r/CNC • u/trcastle • 2d ago
SOFTWARE Limo CAD: Opensource, Always Free CAD Software
We've been building Limo CAD (formerly noBS CAD), a free, open-source parametric CAD for mechanical parts, assemblies and drawings. It runs entirely on your machine: no account, no cloud, LGPL-2.1+ opensource license. Being open source means you can check the source code yourself, modify it to your taste and make your own version of it. And it is free for ever.
It's pre-alpha. Builds exist for Windows 11 (x64/ARM64), Apple- silicon macOS and Ubuntu 26.04. We'd like feedback on the experience, and we'd like people to try to break it.
What it does:
- Constrained sketches drive editable solid features (extrude, revolve, sweep, loft, fillet, shell, holes, etc.). Change a dimension and everything downstream rebuilds.
- Parts, assemblies with joints and motion/interference checks, and 2D drawings (DXF, PDF) live together in one project file.
- Exports STEP, STL and 3MF.
- A built-in MCP server (stdio) lets an agent build and edit models. What it makes is the same editable feature history you'd make by hand. The repo has three designs built from a blank document that way (a garden bench, a vise, a vertical-axis turbine), with build recordings and sources so you can see exactly what was generated.
- Experimental CAM function (Not production safe, I run program it created on my own machine, but I always run a 6% feed dry cycle first)
Repo: https://github.com/limo-cad/Limo-CAD
Demos and recipes: https://limo-cad.github.io/Limo-CAD/
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u/fortyonethirty2 2d ago
How does it compare to freecad? What are the differences?
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u/MysticalDork_1066 2d ago
One big one for me is that it runs on Linux. I'm sick of windows but fusion is windows and mac only.
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u/TheSerialHobbyist 2d ago
They asked about a comparison to FreeCAD, not Fusion.
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u/MysticalDork_1066 2d ago
D'oh! I was already so excited to see an alternative to Fusion that it was on my mind.
The difference between this and Freecad is that it has an editable timeline. You can scrub back through your editing history, which you can't with Freecad (and it's one of the things I really miss from Fusion).
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u/TheSerialHobbyist 2d ago
Yeah, FreeCAD has a lot of issues and quirks that make it annoying to me, too.
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u/trcastle 2d ago
FreeCAD is a respectable pioneer. It’s been developed for years and has a much bigger collection of real-world edge cases, bug reports, workbenches and features than we do. We share the same OCCT kernel under the hood (another very, very respectable open-source project).
I would say ours is easier for beginners. We aim for a similar intuitive experience to common commercial software. If you have tried FreeCAD I hope you could try ours too, see the differences yourself :)4
u/Acedin 2d ago
Why not use your capacity to extend FreeCAD with features or a bench that provides your featureset?
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u/trcastle 1d ago
FreeCAD has some historical weight that, for us to modify it to the experience we want would equal to completely ripping it apart, hence we are building our own from the ground up.
We are also trying to migrate our code base entirely to rust (Except for the Cpp OCCT kernel. The current release is rust doing the processing and viewport, react on UI and all live inside Tauri into system webview.)
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u/trcastle 1d ago
A quick clarification for anyone considering trying this: Limo CAD is pre-alpha, and we’re a small team. We’re sharing it now for testing and feedback, and we don’t recommend relying on it for production work yet.
It runs locally with no account or required cloud service. That matters for control over your files, but it isn’t a guarantee of security. Reliability and trust have to be earned as the project matures.
Our intention is to keep Limo CAD free and open source. We’re building something we want to use ourselves, and sharing it so others can use it, inspect it, and help improve it.
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u/No-Character9756 2d ago
Already I like the idea I typically use Fusion 360 so I'll let you know but and I don't want to deter you from doing this but Fusion 360s free functions are more than likely superior to what you are doing...however the fact that it is open source in my opinion makes it more than likely worth the effort and is enough to convince me to try it
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u/UncleAugie 2d ago
until this gets huge traction... open source is a liability risk for any company working with IP you dont own.
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u/No-Character9756 2d ago
Yes I agree with that but for personal use I feel that it makes sense. Which leads me to believe this should probably be in the hobbycnc subreddit not the CNC one
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u/trcastle 2d ago
Could you elaborate why open source is a liability risk for any company working with IP that they don't own? Id like to learn the business aspect of it.
From my perspective, the LGPL license only covers Limo CAD itself, not any designs made with it. Everything also runs locally, so nothing gets uploaded anywhere. But I’d like to hear what concerns a company would have.-10
u/UncleAugie 2d ago
You dont have the skillset to develop a CAD program that is nearly as secure at large closed source... what happens if you get hacked and someone updates/inserts malicious code into your repo without you knowing... As a buisness owner there is zero chance Im using anything by a small dev who likely doesnt carry a liability policy.... If I get sued by a multi national because your software leaked their drawings... Im f'ed
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u/EvilGeniusSkis 2d ago
You are already using open source software somewhere on your work computers. Open source doesn't mean that anyone's code is automatically added to a release version, and the hacking risk is present in closed source software too, but with closed source you are relying on the dev to catch it, whereas with open source every other user is someone who could possibly notice the software is acting funny, look into why, and then sound the alarm. Just look at the SolarWinds hack versus the XZ utils hack.
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u/UncleAugie 1d ago
Critical Reasoning when reading is important. I gave you the case that worries me about a small developer, who does not have a team looking for vulnerabilities, and another team to handle quick patches to close them. There are not enough eyes on this software to reduce the risk profile when making a buisness case.
Opensource is awesome when the software gains enough traction that you have thousands of eyes looking at the code, but OP doesn't have that.
I agree that Opensource is crazy powerful when you have tens of thousands of knowledgeable experts looking at the software/code, but your examples are not valid to defend OP and his software at this point, when you are weighing liability, and risk...
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u/UncleAugie 2d ago
Self promotion is a no no.... also your own admission that you dont trust the software means you are using the sub to beta your software, likely before you start charging for it at some point...
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u/trcastle 2d ago edited 2d ago
It’s our own project, and we’ve worked on it for months. I believe it’s very relevant to this sub, so I hope it isn’t against the rules here.
It’s still before beta, as I admitted in my post. I’d love for people in the trade to tell me what they think of it and what they’d like to see in it.
The source code is already public. Someone could technically try to charge for it, but anyone with a copy can build their own running version from the source, so charging for it would be pointless. That’s part of the idea behind open source: no one can ever take it away from the community.
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u/MehImages 1d ago
how do you start charging for software released under LGPL? I mean you are allowed to, but people can just choose not to pay you if it's open source...
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u/UncleAugie 1d ago
When I was much smaller I was using a CRM that was opensource, initially pay for support, over time they pivoted and changed the license stopped providing updates and bug fixes. IT allows the dev to work out bugs cheaper than paying people, then when they get a good product people will pay for they change the license structure and start charging. Yea you can keep using the old software but as soon as security patches stop being supplied, as a buisness you can not carry that liability.
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u/UncleAugie 1d ago
FYI, since you posted and retracted, for you and anyone else who is mistaken.
as the copyright holder of the software, you can stop providing updates under the LGPL and change the license type to commercial closed-source for all future releases
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u/Swimming_dasa 2d ago
the editable feature history is what really stands out here. ai-generated cad becomes much useful when you can inspect, modify and understand how the model was built.