Limo CAD: Opensource, Always Free CAD Software

[u/trcastle]

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/

[u/trcastle]

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.

[u/UncleAugie → u/trcastle]

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

[u/EvilGeniusSkis → u/UncleAugie]

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.

[u/UncleAugie → u/EvilGeniusSkis]

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...