Has anyone completed a serious engineering project in OpenSCAD? I just can't imagine how that would work. I suppose the actual design work wouldn't be that much different, but I can't imagine a way to collaborate with it. You'd need a mechanical engineer, who is also a programmer, who is also willing to learn OpenSCAD. That is expensive.
With FreeCAD, even if you never used it before, a CAD person could figure it out. Its mostly learning which icons do what. (IB4, someone mentions the topological naming problem, that its completely avoidable with a 10 minute youtube video on the subject, or you can download the RealThunder fork of FreeCAD if that 10 minute youtube video is too time consuming)
I guess my point is: Yes its technically possible to do a lot of things on any OS, but it isnt practical.
> You'd need a mechanical engineer, who is also a programmer, who is also willing to learn OpenSCAD. That is expensive.
I disagree. I'd expect any engineer these days to have at least modest skills in programming.
And OpenSCAD is a rather modest programming, the script itself always finishes, so it's not even Turing complete. So having mechanical engineer to be comfortable with OpenSCAD looks like a quite reasonable thing.
With FreeCAD you have a lot of useful and convenient things, but you immediately lose the parametrization. Can't convert back to OpenSCAD if you'd like. So it's hard to move to FreeCAD from OpenSCAD if you got used to OpenSCAD capabilities.
Parameterisation is actually one of the things you can do with freecad. Most of my projects have a spreadsheet with the parameters in them.
You can run into annoying problems with the sketch constraint solver when changing those parameters though. Depends which parameters and what you've used them for.
If changing the parameters upsets the constraint solver, you can sometimes work around it by changing them in smaller increments (e.g. so that a "length" doesn't flip to the other side of a line).
Yes, and there are some other tricks you can do. The underlying problem is that "fully constrained", to the solver, means "cannot be continuously varied". It doesn't mean "there is only one solution". So what you get, for instance, is a point being constrained to a distance from a line that the solver will allow to be on either side of that line, at the correct distance, so if the line moves further than the distance when you update parameters, everything falls apart as the solver picks the other solution.
That specific one you can force by adding a construction line between the point and the constraint line, with an absolute angle constraint on the construction line. Because lines have direction (a hidden direction! Got to love critical functionality with no representation or control in the UI whatsoever!) the angle constraint forces the solver to pick only one of the two solutions because the other would make the angle 180 degrees out.
There are other problems that are much harder though, that I haven't yet figured out how to work with, mostly involving arcs. It's easy for the solver to flip which side of a circle a tangent constraint solves to, and because in that case there often isn't a fixed angle to work with the construction line trick doesn't work. When that happens on an arc, you end up terminating a line in free space, or wrapping the arc the other way round the circle, or something. I do wish arcs would only allow constraints between their endpoints.
What would solve a lot of these cases is a winding order constraint you could apply to a set of points - "make sure these 3 points in this selection order are always anticlockwise around their median" or something - to disambiguate solution pairs, but I dread to think what the UI for that would end up looking like.
FreeCAD is a parametric CAD program. You can create a "spreadsheet" in FreeCAD where you define your parameters and then reference these cells in formulas that drive your constraints.
Thanks, didn't know about that. Maybe then the parametrization in OpenSCAD is subjectively more conveniently implemented, I don't know. Why it's not too well known?
One difference is that sites like thingiverse allow the parametrization of OpenSCAD projects right on the site, so downloaders can customize their STL without needing to run OpenSCAD themselves. To the best of my knowledge, there is no such ability for FreeCAD.
For one of my projects, this seemed to be enough of a benefit that I redid my original FreeCAD design in OpenSCAD for eventual uploading.
I've tried to use FreeCAD myself and didn't see that feature. I guess more learning are encouraged here. Now I know to look for parametrization as well.
With FreeCAD, even if you never used it before, a CAD person could figure it out. Its mostly learning which icons do what. (IB4, someone mentions the topological naming problem, that its completely avoidable with a 10 minute youtube video on the subject, or you can download the RealThunder fork of FreeCAD if that 10 minute youtube video is too time consuming)
I guess my point is: Yes its technically possible to do a lot of things on any OS, but it isnt practical.