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28 Mar 2024 12:28:19 EDT (-0400)
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From: Bald Eagle
Subject: Re: Wood program but still develop
Date: 13 Aug 2022 22:55:00
Message: <web.62f8632c5b6ed241f9dae3025979125@news.povray.org>
"And" <49341109@ntnu.edu.tw> wrote:

I didn't read this paper (yet), but it just showed up in my email inbox.
Maybe it will inspire some ideas, serve as an entry to other similar research
papers, and be of some practical use in developing your challenging project.

(I hadn't thought of using L-systems!)

-BW

https://www.academia.edu/keypass/TklERytmOFYyc2ZaWDhzZ2lKd1p2RzlPdVR5SFQ3OC9wZVB0NzAvOFI2bz0tLUdSbDRQT1R4dFpCVEFBV1lRWm
Naamc9PQ==--4e10a79e4ba8dd769635ce68308bdbcc2e9e8f3f/t/jZTSw-QwzUMmQ-CC8f8/resource/work/23491795/3Gmap_L_systems_an_ap
plication_to_the_modelling_of_wood?email_work_card=view-paper&li=0


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From: And
Subject: Re: Wood program but still develop
Date: 23 Aug 2022 05:45:00
Message: <web.6304a0c35b6ed2442316af7aa81652d@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "And" <49341109@ntnu.edu.tw> wrote:
>
> I didn't read this paper (yet), but it just showed up in my email inbox.
> Maybe it will inspire some ideas, serve as an entry to other similar research
> papers, and be of some practical use in developing your challenging project.
>
> (I hadn't thought of using L-systems!)
>
> -BW
>
>


Oh, ... I wouldn't like to make any detailed tree trunk "3D Model"(that is
another
challenge), I just generate a (3D)texture. I implement my texture in POV-Ray,
outputing "pigment {...}" as its final form.



Maybe I will release that next version in two - three weeks, I have completed a
little bit new feature, which can adjust earlywood-latewood ratio(varying during
year) as you suggest.


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From: Bald Eagle
Subject: Re: Wood program but still develop
Date: 23 Aug 2022 06:55:00
Message: <web.6304b1885b6ed241f9dae3025979125@news.povray.org>
"And" <49341109@ntnu.edu.tw> wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> > "And" <49341109@ntnu.edu.tw> wrote:
> >
> > I didn't read this paper (yet), but it just showed up in my email inbox.
> > Maybe it will inspire some ideas, serve as an entry to other similar research
> > papers, and be of some practical use in developing your challenging project.
> >
> > (I hadn't thought of using L-systems!)
> >
> > -BW
> >
> >
>
>
> Oh, ... I wouldn't like to make any detailed tree trunk "3D Model"(that is
> another
> challenge), I just generate a (3D)texture. I implement my texture in POV-Ray,
> outputting "pigment {...}" as its final form.

Naturally.  The wood pigment patterns we've almost all been using for the past
30 years are just a bunch of concentric cylindrical rings.   Seems to work well
enough for most purposes.
To add a bit of realism by simulating the cross-section of those 3D branches,
the black hole warp can be used, and that's what I was thinking when I suggested
looking this over - not copying the paper's method verbatim.

So rather than create a whole 3D tree and then slice it (which would necessarily
limit the pattern to the locus of the individually modeled tree), I was thinking
that you could assemble a pattern of black hole warps using an L-system in code,
which would then be used to define the pigment {}.

I my mind, this would be very much like the way Tor Olav Kristensen uses a macro
to assemble the terms of a long Bernstein polynomial function.

jr has also done a lot of development using the method of including the parsed
text of temporary files to assemble complex data/code structures, as well as
some pretty complex data "trees" - which might serve as inspiration to you or
others for generating complex pigment pattern definitions.

TdG may have code of a similar nature in his vast archive, or have other ideas
of his own about how to approach the branch/knot aspect of the wood pattern.


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From: Thomas de Groot
Subject: Re: Wood program but still develop
Date: 24 Aug 2022 02:49:54
Message: <6305ca12$1@news.povray.org>
Op 23/08/2022 om 12:52 schreef Bald Eagle:
> TdG may have code of a similar nature in his vast archive, or have other ideas
> of his own about how to approach the branch/knot aspect of the wood pattern.
> 

Not really. The best I can come up with is isowood by Christoph Hormann

http://www.imagico.de/iso_wood_en.php

Dan Hentschel and Nicolas Rougier did a couple of wood textures some 15 
years ago, Nicolas using black hole warps.

Warp has some interesting things to say, about wood, incidentally

http://warp.povusers.org/povtips/


-- 
Thomas


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From: And
Subject: Re: Wood program but still develop
Date: 26 Aug 2022 02:35:00
Message: <web.6308694a5b6ed2416f25abcaa81652d@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "And" <49341109@ntnu.edu.tw> wrote:
> >
> > Oh, ... I wouldn't like to make any detailed tree trunk "3D Model"(that is
> > another
> > challenge), I just generate a (3D)texture. I implement my texture in POV-Ray,
> > outputting "pigment {...}" as its final form.
>
> Naturally.  The wood pigment patterns we've almost all been using for the past
> 30 years are just a bunch of concentric cylindrical rings.   Seems to work well
> enough for most purposes.
> To add a bit of realism by simulating the cross-section of those 3D branches,
> the black hole warp can be used, and that's what I was thinking when I suggested
> looking this over - not copying the paper's method verbatim.
>
> So rather than create a whole 3D tree and then slice it (which would necessarily
> limit the pattern to the locus of the individually modeled tree), I was thinking
> that you could assemble a pattern of black hole warps using an L-system in code,
> which would then be used to define the pigment {}.

I just notice "black hole warps" this time. It seems it is a 'spherical'
distortion around a sphere-center?

However, I can make more natural knot shape by myself. I use function as pigment
input, it is more flexible than the built-in pigment-warp of POV-Ray. I still
need several months to integrate it with my GUI java program. But I will
investigate this feature(black_hole warp) for it being a convenient effect.


>
> I my mind, this would be very much like the way Tor Olav Kristensen uses a macro
> to assemble the terms of a long Bernstein polynomial function.
>

'Bernstein polynomial function' looks like some special function I know, but I
don't know this one.


> jr has also done a lot of development using the method of including the parsed
> text of temporary files to assemble complex data/code structures, as well as
> some pretty complex data "trees" - which might serve as inspiration to you or
> others for generating complex pigment pattern definitions.

Oh, jr had e-mail me and told me something, thereby I fix the 'locale' problem
of number quickly last time.


>
> TdG may have code of a similar nature in his vast archive, or have other ideas
> of his own about how to approach the branch/knot aspect of the wood pattern.


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From: And
Subject: Re: Wood program but still develop
Date: 26 Aug 2022 02:50:00
Message: <web.63086be05b6ed2416f25abcaa81652d@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 23/08/2022 om 12:52 schreef Bald Eagle:
> > TdG may have code of a similar nature in his vast archive, or have other ideas
> > of his own about how to approach the branch/knot aspect of the wood pattern.
> >
>
> Not really. The best I can come up with is isowood by Christoph Hormann
>
> http://www.imagico.de/iso_wood_en.php
>
> Dan Hentschel and Nicolas Rougier did a couple of wood textures some 15
> years ago, Nicolas using black hole warps.
>
> Warp has some interesting things to say, about wood, incidentally
>
> http://warp.povusers.org/povtips/
>
>
> --
> Thomas

I visited Christoph Hormann's site long time ago. I have clear impression of it
by the natural wood appearance and color.
I know it use 'isosurface', not simple texture.


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From: And
Subject: Re: Wood program but still develop
Date: 29 Aug 2023 11:15:00
Message: <web.64ee0ad35b6ed2489131d8aaa81652d@news.povray.org>
I got several wood plunk 2~3 weeks ago from my grandmother's furnitures. She is
just pass away one month ago.
I collect some of the wood, look them and thinking. So far I feel I have
collected enough idea of my wood texture generator program I want to make.

I sign up a computer lesson to learn spring framework (about Java programming
languish) September. If everything well, I will rewrite some component(with Java
program) after learning that lesson.
I wish the wood texture program become sufficient good after developing.

I have found some good method to generate bumps associate pattern for making
complex pattern these days. So I'm preparing.

But I need some career planing (suggestion, ...), too. Because I delay something
important on my life again and again...


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Attachments:
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Preview of image 'dsc_0814.jpg'
dsc_0814.jpg


 

From: And
Subject: Re: Wood program but still develop
Date: 31 Aug 2023 11:10:00
Message: <web.64f0aaea5b6ed2489131d8aaa81652d@news.povray.org>
And then, anyone know why the wood grains becomes so white(or ever saw the same
) on my last post image(dsc_0814)? I don't know why.

------------------------------------------------------------------
If I can simulate the most of the wood pattern detail like this attached pic
(the
desk has been thrown away...) one day, my program will be valuable.
------------------------------------------------------------------

In the future I need to learn something about call/invoke POV-Ray in another
program.

I have many reasons.
The one reason is that I need correct information about the f_bumps pattern.
Another is preview, but not only preview.


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dsc_1003.jpg


 

From: Bald Eagle
Subject: Re: Wood program but still develop
Date: 31 Aug 2023 18:05:00
Message: <web.64f10e605b6ed241f9dae3025979125@news.povray.org>
"And" <49341109@ntnu.edu.tw> wrote:
> And then, anyone know why the wood grains becomes so white(or ever saw the same
> ) on my last post image(dsc_0814)? I don't know why.

What you're seeing there is oxidation of the paint, or a frosting or "bloom"
from when solvent gets on the surface and dissolves out some of the clear
binder, or when water gets on the paint and hydrates/swells the surface coating,
which I believe causes it to develop microscopic cracks, allowing air in, and
giving it a different IOR.
Kind of like taking transparent tape and putting it on a dark surface - it's not
transparent until you rub/burnish it down to exclude all of the air between the
tape and the surface.

> ------------------------------------------------------------------
> If I can simulate the most of the wood pattern detail like this attached pic

I think that what might have to happen is to have a variety of functions that
get interpolated across the surface of the wood, to give rise to a smooth
blending of different patterns.   Right now you're just sort of unioning them.

> I have many reasons.
> The one reason is that I need correct information about the f_bumps pattern.

What needs to be corrected?

- BW


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From: And
Subject: Re: Wood program but still develop
Date: 1 Sep 2023 04:45:00
Message: <web.64f1a4215b6ed24ada9b3b5aa81652d@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "And" <49341109@ntnu.edu.tw> wrote:
> > And then, anyone know why the wood grains becomes so white(or ever saw the same
> > ) on my last post image(dsc_0814)? I don't know why.
>
> What you're seeing there is oxidation of the paint, or a frosting or "bloom"
> from when solvent gets on the surface and dissolves out some of the clear
> binder, or when water gets on the paint and hydrates/swells the surface coating,
> which I believe causes it to develop microscopic cracks, allowing air in, and
> giving it a different IOR.
> Kind of like taking transparent tape and putting it on a dark surface - it's not
> transparent until you rub/burnish it down to exclude all of the air between the
> tape and the surface.

Wow!
Are you an expert of chemical?

>
> > ------------------------------------------------------------------
> > If I can simulate the most of the wood pattern detail like this attached pic
>
> I think that what might have to happen is to have a variety of functions that
> get interpolated across the surface of the wood, to give rise to a smooth
> blending of different patterns.   Right now you're just sort of unioning them.
>
> > I have many reasons.
> > The one reason is that I need correct information about the f_bumps pattern.
>
> What needs to be corrected?

Because I found many beautiful pattern this week, including something
radial-randomize or circular-randomize bump pattern. They are useful and play an
important role.
Maybe my program can automatically pick them(the parameter of control where the
large-value color-block appear), fitting the shape of the woodgrain
angular-shape curve you make. I think maybe they have relation...


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