The hard part with 3d part creation isn’t the graphical interface or language, it’s actually describing and translating part requirements to a manufacturable design, weighing material, weight, fit, geometric, and cost tradeoffs. Openscad, opencascade, etc have been around for a long time and have specs for describing features in a way that llm should be able to handle, but if all the part constraints were available it’s far faster to make accurately in Solidworks.
This is my experience too. I took a course a long time ago in design for manufacturing, and it became abundantly clear that just because you can conceive of an idea doesn't mean that you can build it. That requires a lot more work and technical know-how that isn't always put into books or other "training data".
Just yesterday I had an LLM write an openscad module for generating a 2d rounded rectangle. It worked great! I then tried to get it to write a module to extrude a 2d shape into a 3d shape and it failed spectacularly several times before I gave up.
Interesting. I’m building a SaaS around this idea. And I managed to do things waaay more complex than that using LLMs. Especially “several times”. My AI can do a parametric trophy cup from one prompt in a couple of attempts, I would be shocked if it didn’t know how to make rectangular cube…