[OpenSCAD] What's your opinion on these criticisms of Openscad?

Peter Falke stempeldergeschichte at googlemail.com
Thu Sep 17 14:10:51 EDT 2015


Have a look at some of the (video) tutorials to get an impression of
Openscad:

https://www.youtube.com/watch?v=XNghpq9sKRc

http://edutechwiki.unige.ch/en/OpenScad_beginners_tutorial

(I just googled these, ther are more around.)

All things on http://www.thingiverse.com/ that use the costumiser are using
Openscad, and a lot of other model are made with Openscad, there, as well.

2015-09-17 19:39 GMT+02:00 G. Wade Johnson <gwadej at anomaly.org>:

> That review is relatively amusing.
>
> A lot of the complaints are the same ones I've seen in the past from
> programmers who only know one language looking at a language they are
> unfamiliar with. "See it's not a real language, it doesn't have this
> one feature that I like in the form that I like it."<shrug/>
>
> The variables in OpenSCAD could be called "constants" or "immutable
> variables". They cannot change over time, because OpenSCAD models a
> physical object...time is not a factor.
>
> On Thu, 17 Sep 2015 16:04:00 +0000 (UTC)
> Qiang <godblessfq at gmail.com> wrote:
>
> > I am in the process of choosing a CAD software to learn. I find a
> > review on openscad, and would like to see expert opinions on the
> > following criticism.
> > If these are ture, what is the impact on product design?
> >
> > 1 language does not have variables, for example. It has things
> > which look as if they should be variables, but they are in fact
> > evaluated statically at compile-time and are really just
> > constants. There is an "assign" function which can alter values
> > at run-time, but it does not give the full behavior of a
> > variable (you cannot use it to pass variable parameters, for
> > example). It's a bit like one of the (so called) "functional
> > programming language" beloved of mathematicians, but wrapped in
> > the syntax of a procedural programming language without even
> > the (dubious, in my opinion) clarity of a real functional
> > programming language.
>
> Note that this is his opinion. Many of us have done functional
> programming in more procedural languages for years.
>
> > 2 Openscad does not really do CSG. It is a front-end for either
> > of two "rendering" (using the term loosely) libraries: OpenCSG
> > and GCAL. OpenCSG is a splendidly tricky program which appears to
> > do CSG without actually ever doing the calculations for the
> > geometry. As a display engine, OpenCSG is brilliant. But there's
> > more to CAD than display. GCAL is indeed a library of
> > computational graphics algorithms which can do the geometry "for
> > real." But OpenSCAD uses CGAL just to generate
> > STL (stereolithography) output files. There is no way to get at
> > the geometry calculated by GCAL within the OpenSCAD model.  He
> > then gives an example that openscad can't find the intersection
> > point of 3 planes.
>
> It could be fair to point out that OpenSCAD does not deal with infinite
> objects like planes. The 0-dimensional point at the intersection of 2
> planes is kind-of outside the scope of a tool for generating 3D models
> for fabrication. It's kind of like making the argument that all
> programming languages are bad, because they can't properly deal with
> infinite precision real numbers.
>
> However, as a practical point, I can easily find the intersection
> volume of 3 thin planes.
>
> > 3 OpenSCAD lacks the powerful capabilities of local
> > coordinate systems.
>
> That's a fair point. I haven't actually needed it in my designs. But, I
> could pretty easily simulate it in my modules.
>
> > The link to the review is here
> >
> http://www.circuitousroot.com/artifice/drafting/reviewing-the-options/index.html#brl-cad
>
> I would have really loved to see his example code, (it seems to be
> giving a 404 at the moment). From his description, he seems to be
> mistaking his inexperience with the tool for limitations of the tool.
>
> G. Wade
>
> > Thank you for your help!
> >
> >
> >
> > _______________________________________________
> > OpenSCAD mailing list
> > Discuss at lists.openscad.org
> > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
>
>
> --
> A tautology is a thing which is tautological.
>
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