Very high with the correct tooling. Vision tends to be the worst reasoning mode for LLMs compared to code, which is why I rely on a code-first approach for my own software stack. Essentially, they need to have a way to keep part of the drawing in focus to avoid getting distracted by the dimensions they don't need in their vision.

https://github.com/yuechen-li-dev/Aetheris/blob/master/sampl...

The initial dimensions of this phone were one-shot by Codex Astra from the publicly available 2D drawing, and we spent another turn implementing the G2 continuous fillet blend surface for that particular camera bump. If you have a STEP viewer, you can check the dimensions against that phone company's drawings which was posted on HN with their other products yesterday I think, and all of them should match exactly down to the drawing tolerances.

It really depends on the complexity of the model you are trying to generate and the budget you have.