I have a library that has parametric screws and nuts and 3D printable items that can be called as assemblies or subassemblies. https://github.com/nophead/NopSCADlib#Screws [image: image.png] https://github.com/nophead/NopSCADlib#Nuts [image: image.png] https://github.com/nophead/NopSCADlib#Camera_housing [image: image.png] https://github.com/nophead/NopSCADlib#Butt_box [image: image.png] Variables prefixed with a $ are global. On Thu, 26 Nov 2020 at 20:57, David <ainut@hiwaay.net> wrote: > I think the point of the discussion is that at the moment, OpenSCAD is a > great tool but, like any tool, it has it's limitations. > > Where I, as a newbie, would like to get is more 'programmatic' structure > in the building of our tools. That is, for example, 'includes' that > don't eat it's young while trying to be parsed. More streamlined > lexicology. Variables that can be either global or local, depending > upon the particular syntax the designer/programmer declares. > Implementation of 'libraries' that we can share with each other, like > the parametric design of screws and nust, or 3D printable items that can > be called as assemblies or subassemblies. And suchlike. > > Am I the only one? > > David > > > On 11/26/20 2:03 PM, adrianv wrote: > > Note that I'm not taking a position on the OpenSCAD language being > replaced. > > I'm just making observations about challenges and limitations. > > > > What does it mean to use a language "as intended"? You can only model > > things the original designer imagined? Seems like a weird way to think > > about things. When computer languages are released into the wild users > will > > use them to do what *they* want, not what the designers imagined. > Where's > > the threshold for a model being "wrong" for OpenSCAD? Note that OpenSCAD > > certainly is a language in the classical sense. It's got functions and > > recursion and can theoretically do anything. It's just that doing > things is > > not always easy, or efficient. The code is harder to write. Of course, > > once it's written then the complexity is hidden, and the actual models > are > > easy to construct. > > > > The question about what OpenSCAD is "for" I think leads to the question > of > > whether it's a toy environment or an environment for real design. The > > driving problem I generally struggle with is that every edge and corner > in > > my 3d printed models should be filleted or rounded, and this tends to be > > very difficult, even though my models are pretty simple. I think I may > have > > this problem mostly solved, but it wasn't easy. Is there a better tool > for > > this, for constructing simple models with specified parametric > dimensions, > > where parts can have roundovers applied without a struggle? > > > > > > Alan Cox-2 wrote > >> On Thu, 26 Nov 2020 11:28:44 -0700 (MST) > >> adrianv &lt; > >> avm4@ > >> &gt; wrote: > >> > >>> If you think the OpenSCAD language is "fine" then probably you're not > >>> trying > >>> to do anything nontrivial. > >> Or you are using it as intended - it's not a "language" in the classic > >> interpretive sense - it's a data structure with some compression > features. > >> > >> My tools output OpenSCAD, it's great for that. I think it's kind of > >> meaningless to talk about replacing OpenSCAD's language with python > >> because they are just not the same thing. OpenSCAD is a definition, > >> python would produce a program which instantiated and bound objects to > >> some kind of scene. By all means go and build that - but you will end up > >> working at the library level with csg libraries, or outputting an > openscad > >> file of the resulting construct. The former means you can query internal > >> state more easily, the latter is easy to do and has been done many times > >> already. > >> > >> Either way you don't end up with anything connected to OpenSCAD beyond > >> perhaps being able to recycle code. > >> > >> Alan > >> > >> _______________________________________________ > >> OpenSCAD mailing list > >> Discuss@.openscad > >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > > > > > > > > > -- > > Sent from: http://forum.openscad.org/ > > > > _______________________________________________ > > OpenSCAD mailing list > > Discuss@lists.openscad.org > > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

 I think the point of the discussion is that at the moment,
 OpenSCAD is a
 great tool but, like any tool, it has it's limitations.

 Where I, as a newbie, would like to get is more 'programmatic'
 structure
 in the building of our tools.  That is, for example, 'includes' that
 don't eat it's young while trying to be parsed. More streamlined
 lexicology.  Variables that can be either global or local, depending
 upon the particular syntax the designer/programmer declares.
 Implementation of 'libraries' that we can share with each other, like
 the parametric design of screws and nust, or 3D printable items
 that can
 be called as assemblies or subassemblies.    And suchlike.

 Am I the only one?

 David


 On 11/26/20 2:03 PM, adrianv wrote:

 being replaced.

 model

 to think

 wild users will

 imagined.  Where's

 OpenSCAD

 functions and

 doing things is

 course,

 models are

 question of

 design.  The

 corner in

 tends to be

 I may have

 better tool for

 dimensions,

 you're not

 classic

 compression features.

 objects to

 will end up

 an openscad

 internal

 many times

 beyond

 http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
 <http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org>

 http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
 <http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org>

 _______________________________________________
 OpenSCAD mailing list
 Discuss@lists.openscad.org <mailto:Discuss@lists.openscad.org>
 http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
 <http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org>

OUTSTANDING!  Thanks. On 11/26/20 3:17 PM, nop head wrote: > I have a library that has parametric screws and nuts and 3D printable > items that can be called as assemblies or subassemblies. > > https://github.com/nophead/NopSCADlib#Screws > <https://github.com/nophead/NopSCADlib#Screws> > image.png > https://github.com/nophead/NopSCADlib#Nuts > <https://github.com/nophead/NopSCADlib#Nuts> > image.png > https://github.com/nophead/NopSCADlib#Camera_housing > <https://github.com/nophead/NopSCADlib#Camera_housing> > image.png > https://github.com/nophead/NopSCADlib#Butt_box > <https://github.com/nophead/NopSCADlib#Butt_box> > image.png > > Variables prefixed with a $ are global. > > > On Thu, 26 Nov 2020 at 20:57, David <ainut@hiwaay.net > <mailto:ainut@hiwaay.net>> wrote: > > I think the point of the discussion is that at the moment, > OpenSCAD is a > great tool but, like any tool, it has it's limitations. > > Where I, as a newbie, would like to get is more 'programmatic' > structure > in the building of our tools.  That is, for example, 'includes' that > don't eat it's young while trying to be parsed. More streamlined > lexicology.  Variables that can be either global or local, depending > upon the particular syntax the designer/programmer declares. > Implementation of 'libraries' that we can share with each other, like > the parametric design of screws and nust, or 3D printable items > that can > be called as assemblies or subassemblies.    And suchlike. > > Am I the only one? > > David > > > On 11/26/20 2:03 PM, adrianv wrote: > > Note that I'm not taking a position on the OpenSCAD language > being replaced. > > I'm just making observations about challenges and limitations. > > > > What does it mean to use a language "as intended"?  You can only > model > > things the original designer imagined?  Seems like a weird way > to think > > about things.  When computer languages are released into the > wild users will > > use them to do what *they* want, not what the designers > imagined.  Where's > > the threshold for a model being "wrong" for OpenSCAD? Note that > OpenSCAD > > certainly is a language in the classical sense.  It's got > functions and > > recursion and can theoretically do anything.  It's just that > doing things is > > not always easy, or efficient.  The code is harder to write.  Of > course, > > once it's written then the complexity is hidden, and the actual > models are > > easy to construct. > > > > The question about what OpenSCAD is "for" I think leads to the > question of > > whether it's a toy environment or an environment for real > design.  The > > driving problem I generally struggle with is that every edge and > corner in > > my 3d printed models should be filleted or rounded, and this > tends to be > > very difficult, even though my models are pretty simple. I think > I may have > > this problem mostly solved, but it wasn't easy.   Is there a > better tool for > > this, for constructing simple models with specified parametric > dimensions, > > where parts can have roundovers applied without a struggle? > > > > > > Alan Cox-2 wrote > >> On Thu, 26 Nov 2020 11:28:44 -0700 (MST) > >> adrianv &lt; > >> avm4@ > >> &gt; wrote: > >> > >>> If you think the OpenSCAD language is "fine" then probably > you're not > >>> trying > >>> to do anything nontrivial. > >> Or you are using it as intended - it's not a "language" in the > classic > >> interpretive sense - it's a data structure with some > compression features. > >> > >> My tools output OpenSCAD, it's great for that. I think it's kind of > >> meaningless to talk about replacing OpenSCAD's language with python > >> because they are just not the same thing. OpenSCAD is a definition, > >> python would produce a program which instantiated and bound > objects to > >> some kind of scene. By all means go and build that - but you > will end up > >> working at the library level with csg libraries, or outputting > an openscad > >> file of the resulting construct. The former means you can query > internal > >> state more easily, the latter is easy to do and has been done > many times > >> already. > >> > >> Either way you don't end up with anything connected to OpenSCAD > beyond > >> perhaps being able to recycle code. > >> > >> Alan > >> > >> _______________________________________________ > >> OpenSCAD mailing list > >> Discuss@.openscad > >> > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > <http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org> > > > > > > > > > > -- > > Sent from: http://forum.openscad.org/ <http://forum.openscad.org/> > > > > _______________________________________________ > > OpenSCAD mailing list > > Discuss@lists.openscad.org <mailto:Discuss@lists.openscad.org> > > > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > <http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org> > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org <mailto:Discuss@lists.openscad.org> > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > <http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org> > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org

polyhedra.scad: Modules to create various regular and stellated

I asked about libraries when I first encountered OpenSCAD a couple years ago, I think. And I got a remarkably negative reception, with hostility to libraries. A vocal group seemed to oppose the idea that libraries should exist---everybody should design their own code in private from the ground up. Maybe things have improved a bit, but there's still no good mechanism for managing them, or dealing with them, and we have the bug with "use" that creates big performance issues, which is apparently seen as very low priority. (The issue for this bug was first opened in 2012, I think, by someone who thought the fix was not hard.) There are tons of OpenSCAD files on thingiverse that implement a variety of interesting and useful things. If you need a particular thing it's certainly a good place to start. But hunting around on thingiverse can be pretty frustrating as a way to find libraries, and quality is variable. Screw libraries abound if you want screws. In addition to nopscadlib you might take a look at BOSL2. There's also dotSCAD, though I think it provides basic modeling commands rather than parametric parts. The BOSL2 library does both. https://github.com/revarbat/BOSL2/wiki If you're specifically looking for parts scroll down to the "Miscellaneous Parts" section, which includes: Miscellaneous Parts polyhedra.scad: Modules to create various regular and stellated polyhedra. walls.scad: Modules to create walls and structural elements for 3D printing. cubetruss.scad: Modules to create modular open-framed trusses and joiners. involute_gears.scad: Modules and functions to make involute gears and racks. joiners.scad: Modules to make joiner shapes for connecting separately printed objects. sliders.scad: Modules for creating simple sliders and rails. screws.scad: Functions and modules to make metric and UTS screws and nuts. metric_screws.scad: Functions and modules to make metric screws, nuts, and screwholes. linear_bearings.scad: Modules to make mounts for LMxUU style linear bearings. nema_steppers.scad: Modules to make mounting holes for NEMA motors. phillips_drive.scad: Modules to create Phillips screwdriver tips. torx_drive.scad: Functions and Modules to create Torx bit drive holes. wiring.scad: Modules to render routed bundles of wires. hingesnaps.scad: Modules to make foldable, snap-locking parts. bottlecaps.scad: Modules to make standard beverage bottle caps and necks. skypuppy wrote > I think the point of the discussion is that at the moment, OpenSCAD is a > great tool but, like any tool, it has it's limitations. > > Where I, as a newbie, would like to get is more 'programmatic' structure > in the building of our tools.  That is, for example, 'includes' that > don't eat it's young while trying to be parsed. More streamlined > lexicology.  Variables that can be either global or local, depending > upon the particular syntax the designer/programmer declares.  > Implementation of 'libraries' that we can share with each other, like > the parametric design of screws and nust, or 3D printable items that can > be called as assemblies or subassemblies.    And suchlike. > > Am I the only one? > > David > > > On 11/26/20 2:03 PM, adrianv wrote: >> Note that I'm not taking a position on the OpenSCAD language being >> replaced. >> I'm just making observations about challenges and limitations. >> >> What does it mean to use a language "as intended"? You can only model >> things the original designer imagined? Seems like a weird way to think >> about things. When computer languages are released into the wild users >> will >> use them to do what *they* want, not what the designers imagined. >> Where's >> the threshold for a model being "wrong" for OpenSCAD? Note that OpenSCAD >> certainly is a language in the classical sense. It's got functions and >> recursion and can theoretically do anything. It's just that doing things >> is >> not always easy, or efficient. The code is harder to write. Of course, >> once it's written then the complexity is hidden, and the actual models >> are >> easy to construct. >> >> The question about what OpenSCAD is "for" I think leads to the question >> of >> whether it's a toy environment or an environment for real design. The >> driving problem I generally struggle with is that every edge and corner >> in >> my 3d printed models should be filleted or rounded, and this tends to be >> very difficult, even though my models are pretty simple. I think I may >> have >> this problem mostly solved, but it wasn't easy. Is there a better tool >> for >> this, for constructing simple models with specified parametric >> dimensions, >> where parts can have roundovers applied without a struggle? >> >> >> Alan Cox-2 wrote >>> On Thu, 26 Nov 2020 11:28:44 -0700 (MST) >>> adrianv &lt; >>> avm4@ >>> &gt; wrote: >>> >>>> If you think the OpenSCAD language is "fine" then probably you're not >>>> trying >>>> to do anything nontrivial. >>> Or you are using it as intended - it's not a "language" in the classic >>> interpretive sense - it's a data structure with some compression >>> features. >>> >>> My tools output OpenSCAD, it's great for that. I think it's kind of >>> meaningless to talk about replacing OpenSCAD's language with python >>> because they are just not the same thing. OpenSCAD is a definition, >>> python would produce a program which instantiated and bound objects to >>> some kind of scene. By all means go and build that - but you will end up >>> working at the library level with csg libraries, or outputting an >>> openscad >>> file of the resulting construct. The former means you can query internal >>> state more easily, the latter is easy to do and has been done many times >>> already. >>> >>> Either way you don't end up with anything connected to OpenSCAD beyond >>> perhaps being able to recycle code. >>> >>> Alan >>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> Discuss@.openscad >>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> > Discuss@.openscad >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > _______________________________________________ > OpenSCAD mailing list > Discuss@.openscad > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org -- Sent from: http://forum.openscad.org/

I need the algorithms to build the missing primitives so I can compose things with CSG. If you're doing sweep then that means you're also coding a missing primitive. A full path sweep implementation is an algorithm. You need to make decision about how you're going to manage the twist of the sections as you move along the path, and it's not obvious how to do this in general. nophead wrote >> But if you want to write nontrivial geometric algorithms (to fill in the > missing functionality) then challenges quickly mount. > > Yes no doubt they would but I can make everything I need without > nontrivial > geometric algorithms. I do just compose cube and cylinders in the main > plus > a few sweeps, isn't that what CSG is? If you don't want to make > geometry with CSG then OpenSCAD doesn't seem to be the right tool. It is > certainly not a good language for coding algorithms. -- Sent from: http://forum.openscad.org/

  polyhedra.scad: Modules to create various regular and stellated

People objected to sharing their creations?  Sounds kinda small minded.  I understand protectionism, esp of work stuff, but object to SCREWS and NUTS?  That's nuts (if you'll pardon the pun.) Adrianv, some of the items in your list I actually recognize and I'm not a machinist.  :)  With the parametric abilities of OpenSCAD, I think it's wonderful that we can have libraries like these.  Common and not so common everyday stuff that -everyone- uses routinely are prime candidates for saving repetitive donkey labor.  If made available in the form of 'libraries' will make OpenSCAD MUCH more useful, thereby also growing the user base. Aside: how does one find these existing libraries in thingiverse?  I've looked but I'm not using the correct magic incantations. Aside thought #2: OpenSCAD is a prime candidate for getting tough concepts across to other people visually and when animated, improves understanding by leaps and bounds.  Calc III, anyone? :)  :) David On 11/26/20 6:43 PM, adrianv wrote: > I asked about libraries when I first encountered OpenSCAD a couple years ago, > I think. And I got a remarkably negative reception, with hostility to > libraries. A vocal group seemed to oppose the idea that libraries should > exist---everybody should design their own code in private from the ground > up. Maybe things have improved a bit, but there's still no good mechanism > for managing them, or dealing with them, and we have the bug with "use" that > creates big performance issues, which is apparently seen as very low > priority. (The issue for this bug was first opened in 2012, I think, by > someone who thought the fix was not hard.) > > There are tons of OpenSCAD files on thingiverse that implement a variety of > interesting and useful things. If you need a particular thing it's > certainly a good place to start. But hunting around on thingiverse can be > pretty frustrating as a way to find libraries, and quality is variable. > Screw libraries abound if you want screws. > > In addition to nopscadlib you might take a look at BOSL2. There's also > dotSCAD, though I think it provides basic modeling commands rather than > parametric parts. The BOSL2 library does both. > > https://github.com/revarbat/BOSL2/wiki > > If you're specifically looking for parts scroll down to the "Miscellaneous > Parts" section, which includes: > > Miscellaneous Parts > > polyhedra.scad: Modules to create various regular and stellated > polyhedra. > walls.scad: Modules to create walls and structural elements for 3D > printing. > cubetruss.scad: Modules to create modular open-framed trusses and > joiners. > involute_gears.scad: Modules and functions to make involute gears and > racks. > joiners.scad: Modules to make joiner shapes for connecting separately > printed objects. > sliders.scad: Modules for creating simple sliders and rails. > screws.scad: Functions and modules to make metric and UTS screws and > nuts. > metric_screws.scad: Functions and modules to make metric screws, nuts, > and screwholes. > linear_bearings.scad: Modules to make mounts for LMxUU style linear > bearings. > nema_steppers.scad: Modules to make mounting holes for NEMA motors. > phillips_drive.scad: Modules to create Phillips screwdriver tips. > torx_drive.scad: Functions and Modules to create Torx bit drive holes. > wiring.scad: Modules to render routed bundles of wires. > hingesnaps.scad: Modules to make foldable, snap-locking parts. > bottlecaps.scad: Modules to make standard beverage bottle caps and > necks. > > > > > skypuppy wrote >> I think the point of the discussion is that at the moment, OpenSCAD is a >> great tool but, like any tool, it has it's limitations. >> >> Where I, as a newbie, would like to get is more 'programmatic' structure >> in the building of our tools.  That is, for example, 'includes' that >> don't eat it's young while trying to be parsed. More streamlined >> lexicology.  Variables that can be either global or local, depending >> upon the particular syntax the designer/programmer declares. >> Implementation of 'libraries' that we can share with each other, like >> the parametric design of screws and nust, or 3D printable items that can >> be called as assemblies or subassemblies.    And suchlike. >> >> Am I the only one? >> >> David >> >> >> On 11/26/20 2:03 PM, adrianv wrote: >>> Note that I'm not taking a position on the OpenSCAD language being >>> replaced. >>> I'm just making observations about challenges and limitations. >>> >>> What does it mean to use a language "as intended"? You can only model >>> things the original designer imagined? Seems like a weird way to think >>> about things. When computer languages are released into the wild users >>> will >>> use them to do what *they* want, not what the designers imagined. >>> Where's >>> the threshold for a model being "wrong" for OpenSCAD? Note that OpenSCAD >>> certainly is a language in the classical sense. It's got functions and >>> recursion and can theoretically do anything. It's just that doing things >>> is >>> not always easy, or efficient. The code is harder to write. Of course, >>> once it's written then the complexity is hidden, and the actual models >>> are >>> easy to construct. >>> >>> The question about what OpenSCAD is "for" I think leads to the question >>> of >>> whether it's a toy environment or an environment for real design. The >>> driving problem I generally struggle with is that every edge and corner >>> in >>> my 3d printed models should be filleted or rounded, and this tends to be >>> very difficult, even though my models are pretty simple. I think I may >>> have >>> this problem mostly solved, but it wasn't easy. Is there a better tool >>> for >>> this, for constructing simple models with specified parametric >>> dimensions, >>> where parts can have roundovers applied without a struggle? >>> >>> >>> Alan Cox-2 wrote >>>> On Thu, 26 Nov 2020 11:28:44 -0700 (MST) >>>> adrianv &lt; >>>> avm4@ >>>> &gt; wrote: >>>> >>>>> If you think the OpenSCAD language is "fine" then probably you're not >>>>> trying >>>>> to do anything nontrivial. >>>> Or you are using it as intended - it's not a "language" in the classic >>>> interpretive sense - it's a data structure with some compression >>>> features. >>>> >>>> My tools output OpenSCAD, it's great for that. I think it's kind of >>>> meaningless to talk about replacing OpenSCAD's language with python >>>> because they are just not the same thing. OpenSCAD is a definition, >>>> python would produce a program which instantiated and bound objects to >>>> some kind of scene. By all means go and build that - but you will end up >>>> working at the library level with csg libraries, or outputting an >>>> openscad >>>> file of the resulting construct. The former means you can query internal >>>> state more easily, the latter is easy to do and has been done many times >>>> already. >>>> >>>> Either way you don't end up with anything connected to OpenSCAD beyond >>>> perhaps being able to recycle code. >>>> >>>> Alan >>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> Discuss@.openscad >>>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >>> >>> >>> >>> -- >>> Sent from: http://forum.openscad.org/ >>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> >> Discuss@.openscad >>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> _______________________________________________ >> OpenSCAD mailing list >> Discuss@.openscad >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > > > > -- > Sent from: http://forum.openscad.org/ > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

I know when I made my own parametric bezier sweep, accounting for twist along the path was most vexing On Thu, 26 Nov 2020, 20:02 adrianv, <avm4@cornell.edu> wrote: > I need the algorithms to build the missing primitives so I can compose > things > with CSG. If you're doing sweep then that means you're also coding a > missing primitive. A full path sweep implementation is an algorithm. You > need to make decision about how you're going to manage the twist of the > sections as you move along the path, and it's not obvious how to do this in > general. > > > nophead wrote > >> But if you want to write nontrivial geometric algorithms (to fill in the > > missing functionality) then challenges quickly mount. > > > > Yes no doubt they would but I can make everything I need without > > nontrivial > > geometric algorithms. I do just compose cube and cylinders in the main > > plus > > a few sweeps, isn't that what CSG is? If you don't want to make > > geometry with CSG then OpenSCAD doesn't seem to be the right tool. It is > > certainly not a good language for coding algorithms. > > > > > > -- > Sent from: http://forum.openscad.org/ > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

> Here's that same model (modulo that I don't have a trivial way to make > equilateral triangles) expressed in my Python-based prototype: You are using python to encode the data structure in this exmple rather than doing anything truely programmatic. The moment you add any input, output or other externally conditional behaviour they diverge completely. The python one becomes a program not a data structure expression. That has enormous consequences for efficiency if parallelism was supported which in the OpenSCAD case it isn't but in other SCAD systems is. It also becomes a completely different beast to work with using tools. Alan

  polyhedra.scad: Modules to create various regular and stellated

The easiest way to find a library on thingiverse is to have someone give you a link to it or mention its name and then you are able to find it with google. If you have a specific thing you want to make you can try searching for it, e.g. "gears" I tried searching thingiverse for "gears" and looked through about 5 screens of hits and found this library: https://www.thingiverse.com/thing:1604369 Like I said, stuff is there on thingiverse, but not necessarily easy to find. It's a terrible method for distributing library code. Other libraries are on github. Maybe you can stumble across them. There is this list: https://www.openscad.org/libraries.html People are not obligated to share their creations. One person complained quite aggressively that sharing work creates the burden of maintenance. That is fine. I agree, that if you share something people may bug you about it, and maybe you don't want to deal with that. So again, nobody should be expected to share their work. What I found puzzling was that people objected to *others* sharing libraries. They argued that libraries served no purpose, they weren't desirable or necessary, and we shouldn't try to support them, or develop capabilities to make it easier to use them in OpenSCAD. This group apparently thought that everybody should just write their own stuff, alone. That was how they worked, and it was how everyone should work. Unfortunately, based on private emails I had, this hostility seemed to be driving away people who might have been interested in making contributions. :( Another issue with libraries is how you actually use the objects in the library. For example, BOSL2 has an attachment mechanism that can make it easy to stick library objects onto other objects (similar to the Relativity library). But this type of feature is by no means universal. The question I guess is whether any library can become sufficiently adopted as to be seen as a standard. (There is a "standard" library called MCAD. I don't recommend it.) skypuppy wrote > People objected to sharing their creations?  Sounds kinda small minded.  > I understand protectionism, esp of work stuff, but object to SCREWS and > NUTS?  That's nuts (if you'll pardon the pun.) > > Adrianv, some of the items in your list I actually recognize and I'm not > a machinist.  :)  With the parametric abilities of OpenSCAD, I think > it's wonderful that we can have libraries like these.  Common and not so > common everyday stuff that -everyone- uses routinely are prime > candidates for saving repetitive donkey labor.  If made available in the > form of 'libraries' will make OpenSCAD MUCH more useful, thereby also > growing the user base. > > Aside: how does one find these existing libraries in thingiverse?  I've > looked but I'm not using the correct magic incantations. > > Aside thought #2: OpenSCAD is a prime candidate for getting tough > concepts across to other people visually and when animated, improves > understanding by leaps and bounds.  Calc III, anyone? :)  :) > > David > > > On 11/26/20 6:43 PM, adrianv wrote: >> I asked about libraries when I first encountered OpenSCAD a couple years >> ago, >> I think. And I got a remarkably negative reception, with hostility to >> libraries. A vocal group seemed to oppose the idea that libraries should >> exist---everybody should design their own code in private from the ground >> up. Maybe things have improved a bit, but there's still no good >> mechanism >> for managing them, or dealing with them, and we have the bug with "use" >> that >> creates big performance issues, which is apparently seen as very low >> priority. (The issue for this bug was first opened in 2012, I think, by >> someone who thought the fix was not hard.) >> >> There are tons of OpenSCAD files on thingiverse that implement a variety >> of >> interesting and useful things. If you need a particular thing it's >> certainly a good place to start. But hunting around on thingiverse can >> be >> pretty frustrating as a way to find libraries, and quality is variable. >> Screw libraries abound if you want screws. >> >> In addition to nopscadlib you might take a look at BOSL2. There's also >> dotSCAD, though I think it provides basic modeling commands rather than >> parametric parts. The BOSL2 library does both. >> >> https://github.com/revarbat/BOSL2/wiki >> >> If you're specifically looking for parts scroll down to the >> "Miscellaneous >> Parts" section, which includes: >> >> Miscellaneous Parts >> >> polyhedra.scad: Modules to create various regular and stellated >> polyhedra. >> walls.scad: Modules to create walls and structural elements for 3D >> printing. >> cubetruss.scad: Modules to create modular open-framed trusses and >> joiners. >> involute_gears.scad: Modules and functions to make involute gears >> and >> racks. >> joiners.scad: Modules to make joiner shapes for connecting >> separately >> printed objects. >> sliders.scad: Modules for creating simple sliders and rails. >> screws.scad: Functions and modules to make metric and UTS screws and >> nuts. >> metric_screws.scad: Functions and modules to make metric screws, >> nuts, >> and screwholes. >> linear_bearings.scad: Modules to make mounts for LMxUU style linear >> bearings. >> nema_steppers.scad: Modules to make mounting holes for NEMA motors. >> phillips_drive.scad: Modules to create Phillips screwdriver tips. >> torx_drive.scad: Functions and Modules to create Torx bit drive >> holes. >> wiring.scad: Modules to render routed bundles of wires. >> hingesnaps.scad: Modules to make foldable, snap-locking parts. >> bottlecaps.scad: Modules to make standard beverage bottle caps and >> necks. >> >> >> >> >> skypuppy wrote >>> I think the point of the discussion is that at the moment, OpenSCAD is a >>> great tool but, like any tool, it has it's limitations. >>> >>> Where I, as a newbie, would like to get is more 'programmatic' structure >>> in the building of our tools.  That is, for example, 'includes' that >>> don't eat it's young while trying to be parsed. More streamlined >>> lexicology.  Variables that can be either global or local, depending >>> upon the particular syntax the designer/programmer declares. >>> Implementation of 'libraries' that we can share with each other, like >>> the parametric design of screws and nust, or 3D printable items that can >>> be called as assemblies or subassemblies.    And suchlike. >>> >>> Am I the only one? >>> >>> David >>> >>> >>> On 11/26/20 2:03 PM, adrianv wrote: >>>> Note that I'm not taking a position on the OpenSCAD language being >>>> replaced. >>>> I'm just making observations about challenges and limitations. >>>> >>>> What does it mean to use a language "as intended"? You can only model >>>> things the original designer imagined? Seems like a weird way to think >>>> about things. When computer languages are released into the wild users >>>> will >>>> use them to do what *they* want, not what the designers imagined. >>>> Where's >>>> the threshold for a model being "wrong" for OpenSCAD? Note that >>>> OpenSCAD >>>> certainly is a language in the classical sense. It's got functions and >>>> recursion and can theoretically do anything. It's just that doing >>>> things >>>> is >>>> not always easy, or efficient. The code is harder to write. Of >>>> course, >>>> once it's written then the complexity is hidden, and the actual models >>>> are >>>> easy to construct. >>>> >>>> The question about what OpenSCAD is "for" I think leads to the question >>>> of >>>> whether it's a toy environment or an environment for real design. The >>>> driving problem I generally struggle with is that every edge and corner >>>> in >>>> my 3d printed models should be filleted or rounded, and this tends to >>>> be >>>> very difficult, even though my models are pretty simple. I think I may >>>> have >>>> this problem mostly solved, but it wasn't easy. Is there a better >>>> tool >>>> for >>>> this, for constructing simple models with specified parametric >>>> dimensions, >>>> where parts can have roundovers applied without a struggle? >>>> >>>> >>>> Alan Cox-2 wrote >>>>> On Thu, 26 Nov 2020 11:28:44 -0700 (MST) >>>>> adrianv &lt; >>>>> avm4@ >>>>> &gt; wrote: >>>>> >>>>>> If you think the OpenSCAD language is "fine" then probably you're not >>>>>> trying >>>>>> to do anything nontrivial. >>>>> Or you are using it as intended - it's not a "language" in the classic >>>>> interpretive sense - it's a data structure with some compression >>>>> features. >>>>> >>>>> My tools output OpenSCAD, it's great for that. I think it's kind of >>>>> meaningless to talk about replacing OpenSCAD's language with python >>>>> because they are just not the same thing. OpenSCAD is a definition, >>>>> python would produce a program which instantiated and bound objects to >>>>> some kind of scene. By all means go and build that - but you will end >>>>> up >>>>> working at the library level with csg libraries, or outputting an >>>>> openscad >>>>> file of the resulting construct. The former means you can query >>>>> internal >>>>> state more easily, the latter is easy to do and has been done many >>>>> times >>>>> already. >>>>> >>>>> Either way you don't end up with anything connected to OpenSCAD beyond >>>>> perhaps being able to recycle code. >>>>> >>>>> Alan >>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> Discuss@.openscad >>>>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >>>> >>>> >>>> >>>> -- >>>> Sent from: http://forum.openscad.org/ >>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> >>> Discuss@.openscad >>>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >>> _______________________________________________ >>> OpenSCAD mailing list >>> Discuss@.openscad >>> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> > Discuss@.openscad >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > > _______________________________________________ > OpenSCAD mailing list > Discuss@.openscad > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org -- Sent from: http://forum.openscad.org/

I think this is the reason why it's frustrating to see that everybody writes their own library. Some of these issues are pretty tricky...and they've also been discussed at great length for years on this forum or in other places. Instead of building on previous work, everybody just reinvents the wheel. Again and again and again. When I implemented path sweep I took a look at those discussions and prior work and I concluded that you need multiple options for handling twist because no one method works for all cases. There is a method that is robust and will work for any path, but it tends to produce mysterious and often obnoxious twisting. There are other methods that control the twist, but they can fail if the path has certain properties. There's also the case where you actually know what twist you want, such as putting an object onto the surface of another object. I wonder how many people realize that the fastest way to compute beziers in openscad is using matrix products instead of the recursive casteljau method. Again, the constant reinvention of the wheel really stands in the way of progress. acwest wrote > I know when I made my own parametric bezier sweep, accounting for twist > along the path was most vexing > > On Thu, 26 Nov 2020, 20:02 adrianv, &lt; > avm4@ > &gt; wrote: > >> I need the algorithms to build the missing primitives so I can compose >> things >> with CSG. If you're doing sweep then that means you're also coding a >> missing primitive. A full path sweep implementation is an algorithm. >> You >> need to make decision about how you're going to manage the twist of the >> sections as you move along the path, and it's not obvious how to do this >> in >> general. >> >> >> nophead wrote >> >> But if you want to write nontrivial geometric algorithms (to fill in >> the >> > missing functionality) then challenges quickly mount. >> > >> > Yes no doubt they would but I can make everything I need without >> > nontrivial >> > geometric algorithms. I do just compose cube and cylinders in the main >> > plus >> > a few sweeps, isn't that what CSG is? If you don't want to make >> > geometry with CSG then OpenSCAD doesn't seem to be the right tool. It >> is >> > certainly not a good language for coding algorithms. >> >> >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> > Discuss@.openscad >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > > _______________________________________________ > OpenSCAD mailing list > Discuss@.openscad > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org -- Sent from: http://forum.openscad.org/

> the threshold for a model being "wrong" for OpenSCAD? Note that OpenSCAD > certainly is a language in the classical sense. It's got functions and > recursion and can theoretically do anything. It's just that doing things is > not always easy, or efficient. The code is harder to write. Of course, > once it's written then the complexity is hidden, and the actual models are > easy to construct. It's not a programming language in the classic iterative sense because it has no external inputs or behaviour changes. It's just a data structure encoding. There is a fixed mapping between an openscad file and an STL file so they are basically the same thing. One happens to be easier to write. > The question about what OpenSCAD is "for" I think leads to the question of > whether it's a toy environment or an environment for real design. The > driving problem I generally struggle with is that every edge and corner in > my 3d printed models should be filleted or rounded, and this tends to be > very difficult, even though my models are pretty simple. I think I may have > this problem mostly solved, but it wasn't easy. Is there a better tool for > this, for constructing simple models with specified parametric dimensions, > where parts can have roundovers applied without a struggle? There is at least one OpenSCAD relative that can do rounding nicely, but it lacks the nice UI which is a key bit of OpenSCAD. What I was trying to say though is If you wanted to write a python library for working with openscad models or using python syntax for it you can trivially write it so that the python just outputs an openscad syntax file. In fact it's been done - several times. If you want to be able to manipulate the object through python effectively though you end up with something that looks very different to OpenSCAD because to provide useful extra power you need access to the underlying data structures. Take a look at the python bindings to blender and the access you have. Without that level of access and the ability to mix in conditional behaviour and impure calculations you are just writing openscad in a different format. With that, you don't actually want it to look like OpenSCAD IMHO because you want to be able to do stuff like reach into the vertex lists. A good example would be creating a flat 2D object, extruding it and then bending it. It's a classic problem when moving flat media model designs to 3D print. OpenSCAD can't do it. You can take the flat 2D object, give it thickness but you can't then bend it. A python syntax openscad would be the same. Blender *can* do it because you can reach into the data structures to do the bend in python. IOW to make a meaningfully better programming language interface you need to be able to reach into objects and directly manipulate them so you can write stuff like bend(), centreof(), volumeof() etc. If you are a programmer then that blender like interface is powerful. If you are a non programmer then you want a primitive that bends an object along a vector so you don't have to be a programmer. Alan