Comment by alnwlsn

It's also going to be about diagnosing issues. "This part broke right here, explain why and come up with a solution", "Evaluate the robustness of this solution", "Can I save some material and reduce the weight", etc.

Those are the kind of high level questions that an LLM with a decent understanding of CAD and design might be able to deal with soon and it will help speed up expensive design iterations.

A neat trick with current LLMs is to give them screenshots of web pages and ask some open questions about the design, information flow, etc. It will spot things that expert designers would comment on as well. It will point out things that are unclear, etc. You can go far beyond just micro managing incremental edits to some thing.

Mostly the main limitation with LLMs is the imagination of the person using it. Ask the right questions and they get a lot more useful. Even some of the older models that maybe weren't that smart were actually quite useful.

For giggles, I asked chatgpt to critique the design of HN. Not bad. https://chatgpt.com/share/6809df2b-fc00-800e-bb33-fe7d8c3611...

You're right, but I think we have a long way to go. Even our best CAD packages today don't work nearly as well as advertised. I dread to think what Dassault or Autodesk would charge per seat for something that could do the above!

I think this is correct, especially the part about how we actually do modelling. The topological naming problem is really born from the fact that we want to do operations on features that may no longer exist if we alter the tree at an earlier point. An AI model might find it easier to work directly with boolean operations or meshes, at which point, there is no topological naming problem.

The problem is that this isn't very useful except for the very earliest ideation stages of industrial design, which hardly need CAD anyway.

Most parts need to fit with something else, usually some set of components. Then there are considerations around draft, moldability, size of core pins, sliders, direction of ejection, wall thickness, coring out, radii, ribs for stiffness, tolerances...

LLMs seem far off from being the right answer here. There is, however, lots to make more efficient. Maybe you could tokenize breps in some useful way and see if transformers could become competent speaking in brep tokens? It's hand-wavy but maybe there's something there.

Mechanical engineers do not try to explain models to each other in English. They gather around Solidworks or send pictures to each other. It is incredibly hard to explain a model in English, and I don't see how a traditional LLM would be any better.

There's a mindset change needed to use a feature tree based constructive solid geometry system. The order in which you do things is implicit in the feature tree. Once you get this, it's not too hard. But figuring out where to start can be tough.

I miss the TechShop days, from when the CEO of Autodesk liked the maker movement and supplied TechShop with full Autodesk Inventor. I learned to use it and liked it. You can still get Fusion 360, but it's not as good.

The problem with free CAD systems is that they suffer from the classic open source disease - a terrible user interface. Often this is patched by making the interface scriptable or programmable or themeable, which doesn't help. 3D UI is really, really hard. You need to be able to do things such as change the viewpoint and zoom without losing the current selection set, using nothing but a mouse.

(Inventor is overkill for most people. You get warnings such as "The two gears do not have a relatively prime number of teeth, which may cause uneven wear.")

>> I have come across a significant number of non engineers wanting to do, what ultimately involves some basic CAD modelling.

I very much want Solvespace to be the tool for those people. It's very easy to learn and do the basics. But some of the bugs still need to get fixed (failures tend to be big problems for new users because without experience its hard to explain what's going wrong or a workaround) and we need a darn chamfer and fillet tool.

Feels a bit like being on a call with someone at the hardware store, about something that you both don't know the name for. Maybe the person on the other end is confused, or maybe you aren't describing it all that well. Isn't it easier to take a picture of the thing or just take the thing itself and show it to someone who works there? Harder again to do that when the thing you want isn't sold at the store, which is probably why you're modeling it in the first place.

Most of the mechanical people I've met are good at talking with their hands. "take this thing like this, turn it like that, mount it like this, drill a hole here, look down there" and so on. We still don't have a good analog for this in computers. VR is the closest we have and it's still leagues behind the Human Hand mk. 1. Video is good too, but you have to put in a bit more attention to camerawork and lighting than taking a selfie.

And I can think faster than I can speak, which means it's easier for me to think about what I need to do and then do it, rather than type or speak to an LLM so they can work out what I need to do instead

I spend a lot of time using proprietary CAD package A to redraw things from Who Knows What, but that's mostly because the proprietary CAD data my vendor would send me is trapped behind an NDA for which getting legal approval would take more time and effort than just modeling the things in front of me with minimum viable detail, or else my vendor is 2 businesses removed from the person with the CAD data that I need (and may require a different NDA that we can't sign without convincing our vendor to do the same). Anyone I've ever been able to request CAD data from will just send me STEP or parasolid files and they will work well enough for me to do my job. Often I spend more time removing model features so my computer will run a little faster.

I appreciate that you have given this some thought, but it is clear that you dont have much or any professional experience in 3D modeling or mechanical design.

For the guitar amp, ok. Maybe that prompt will give you a set of surfaces you can scale for the exterior shell of the amp. Because you will need to scale it, or know exactly the dimensions of your speakers, internal chambers, electronics, I/O, baffles, and where those will all ve relative go eachother. Also...Do you need buttons? Jacks/connectors/other I/O? How and where will the connections be routed to other components? Do you need an internal structure with an external aesthetic shell? Or are you going to somehow mold the whole thing in one piece? Where should the part be split? What kind of fasteners will join the parts and where should they be joined? What material is the shell? Can it be thinner to save weight? Or need ribs or thickness for strength? Where does it need to be strong?

These are the issues from 30 seconds of thinking about this. AI (as suggested) could maybe save me from surfacing an exterior cosmetic cover, given presice constraints and dimensions, but at that point, I may as well just do it myself.

If you have a common, easy, already solved an mechanical design problem (hinge e.g.), then you buy an off the shelf component. For everything else, it is bespoke, and every detail matters. Every problem is a "wine glass full to the brim"

In your example, what about mounting the electronics or specifying that the control knobs need to fit within these dimensions? I guess its easy if those objects are available as a model, but thats not always the case.. 3d scanner maybe?

Most of the things I work on are "make this fit onto that like this". There's not that much information contained in that sentence, it's contained in the 2 objects I was just handed. Sometimes we have drawings for that stuff, most of the time we don't. The "like this" part can be a conversation, but the rest of the info is missing and needs to be recreated.

I said this below, but most of the mechanical people I've met are good at talking with their hands. "take this thing like this, turn it like that, mount it like this, drill a hole here, look down there" and so on. We still don't have a good analog for this in computers. VR is the closest we have and it's still leagues behind the Human Hand mk. 1. Video is good too, but you have to put in a bit more attention to camerawork and lighting than taking a selfie.