volume of the manifold, while keeping enough clearance for the tubes connected to it. We ended up connecting the 3 fittings in a Y-shape and lofted the pipes together. Without seeing the resulting shape I can’t even start to guess how many edges it would have. And I have no idea how I would refer to which edges i want filleted. How would you approach something like that with your prefered method?

WillAdams8• 8 months ago

Well, there's OpenSCAD already, and for folks who like Python:

https://pythonscad.org/

constantcrying• 8 months ago

Neither is 3D printing going mainstream nor do I see any reason why it would push people away from industry standard CAD software.

CAD is already complex. Why would giving those people an extremely underpowered programming language, which makes creating even the simplest 3D models a chore, cause change in the CAD world.

octoberfranklin• 8 months ago

So what is the big advantage of this over OpenSCAD?

beeflet3• 8 months ago

I found this:

https://docs.microcad.xyz/language/book/intro/preface.html

While OpenSCAD is easy to learn and has a syntax reminiscent of C, we felt the language could be improved in several ways:
- more specialization for creating graphics,
- better support for modular programming,
- strict typing and unit handling,
- a syntax closer to Rust than to C,
- a solid library system,
- plugin support for other programming languages,
- and a more powerful visualization concept.

Surac• 8 months ago

I like openscad because it use a syntax more like c than rust. Making the syntax more c like opens the user base up. Not everyone sees rust syntax as a benefit. Just my 2 cents

theamk• 8 months ago

So.. OpenSCAD, but with strong types and rust-flavored syntax?

cke• 8 months ago

This almost feels like going back to old school Autocad.

WillAdams8• 8 months ago

Yes, but if one wants to use that sort of thing, why not go _all_ the way back:

https://brlcad.org/

aclindsa2• 8 months ago

One of the best things about openscad is the ability to immediately see the results of a code change in the 3D view (all I do is save the file with :w in neovim and openscad re-renders it). Being able to interact like this makes it much quicker and easier to iterate on a design.

I read through the ucad website and book for 10 minutes and haven't been able to figure out if there is an analogue to this for ucad?

There are several things that look neat about ucad's language, but I would need to recreate something like openscad's workflow to consider switching.

don-bright• 8 months ago

That immediacy is mostly thanks to OpenCSG which is essentially a magic trick to quickly fake 3d rendering of booleans between 3d objects using stencil buffer of gpu. http://opencsg.org/

In other words it renders the cylinders cubes spheres etc and their unions differences etc, to a 2d screen without actually calculating the intersection of those meshes / solids in 3d space.

This is the special thing about OpenSCAD design is they figured out how to build an abstract syntax tree that could either be sent to OpenCSG, CGAL (old engine), Manifold (new engine), or even the bare bones 'ThrownTogether' renderer (ancient engine on machines with no gpu that just draws 'negatives' as green blobs iirc).

It should be theoretically possible for any CAD program to do this. its just a lot of work.

beeflet3• 8 months ago

wow, this is really neat. I always noticed how, when panning around with ortho view, it didn't need to re-render

marcosscriven• 8 months ago

I didn’t know they’d added an alternative kernel. The CGAL one used arbitrary precision which massively slowed it down.

Also, fillets are made using the Minkowski operation, which is super slow.

spacedcowboy• 8 months ago

This is the special thing about OpenSCAD design is they figured out how to build an abstract syntax tree that could either be sent to OpenCSG, CGAL (old engine), Manifold (new engine), or even the bare bones 'ThrownTogether' renderer (ancient engine on machines with no gpu that just draws 'negatives' as green blobs iirc).

Mostly.

I've still had several instances when drawing curved solids that the OpenCSG renderer worked well with (visually) but when it came to render-time, there was something wrong. It is very hard to debug things, or at least I found it so, when it goes wrong like that.

MrGreenTea• 8 months ago

A viewer/preview is in development.

they got a grant for that. i couldn't find an english version though, sorry.

https://www.prototypefund.de/projects/microcad-viewer

gwbas1c2• 8 months ago

This implies that you can preview in VS Code: https://docs.microcad.xyz/tutorials/book/lego_brick/preparat...

I'm not sure if it's on par with what you want, though.

awinter-py2• 8 months ago

Tried openscad and then cadquery for some geometry iteration projects and found them clunky. It wasn't just that I was missing a UI; the functions, constraints and geometry kernel weren't as powerful as onshape, which I've used a bit, and presumably light years behind fusion 360, which I haven't used.

Even freecad, a UI-based oss cad, is not quite ergonomic for a beginner-to-intermediate user, though it has come a long way in the past few years.

I'm excited for there to eventually be a good open source cad option, whether language-only or language-plus-GUI, but am also increasingly on team 'tools matter for your productivity'.

WillAdams8• 8 months ago

The great thing about OpenSCAD is that it makes it easy to programmatically model objects using cubes, cylinders, cones, and spheres by placing, stretching, and rotating them.

The awful thing about OpenSCAD is that one's ability to model in it is strongly bounded by one's fluency with mathematics and ability to use math to programmatically model objects using cubes, cylinders, cones, and spheres by placing, stretching, and rotating them.

The one tool I'm aware of which is looking at a new geometry kernel which I can recall is:

https://fornjot.app/

nicman23• 8 months ago

freecad with the new ui + its openscad integration is pretty good.

openscad in general is quite easy if you can functionally program

exasperaited11• 8 months ago

AFAIK FreeCAD's core OpenSCAD replacement is being suggested for replacement with an alternative so things may further improve.

OpenSCAD in a FreeCAD context does address many of the limitations of OpenSCAD, but it's not perfectly compatible.

jandrese• 8 months ago

I find OpenSCAD to be decent, if somewhat tedious, when making mechanical parts but extremely limiting if you want to work with organic shapes. Even mechanical shapes that just avoid sharp edges require a fair bit of effort. One thing I do like about it is how it encourages users to parameterize their models just by the nature of the language. Pretty much everything I make in OpenSCAD has a list of named parameters at the top I can later tweak if I need to shrink or enlarge some aspect of it.

imtringued• 8 months ago

As someone who has been using FreeCAD starting in 2020, I can't tell any major differences. The problems are the same they have ever been. It's only the renderer that got a little bit more "sexy", but that is just looks.

arcanemachiner3• 8 months ago

This is my understanding as well.

mft_3• 8 months ago

I'm self-taught with CAD, and have repeatedly tried and discarded FreeCAD for several years. (Tangent: perceived absence of a decent CAD solution in Linux is one of very few things keeping me using Windows.)

I recently happened upon a video which mostly changed my mind [0], in which someone successfully passed a Solidworks professional certification using FreeCAD. And to my eyes, their workflow was only rarely any worse than e.g. Fusion360, Solidworks, etc.

I've since been trialling FreeCAd via the 'bleeding edge' weekly development builds [1]... and it's not perfect, and it's a touch clunky in certain areas, but it's now more than usable. (In some areas, it's actually better than the competition I've tried, IMO - for example making and cutting threads.)

[0] https://www.youtube.com/watch?v=VEfNRST_3x8 [1] https://github.com/FreeCAD/FreeCAD/releases

juliangmp• 8 months ago

If you want a classical GUI based cad tool for 3D modelling, I'd suggest taking a look at solve space and dune3d

awinter-py2• 8 months ago

thanks for recs, will check them out

augunrik• 8 months ago

You can try out AstoCAD, a reskin of FreeCAD. The author also fixes a lot of FreeCAD bugs.

deckar01• 8 months ago

This does not seem to have a constraint solver or any documented plans to integrate one. I love math, but I don’t enjoy maintaining walls of trig to make trivial constraints parametric.

beeflet3• 8 months ago

Interesting project, I will look into it.

This site sucks. Why does it use php, and why is every link a query? Just make it a static page.

jwilber• 8 months ago

Yeah, my guess is the team vibe-coded it because wow is does it have poor performance /is difficult to use. A few links didn’t even work for me…

iammattmurphy• 8 months ago

The server appears to be down right now too :/

teaearlgraycold• 8 months ago

If so that means they asked the AI to use PHP. Which is even more horrifying.

swaits• 8 months ago

PHP is fine. If the site sucks it’s not because of the language.

altmanaltman• 8 months ago

yeah, a lot of frontend/styling choices are pretty non-asthetic other than the suboptimal performance.

GaryBluto2• 8 months ago

https://microcad.xyz/?brx_pyuqqz%5B%5D=code&brx_pyuqqz%5B%5D...
brx_pyuqqz

That's certainly an array name.

masfoobar• 8 months ago

While PHP is not my goto language.. and the language has likely changed a fair bit when I last used it.. I don't think the issue is PHP.

coldtea• 8 months ago

Half the web uses PHP. Nothing wrong with PHP for web work, and absolutely nothing bad about the site is related to its use of PHP.

pedropaulovc3• 8 months ago

I've been using zoo and its KCL language with some success for boundary-representation CAD writing. If I understood correctly, µcad serves the same purpose. Comparing code samples between both of them, I personally enjoy KCL's pipelined approach more.

My main beef with zoo is the fact that they are promoting vendor lock-in by forcing users to use their cloud-hosted geometry kernel with absolutely no local alternative. It's not clear to me how µcad solves this problem.

[1] Lego brick in KCL: https://zoo.dev/docs/kcl-samples/lego

[2] Lego brick in µcad: https://microcad.xyz/index.php/2025/11/12/lego-bricks/

[3] Gear in KCL: https://zoo.dev/docs/kcl-samples/spur-gear

[4] Gear in µcad: https://microcad.xyz/index.php/2025/11/12/gears/

its-summertime• 8 months ago

Doesn't it solve the problem by being local? https://codeberg.org/microcad/microcad

fallat3• 8 months ago

Zoo has said it's open to local hosting of the kernel for years. I believe it's a matter of time because it's mostly about legal tape.

ucad is based on Manifold, so unfortunately, not really comparable, since it's all meshes vs brep, like OpenSCAD.

Note KCL could be completely augmented with another kernel. There are people who've already tried :)

adastra22• 8 months ago

Don't they use their own kernel? What legal tape?

fransje26• 8 months ago

There are people who've already tried :)

And they were never heard of, ever again? :-)

durin42• 8 months ago

I asked sometime in 2024 and I got a pretty clear response that local/self hosting is not planned.

hantusk• 8 months ago

Lego brick in build123d: https://build123d.readthedocs.io/en/latest/tutorial_lego.htm...

Gear in build123d: https://github.com/GarryBGoode/gggears

_flux2• 8 months ago

Hm, at least build123d (which I had never heard of, thanks!) can export STEP, which I believe is becoming a necessity if one wants to assemble real-world models with FreeCAD (and nicely also slicers are picking up support to it). I'm on the edge though if I'd really like a proper DSL instead of building it on top of Python, although I can see that too has its benefits (e.g. library access).

Does anyone have idea about the STEP export support status for KCL/µcad? To me it looks like KCL cannot, and I cannot find information on it about µcad. The one tool I'm familiar within this space is OpenSCAD and it cannot. While FreeCAD is able to (sometimes?) convert from STL to STEP, it seems actually working with such models in FreeCAD is quite compute-inefficient.

pedropaulovc3• 8 months ago

Fascinating, thanks for sharing!

galfarragem• 8 months ago

When I see these examples I miss Autolisp…

stocksinsmocks• 8 months ago

These are your father’s parentheses. An elegant weapon for a more civilized age.

hekkle• 8 months ago

Looks like a promising alternative to OpenSCAD.

Although am I the only one to notice the swastika in their logo?

GaryBluto2• 8 months ago

Although am I the only one to notice the swastika in their logo?

Possibly. Although I know it's the wrong way round to be a Nazi swastika, it's made all the more odd by the fact that this is a German project.

ruicraveiro• 8 months ago

Maybe it could be Bauhaus inspired instead. (This isn't a serious suggestion, but if you're biasing your opinion based on their German origin, why not from the good stuff instead?)

fainpul5• 8 months ago

It's probably just AI generated.

fainpul5• 8 months ago

If you see a swastika there, do you also see it in the Python logo?

lukan• 8 months ago

Personally I would not have seen a swastika here, but when looking for it, here it would be more obvious, the python logo has only half of it.

Still, questionable if it was intentional .. and if it was, does not necesarrily mean they are Nazis (they did not invent, but just used the old symbol).

Also this project was funded in part by the german Federal Ministry of Research, Technology and Space and they are not known to fund open Nazis in general.

Karliss2• 8 months ago

If you look hard enough almost any 4 way rotation symmetry will result in a variation of swastika like shape. You would have to almost completely ban 4 way rotation symmetry to avoid it.

I personally find it unhealthy to actively search, extend and strengthen the association of hate symbols based on vague similarity out of context. Sure remember the crimes they have done and avoid the exact specific shape, proportions, color commonly used by the hate groups, but also take context into account. Don't promote them by giving them credit for things they didn't do. Don't let the hate groups win by allowing few dozen years of years of activity destroy thousands of years of cultural and language history and future for wide category of symbols and simplest geometric patterns. Don't erase words from common language. Don't let them make your life worse by self inflicted excessive censorship. Grow the good associations not the bad ones, dilute and take away the strength from hate groups instead of letting them take away common language from you. If you look at thousand year old budhist or ancient greek stone carving which uses one of the few dozen swastika variations and think those time traveling Nazis plastering their symbols all over the place they win.

When looking at children playing with paper pinwheel, is your first thought also they must be Nazi? When you look at cardboard box with 4 flaps overlapped on top of each other do you think Nazi?

With regards to other people speculation how this happened I doubt they intentionally tried to create a swastika, it just happens naturally when you use rotational symmetry. Looking at this logo I personally see the overall cross and spinning shape formed by positive space first. The image of swastika formed by negative space is kind of weak and clunky due to thickness mismatch created by curved rhombus. If they had used 4 overlapping squares or circles it would be more problematic, at that point a logo designer would likely stop and try to mixup things to get rid of it.

cyrusradfar• 8 months ago

Super fascinating project. I'm very interested in this. I truly hate using the tools by hand and as a programmer, this feels waaaay more intuitive. That said, when reviewing the gear video, I think understanding to start with the gear primitive would require giving the libraries a good once over as I wouldn't have assumed those existed.

Can imagine more and more forms being built in as the community goes.

kudos!

sciencesama• 8 months ago

Why not openscad

willvarfar• 8 months ago

I've been searching for a CAD language that supports iteration in a good way. I've been designing a self-build house and it occurs to me that, once I have the walls etc, filling in the details for the manufacture of those walls could be done by a programming routine. Such a routine could work out how many studs are needed and their placement etc and generate the kind of cut-throughs where you can see the construction inside the wall that you sometimes see in construction books. Anyway, without for-loops that kind of thing is really difficult and I've given up.

nakedneuron• 8 months ago

Then build123d might be for you.

arcanemachiner3• 8 months ago

I know that FreeCAD has architectural support.

I think it's called BIM, which tells you how well-informed on the subject I am (not).

tnlogy• 8 months ago

Nice with another alternative. I have been using shapescript, which I think is easier than openscad, and available on ios. https://shapescript.info/

betimsl• 8 months ago

Could you please make the book into a PDF?

kulhur• 8 months ago

Just click print in the top right.

naaqq• 8 months ago

It makes LLMs stronger because code is something LLMs are good at.

0xFEE1DEAD2• 8 months ago

You should remove any reference to LEGO from the website and the examples. LEGO is extremely protective of its brand (similar to / worse than Nintendo) and does not want third parties using its name, because it is concerned that LEGO could become a generic term which could put its trademark at risk.

See: "Lego sues Dutch firm over anti-terror blocks using name and shape" https://www.thetimes.com/world/europe/article/lego-sues-dutc... ( http://archive.today/q5XrX )

hju22_-3• 8 months ago

I'm willing to die on the hill that lego already is a commonplace word, but I can't argue that they've held on to the LEGO trademark for pretty long. Though, I'd say Nintendo is a lot worse than LEGO, and I've never heard LEGO do the frankly insane crap that Nintendo has.

0xFEE1DEAD2• 8 months ago

They actually sued a lego youtuber (or threatened to sue - unsure) for using a lego brick in his logo. this lead to him creating a new word for lego bricks "Klemmbausteine" which means "clamping building bricks".

utopiah• 8 months ago

No Web notebook for https://docs.microcad.xyz/tutorials/book/lego_brick/ no install?

(as https://machineblocks.com/docs/scad-crash-course-101 does)

knollimar• 8 months ago

So this is more an autocad equivalent? Does it have interfaces to enable reusability in some other file format (e.g. any way to get it into generic models eventually importable into revit?)

thesurlydev• 8 months ago

Please provide a trivial example of the code and the generated sketch front and center on your front page.

gcr• 8 months ago

There’s tons of examples just past the fold!

estimator7292• 8 months ago

There is zero reason for you to have a cookie banner taking up a third of the page.

At this point, everyone making websites should be well aware that there is no requirement for cookie banners and that implementing such is active disrespect towards your users. Your cookie banner does not tell me you care about my privacy, it tells me you're trying to collect some type of data about me and want to annoy me into letting you sell that data.

A cookie banner is exactly as much a red flag as an obviously AI generated hero image at the top of your page. Disrespectful.

tasn• 8 months ago

Many many years ago I created my own JS -> OpenScad generator, so I defo agree the OpenScad language could be better. Though the engine worked well.

Putting it here in case anyone is curious: https://github.com/tasn/scadjs

skolos• 8 months ago

Looking at examples I see:

``` c = Sector(radius, start = 180°, end = 270°).translate(y = radius); ```

Programming language that requires (maybe it does not require, but then example is not good) to type degrees. Or maybe it is not designed to be typed and rather ai generated?

UncleEntity• 8 months ago

I saw another example where they had 'mm' as well so I'm guessing that's all part of the type system as postfix attributes?

Poked around in the docs a bit but didn't see a grammar so, dunno... I can only guess it does automatic type conversion if you only type the numbers without the qualifier.

WilstonOreo2• 8 months ago

Yes, we use units as postfix attributes. The grammar is here, in case you are interested: https://codeberg.org/microcad/microcad/src/branch/main/lang/...

addaon• 8 months ago

opt-shift-8

conorbergin• 8 months ago

Can it do fillets?

zombot• 8 months ago

I find it horrible that all the examples are given as videos. No can do.

winlundn2• 8 months ago

Yesterday, these people pulled their microcad-based Spirograph code. No explanation given... now it's just a 404 page.

What's up with that, Microcad? This kind of reflects poorly on your overall ability to do things like host the actual code for microcad itself.

winlundn2• 8 months ago

Reference: https://microcad.xyz/2025/11/20/spirograph/

^ This link worked yesterday when Ycombinator cited them. Now it doesn't work. Who at Microcad is scared right now? Or does this removal regard perhaps a more common situation -- such as their code wouldn't compile with microcad and so they had to pull it, rewrite it, and will publish Spirograph later?

WilstonOreo2• 8 months ago

Hey, microcad dev here. We are definitely not scared, just a bit overwhelmed by the amount of good and constructive feedback. The new link is here: https://microcad.xyz/spirograph/

iddar• 8 months ago

That's interesting project, what do u think about include more export types for 3d print?

morcutt• 8 months ago

Quite excited to try this.

µcad: New open source programming language that can generate 2D sketches and 3D

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