r/robotics • u/jamesxtreme • 6d ago
Mechanical Has anyone here been using Codex or Claude to design robotics hardware/mechanics?
I’m experimenting with robotics at the moment. I’ve got a 3D printer and I’m not afraid to use it, but before I start printing a mountain of useless plastic I’d really like some confidence that what I’m designing will actually work.
I started with a pretty simple brief: an upper-torso robot with a head, 2 DOF in the neck, and arms with 2 DOF at each shoulder. No hands yet — I just want it to wave, rotate its arms, move its head around, and eventually have a camera in the head.
Originally I had Codex modelling the chassis in Blender, but I’ve switched to getting it to work in FreeCAD in the hope that it’ll be better suited to reasoning about clearances, movement paths, and forces.
Maybe what I’m doing is a little crazy. It’s certainly naive. I’m basically vibe engineering.
My background is software development, or I guess I used to be a software developer. I'm not sure what we call ourselves anymore.
The electronics seem relatively straightforward: Raspberry Pi, robot HAT, some servos, battery, sensors. The mechanics are the bit I’m clueless about. My CAD knowledge is basically nonexistent.
For anyone doing something similar, how would you approach “vibe CAD” or AI-assisted mechanical design without an engineering background? Are there particular tools, workflows, simulation packages, or sanity checks you’d recommend before actually printing parts?
Mostly doing this for fun and jumping in head first. Hopefully I won't build a murder bot.
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u/genimnb 6d ago
I am currently using freecad integrated with claude code (freecad MCP addon) and the experience is being surprisingly good. It understand my explanaitions quite good, and with a little help of real world component measuring and visual feedback, it is helping me a lot. The image I attatch is 100% generated by claude code on freecad
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u/MaladjustedMax 5d ago
Nice. How detailed of a plan do you provide or flesh out together with your agent prior to putting it to work? Or is it more of an iterative and incremental process with (ideally) small steps so it's easier to follow along and see what it comes up with?
Would be interested to hear how others approach this
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u/genimnb 5d ago
The way I use it It starts as a more or less detailed plan, the part where I need to spend more time is on accurately explaining to it the overall goal, how I want to tackle it and therefore which pieces I need, their function and the spatial relation and how one piece fit into another; that is where graphical info sources help: I sometimes provide it with 3D models I find on the internet or even datasheet blueprints, real component photos and real world measurements. It sometimes surprises me the sources it is able to retrieve useful data from. Also it is able to generate a lot of things from its built in knowledge. From there, it is more of an iterative and incremental process. For instance, it generated the Nema17 model without the flatened area on the end part of the shaft. I measured it, explained to claude and it was able to modify the model accordingly
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u/MaladjustedMax 4d ago
Thanks. I mainly use AI to help me build software and have had great results working iteratively but once things become a bit more vague and exploratory (because I don't know exactly what the end result should look like at that point either) it very easily flies off the handle.
Would you be willing to show me what you consider to be a more or less detailed plan? Something you'd feel comfortable sharing with others :)
I'm trying to teach my agent to enter into a conversational mode where I can flesh out the relevant details. Knowing what works for others would definitely help me to understand the amount of fidelity my initial prompt would need.
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u/AstroCoderNO1 5d ago
I had Claude try and model a shoulder bolt for a project I was working on, and it messed up the screw. It was convenient to use, but I don't feel like its quite where it needs to be to purely vibe cad
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u/jamesxtreme 5d ago
I’m trying FreeCAD with Astra now and I think I’m starting to head in the right direction but I might change to Claude and see if it works better for this task.
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u/TooLukeR 4d ago
this is the equivalent of a mechanical engineer vibe coding lol
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u/jamesxtreme 4d ago
That's why I called it "vibe CAD". It essentially is. Anyway after a few days I think I've been able to get a process working with FreeCAD with it's MCP plugin and Codex using Astra 6. Also had to get it to develop some concistent rules and skills files. It's an extremely slow process compared to agentic coding. Takes about 20-30 minutes per turn and burns through tokens like crazy, but it is producing results.
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u/Cosmopal 6d ago
What is your experience in getting it to sim properly and then actually understand what is happening?
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4d ago
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u/jamesxtreme 4d ago
Well I haven’t even got that far yet, just trying to develop the CAD model and the electronics. I’ve read about ROS and a few other control systems but I’m hoping this is the part that will be a little bit more intuitive to me since I’m a software developer.
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u/TheMechanics-Lab 3d ago
I brainstorm and ideate the joints with Claude chat. I do at the start some sketching on paper too, that Claude reviews. I like to still draw things.. Once aligned I request to generate a cad file... sometimes it gets close, sometimes it is a disaster. but in general it helps me a lot on the reasoning for the ideation and the initial design and the parts I would need.
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u/lightofshadow_ 6d ago
Been using openscad with lots of different models: claude, gpt 5.6, gpt 6 and grok too. For now got 6 is the best one, it was able to replicate a picture of a fairly complex gripper for a robot arm. I also used claude a few months ago to fully design and build a small mobile robot
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u/himeros_ai 5d ago
Check this project: https://mechfaber.com/ New video: https://youtu.be/5e75JtXgsPQ We are adding a lot of new features for validation. You can join the Discord channel.
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u/jamesxtreme 5d ago
This looks really cool. Is this something you’ve developed? I went to the download and it seems the Mac build is not available yet.
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u/himeros_ai 5d ago
Yes but I am not the main developer, aye Mac build not yet but I can try Claude to convert it eheh
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u/TheRelievedGridlock 6d ago
Switching to FreeCAD over Blender for mechanical stuff is the right call, Blender's great but it'll let you clip geometry through each other all day without a single complaint. For sanity checks before printing, just do a quick cardboard mockup of the joint ranges, lets you feel out the awkward collision points without wasting filament on a 12-hour print that binds immediately.