> I did this in order to get agentic LLMs capable of designing buildable, physical things!
I've been experimenting with FreeCAD + freecad-mcp + Claude recently and have been similarly surprised how well this works. I've produced three useful parts from Claude's designs: a 3d printed case for an OLED display + some inputs + an ESP32, and a milled aluminium hotend mount adapter for a 3d printer, and a printed pen + pressure sensor mount to use the printer as a plotter. I just provided part/model numbers plus a couple of caliper measurements Claude wasn't able to find online and went through two or three cad revisions before making the parts. All three worked on the first hardware revision.
The biggest thing I've found it seems to struggle with is understanding how the parts will be assembled. The pen mount in particular was tricky to put together, having a part which needed to fit through a slightly too small space to get to its spot. Although it's hard to blame the AI for that when I didn't notice it either I suppose.
I've been experimenting with FreeCAD and freecad-mcp too, even managed for Claude to create a new LDraw benchmark for it.
However, given the amount of parts some LDraw models have, FreeCAD performance would not be enough, something to do with its solver trying to work out too many constraints at once.
The thing about how to assemble the parts, yes, that drove me crazy for quite a while.
A way I found that helps is to provide the agents information about contacts, e.g. what parts of a brick are actually connectors.
With that in place, it can create tools to automatically check if two parts are connected "the right way" ;-)
I got LEGO connectors info from here: https://www.melkert.net/LDCad/tech/shadowLib