Answer: It's extremely hard to build any equivalent to Fusion 360 or any full featured CAD/CAM tool. This is not a weekend hackathon problem!
There are so many fundamental building blocks, with many requiring teams of PhDs to produce: CAD kernels, constraint solvers, file format interop, sketching tools, assembly support (mating), simulation, etc... Not to mention the manufacturing specific modeling tools for sheet metal, generative design for milling & 3D printing.
Parasolid, the CAD kernel owned by Siemens, is more than 30 years old at this point. The same amount of effort has gone into many of the other building blocks as well. OPENCASCADE is a FOSS CAD kernel but doesn't work well for real CAD, and support is hard to come by for companies building on it.
Most startups tend to license these tools instead of building them, but that comes at a large cost that must be pushed down to customers, hence the $$$$ cost of CAD today.
Plus, they are not shy about acquisitions. It's how they maintain their dominance. Any company that builds a remotely useful product in that space will find themselves sitting in front of a Big Fucking Check that's going to be hard to turn down. Anyone who turns it down will probably find themselves sitting in front of several patent lawsuits all over the world.
For "free as in beer" there's OnShape with the caveat that all your projects in the free tier are public, and that it runs on the browser or via mobile apps. The iPadOS app has Apple Pencil support which is pretty neat.
The only decent FOSS parametric CAD software I've found is SolveSpace, but it is quite limited, e.g. it doesn't even have a bevel tool, and there's no CAM. It's pretty much the Notepad of CAD.
CAD is just one of those things that is too complicated and niche for FOSS to do well.
It's arguably too complicated for hackers to do well in their spare time, but there are plenty of FOSS projects in similarly complicated niche areas. The most successful ones tend to have companies or consortiums backing them, who aren't looking to make money on the softare itself but have it complement or support their other activities. OpenModelica for one example.
I always wonder why a consortium of big manufacturers (say Ford, Caterpillar, Hitachi, etc) don't just throw their weight behind some FOSS CAD initiative and get something standard that they can rely on forever. I don't think it would cost them more than 3rd party software in the long run.
> in the long run
People have taken the initiative and talked to the engineering departments and bean counters at large engineering houses (brands you're not familiar with, that do the engineering for e.g. Ford, etc but not the design which is typically in-house). The reasons are A) short term cost with no benefit, B) having to train staff, and C) compatibility with extant files. Not only will the current staff have to be retrained but nobody can be hired with experience with the tool.
The problem for these businesses is that their internal CAD libraries are essentially proprietary tooling, they don't have an interest in making it open source, and much of the tooling around those libraries and software packages is proprietary or patented.
It's kind of analogous to Qualcomm's stranglehold over cellular communications. If you don't pay them you're also throwing away decades of IP and tooling around it, and lose interoperability.
https://www.youtube.com/watch?v=geSQlBczsWY
After that, I spent a month last year doing a daily household item challenge, which really leveled up my skills and now there's no turning back.
If you drop by github to look at the code, make sure to check out some of the other awesome projects by @whiteshark (who is one of the authors).
[solvespace]: http://solvespace.com/index.pl
Honestly, I'll just end up paying. It pisses me off that they managed this so poorly, and even more that their pricing tiers include so much BS. Oh well.
> make sure to check out some of the other awesome projects by @whiteshark
Typo Fix: @whitequark[1]
[0] https://github.com/Symbian9/SolveSpace-Daily-Engineering
How hard is to build the equivalent of "Affinity Photo" to Autodesk Fusion 360? Maybe this is a good startup idea.