Show HN: Hestus – AI Copilot for CAD

I've been using parametric CAD (Pro/E / Creo, Solidworks, and Onshape) for 30+ years. Automatically adding sketch constraints is nothing new. Just about any 2D sketching tool out there will have some sort of snapping and/or auto-constraint-adding system. What's often more frustrating is fixing things when they get accidentally over-constrained. Solidworks tries to help with this in the form of cycling through what it thinks are the most likely constraints to remove and then re-solving the sketch. It's OK, but that sort of tool could be better.

A number of popular CAD systems use the D-Cubed 2D sketch constraint solver [0]. Siemens owns this and the Parasolid kernel, along with NX. All have been in constant development since the 80's. I really question what major new problems a startup is going to fix in 2D sketching constraints. I'm sure there a bunch of small quality of life things which may be out there, but most of the hard issues are more 3D or spline related, not finding things which could be tangent or equal.

Probably the biggest paradigm shift with constraints that still hasn't really taken off is what Siemens is doing with SolidEdge. It allows for defining the 3D equivalent of constraints between surfaces, holes, edges, etc. and then using direct modeling techniques to modify solids. Perhaps adding more intelligence to that approach would make direct modeling more popular.

Onshape has innovated in the way that it's brought Google Docs-like collaboration and GITHub like versioning, branching and merging to parametric CAD. Nothing else has these capabilities at the moment. To me that has been one of the most innovative changes in the mechanical CAD industry.

Onshape also has FeatureScript, which is the programming language which describes all the parametric features. Right now, none of the LLMs know FeatureScript well enough to be the least bit useful. They hallucinate wildly. I'd be very happy to have a Copilot for FeatureScript.

[0] https://plm.sw.siemens.com/en-US/plm-components/d-cubed/

Was a Mechanical Design Engineer for about a decade. Personally, the CAD part was the easy and fun part (Used Solidworks, Creo, Inventor, Catia v5 extensively. Professionally trained in all four as well). The “tedious” part was SAP (part number and material management), drafting, ECN/R/O, BOM handling, etc. I would be more excited for “AI” for PLM like Windchill, TeamCenter, or Cadedge (or whatever SAP PLM packages you used)

I've used CAD nearly every day for my entire engineering career, and this feels like a logical step. My day is filled with a tedium of micromanaging Solidworks or NX to simply do what I need. It takes very little time for me to envision a solution, but it takes ages of clunking through UI to actualize it. I'll be on board once you have SW support, I'd be interested in implementing it immediately.

My questions: 1) What's your CAD background? 2) What led you to realize that this was a problem that needed solving?

That's neat.

Autodesk Fusion already knows how to apply those kinds of constraints. This is an easier way to input them. The general problem is to express "what am I pointing at" in cluttered situations. Just figuring out how to do that was a huge problem in CAD. For decades, you had to have multiple views on screen just to select. The UI for doing it in one view was really tough.

It still doesn't translate well to fat-fingered devices such as tablets and phones. There are lots of construction people who could really use a tablet that has the design, knows where it is in space, and shows what's supposed to go there.

I wonder if the prevalence of coding LLMs will bring renewed attention to code-based modeling systems like OpenSCAD. It seems much easier to get them to generate code vs. translating into GUI interactions or modifying some other internal state directly.

Nice work!!

I tried to run it, but got an API Error:

Due to some internal changes made to the Fusion API, the Add-In: 'sketch_helper' from 'Hestus, Inc.' cannot be loaded. You need to install a new version of the Add-In that is compatible with this version of Fusion.

Can you just put it up on the Autodesk app store?

I struggle with this model, because of the capture by Autodesk and the other CAD providers. If you read the Autodesk EULA, I think it prohibits use of any open-source software in these add-ins. And I don't think anyone can use this software outside of Fusion 360. And if this add-in becomes popular, Autodesk can trivially release something that has the same functionality, built into Fusion 360 by default. And, as you are no doubt painfully aware, the Fusion API can be limiting.

If you can have your LLM ingest a non-parametric CAD model and spit out a parametric model with a beautiful, complete, editable feature tree full of Extrudes, fully defined parametric sketches with these nice constraints, all tied to the sketch origin, now that's something.

I think Autodesk BIM is $5000/mo/user, Fusion is $500/mo/user. I have thought that means the money is in architectural/structural.

As a side note - one other tip I have, for all CAD users everywhere: avoid Tangent relationship wherever possible! Stick to vertical/horizontal on the lines and arc endpoints, and you will be golden. The Fusion sketch solver is badly compromised, it can't do more than two or so simple successive Tangent relations without bugging out. And, my experience with Solidworks is the same, not sure if this is still true.

Curious if you dealt much with the Fusion constraint model, and have any insights into why it works so poorly, or even how it works? Many times, you click on a line, and it turns from blue to black, and back to blue again.

I have been using fusion360, at least once a week for 7 years. I don't find I am ever bogged down in tedious, repetitive tasks. The sort of thing in your video is completely second nature to me and the least of my problems.

This said, it sure looks cool.

What would be good would be something more like "I want to make a shape centered on this object on this other complex object, what's the best way to do it with the simplest constraints". With Fusion there are many ways to do anything and I often watch videos whose producers are way less experienced than me but they often have some really good hints, they have come across themselves or from others.

Like when you ask ChatGPT: "What's the best idiomatic way to do XXX in C++", or similar, say in a language I don't use every day, like TypeScript.

Good luck guys! I watched the video on YT - hopefully will get around to trying the Fusion 360 add-in at some point.

Does the current add-in use AI at all?

What is your plan when, in the event of you getting some traction, Autodesk etc. copy you innovations into the main product?

As per my other comments [1][2], I worked on this area at D-Cubed and Solidworks from 1995 to 2002. Feel free to connect with me via twitter DM @delhanty [3].

[1] https://news.ycombinator.com/item?id=41440016

[2] https://news.ycombinator.com/item?id=41440150

[3] https://twitter.com/delhanty

You might be mildly interested in the fact that "hestus" in Greek can (and will) be read as "shit (on) them!"

My brother in law is in construction and has built and project managed dozens of houses, small apartment blocks etc. He said that if a building job doesn't require planning permission (small extension, temporary structure, certain farm buildings, large sheds, pergolas, verandas, sunrooms etc) then the customer might ask if he can save money by skipping the architect and engineer. A competent builder can generally work that stuff out, but it does still require rudimentary drawings (elevation, plans, end view) and some spacial figuring out. And like a lot of construction guys he has almost zero computer skills, so this shit is literally pencil, paper, squares and rulers.

I always wondered if there's a VR app (or market for one) that can map out an area and let you virtually model your project within it using standard building components (9" solid blocks, cavity blocks, lengths of timber in standard sizes, various sheets materials etc). It should be able to do basic calculations (rafter spans, roof pitch etc). Once you're done, it spits out CAD files, bill of materials etc. Bonus points for looking up local suppliers and offering to order everything for you, or even modifying the design to accommodate what's available.

It's a completely different project and target audience to OP's app, so sorry for the tangent.

This looks like pretty much the exact kind of thing I’ve wanted. I’m just a very occasional user of Fusion 360 for personal 3d printing use - and I’m pretty terrible with CAD especially if I haven’t used it in a few weeks.

This doesn't really seem like a copilot, but it's still cool! It reminds me of the plugins for Glyphs [0], which allow font designers to speed up their process.

[0]: https://glyphsapp.com/features#plug-ins

I've no idea what I'm looking at but it looks cool. Could use a bit of an explanation what 'HV lines' are (don't look high voltage to me!) or why 'equating circles' is a good idea for us non-mechanical engineers.

Neat! At first glance, I was a little worried this was a "make me a hinge, Hestus!" sort of AI integration. This seems very logical! Coming from CAD from the purely hobbyist 3D-printing side of things, I'm pretty familiar with the tedium of some operations, (mostly because I can only assume I do most things wrong) so it makes a lot of sense to automate the scripts that would otherwise be an annoying task of "click part A... click arc... click the pivot point... click part B..."

That bit about auto-generating BOMs is awesome. Any chance you've thought about supporting the engineer with cost-saving recommendations?

I met a bunch of aerospace engineers a long time ago -- thinking about working on a software product in contract manufacturing or PDM -- and a common theme was the struggle to optimize the design for cost of manufacture.

Seems like something you guys are thinking about if focused on manufacturability.

Some things I’d love to see in AI for CAD that would be above this are 1) Is it manufacturable - where it analyzes different mfg methods, for feasibility and estimated cost. So many engineers design impossible or expensive to manage parts. AI could help make this not the case 2) as others have said, BOM/SAP/etc. 3) make the drawing for a machine shop

This is cool but I'd like to see some focus for civil engineers doing land development. 98% of them use autocad, and are stuck with it, but also they only really use no more than 100 different commands - it's just the scale of everything that's difficult and really matters.

I expected something like the blender text to shape plug-in (via GPT)

I'd suggest re-doing the YouTube video so it's legible/understandable when viewing on mobile. Full desktop UI demos don't really work on mobile; need to zoom and highlight etc.

Is anyone doing something in the space for architecture mockups? I was talking with a friend who is an architect and he would love a tool that could iterate designs.

This demo is lame and it isn't really providing much value. Hopefully it is just the beginning, but it currently isn't impressive.

The plugin does not load with Fusion 2.0.19994

Cadpilot