For OpenSCAD, AI models from about GPT4.5 onwards have been able to build and combine shape primitives pretty well, but that was never immensely useful.

Just last week I had Gemini 3.8 Flash and Antigravity take an existing STL of a part and swap out a piece of it with another design (fan shrouds on a computer case front plate). In the process it created exploded parts diagrams from the STL, created 2D renders from each axis (for its own visual re-ingestion, presumably, since I neither asked for or needed them), projected measurements, and then it implemented my design swap request. Which it didn't do with SCAD, it wrote a Python program and directly manipulated the STL geometries. It went perfectly. A week before that I had GLM 5.3 and Hermes take one model that was intended to fit into a part from another designer's part and change it; I didn't really like the interior part's design so I gave both STL files to Hermes and asked for a new interior part design that could be printed with vase mode to speed it up. It did and the new part is better than the human-designed part I grabbed off the internet.

I had another task mid week where I needed a case for something but didn't have the dimensions, so I just had Gemini do deep research lookup for dimensions and to then spit out a case STL for me. It was boring but functional and a good enough starting point for me to work with.

Right now my wife is enamored with a 3D printed purse design for halloween but the separately printed hinges are a weak design (a circular mortise and tenon rotating hinge). Working with Antigravity again, it's been able to take measurements, rotate parts in space on its own and create me a new object design that's better suited to be printed in TPU. It's held dimensional accuracy and even inferred some dimensions and spacing I didn't have out of the primary purse's shape. It's gone great. Next up will be having it combine all the parts into a single STL so I can do a multimaterial print in one shot, printing the purse in PETG but the living hinge in TPU without assembly needed.

I think "it's here, now" for home and hobbyist CAD needs for functional prints. It's not displacing a mechanical engineer's job yet, but this recent iteration is markedly better than the previous generation of models at spatial reasoning and 3D design because it's suddenly capable of it at all when even 4 months ago it was not.

In your other comment you mentioned "just learn CAD", and I have already, I could have cobbled together all of this myself in Fusion 360, but that would have taken far more time than a few minutes of prompting and walking away. I know enough domain lingo to describe the task well, and if it falls flat I will do it myself, but it's coming along faster than you seem willing to accept.

> I know enough domain lingo to describe the task well, and if it falls flat I will do it myself, but it's coming along faster than you seem willing to accept.

Could you do meaningful things without domain language you learned the long way?

I don't doubt it is coming along. But as with all of these things, this one is painted into a corner from the very start by using OpenSCAD.

And a mechanical engineer's job isn't just fiddling away in CAD, is it? If it was I would be on the way to being one by now, and I am not.