[tda]

The real problem is that BREP CAD kernels are hard. A few of proprietary kernels dominate the scene: Parasolid powers NX, SolidWorks, Fusion, and Onshape, while ACIS (owned by Dassault) is used by Inventor and BricsCAD. Catia uses Dassault's own CGM kernel. The open-source world relies mostly on OpenCASCADE, which is unfortunately a lot less capable than any of these.

Fillets and chamfers are a good example. They seem simple but are geometrically non-trivial, and OCC will fail on cases that Parasolid handles without complaint. You can push either kernel to its limits if you try hard enough, but OCC hits that ceiling much sooner. So any CAD tool built on top of it inherits that ceiling too.

[martinpw]

> Fillets and chamfers are a good example. They seem simple but are geometrically non-trivial, and OCC will fail on cases that Parasolid handles without complaint.

A long time ago I interviewed at one of the large CAD companies. I remember getting an office tour and the person showing me around pointed into a corner with six desks and said "that is the team that does fillets".

Open source tools can handle some cases, but to handle the full complexity of real world problems is a huge extra step that I doubt they will manage any time soon.

[MengerSponge]

Were their desks shaped like this? https://www.staples.com/bush-business-furniture-cubix-48w-co...

[regularfry]

That's one of the real problems. The other real problem is an active resistance to UI improvement simply because another CAD package did something similar.

[obelisk79]

FreeCAD doesn't resist those comparisons anymore. They happen regularly. Implementing change is just slow, and purely copying how xyz cad built their UI isn't always compatible with FreeCAD, so a lot of careful consideration goes into things before concepts from other software get implemented. Not to mention that developers seem to really dislike doing frontend work.

[randusername]

Do you think this is why CAD software UI/UX is often so clunky? The kernels are complicated and error-prone given the incalculable number of edge-cases, which puts error reporting at a disadvantage, leads to counter-intuitive feature wizards with some having way too many parameters and others being very single-purpose?