[onthecanposting]

"The biggest reason this hasn't happened so far is the lack of a truly capable parametric kernel"

Does parasolid not fit this requirement? The capabilities I've seen in Plasticity are very impressive. Or do you specifically mean FOSS?

The more I use CAD platforms, the more I develop the sense that general-purpose CAD is much less useful than single-purpose applications that provide tailored solutions to narrow problem domains. SVG/DXF/DWG output is a plus, but I think a drawing software that works for high-volume machine parts, one-of-a-kind architecture, highways, 50-mile pipelines, circuits, urban transit plans, and art is the wrong direction. I use industry standard roadway design software and a "road" does not exist in the object model. Horizontal, vertical, and sectional components are all independently defined despite these things being inseparable and having some very obvious and well-specified rules about their interaction. I really think designers should spend more time thinking about outcomes and less time telling the computer how to display them.

[eliasson]

Absolutely agree. I just finished a project were where users can design / construct solutions in a specific domain in either 2D or 3D, with support for exporting CAD and STP.

The user works with rich domain objects that limit the possibilities to what actually works or is practice; much like a game level builder. This allows non-experts to design solutions in this particular domain, which of course is great for business / sales.

[Fr0styMatt88]

I think this is a great point. When looking at ‘best practices’ for constructing robust parametric models I keep thinking “this is so much like software engineering where the programming language is the CAD system” (as an aside, I’ve tried OpenSCAD but found the rendering UI waaay too slow even with simple stuff to be usable for me).

So as a model builder you end up trying to build these higher-level abstractions into your model, where the parameters are your top-level interface.

I think CAD is so much like programming in those ways, although I could just be biased since I’m a software engineer.

[onthecanposting]

You are right! CAD users encode a design intent into the software, just like you encode a design intent into an editor. I model a construction outcome with geometry like you might model business rules with functions and objects.

Some of the wisdom from programming would do well to pass onto design software. Like how strong type systems can provide safety by pushing rules to compile time and make some errors unrepresentable. Meanwhile, I can fire up Microstation, draw roads crossing at the same elevation with no intersection (think stops and signals, not geometry) between them. Or a drain culvert could terminate in a big Hello Kitty picture. These things should be impossible. If the task is designing a road, I don't need the ability to draw anything I can possibly imagine. I really need the software to know what a road can and can't do, produce a model that obeys those constraints, and to give me files and documents I can give to an owner and a contractor which convey an accurate understanding of what that model is.

[WillAdams]

For OpenSCAD, try the nightly build and enable MANIFOLD --- that's an order of magnitude (or two) of increase in the performance.

[pyb]

100% agree. The future of CAD consists in more specialized CAD platforms, not tweaks to general mechanical CAD. Cabinet Vision is one good example.

[iancmceachern]

Parasolid is owned by Siemens, it's not open source really