Re: [OpenSCAD] Discuss Digest, Vol 9, Issue 1
On Fri, 31 Jul 2015 19:27:31 -0700 (MST) Steve wrote:
I have written an Instructable with some more advanced topics. I think it
will have more value to members of this forum than my introductory one.
I noticed the following text in your instructable:
"One should not expect to do many things one would do with most programming languages. Unfortunately, it was a little too limited, the
recent addition of list comprehensions has been a huge addition to OpenSCAD."
I beg to differ. It just takes a bit of brain twisting to get the hang of functional languages and recursive list structures:
http://www.thingiverse.com/thing:942566/
Check out ellerscad_v4.scad, where I have various [recursive] functions involving dynamic arrays without involving list comprehensions. You
just have to store your variables as the arguments of the function.
- David
2015.03 didn't just add list comprehensions, it also added 'concat'. With
concat, a function can now return a list whose length is determined at run
time. Before these additions, I agree that OpenSCAD was "a little too
limited".
On 2 August 2015 at 00:48, David Eccles (gringer) <
bioinformatics@gringene.org> wrote:
On Fri, 31 Jul 2015 19:27:31 -0700 (MST) Steve wrote:
I have written an Instructable with some more advanced topics. I think
it
will have more value to members of this forum than my introductory one.
I noticed the following text in your instructable:
"One should not expect to do many things one would do with most
programming languages. Unfortunately, it was a little too limited, the
recent addition of list comprehensions has been a huge addition to
OpenSCAD."
I beg to differ. It just takes a bit of brain twisting to get the hang of
functional languages and recursive list structures:
http://www.thingiverse.com/thing:942566/
Check out ellerscad_v4.scad, where I have various [recursive] functions
involving dynamic arrays without involving list comprehensions. You
just have to store your variables as the arguments of the function.
- David
OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Going through the digest, I came across this message. If it had been made in
the original topic I would have responded sooner.
gear_trains.scad http://forum.openscad.org/file/n13421/gear_trains.scad
The uploaded file is from a series of files I am working on. There is a
file for describing gears and another file with gear mounting options. But
I think you will see in this file that I understand the power of OpenSCAD
and how to write very powerful functions.
But the point I was trying to make was that OpenSCAD is not procedural
language and nor should it be. I am trying very hard to impress on people
that it doesn't necessarily make sense for it to have run time variables.
Someday someone might come up with a method to shoe horn OpenSCAD into a run
time environment. I don't think it is a very fruitful endeavor however.
OpenSCAD does what it is supposed to do very well. In fact, better than any
other language. The way I see it, the developers are making great choices
about the which areas to work on next.
And list comprehensions is a huge step. It has given us many things that
make it possible to make almost anything. I once read somewhere that
OpenSCAD is not good for organic shapes. Well that is no longer true. I am
hard pressed to come up with something it can't do now.
The thing I am using a lot is sweeps. It is replacing the unioned hulls.
In my gears.scad file I was creating gears using the cutting gears concept.
I was able to create spiral gears with unioned hulls. But there was a big
problem doing them. With bevel gears I could hull the trapezoidal shapes
and ultimately I was able to speed things up greatly with a scaled
linear_extrude of the trapezoidal shape. But the spiral gears resist any
simple solution like that. The sweep solves those problems. In fact I am
looking at using the sweep to directly generate the spiral gear teeth and
skipping the cutting gear. I expect it to be orders of magnitude faster
than my present approach.
Steve
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I haven't worked on the gear stuff for a few months. But I think the
animation at the link below is of the example gear train found at the bottom
of the file.
http://www.highergraphics.com/pub/gear_train.avi
http://www.highergraphics.com/pub/gear_train.avi
Steve
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BTW, the maze creation is very clever. And I get that you understand how to
use OpenSCAD functions.
Steve
David Eccles (gringer) wrote
On Fri, 31 Jul 2015 19:27:31 -0700 (MST) Steve wrote:
I have written an Instructable with some more advanced topics. I think
it
will have more value to members of this forum than my introductory one.
I noticed the following text in your instructable:
"One should not expect to do many things one would do with most
programming languages. Unfortunately, it was a little too limited, the
recent addition of list comprehensions has been a huge addition to
OpenSCAD."
I beg to differ. It just takes a bit of brain twisting to get the hang of
functional languages and recursive list structures:
http://www.thingiverse.com/thing:942566/
Check out ellerscad_v4.scad, where I have various [recursive] functions
involving dynamic arrays without involving list comprehensions. You
just have to store your variables as the arguments of the function.
- David
OpenSCAD mailing list
Discuss@.openscad
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Sent from the OpenSCAD mailing list archive at Nabble.com.