Hi HN,
I have a 3D printer but I’m pretty bad at CAD. Using LLMs for coding has worked extremely well for me, so I’ve been trying to apply a similar workflow to CAD/modeling.
For simple functional parts (jigs, brackets, adapters, small fixtures), I can use an LLM + OpenSCAD in a loop: it writes OpenSCAD, I compile/render, I render a few views, the LLM “looks” at the images, and we iterate until it looks right. This is already helpful, but it hits a ceiling quickly. Anything beyond simple parametric primitives becomes painful (complex geometry, precise interfaces, assemblies, tolerances/fit, etc.).
I’m curious about two things. First: any intuition on when we’ll be able to generate models at a professional level, comparable to what LLMs can do for coding right now? Second: what will that workflow look like in practice? Will it stay mostly parametric (OpenSCAD / constraints), or will it look more like an interactive “CAD copilot” inside tools like SolidWorks/Fusion that can edit the feature tree via screenshot + click style interaction? Or something else entirely, like text turning into a full feature history with constraints and checks.
If you’re already doing this, what tools/workflows are giving the best results today, and where do they fail?
Thanks!
Current approaches hit the same wall: you can't easily go from geometry back to code. When an LLM generates OpenSCAD and the output is wrong, you're staring at an STL with no way to point at a face and say "this edge should be 2mm shorter." The LLM is flying blind.
The tools that work best right now are the ones that keep geometry minimal and code iterative. OpenSCAD with an LLM in a loop can handle simple parts because the code is the source of truth and changes are surgical. But complex assemblies? The boolean operations cascade failures in ways that are brutal to debug even for humans.
The real unlock isn't better prompting or bigger models: it's a representation that supports bidirectional editing. F-Rep/SDFs are interesting here because the math is more compositional and less "undo history dependent" than B-Rep.
Manufacturing constraints (tolerances, printability, material limits) are a separate unsolved problem. Geometry that looks right but won't print is the silent killer.
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