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WillNickolsyesterday at 5:59 PM1 replyview on HN

Thanks for the input! Haven't done much with Altium but it seems like you get at least somewhat of a boost for it being slightly more about the logic and less about the spatial reasoning.

2 things related to what you said I hadn't put in the original post:

1. In our experience, the LLMs were awful at taking actions directly with any of the SolidWorks API scripting formats (C#, VBA, etc.). Probably 75% of what they wrote just failed to run, and even when they had access to browse the documentation it wasn't much better. If you're getting Opus or anything else to interact with SolidWorks from the CLI, can you say more about how you're getting it to interface effectively?

2. The LLMs are indeed surprisingly bad at spatial reasoning unless prompted specifically and individually. The most notable case of this is when they need to choose the right plane to sketch on. When creating revolve features, they'll often choose the face that would've only worked if they were going to extrude rather than revolve, and when creating sweeps they'll often try to put the sketch that's going to be swept on the same plane as the path that's being swept. If you go back and ask them why they did that and point out that it's wrong, they can fix it pretty fast, but when left to their own devices they often get quite stuck on this.


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akiselevyesterday at 7:02 PM

> If you're getting Opus or anything else to interact with SolidWorks from the CLI, can you say more about how you're getting it to interface effectively?

I just have a Solidworks plugin that translates CLI calls to JSON to Solidworks API calls and back again.

What really started working was creating a bunch of high level CLI commands so that Claude Code could query the part/assembly by asking stuff like "What is the closest distance between the southmost surface of Extrusion1 and the surface of Cylinder2" which would then be translated to a specific high level command or a bunch of lower level commands by Gemini 3 Flash. Those would then be translated to Solidworks API calls, as would any editing commands. It also really helps to give it the ability to parametrize the queries so instead of "all features smaller than 2mm" it can say "all features smaller than $MinFeatureSize", with some logic and a downstream LLM to translate that parameter into values in the design and review it with the human in the loop before committing it to the project.

The key is to absolutely minimize how often the LLMs think about numbers and have them think in relationships instead. The hard part is translating those relationships back to the CAD API calls but LLMs are much better at hot hallucinating if you resolve all the parametrized equations last.