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
Do you find the models generally manage to avoid making errors when placing parts (e.g. placing parts which intersect, don't connect properly, etc) or do they rely on validation and correction cycles?
When giving them enough examples, like e.g. houses, they tend to do well in that category, but not perfect.
My guess is that what happens is, given that most LEGO parts have a very limited, discrete set of legal positions and rotations, expressed as integer numbers, the agent finds patterns between different models, like e.g. a brick close to the center of a model usually has very similar (integer) coordinates and rotation components to another central brick from another model.
However, it still messes up very often, with things like e.g. +/- signs that flip parts due to rotations becoming -90deg when they should be +90deg; then, validation and correction cycles, running tools that verify the presence/absence of collisions, really helps in finishing the job.
Yup. I’ve been getting some pretty decent 3d models directly on stl format + the slicer file with all the right configs for my printer
It’s cool to create a simulation, run some visualizations on web directly from Claude desktop, and then choosing a model to print and build
I also added some genetic algorithms to make it fun iterating on different shapes/mechanisms
I really enjoy how much creativity these tools are unlocking by enabling bridging so many elements together
On that note- have you considered adding constraints for part availability? It would be useful to be able to create designs using only parts which are on hand.
I recall seeing a project a while ago which could take a photo of a pile of lego as input and produce models that could be made with those parts. Although I think in that case the models were sorta just random arrangements.