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I'm working on an MPL-licensed, free forever CAD environment for molecular nanotechnology. It is extremely early, indeed I hesitate to even mention it as it is currently undergoing the final stages of a rewrite to run on a game engine back-end, and it isn't much more than boilerplate at the moment. But we have a small community of people interested in this, and we are currently raising money to support further development, among other things.

The key point though is that the atomistic modeling is sort-of an add-on to a bog-standard CAD workflow. You still use boolean geometry to produce surface representations, even if those surfaces are discretized crystal structures.

I had intended that once it was up and running I would reach out to some people I know that are interested in a more modern alternative to FreeCAD. Perhaps it would make sense to combine efforts?

[1] https://github.com/atomCAD/atomCAD

I personally don’t think FreeCAD needs an alternative. It’s good enough for most needs and it’s maturing. But it needs to be used for what it is good for: visual workflows. FreeCAD and all other CAD tools (that might be needed or preferred for some workflows) need to get out of the business of storing CAD data in proprietary binary files that are no good for any collaboration. Instead, either natively or through plugins, they need to import/export code. Once the design is stored like code, regular coding techniques kick in. And don’t just mean merging. Linting, code coverage, the whole shebang. That’s the kind of workflow that PartCAD aims to facilitate.

I understand and agree with that. But to push back on the first sentence, I really don't think FreeCAD is acceptable. It's clunky, it's notorious for crashing on large models, its user interface is antiquated and really difficult to learn, and the code base is a monstrosity.

I only draw simple hobby projects from time to time and have given freecad a chance several times, but it can't even begin to keep up with commercial tools.

Yeah, it did steal some of my time and gave me some gray hair too. However as I mentioned in another comment, PartCAD is not there to replace existing CAD tools. It’s there to extend the definition of computer aided design to include modularity and collaboration. The tools that we called CAD-tools will be called “CAD Design GUI” tools. For decades their marketing departments have successfully sold us the idea of those tools being the complete technology solution. Charging ridiculous amounts of money for any collaboration feature. And I don’t blame them. They are smart. But we, as a humanity, need to be even smarter. Smarter than agreeing to having no “merge/rebase” functionality in 2023.

This sub thread isn’t about PartCAD.

But on the topic of CAD/CAM systems, there IS value in having a single workflow tool from design to manufacture. Fusion 360 shows how beneficial it can be to have these different aspects of the workflow be seamlessly integrated.

There’s no justifiable reason to Balkanize all the CAD tools based on function. Users don’t want that.

Users who want to continue paying for the value of having all tools under one roof can continue doing so. From time to time they might not be opposed to the idea of importing a part or two from a public repository. At least for some simulation tests. They might also find value in using a proprietary private PartCAD repository when they migrate from one all-under-one-roof tool to another after being squeezed dry by the previous vendor.

No one really knows what all of the users want. The commercial tool vendors would tell us that all users want exactly what they sell. My subjective experience suggested a hypothesis that some users might want something different. After two days of PartCAD’s initial revision being out there, it would be fair to say that a lot of users want it. The demand and feedback exceeded all expectations.

So you agree there is value to be had?

Of course! There is more than one concept that has value. And each concept also has a price (or price range as there will always be multiple implementations of each concept, each implementation will deteriorate over time and so on and so forth). There will always be more than one class of consumers, more than one set of value/costs preferences. Otherwise we would only have one programming language, wouldn’t we? So acknowledging one concept has value doesn’t mean announcing that it is the only concept worth existing.

Well, as a professional mechanical engineer with 20 years of cad experience, I disagree that FreeCAD is “good enough for most needs”. It didn’t even have assembly support until a preview of that feature was added to a fork a month or so ago, and it was a non-starter before that. I currently believe FreeCAD is the best hope we have but there’s a long road ahead before it is “good enough”.

As far as storing cad files as you describe, how does that interface with OpenCASCADE file formats? The data storage is related to the CAD kernel I think, so it might be difficult to move to a “store models as code” storage model.

That’s why I said other CAD tools can be used for some workflows. For most humans interacting with technology nowadays out there FreeCAD will do. Anyway, even if I’m wrong about FreeCAD, PartCAD doesn’t have much to do with what happens between “Load” and “Save”. CAD is a tool that some people will use. PartCAD should support as many of those tools as possible.

The question of format used to store part info is more relevant to PartCAD. However I do not think PartCAD should prescribe any. PartCAD must be modular and support as many formats as it can. And let the competition decide. Maybe the supported/compatible CAD kernels will contribute to the competition of file formats. Maybe the file format chosen by the community (e.g. for LLM related reasons) will contribute to what CAD tools support. We’ll see in 20 years.

I personally don’t think the community at a whole will gravitate towards anything like OpenCASCADE file formats. I find CadQuery and build123d more promising (no matter what’s under their hood at the moment). I believe it must be human-readable (and, thus, LLM-readable) text. But CadQuery and build123d are not the end of the evolution. I’m sure we will face next technology iterations that are at least more LLM friendly, secure (e.g. to prevent arbitrary I/O from code), and more structured (to help retain the code structure and formatting in the “Load”-“Change”-“Save” cycle).

PartCAD will be there to facilitate modular design and collaboration, and to include as many people and their tools as possible. Not to facilitate any closed formats or tool ecosystems that commercial tool vendors are trying to prescribe to us today, no matter how convincing their arguments sound. Large profits enable generation of very convincing arguments.

No matter how difficult it is going to be to “store models as code”, I personally believe the humanity will succeed at that. However PartCAD will support all common file formats. It currently (2 days after a preview release which somehow went huge) supports CadQuery, build123d and STEP files.

I reread the sub-thread and I can see how my attention got carried away from the topic. The maintenance of models might be perceived as an add on to a much more scientific-heavy CAD workflows. The value of engineering tools is not going to go away no matter how data exchange and collaboration tools advance. I hope you find people who can help with the scientific-heavy work that would certainly require funding.

However I would still like to learn how PartCAD (and part-time open source hobbyists behind it, without any funding) can help nonetheless.

I’d really like to learn what are the modelling needs of molecular nanotechnology. Would it need another packaging tool, or just a separate index repository to main another set of parts? Is there any chance you can consider the persistence layer being modular and implemented as code from day one? I would appreciate an opportunity to debate about it with an experienced professional.

We’re looking at various options for code representations of models. Stuff like cadquery is inspirational, but a stronger type system and runtime guarantees are needed. It also ties very closely to version control, as an AST-aware VCS can effectively merge edit histories with visual diffs, and permit editing the history itself. This more resembles the workflow of f-reps than b-reps, but we haven’t made a firm decision on representation.

Having a standard repository of parts is also critical. We are also considering ways that the interface can be made modular and plugin driven such that importing a part into a workspace also imports widgets for instantiating and interacting with that part.

I wonder myself why would we run third party Python scripts that can do anything, run an infinite loop, download something from Internet or delete files from the home folder, and keep our fingers crossed it calls “show_object” at the end… Have you considered using Java? I mean real classes that implement interfaces you introduce, not classes with a single “main()” method. So you instantiate an instance of that class when you add a part. You can use a handcrafted JVM or Javaagents to ensure that it’s only doing the things you want (like they do on Spark clusters to ensure that ML jobs are only doing ML). Since you are after describing and instantiating objects, why not using something so object oriented?

I want to introduce something like that as an option in PartCAD to see if anyone likes to use it.

Let me know if you want to give PartCAD a try for your model storing/sharing needs. I’ll be happy to customize/extend it for your needs. I always loved chemistry and physics but never had a chance to apply that at work.

Web assembly makes a lot more sense than JVM these days. But I suspect we don’t want something Turing complete.

Hmm. Indeed that makes a lot of sense to use wasm instead. Let’s table the language aside for a moment. What data format would you expect to be spit out by third-party models? Is there anything generic enough to store both b-reps, f-reps, and whatever might be suitable for nanotechnology?

Cool, that sounds hopeful. FreeCAD's Assembly workbench mess (aka several competing ones instead of a single blessed one) is why I stopped using it. So if that gets solved it'll be very welcome (by me). :)

Good news on that front, FreeCAD is working on adding an official Assembly workbench as we speak. They added OndselSolver as the core back in november, and seem to be working to add the workbench by the next major version. https://blog.freecad.org is a great place to keep an eye on things.

> There is an organization called Ondsel which is taking on a lot of UI and assembly bench improvements,

They don't have any screenshots on their site.

> They don't have any screenshots on their site.

The website is WIP. You can find screenshots and videos in the blog.

https://ondsel.com/blog/assembly-wb-prerelease/

https://ondsel.com/blog/floating-input-widgets/

https://ondsel.com/blog/ondsel-made-constraining-sketches-fa...