Hi, Torleif.

We surely have different perspectives. I have some difficulties at
operational level (I have never been able to memorize the multiplication
table, for instance) and some skills at the conceptual level. So I usually
try to understand what is behind before seeing the front end. That is why I
use functions and modules a lot. Each one has a meaning and represent a
concept. And as they usually have fewer lines and key comments, I can
understand them months or years later. The same happens with code
formatting: I need a minimum of ruled format style to easily understand a
code.

I use that approach even for building an ad hoc code. Eventually I found
there something that may be reusable and worth to have in a library
although that is not my goal.

I rarely consider operator modules during the development phase. They
sometimes emerge later when I try to "wring" the code, a phase required by
some obsession.

If there is really such a discrimination, yes, I am more a software
programmer than a CAD programmer.

2017-12-30 18:53 GMT-02:00 TLC123 torleif.ceder@gmail.com:

On Sun, 31 Dec 2017 09:17:46 -0700 (MST)
Chocrates rougechampion2002@gmail.com wrote:

I have my own libraries that I maintain in version control exactly like
I do any other code. I have used some libraries from others.

Honestly, I suspect that maintenance of cad libraries will follow the
same model as code libraries: some maintained, some not; some forked,
some not.

Remember that many people working with OpenSCAD are not programmers and
may not immediately think of libraries as a resource. Also OpenSCAD is
relatively new as languages go, this can result in many libraries
that scratch one person's itch but are not quite as re-usable or
simple as needed for others to use. Some language issues have also made
general libraries harder to make and maintain than we'd like.

These issues are improving, so keep an eye out.

G. Wade

--
Be careful about reading health books. You may die of a misprint.
-- Mark Twain

I use my own library in all but my simplest projects and find I need to​
add to it for most projects. It is mainly models of non printed parts that
I use in assemblies but does have some utilities and some printed parts
that I use across projects such as boxes, feet, handles and fixing blocks.
I started it about a year ago. I include it in every printed part design
because at the very least it sets $fa and $fs for printing and defines
polyholes. These are the the larger things I have made with it over the
last year.

Cover and laser mount for HydraRaptor.

RPI LCD display case.

ATX lab PSU.

Mains PSU.

​

WiFi controlled photographic turntable.

Solder fume filter.
​

​

On 31 December 2017 at 16:17, Chocrates rougechampion2002@gmail.com wrote:

I have a lot of small library components that I continually reuse in other
projects.

CAD libraries can be useful, but there are a lot of factors involved:

1. Is the library well designed and easy to use?
2. Is the library robust, or does it fail on edge cases. This is related
   to ease of use.
3. Is the library well documented? An issue for using someone else's
   library.
4. How easy is it to install the library and start using it?
5. How compelling is the library? Is it easier to write the code from
   scratch than it
   is to figure out how to install and use the library? An issue for
   using someone
   else's library.

Factors 1-3 are a job for the library designer. It's lot of work to make a
library useful to other people: you need well designed interfaces,
robustness, good documentation. About half of my "reusable code" can only
be reused by copying, pasting and hacking the code, since I haven't figured
out good general purpose APIs, or the code only works for a narrow range of
cases.

Factor 4 is a tool issue. In web programming, you can often start using a
3rd party javascript library just by pasting a URL into your web page,
which is super easy. In the Rust language, it's the same, if you use the
cargo tool: you can reference an external library using the URL of a git
repo. This means you can download somebody else's program and external
library dependencies are automatically taken care of, you don't need to
think about it. In OpenSCAD, it's not so easy.

On 31 December 2017 at 11:17, Chocrates rougechampion2002@gmail.com wrote:

programming in that there is less returned value in the effort to find very
general solutions to a loose set of problems.

I don't agree, I find it extremely useful to have a good library of useful
generic code, both for convenience and for readability.

Unlike most here, I use OpenSCAD for making plans for builds, not for 3D
printing. So, I have a library with all the parts I use, screws, eyebolts,
threaded bars, nuts, washers, wooden parts, chains, hinges and so on. I also
have some useful math functions. There is also a bunch of useful operations,
such as modules to put a radius on a corner, drilling holes, making
transition curves and so on.

How does this help me?

• I don't have to re-do each part.

• If I make a better, more detailed model, it'll be replaced in every
  design. Fix once, apply everywhere.

• Sure, I could just to a difference with a cylinder to make a hole, but if
  I make a difference with a hole object, it will clearly say "hole" in the
  code. Likewise, a threaded bar is simply a cylinder if a certain diameter in
  a certain color, but it makes for clearer code if it says threadedbar().

• Since each object has it's own call, I get a part list. I know exactly how
  many screws I need, how many meters of each type of wood I need and so on. I
  get it with prices, where to buy it, product number, sometimes even which
  shelf in the store, and even the weight of the parts.

• Since each object and operation have it's own call, I also get an
  "operations list". So, I know that I will have to measure and drill 300
  holes, and that'll take approximataley so many minutes. I know that I'll
  have to cut this many planks, and it'll take this long. If I want, I can
  also add extra operations that aren't parts-based, or just because I know
  that "rigging this up squarely will take some extra time...".

• It helps me remember what resources I have. Often, I sit and think "how
  will I solve this problem?", looking at the parts and suddenly "Hmm, if I
  take a hinge and lock it with a slide bolt...".

• It helps me keep a certain selection of standard parts. Nothing wrong with
  having more different parts, but if there is no good reason for it, stick
  with a part you have.

• You can adapt the modules so that it's more handy to use. For example, my
  screws and bits that goes on screws (nuts, washers, wingnuts...) all have a
  z-offset and a parameter to flip them (where applicable). So, I create the
  screw, then simply stack everything that goes on it using only the z-offset,
  then move it in place. Example:

  bolt_M10(3);
  squarewasher_M10(0,false);
  squarewasher_M10(45,true);
  wingnut_M10(48,true);

This creates a bolt with a wingnut on the other end, and two square washers.
This can then be translated and rotated to wherever it's supposed to be.
Very simple and clear code.

--
Sent from: http://forum.openscad.org/

On 02. jan. 2018 15:19, Troberg wrote:

I guess this is the recurring talk about the functional language in
OpenSCAD. The features you describe imply a procedural language. I have
had similar ideas regarding use of a scripting language. Your example
can be expressed as below using my AngelScript* implementation.

*AngelScript is a procedural language with strong types
http://www.angelcode.com/angelscript/sdk/docs/manual/doc_script.html
The @ notation refers to "object handles".

shape@ main_shape()
{
solid@ sph = translate(200,300,400)sphere(r:50);
sphere@ s  = cast<sphere@>(sph);
pos3d@ c  = s.box().center();
return translate(c.x(),c.y(),c.z())
cylinder(r:s.radius(),h:1000) + s;
}

It may be possible to eliminate the second line to make it more compact,
but this runs as shown now creating an explicit union of a cylinder and
the given sphere 's', much like you explained.

The attached OpenSCAD file was generated from the above script.

Carsten Arnholm