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Comment by throwitaway222 | Hacker News Reader

I've been using Astra to just create things in Blender. It's great.

Kill the scroll jacking. It's a sign you're on Windows.

CAD is a different beast than mesh modeling. For product design you need a parametric model that can have precise dimensions and is constructed mathematically step by step. Mesh modeling is just moving a pile of triangles around in a very imprecise way. Works fine for 3D printing or digital assets, but if you want something that can be manufactured that's not good enough. And there isn't a good way to go from STL -> Parametric CAD so there's still room for a product here.

> there isn't a good way to go from STL -> Parametric CAD

yet.

as a matter of fact, you should try what AI can do on that problem, you'd be surprised.

I have tried, I really wish it would be better because CAD is a slog and I want it to be automated. It's pretty bad at real world tasks.

It's just a matter of time. Astra was trained on a new 3D modelling dataset. They will surely train it on CAD apps (if they have not already done so). I don't hold out much hope for competitors hoping to get in front of that train.

Astra can use build123d, too. You'll get a STEP out of that.

I've tried Sol on build123d and it was completely unusable, I should take another stab with Astra though.

I had a similar experience, but it worked just well enough that I wanted to try my own similar experiment, but using a functional API in Elixir and giving the agent some introspection tools. I'm very much a novice to this space and learning as I go, but I've been able to make some interesting projects with the library so far, which is all I really want to do: https://smith.hexdocs.pm

If you want to build by hand, there is a Kino renderer to build your projects interactively in Livebook, which is actually surprisingly helpful for learning.

CATIA has had mesh import with canonical feature detection, and automatic replacement with parametric part features, for at least 25 years. It's in the "Quick Surface Reconstruction" and "Basic Surface Recognition" tools. They even work sometimes.

https://3dswym.3dexperience.3ds.com/wiki/catia-user-communit...

https://resources.rand3d.com/insights-from-within/scanned-da...

Unfortunately the P3 license costs like $15k per year, and it is f'in ugly clunky software.

I was able to have Astra accurately solid model with plasticity (NOT import from Blender) and presumably it would be trivial with autocad, but I haven’t tried it yet.

I suppose you might be able to force a Blender agent to do parametric modeling via geometry nodes. It would be a horrible, kludgy, slow workflow for a human, but the AI won't complain.

The only way to go from STL to BREP is through decompilation style recovery/reconstruction, because of the semantic information loss, so it's a task that can only be done via LLMs or human CAD users. Essentially, they pretty much have to remake the model from scratch using the STL as a reference to make the CAD. There really isn't a good way to automate this without machine learning/LLMs.

Fusion 360 can convert many STLs to BREP automatically. It can be slow and error prone but it does work. It will recognize large regularly curved areas and replace thousands of triangles with a single smooth curve.

" if you want something that can be manufactured that's not good enough"

People design all sort of buildable things in SketchUp and it's just about dragging polygons around.

You _may_ need accurate surface if you run your model to CAM.

But to this day lot of manufacturing is still done via drawings and there the only thing that matters is that can you draw some type of lines and attach clear dimensions to them. So the shapes don't necessarily need to be accurate for all flows since they are more like topological hints to the person reading the drawing rather than accurate replica of the thing to manufacture.

Exactly. I just give Astra an image such as furniture, and it creates an 3D reproduction in Blender. You don’t even need computer use. Codex and Blender’s scripting engine is enough.

Can you do this with the 20 dollar plan?

Yes, but it eats your 5-hour quota really quick.

I have an example here. Took 3 hours with Pro Plan.

https://simulationcorner.net/chair/chair-evolution.gif

That's cool as hell.

I gave some very bad sketch made in jspaint to Astra, plus some text instructions, and I got back some clean STL file and a beautiful 3D render.

It even made a second STL file with the same model rotated for 3D printing.

I remember all those hours on SolidWorks many years ago, and now you can just speak and present bad drawings to the computer, and it does it okay.

I've had decent success getting Claude Opus to design models using the python cadquery library, and then I can import the step file to fusion 360 to make any changes I want afterwards.

Are you hooking it up to blender via some MCP or are you just creating files and opening in blender?

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