Obligatory mention of https://zoo.dev/ the leader in this space.

I will say I explored this reasonably deeply and came away with the conclusion that even though we have OpenSCAD and all these examples, LLMs are still very weak at spatial reasoning compared to diffusion models.

You can do all sorts of tricks like have a parts library to get around this and do physics checks but another inconvenient truth is whenever you design a complex assembly, every change to that part needs to be aware of the other parts in the design -- thus you need a global part-aware editing capability from diffusion.

That's getting solved already in china leading labs, and bottlenecked by the lack of good training data, which china is solving with mass labor.

This will be solved overseas first before we will in the US.