kurtz le pirate <kur### [at] freefr> wrote:
> On 20/04/2026 14:25, Kenneth wrote:
> >
> > Has anyone in the POV-ray community ever built a version that will run? I seem
> > to vaguely remember *someone* doing that in the past...or maybe it was
> > just for Linux/Unix?
> >
> Some interesting links:
>
> <http://jeberger.free.fr/povray/cloth/cloth.html>
> <https://www.imagico.de/pov/tools_en.php>
>

YES, I think it was one of those that I saw years ago. Thanks!

If I understand what I see there,  it looks like there *is* a way to run some
bullet physics in Windows-- by way of installing Cygwin(?) and a particular
Cygwin DLL, along with the pre-compiled version of 'cloth.exe' that's also
available:

https://www.imagico.de/cloth/index.php

That's my guess, anyway! But I'm a virgin regarding Unix, ha, so it's not
totally clear to me as to how to go about the process of installing these and
getting them to work together (and with Windows). I need to give it some deep
thought. Maybe it's not as complicated as I imagine.

------------
By the way, it was your earlier fascinating thread about epicycles, and the
links you provided,  that re-started my interest in imaginary/complex numbers.
(Rotating/cascading epicycles that can draw a complicated outline of a T. Rex--
that was a profound discovery for me!)

https://news.povray.org/povray.animations/thread/%3C6901f3da%241%40news.povray.org%3E/

I meant to comment at the time, but got side-tracked with brain-twisting
research-- to try and understand what it was all about.

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"Kenneth" <kdw### [at] gmailcom> wrote:

> By the way, it was your earlier fascinating thread about epicycles, and the
> links you provided,  that re-started my interest in imaginary/complex numbers.
> (Rotating/cascading epicycles that can draw a complicated outline of a T. Rex--
> that was a profound discovery for me!)
>
>
https://news.povray.org/povray.animations/thread/%3C6901f3da%241%40news.povray.org%3E/
>
> I meant to comment at the time, but got side-tracked with brain-twisting
> research-- to try and understand what it was all about.

What you want is Grant Sanderson's episode on this.

https://www.youtube.com/watch?v=r6sGWTCMz2k

Makes all as clear as crystal compared to anything else I've read about it.

- BE

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hi,

"Bald Eagle" <cre### [at] netscapenet> wrote:
> "jr" <cre### [at] gmailcom> wrote:
> > ... guessing BE will rub
> > his hands in glee.. :-))
> I'm not sad about it.

"anticipation" I had in mind, sorry.


> It's great that there's a whole include file that reliably implements
> quaternions.
> It's not copyrighted.
> It's all in SDL, so it can be experimented with by anyone, and any code written
> in c++ to provide source-level capability can be checked against the extant SDL.
>
> I'm nominating this as a file to be put on the wiki as a special resource.
> If TOK or someone with knowledge of the use of quaternions can look it over to
> determine if there are any other functions/macros that would be needed for a
> more complete quaternion library, that would be great.

yes, a thorough assessment and perhaps a little "spit & polish", and I'd second
your "nomination".


> It would also be nice of someone could rewrite the macros as functions so that
> they can be used at render time.

I was/am "chuffed" the 20-odd years old code renders unmodified using beta.2
:-).


regards, jr.

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"jr" <cre### [at] gmailcom> wrote:
> Hi
>
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> > "jr" <cre### [at] gmailcom> wrote:
> > > ... guessing BE will rub
> > > his hands in glee.. :-))
> > I'm not sad about it.
>
> "anticipation" I had in mind, sorry.
>
>
> > It's great that there's a whole include file that reliably implements
> > quaternions.
> > It's not copyrighted.
> > It's all in SDL, so it can be experimented with by anyone, and any code written
> > in c++ to provide source-level capability can be checked against the extant SDL.
> >
> > I'm nominating this as a file to be put on the wiki as a special resource.
> > If TOK or someone with knowledge of the use of quaternions can look it over
> > determine if there are any other functions/macros that would be needed for a
> > more complete quaternion library, that would be great.
>
> yes, a thorough assessment and perhaps a little "spit & polish", and I'd second
> your "nomination".
>
>
> > It would also be nice if someone could rewrite the macros as functions like that
> > they can be used at render time.
>
> I was/am "chuffed" the 20-odd years old code renders unmodified using beta.2
> :-).
>
>
> regards, jr.

Guys, I have an idea to make POV-Ray popular on phones

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On 23/04/2026 19:21, Kenneth wrote:

> 
> ------------
> By the way, it was your earlier fascinating thread about epicycles, and the
> links you provided,  that re-started my interest in imaginary/complex numbers.
> (Rotating/cascading epicycles that can draw a complicated outline of a T. Rex--
> that was a profound discovery for me!)
> 
>
https://news.povray.org/povray.animations/thread/%3C6901f3da%241%40news.povray.org%3E/
> 
> I meant to comment at the time, but got side-tracked with brain-twisting
> research-- to try and understand what it was all about.
> 
> 


Complex numbers are a fascinating area of mathematics. It’s my favorite 
playground. You find them everywhere, even in unexpected places.

It all depends on your level of math.

There are other pages on my website about them.



In fact, for epicycles, the hardest part is obtaining the <x,y> 
coordinates of all the points that make up the figure !





-- 
kurtz le pirate
compagnie de la banquise

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About Bullet Physics: Back in July of 2013, Bill Pragnell posted some 'falling
rocks' animations that he created. Not much info as to how it was done, but the
animations look great:

https://news.povray.org/povray.binaries.animations/thread/%3Cweb.51dc6d40c6eb1333354ba950%40news.povray.org%3E/

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On 23/04/2026 17:51, jr wrote:
> I like the idea of putting the "phone" to a proper use :-)  if you also use a
> PC, how do the render times compare, roughly ?  seeing your related thread ("How
> to install UberPov on termux"), have not used UberPov, so cannot comment/help,
> sorry, hope someone will, but I think that it would be real good ("informative")
> if you could (continue to) post about using POV-Ray on an Android; here I have a
> 2nd hand iPhone SE I would like to put to work </grin>.

I guess the first step should be a putting Linux on iPhone :).
-- 
YB

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hi,

> ...
> > I'm nominating this as a file to be put on the wiki as a special resource.
> > If TOK or someone with knowledge of the use of quaternions can look it over to
> > determine if there are any other functions/macros that would be needed for a
> > more complete quaternion library, that would be great.
>
> yes, a thorough assessment and perhaps a little "spit & polish", and I'd second
> your "nomination".

re that, if someone "maths-minded" is thinking about 'quaternions.inc', some
"metrics".  the file is quite small (<250 lines), in well written "greek" :-);
23 macros, some 60-odd local variables (bar three declared).  also, attached a
cross-reference.  thx.


regards, jr.

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Attachments:
Download 'adqxref.txt' (7 KB)

hi,

yesbird wrote:
> On 23/04/2026 17:51, jr wrote:
> > I like the idea of putting the "phone" to a proper use ...
> > 2nd hand iPhone SE ...
> I guess the first step should be a putting Linux on iPhone :).

the "app store" has something called 'iSH' </sigh>, billed as an "Alpine Shell",
will look into that.  (thanks for the "push" :-))


regards, jr.

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hi,

"Cossack " <nomail@nomail> wrote:
> ...
> Guys, I have an idea to make POV-Ray popular on phones

.... to be continued ...  </grin>


regards, jr.

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