I would also like to add that part of the value of Fusion 360 and similar packages is that they use either the Parasolid Kernel (developed by Siemens), or the ACIS Kernel (developed by Dassault Systemes), or a variant (I think AutoCAD has their own ACIS fork from long ago). If you use either of those kernels, you can handle incredibly complex geometry (or even just things that seem simple but aren't, like Fillets) with ease and good compatibility with other programs. Both of those kernels started development in the late 1980s. Parasolid alone claims over 350 3D Programs license their system.

FreeCAD uses OpenCASCADE, because it's the only free option. You will notice that almost no other 3D Program, paid or free, uses it. OpenCASCADE is, compared to Parasolid or ACIS; buggy, broken, incomplete, unergonomic, and obsolete. There is almost no commercial software that uses it - they all find it better to license Parasolid or ACIS despite the heavy royalties those packages require.

This puts FreeCAD in kind of a chicken-or-egg situation. The geometry kernel they use is considered unanimously inferior to the licensed kernels for almost every task, to the point that even people building new CAD programs (like the recent Plasticity beta) don't even consider it as an option. The 3D packages that license the kernels think that rebuilding ~35 years of work with extremely complex math equations requiring dozens, or even hundreds, of PhD-level math professors is too much work to justify not paying a license fee. To them, it's like saying we should rebuild Windows, but it's PhD-level math instead of APIs.

Good summary — Parasolid is indeed the key here. I think it’s a similar story in the chip design space — there are not many good open source tools at scale, most people turn to Cadence and Synopsys who have been developing crazily complex (and buggy!) EDA tools since the 1980s.

> To them, it's like saying we should rebuild Windows, but it's PhD-level math instead of APIs.

Sage Math and all of it component software succeeded in that. Thus, I don't think it's something impossible.

It sounds like the best approach is to invest in a FOSS alternative that uses the metaphors you are used to.

I'm sure it's unrealistic for a small design house to do it on their own, but that doesn't mean the industry couldn't band together.

I wonder what would happen if everyone donated 10% of their Autodesk licensing fees to a foundation, or if a big shop decided to hire a dozen autodesk veterans for a few years.

Sadly FOSS tends to suffer from an effect that isn't quite a tragedy of the commons but feels related. If everyone who stood to benefit from a good FOSS solution in a given problem space did invest a fraction of what they currently give to extremely profitable commercial entities for the proprietary equivalent then almost everyone (not the over-greedy corporations) could be better off. But many of these dominant software products are defended by powerful lock-in and networking effects that create very high barriers to entry for would-be competitors.

In cases where there can be "good enough" solutions that can be achieved with more modest resources and then grow after gaining some traction we have seen some success stories. But for a lot of professional software in specialised markets it's almost an all-or-nothing proposition and that defeats the incremental adoption that has been somewhat successful elsewhere. Even well-capitalised commercial competitors have failed to make dents in the market share of the established giants in some of these industries and the odds are stacked even more heavily against any FOSS effort building up from the grassroots.