Op 18/04/2021 om 19:13 schreef Bald Eagle:
> (I'm guessing something got omitted in there, but I understand where you're
> going)

My fault, sorry. I talked about "benefit of the doubt"

> 
> Indeed.  Now, we don't really need to "be fair" or give Ive/Yve a fair hearing -
> because he can post [virtually] anything he wants here, any time he wants - and
> there's damned little any but a select few can do to stop him.
> 
> [snip]
Again, thanks indeed for your extensive comments. I aappreciate them. I 
have not had too many experiences like this or like what you have been 
up against, and in general I /thought/ I was ready for them, but of 
course it hurts. I am interested in people and why they do or say what 
they do or say. We are social beings aren't we, but the internet is 
something very different indeed and a place where I go reluctantly, with 
the exception of a very few like these ng's.

Well, new lesson learned.

-- 
Thomas

Post a reply to this message

Thomas de Groot wrote on 16/04/2021 08:46:
> [snip]>

Regarding marbles, in my area it was often used marble containing 
ammonites, does this seem an interesting challenge to you?
See the picture as reference.

Paolo

Post a reply to this message

Attachments:
Download 'img_20210417_122316-01.jpg' (1426 KB)

Preview of image 'img_20210417_122316-01.jpg'

Paolo Gibellini <p.g### [at] gmailcom> wrote:
> Thomas de Groot wrote on 16/04/2021 08:46:
> > [snip]>
>
> Regarding marbles, in my area it was often used marble containing
> ammonites, does this seem an interesting challenge to you?
> See the picture as reference.
>
> Paolo

:D   Way to raise the bar, Paolo.


Maybe something akin to Ingo's blob pattern could be used for the ammonites, and
then a repeat warp added in...

Post a reply to this message

Op 19-4-2021 om 11:57 schreef Paolo Gibellini:
> Thomas de Groot wrote on 16/04/2021 08:46:
>> [snip]>
> 
> Regarding marbles, in my area it was often used marble containing 
> ammonites, does this seem an interesting challenge to you?
> See the picture as reference.
> 
> Paolo

A challenge? It would be a very interesting to do indeed. Not 
immediately as I want to complete the granites first, but it is /an 
offer I cannot refuse/ ;-)

-- 
Thomas

Post a reply to this message

I think we are on the verge of version 2.0 of granites21.inc. Thanks to 
your comments important improvements have been made or are pending. So, 
thank you indeed for your comprehensive contributions.

Attached are examples of the latest developments. All the textures have 
been wrapped into material{} with an ior of quartz (1.6) and now include 
a finish with fresnel. The tentative to use the albedo keyword however, 
has been abandoned for the time being as too difficult apparently to use 
in any way. Without being exclusive, thanks to Alain and Maurice, and of 
course the usual suspects Bald Eagle and Kenneth.

In a next stage, the use of more elaborate macros are planned, including 
sslt possibilities for instance. Bald Eagle has proposed a first version 
of such a macro and I am going to study it and see how to integrate 
things. In the same way, Jr proposed a HowTo html file where for 
instance the content of the headers and additional info can be provided. 
Thanks to both of you.

More discussions can and will follow here of course, but a new version 
of the package will be uploaded in a new post in due time.

-- 
Thomas

Post a reply to this message

Attachments:
Download 'mohoganyfro2-1.jpg' (99 KB) Download 'mohoganyfro2-2.jpg' (99 KB) Download 'mohoganypol2-1.jpg' (101 KB) Download 'mohoganypol2-2.jpg' (98 KB)

Preview of image 'mohoganyfro2-1.jpg'

Preview of image 'mohoganyfro2-2.jpg'

Preview of image 'mohoganypol2-1.jpg'

Preview of image 'mohoganypol2-2.jpg'

Op 20-4-2021 om 14:56 schreef Thomas de Groot:
> More discussions can and will follow here of course, but a new version 
> of the package will be uploaded in a new post in due time.
> 

A couple of things I failed to mention but are particularly important:

1. Following Maurice's suggestion to use a pigment_pattern to vary grain 
sizes, there follows that the use of colour /map/ codes becomes 
important. Bald Eagle suggested this also and we need to determine if 
those should go as different files or whatever, then to be addressed by 
macros.

2. Bald Eagle stressed the importance of starting to make list of "all 
those things we've learned in the past 20 years...". This remained 
dormant until now where I am concerned, but I intend to start to 
actively dig around and document.

Later,

-- 
Thomas

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:
> to use the albedo keyword however,
> has been abandoned for the time being as too difficult apparently to use
> in any way.

Interested in hearing why - it's always good to document perceived failures as
much as successes.

> In a next stage, the use of more elaborate macros are planned, including
> sslt possibilities for instance.

I simply figured that with something that had transparency like quartz, it might
be a good thing to include.

> Bald Eagle has proposed a first version
> of such a macro and I am going to study it and see how to integrate
> things.

As always, let me know if there are any questions.   The code was mostly to
demonstrate the rudimentary principles and stimulate further discussion and
development.

Now that some of this has percolated in my head for a bit, I think I see
Maurice's concern more clearly - the distribution of the texture elements are
too uniform.  Yes, there are different grain sizes and colors, but there is no
layering, veins, or variation of scale throughout the texture.

Should we have a color_map .map file, or should we have a texture or material
map for something as complex as a granite?   Different grains are different
minerals, with different colors, iors, sslt attributes, finishes, etc.  Maybe
make materials for each individual mineral and then combine them into the final
granite.  More than simplistic, less than explosively complex.   Put some
comments in where we're leaving excessively complicated things out of the stock
new granites, and leave those as avenues to pursue for those wishing to craft
more complex materials.
Part of what I'm thinking is to be able to select from a list of "complete"
materials and use them combinatorially, like in Jonathan Hunt's "Pebbles.pov"

Going even further along that line of include file development, it would be
beneficial to create an array of default versions of all the macro textures so
that the user could address and select them _numerically_.  A macro in the
include file could be called to instantiate such an array if desired, so that
it's not generated each time the include file is called.

I'm thinking that the variation of the granite will probably either have to be
controlled / achieved with layering, or by elevating the level of the underlying
"granite" pattern with a pattern map or function or some other approach.  Here
at the outset, it's not so crucial to actually achieve the goal, but to define
it, so that we can see what theoretically should be done, and then decide what
compromises and tricks can be used to approach that without undue complexity.
Set out some must-have attributes for what, geologically, a proper granite
should embody, and then at least we have something to shoot for.

I also think that the white that got added into some of the granite texture
examples seems "off".   Like they are clouds and are floating over and apart
from the underlying stone and are not a part of it.  Not sure what should be
done to address that, or if you see it as a problem.


Anyway, that's what was bouncing around in my head.

Post a reply to this message

Op 20/04/2021 om 20:06 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> to use the albedo keyword however,
>> has been abandoned for the time being as too difficult apparently to use
>> in any way.
> 
> Interested in hearing why - it's always good to document perceived failures as
> much as successes.
> 
In a nutshell (I want to investigate more of course) I fail to tweak the 
different values (following the rules) without drastically changing the 
colour/aspect of the texture too. Something fundamental escapes me.

>> In a next stage, the use of more elaborate macros are planned, including
>> sslt possibilities for instance.
> 
> I simply figured that with something that had transparency like quartz, it might
> be a good thing to include.
> 
Yes, and it certainly needs more work.

>> Bald Eagle has proposed a first version
>> of such a macro and I am going to study it and see how to integrate
>> things.
> 
> As always, let me know if there are any questions.   The code was mostly to
> demonstrate the rudimentary principles and stimulate further discussion and
> development.
> 
Of course.

> Now that some of this has percolated in my head for a bit, I think I see
> Maurice's concern more clearly - the distribution of the texture elements are
> too uniform.  Yes, there are different grain sizes and colors, but there is no
> layering, veins, or variation of scale throughout the texture.
> 
Yes. I tackled the grainsize differences but I am still not happy with 
the aspect overall.

> Should we have a color_map .map file, or should we have a texture or material
> map for something as complex as a granite?   Different grains are different
> minerals, with different colors, iors, sslt attributes, finishes, etc.  Maybe
> make materials for each individual mineral and then combine them into the final
> granite.  More than simplistic, less than explosively complex.   Put some
> comments in where we're leaving excessively complicated things out of the stock
> new granites, and leave those as avenues to pursue for those wishing to craft
> more complex materials.
> Part of what I'm thinking is to be able to select from a list of "complete"
> materials and use them combinatorially, like in Jonathan Hunt's "Pebbles.pov"
> 
Again, yes. I am now exclusively working on the Mohogany granite and I 
want to explore those avenues you suggest. I realise that I have taken 
on a major investigation :-) and that is ok. I am not bound to a 
deadline. I certainly would like to come up with a credible granite 
material and I am beginning to get "obsessed" by it as it were. Slow 
work of trial and error... discussing the issues helps to focus on the 
weak and strong points, and eliminate dead-end issues.

> Going even further along that line of include file development, it would be
> beneficial to create an array of default versions of all the macro textures so
> that the user could address and select them _numerically_.  A macro in the
> include file could be called to instantiate such an array if desired, so that
> it's not generated each time the include file is called.
> 
yes indeed.

> I'm thinking that the variation of the granite will probably either have to be
> controlled / achieved with layering, or by elevating the level of the underlying
> "granite" pattern with a pattern map or function or some other approach.  Here
> at the outset, it's not so crucial to actually achieve the goal, but to define
> it, so that we can see what theoretically should be done, and then decide what
> compromises and tricks can be used to approach that without undue complexity.
> Set out some must-have attributes for what, geologically, a proper granite
> should embody, and then at least we have something to shoot for.
> 
following what was written higher on. The "depth" aspect of the rock is 
crucial but also difficult to achieve.

> I also think that the white that got added into some of the granite texture
> examples seems "off".   Like they are clouds and are floating over and apart
> from the underlying stone and are not a part of it.  Not sure what should be
> done to address that, or if you see it as a problem.
> 
Imo, the white represents the quartz veins that cut through the 
granites. In the original code they came out as mere "clouds" of grey; I 
brought them back at least as something looking like veins (the top 
texture). See the examples I provided.

> 
> Anyway, that's what was bouncing around in my head.
> 
Quite a lot to have bouncing around in there, sir. ;-)

Your comments are much appreciated and keep me on track.

-- 
Thomas

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hi,

Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 20/04/2021 om 20:06 schreef Bald Eagle:
> > ...
> > that the user could address and select them _numerically_.
> yes indeed.

but how will a numpty like self know how to select?  I do hope that there will a
few introductory paragraphs discussing, and a small table laying out, the
principal (POV-Ray) components making "granite"; their role and useful parameter
ranges, etc.


regards, jr.

Post a reply to this message

Bald Eagle wrote on 19/04/2021 12:33:
> Paolo Gibellini <p.g### [at] gmailcom> wrote:
>> Thomas de Groot wrote on 16/04/2021 08:46:
>>> [snip]>
>>
>> Regarding marbles, in my area it was often used marble containing
>> ammonites, does this seem an interesting challenge to you?
>> See the picture as reference.
>>
>> Paolo
> 
> :D   Way to raise the bar, Paolo.
> 
> 
> Maybe something akin to Ingo's blob pattern could be used for the ammonites, and
> then a repeat warp added in...
> 

I agree with Thomas: we could try to do a challenge, and you could make 
these ideas /concrete/...

Paolo

Post a reply to this message

Thomas de Groot wrote on 19/04/2021 13:56:
> Op 19-4-2021 om 11:57 schreef Paolo Gibellini:
>> Thomas de Groot wrote on 16/04/2021 08:46:
>>> [snip]>
>>
>> Regarding marbles, in my area it was often used marble containing 
>> ammonites, does this seem an interesting challenge to you?
>> See the picture as reference.
>>
>> Paolo
> 
> A challenge? It would be a very interesting to do indeed. Not 
> immediately as I want to complete the granites first, but it is /an 
> offer I cannot refuse/ ;-)
> 

Honestly I used the word challenge in a generic way, but a real 
challenge could be interesting, it would add more content to the inc files.

When you are done...

;-)
Paolo

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:
> I realise that I have taken
> on a major investigation :-) and that is ok.

So did I while writing this!


> Imo, the white represents the quartz veins that cut through the
> granites. In the original code they came out as mere "clouds" of grey; I
> brought them back at least as something looking like veins (the top
> texture). See the examples I provided.

IIRC, the marble pattern is just a series of repeating lines that attains a
marble look due to the turbulence.   Maybe make a material_map using turbulated
marble and have the granite and quartz materials be the entries.

Post a reply to this message

"jr" <cre### [at] gmailcom> wrote:

> but how will a numpty like self know how to select?

You won't.  It will be one those fun mystery things, like a grab-bag, an egg
hunt, voting.  Or dating.

Actually, part of the idea I had, which is somewhat demonstrated in the stuff I
posted for TdG, is that, while not self-documenting, the code can be made to be
"self-documentable" - in that, the verbose feature embedded into all of the
macros could be turned on by such an array instantiation macro, and then you'd
generate a list of entries upon execution.  Really, the idea was to have them
available for random selection...

> I do hope that there will a
> few introductory paragraphs discussing, and a small table laying out, the
> principal (POV-Ray) components making "granite"; their role and useful parameter
> ranges, etc.

Could do that, or issue a #warning depending on values of macro parameters.
Might just imply correct values by using min/max in macro definition, or
comments.

I agree, but I can see the line between "include file" and "geology textbook"
becoming rapidly blurred.

Post a reply to this message

Op 21-4-2021 om 12:51 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> I realise that I have taken
>> on a major investigation :-) and that is ok.
> 
> So did I while writing this!
> 
> 
>> Imo, the white represents the quartz veins that cut through the
>> granites. In the original code they came out as mere "clouds" of grey; I
>> brought them back at least as something looking like veins (the top
>> texture). See the examples I provided.
> 
> IIRC, the marble pattern is just a series of repeating lines that attains a
> marble look due to the turbulence.   Maybe make a material_map using turbulated
> marble and have the granite and quartz materials be the entries.
> 
Turbulence is the keyword assuredly. In the latest version (in examples 
shown above) the quartz veins are partly controlled by warp {turbulence 
...}. Which reminds me: warp {} is another one of those things 
"learned". The use of marble (or agate maybe?) may be useful; 
investigation required.

[Tonight, I am going to browse my old textbooks to get some more useful 
info about granites. Feels like old times; I didn't specialise in hard 
rock geology but rather in sedimentary environments. However, those 
stony things were part of the curriculum and, I think I mentioned it, 
the penultimate ice age conveniently brought Scandinavian granites to 
this region, and I have some of them in my backyard. I wouldn't be 
surprised if they were also related to the North American granites of 
the east coast of US and Canada through the action of plate tectonics. 
But that is a completely different story.]

-- 
Thomas

Post a reply to this message

hi,

"Bald Eagle" <cre### [at] netscapenet> wrote:
> "jr" <cre### [at] gmailcom> wrote:
>
> > but how will a numpty like self know how to select?
>
> You won't.  It will be one those fun mystery things, like a grab-bag, an egg
> hunt, voting.  Or dating.

fun, huh?


> Actually, part of the idea I had, which is somewhat demonstrated in the stuff I
> posted for TdG, is that, while not self-documenting, the code can be made to be
> "self-documentable" - in that, the verbose feature embedded into all of the
> macros could be turned on by such an array instantiation macro, and then you'd
> generate a list of entries upon execution.  Really, the idea was to have them
> available for random selection...

for supplementary info perhaps.  but before the parser can spit out info, I
already need to have a scene, no?  so, I would need (some) information up front.


> > I do hope that there will a
> > few introductory paragraphs discussing, and a small table laying out, the
> > principal (POV-Ray) components making "granite"; their role and useful parameter
> > ranges, etc.
>
> Could do that, or issue a #warning depending on values of macro parameters.
> Might just imply correct values by using min/max in macro definition, or
> comments.
>
> I agree, but I can see the line between "include file" and "geology textbook"
> becoming rapidly blurred.

maybe you misread, maybe I put it poorly.  "geology textbook" -- I'm sure that
some "background" info for each variant would be nice to have, to help
contextualise.  what I tried to say is I'd like to read "why we fake granite in
POV the way we do, how do we work around the limitations of the tools in the
box, this POV-Ray feature is used because ..." etc.

note to Thomas: _please_ correct the spelling to 'mahogany'.


regards, jr.

Post a reply to this message

Op 21-4-2021 om 13:56 schreef jr:
> note to Thomas: _please_ correct the spelling to 'mahogany'.

I have been wondering about the spelling. After (again) assessing the 
occurrence of both spellings on the net, it seems indeed that "Mahogany" 
is the correct one.

I followed Daniel Mecklenburg's original (wrong) spelling from the start.

Additional Names: Dakota Mahagony,Dakota Mahogany,Mahogany 
Dakota,Mahogany Dakota America,Rushmore Mahogany,Select Mahogany,Sunset 
Mahogany,Brown Velvet Mahogany,Whetstone Mahogany,American 
Bouquet,Carnelian Granite    :-)

see: https://www.stonecontact.com/dakota-red-granite/s618

I shall correct but I wonder if I am not going to name it: "Dakota Red 
Granite" instead.

-- 
Thomas

Post a reply to this message

in news:web.608012f064981f5c79819d986cde94f1@news.povray.org jr wrote:

> "fake granite

've been looking at this thread with half an eye only. I worked in the 
graphics industry for quite a while and one of my jobs was pattern 
designer & colorist. The one thing I learnt,

People want what they think looks like the real thing. Not what the real 
thing actually looks like.

I have a colorised concrete floor in my house. The top layer has been 
ground off into the "grain". "What a nice marble floor" ... it looks more 
like a coarse granite ... it is closest to man made terazzo .... But still 
"a nice marble floor" ;)

https://ingoogni.nl/stuff/IMG_2021_04_21_0277_s.jpg with a nice line of 
light.

Ingo

Post a reply to this message

hi,

Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 21-4-2021 om 13:56 schreef jr:
> > note to Thomas: _please_ correct the spelling to 'mahogany'.
>
> I have been wondering about the spelling. After (again) assessing the
> occurrence of both spellings on the net, it seems indeed that "Mahogany"
> is the correct one.

perhaps also to do with accessing the net from the Netherlands vs the UK?  both
Google and Wiktionary don't think much -- anything! -- of 'mohogany'.


> I followed Daniel Mecklenburg's original (wrong) spelling from the start.
>
> Additional Names: Dakota Mahagony,Dakota Mahogany,Mahogany
> Dakota,Mahogany Dakota America,Rushmore Mahogany,Select Mahogany,Sunset
> Mahogany,Brown Velvet Mahogany,Whetstone Mahogany,American
> Bouquet,Carnelian Granite    :-)
>
> see: {...}
>
> I shall correct but I wonder if I am not going to name it: "Dakota Red
> Granite" instead.

do "mahogany granites" occur in places other than the Dakotas? if yes, I'd put
the "Dakota Red" plus latin nomenclature with the by-variant "background" info.

(and thanks for making change to spelling)


regards, jr.

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:
> I think we are on the verge of version 2.0 of granites21.inc. Thanks to
> your comments important improvements have been made or are pending. So,
> thank you indeed for your comprehensive contributions.
>
> Attached are examples of the latest developments. All the textures have
> been wrapped into material{} with an ior of quartz (1.6) and now include
> a finish with fresnel. The tentative to use the albedo keyword however,
> has been abandoned for the time being as too difficult apparently to use
> in any way. Without being exclusive, thanks to Alain and Maurice, and of
> course the usual suspects Bald Eagle and Kenneth.
>
> In a next stage, the use of more elaborate macros are planned, including
> sslt possibilities for instance. Bald Eagle has proposed a first version
> of such a macro and I am going to study it and see how to integrate
> things. In the same way, Jr proposed a HowTo html file where for
> instance the content of the headers and additional info can be provided.
> Thanks to both of you.
>
> More discussions can and will follow here of course, but a new version
> of the package will be uploaded in a new post in due time.
>
> --
> Thomas

Getting closer indeed! Now it has much more scale variations. Credit
(unwillingly :-P) deserved by Ive for showing us merits of the original files.
It might appear one could still prefer Ive's restored original version for the
single occurrences showed. At least its contrast curve could stay the reference.

But as you geologist said, its bigger scale is misleading. For having struggled
to do something that stays consistent at various scales, I know that you're
tackling something more demanding but keep hope, do not give up, try to reach an
as pleasing color curve. Theoretically, it could even get better than the
original as the new pov version can produce more nuances. I believe at this
stage showing both the current one and a much closer up framed render would do
it justice.

*Saturation of the colors should be slighly more and brightness slightly less,
but don't look at the picture straight out of the renderer, only after applying
it the gamma above 1.8 and below 2.5. if your rendered frame display gamma
doesn't do that. I would try playing either in very small amounts with the
brilliance keyword. or switch to another shading model if they did get
implemented since Uberpov? if they haven't the #brilliance shift kind of does
that "shading model translation" (OrenNayar Blinn would have sigmas for various
rocks well referenced I think).

*The specularity looks somewhat wrong sorry to be that vague: did you use
specular or phong, because what I more clearly meant was that it looks like
phong : too blurry.


Now it's just all bonus, though, the material feels really official includable
level already!

Thanks for your work !

Post a reply to this message

ingo <ing### [at] tagpovrayorg> wrote:
> in news:web.608012f064981f5c79819d986cde94f1@news.povray.org jr wrote:
>
> > "fake granite
> ...
> People want what they think looks like the real thing. Not what the real
> thing actually looks like.

so true.

for (Heinrich) Heine it was Germany (in English, though it "get's lost in
translation"[*]): if I think of Germany at night, I'm robbed of my sleep.  for
me, it's people.  :-)

[*] "Denk ich an Deutschland in der Nacht,
     dann bin ich um den Schlaf gebracht".

> I have a colorised concrete floor in my house. The top layer has been
> ground off into the "grain". "What a nice marble floor" ... it looks more
> like a coarse granite ... it is closest to man made terazzo .... But still
> "a nice marble floor" ;)

agree.


regards, jr.

Post a reply to this message

Op 21-4-2021 om 15:47 schreef Mr:
> Getting closer indeed! Now it has much more scale variations. Credit
> (unwillingly :-P) deserved by Ive for showing us merits of the original files.
> It might appear one could still prefer Ive's restored original version for the
> single occurrences showed. At least its contrast curve could stay the reference.
> 
Yes, as reference certainly, in combination with what I can find on the 
internet I want to stress.

> But as you geologist said, its bigger scale is misleading. For having struggled
> to do something that stays consistent at various scales, I know that you're
> tackling something more demanding but keep hope, do not give up, try to reach an
> as pleasing color curve. Theoretically, it could even get better than the
> original as the new pov version can produce more nuances. I believe at this
> stage showing both the current one and a much closer up framed render would do
> it justice.
> 
indeed.

> *Saturation of the colors should be slighly more and brightness slightly less,
> but don't look at the picture straight out of the renderer, only after applying
> it the gamma above 1.8 and below 2.5. if your rendered frame display gamma
> doesn't do that. I would try playing either in very small amounts with the
> brilliance keyword. or switch to another shading model if they did get
> implemented since Uberpov? if they haven't the #brilliance shift kind of does
> that "shading model translation" (OrenNayar Blinn would have sigmas for various
> rocks well referenced I think).
> 
Yes, more tweaking needed here indeed, saturation and brightness. 
Display_Gamma is set as sRGB since the days of Clipka at least.

> *The specularity looks somewhat wrong sorry to be that vague: did you use
> specular or phong, because what I more clearly meant was that it looks like
> phong : too blurry.
> 
I don't/never use phong, only specular
> 
> Now it's just all bonus, though, the material feels really official includable
> level already!
> 
Thanks! :-)

> Thanks for your work !
> 
I am getting adicted! ;-)

-- 
Thomas

Post a reply to this message

Op 21-4-2021 om 15:15 schreef jr:
> hi,
> 
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 21-4-2021 om 13:56 schreef jr:
>>> note to Thomas: _please_ correct the spelling to 'mahogany'.
>>
>> I have been wondering about the spelling. After (again) assessing the
>> occurrence of both spellings on the net, it seems indeed that "Mahogany"
>> is the correct one.
> 
> perhaps also to do with accessing the net from the Netherlands vs the UK?  both
> Google and Wiktionary don't think much -- anything! -- of 'mohogany'.
> 
True here too but there are a couple from "commercial" sites in the US.

> 
>> I followed Daniel Mecklenburg's original (wrong) spelling from the start.
>>
>> Additional Names: Dakota Mahagony,Dakota Mahogany,Mahogany
>> Dakota,Mahogany Dakota America,Rushmore Mahogany,Select Mahogany,Sunset
>> Mahogany,Brown Velvet Mahogany,Whetstone Mahogany,American
>> Bouquet,Carnelian Granite    :-)
>>
>> see: {...}
>>
>> I shall correct but I wonder if I am not going to name it: "Dakota Red
>> Granite" instead.
> 
> do "mahogany granites" occur in places other than the Dakotas? if yes, I'd put
> the "Dakota Red" plus latin nomenclature with the by-variant "background" info.
>
Probably not. I suppose it is a local variation name. Remember: these 
are commercial names, not scientific.

> (and thanks for making change to spelling)
> 
Always happy to serve, sir. ;-)


-- 
Thomas

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Op 21-4-2021 om 15:12 schreef ingo:
> in news:web.608012f064981f5c79819d986cde94f1@news.povray.org jr wrote:
> 
>> "fake granite
> 
> 've been looking at this thread with half an eye only. I worked in the
> graphics industry for quite a while and one of my jobs was pattern
> designer & colorist. The one thing I learnt,
> 
> People want what they think looks like the real thing. Not what the real
> thing actually looks like.
>
How true!

> I have a colorised concrete floor in my house. The top layer has been
> ground off into the "grain". "What a nice marble floor" ... it looks more
> like a coarse granite ... it is closest to man made terazzo .... But still
> "a nice marble floor" ;)
> 
> https://ingoogni.nl/stuff/IMG_2021_04_21_0277_s.jpg with a nice line of
> light.
> 
> Ingo
> 

Oh lol! almost but not quite a granite. Nice terrazzo certainly. I have 
tiles on my floor with a "rock" print. They are all identical but 
complex enough to fool the eyes at first glance. However, how fake can 
you get!? I didn't choose them... ;-)

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 21-4-2021 om 15:47 schreef Mr:
> > Getting closer indeed! Now it has much more scale variations. Credit
> > (unwillingly :-P) deserved by Ive for showing us merits of the original files.
> > It might appear one could still prefer Ive's restored original version for the
> > single occurrences showed. At least its contrast curve could stay the reference.
> >
> Yes, as reference certainly, in combination with what I can find on the
> internet I want to stress.
>
> > But as you geologist said, its bigger scale is misleading. For having struggled
> > to do something that stays consistent at various scales, I know that you're
> > tackling something more demanding but keep hope, do not give up, try to reach an
> > as pleasing color curve. Theoretically, it could even get better than the
> > original as the new pov version can produce more nuances. I believe at this
> > stage showing both the current one and a much closer up framed render would do
> > it justice.
> >
> indeed.
>
> > *Saturation of the colors should be slighly more and brightness slightly less,
> > but don't look at the picture straight out of the renderer, only after applying
> > it the gamma above 1.8 and below 2.5. if your rendered frame display gamma
> > doesn't do that. I would try playing either in very small amounts with the
> > brilliance keyword. or switch to another shading model if they did get
> > implemented since Uberpov? if they haven't the #brilliance shift kind of does
> > that "shading model translation" (OrenNayar Blinn would have sigmas for various
> > rocks well referenced I think).
> >
> Yes, more tweaking needed here indeed, saturation and brightness.
> Display_Gamma is set as sRGB since the days of Clipka at least.
>
> > *The specularity looks somewhat wrong sorry to be that vague: did you use
> > specular or phong, because what I more clearly meant was that it looks like
> > phong : too blurry.
> >
> I don't/never use phong, only specular
> >
> > Now it's just all bonus, though, the material feels really official includable
> > level already!
> >
> Thanks! :-)
>
> > Thanks for your work !
> >
> I am getting adicted! ;-)
>
> --
> Thomas

Also, sorry , but ignore the part of my comment about brightness or saturation,
I am not sure of any such thing until I see more close ups or render them myself
if I get some time. However, to push further on the scale variation, I thing the
biggest salmon colour splotches are still  too frequent when looking at
reference photo don't they occur slightly less frequently / more distant from
each other?  ... but your eye should be more expert about this.

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Op 21/04/2021 om 10:48 schreef Paolo Gibellini:
> Thomas de Groot wrote on 19/04/2021 13:56:
>> Op 19-4-2021 om 11:57 schreef Paolo Gibellini:
>>> Thomas de Groot wrote on 16/04/2021 08:46:
>>>> [snip]>
>>>
>>> Regarding marbles, in my area it was often used marble containing 
>>> ammonites, does this seem an interesting challenge to you?
>>> See the picture as reference.
>>>
>>> Paolo
>>
>> A challenge? It would be a very interesting to do indeed. Not 
>> immediately as I want to complete the granites first, but it is /an 
>> offer I cannot refuse/ ;-)
>>
> 
> Honestly I used the word challenge in a generic way, but a real 
> challenge could be interesting, it would add more content to the inc files.
> 
> When you are done...
> 

I did understand it in a generic way indeed. It is a challenging task to 
do.

This particular marble would have to be tackled with an 
*object_pattern*. Never used them seriously, but I guess it would be the 
way to go. Want to try? :-)

-- 
Thomas

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Op 21/04/2021 om 17:06 schreef Mr:

> Also, sorry , but ignore the part of my comment about brightness or saturation,
> I am not sure of any such thing until I see more close ups or render them myself
> if I get some time. However, to push further on the scale variation, I thing the
> biggest salmon colour splotches are still  too frequent when looking at
> reference photo don't they occur slightly less frequently / more distant from
> each other?  ... but your eye should be more expert about this.
> 
Anyway, your comments on brightness and saturation are well taken. They 
need a bit of extra attention imo, even if correct. The whole use of 
finish is still under my scrutiny.

Scale variation: yes, you are absolutely right and I want to get a 
better control on the distribution of the different grains. What in 
particular is missing in this "matrix" is quartz, besides the 
salmon-coloured feldspars. Literature gives the (varying) proportions of 
each and can serve as a guide.

This is going to be the next step now for me with this test granite. As 
soon as I get something working I shall post the code for everybody to 
test and shoot on (if they feel the urge).

-- 
Thomas

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hi,

Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 21-4-2021 om 15:15 schreef jr:
> > ...
> > Google and Wiktionary don't think much -- anything! -- of 'mohogany'.
> >
> True here too but there are a couple from "commercial" sites in the US.
> ...
> Probably not. I suppose it is a local variation name. Remember: these
> are commercial names, not scientific.

had not thought of/forgotten they're trade names.  will try + remember.


> > (and thanks for making change to spelling)
> >
> Always happy to serve, sir. ;-)

</grin>


> I am getting adicted! ;-)

</more-grinning>


regards, jr.

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Op 21-4-2021 om 15:47 schreef Mr:
> Getting closer indeed! Now it has much more scale variations. Credit
> (unwillingly :-P) deserved by Ive for showing us merits of the original files.
> It might appear one could still prefer Ive's restored original version for the
> single occurrences showed. At least its contrast curve could stay the reference.
> 
The sad thing is that Ive made a very valuable contribution to this 
project with his NAP.pov file. As soon as I got the time to browse 
through it, I could see that. But before I could even properly comment, 
he got impatient, pissed-off, uninterested in the first place with 
POV-Ray, I don't even know what or why, and just dropped out. I can say 
at this stage that his file is the perfect vehicle to re-render the 
original granites by Daniel Mecklenburg. With some tweaking (adding an 
extra scale for instance) they even begin to look like granites. ;-)

There are parameters Ive used in NAP.pov of which I had not even be 
aware of, so I learned a number of new things about POV-Ray, and that 
progress is vital/fundamental.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:

> This particular marble would have to be tackled with an
> *object_pattern*. Never used them seriously, but I guess it would be the
> way to go. Want to try? :-)

Or could cheat a bit and use an image map in a function.

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Op 22-4-2021 om 12:19 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>> This particular marble would have to be tackled with an
>> *object_pattern*. Never used them seriously, but I guess it would be the
>> way to go. Want to try? :-)
> 
> Or could cheat a bit and use an image map in a function.
> 
> 
Could, but not sure if it that would work. I thought about an 
image_pattern alternatively, but my feeling is that an object_pattern is 
the way to go.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:

> Could, but not sure if it that would work. I thought about an
> image_pattern alternatively, but my feeling is that an object_pattern is
> the way to go.

Windows.

http://www.shelly.de/features.html

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"Bald Eagle" <cre### [at] netscapenet> wrote:

or, you could do it the giant PITA way:
 (still no internal segmentation)

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Attachments:
Download 'ammonitemarble.png' (116 KB)

Preview of image 'ammonitemarble.png'

Op 23-4-2021 om 02:16 schreef Bald Eagle:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> 
> or, you could do it the giant PITA way:
>   (still no internal segmentation)
> 

I should have some little and very ancient program which does this too. 
I need to dig down to the very basements of my backed up files. 
Otherwise, ShellyLib looks nice too. And your Pita baldeaglensis is a 
excellent (except for the internal segmentation of course which is a 
sine qua non for the marble.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:

> I should have some little and very ancient program which does this too.
> I need to dig down to the very basements of my backed up files.
> Otherwise, ShellyLib looks nice too. And your Pita baldeaglensis is a
> excellent (except for the internal segmentation of course which is a
> sine qua non for the marble.

I'm thinking of doing the shell and the chambering all in one go with something
like the attached.   It seems like a perfect use for the ovus {} object, if it
gets hollowed out with a rounded cone first.   Then they'd all nest together.

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Attachments:
Download 'ammonitemarble.png' (50 KB)

Preview of image 'ammonitemarble.png'

Bald Eagle wrote on 23/04/2021 23:03:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>> I should have some little and very ancient program which does this too.
>> I need to dig down to the very basements of my backed up files.
>> Otherwise, ShellyLib looks nice too. And your Pita baldeaglensis is a
>> excellent (except for the internal segmentation of course which is a
>> sine qua non for the marble.
> 
> I'm thinking of doing the shell and the chambering all in one go with something
> like the attached.   It seems like a perfect use for the ovus {} object, if it
> gets hollowed out with a rounded cone first.   Then they'd all nest together.
> 

A lot of ways to explore.
We can also use fractal patterns maybe.

Paolo

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Attachments:
Download 'texture_20210426_86.png' (313 KB) Download 'texture_20210426_83.png' (347 KB)

Preview of image 'texture_20210426_86.png'

Preview of image 'texture_20210426_83.png'

Op 26-4-2021 om 15:10 schreef Paolo Gibellini:
> Bald Eagle wrote on 23/04/2021 23:03:
>> Thomas de Groot <tho### [at] degrootorg> wrote:
>>
>>> I should have some little and very ancient program which does this too.
>>> I need to dig down to the very basements of my backed up files.
>>> Otherwise, ShellyLib looks nice too. And your Pita baldeaglensis is a
>>> excellent (except for the internal segmentation of course which is a
>>> sine qua non for the marble.
>>
>> I'm thinking of doing the shell and the chambering all in one go with 
>> something
>> like the attached.   It seems like a perfect use for the ovus {} 
>> object, if it
>> gets hollowed out with a rounded cone first.   Then they'd all nest 
>> together.
>>
> 
> A lot of ways to explore.
> We can also use fractal patterns maybe.
> 
> Paolo

  Yes indeed, and especially the chamber sutures of some ammonites are 
fractals like those you show here!

-- 
Thomas

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Paolo Gibellini <p.g### [at] gmailcom> wrote:

> A lot of ways to explore.
> We can also use fractal patterns maybe.

Those came out beautifully!

With a more glassy material (agate?) those would make amzing final renders on
their own   :)

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Op 26/04/2021 om 21:18 schreef Bald Eagle:
> Paolo Gibellini <p.g### [at] gmailcom> wrote:
> 
>> A lot of ways to explore.
>> We can also use fractal patterns maybe.
> 
> Those came out beautifully!
> 
> With a more glassy material (agate?) those would make amzing final renders on
> their own   :)
>

Agreed! What are you waiting for, Paolo!? ;-)

-- 
Thomas

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Thomas de Groot wrote on 27/04/2021 08:39:
> Op 26/04/2021 om 21:18 schreef Bald Eagle:
>> With a more glassy material (agate?) those would make amzing final 
>> renders on
>> their own   :)
>>
> 
> Agreed! What are you waiting for, Paolo!? ;-)
> 

Ugh... a first try.

Paolo

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Attachments:
Download 'texture_20210428_33.png' (324 KB)

Preview of image 'texture_20210428_33.png'

Op 28-4-2021 om 14:35 schreef Paolo Gibellini:
> 
> Ugh... a first try.
> 
Aaah... yes, I can imagine a 'marble' table top with such a texture, 
probably as an artificial stone but with such an intriguing/hypnotic 
texture. I like your colour choices btw; they work extremely well 
indeed. I am not entirely certain about the normal though.

-- 
Thomas

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I know I have it ... somewhere.  Way back someone had posted an animation of a
rotating pyramid, showing off sslt.  It was a glassy agate kind of thing with a
great texture and amazing sslt finish.

I know Robert McGregor has done some very nice work employing sslt as well.
Maybe search the archives for sslt scenes and see what sorts of examples you can
find to get where you want faster.

Post a reply to this message

"Bald Eagle" <cre### [at] netscapenet> wrote:

> I'm thinking of doing the shell and the chambering all in one go with something
> like the attached.   It seems like a perfect use for the ovus {} object, if it
> gets hollowed out with a rounded cone first.   Then they'd all nest together.

A quick cobbling together of an ovus with an ellipsoid subtracted away.
The shell itself renders fairly quickly, the difference to show the cross
section was _slow_ (6.5 min.)

Parameterizing this would be challenging, to get the spiral tightness and
spacing correct while keeping the chambers properly spaced and angled the right
way...

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Attachments:
Download 'ammonitemarble.png' (57 KB)

Preview of image 'ammonitemarble.png'

Op 30-4-2021 om 03:25 schreef Bald Eagle:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> 
>> I'm thinking of doing the shell and the chambering all in one go with something
>> like the attached.   It seems like a perfect use for the ovus {} object, if it
>> gets hollowed out with a rounded cone first.   Then they'd all nest together.
> 
> A quick cobbling together of an ovus with an ellipsoid subtracted away.
> The shell itself renders fairly quickly, the difference to show the cross
> section was _slow_ (6.5 min.)
> 
> Parameterizing this would be challenging, to get the spiral tightness and
> spacing correct while keeping the chambers properly spaced and angled the right
> way...
> 
Good try. Interested to see how this would show in a rock slab.

I found my old program: Helixir, from the 1990's. Saves mesh{} files but 
not yet sure if it will do.

-- 
Thomas

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plane {z, 0
 texture {
  object {Shell
   texture {T_Grnt1} // outside
   texture {T_Grnt14}  // inside
  }
 }
}

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Attachments:
Download 'ammonitemarble.png' (426 KB)

Preview of image 'ammonitemarble.png'

Op 30/04/2021 om 23:32 schreef Bald Eagle:
> plane {z, 0
>   texture {
>    object {Shell
>     texture {T_Grnt1} // outside
>     texture {T_Grnt14}  // inside
>    }
>   }
> }
> 

ok... stylised ammonite ;-) Makes a nice pattern though; I would keep it 
as such, but as an ammonite... not yet there (too high above the uncanny 
valley).

-- 
Thomas

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Bald Eagle wrote on 30/04/2021 23:32:
> plane {z, 0
>   texture {
>    object {Shell
>     texture {T_Grnt1} // outside
>     texture {T_Grnt14}  // inside
>    }
>   }
> }
> 

A nice work!

Paolo

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Bald Eagle wrote on 28/04/2021 19:50:
> I know I have it ... somewhere.  Way back someone had posted an animation of a
> rotating pyramid, showing off sslt.  It was a glassy agate kind of thing with a
> great texture and amazing sslt finish.
> 
> I know Robert McGregor has done some very nice work employing sslt as well.
> Maybe search the archives for sslt scenes and see what sorts of examples you can
> find to get where you want faster.
> 
> 
> 

I will investigate...

Paolo

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Thomas de Groot wrote on 28/04/2021 16:58:
> Op 28-4-2021 om 14:35 schreef Paolo Gibellini:
>>
>> Ugh... a first try.
>>
> Aaah... yes, I can imagine a 'marble' table top with such a texture, 
> probably as an artificial stone but with such an intriguing/hypnotic 
> texture. I like your colour choices btw; they work extremely well 
> indeed. I am not entirely certain about the normal though.
> 

The normal is not related with the content... is just a quick test ;-)

Paolo

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Paolo Gibellini <p.g### [at] gmailcom> wrote:
> Bald Eagle wrote on 28/04/2021 19:50:
> > I know I have it ... somewhere.


Found it.
No idea when it's from, who made it, or where I got it.

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Download 'crystal_sss2.m1v.mpg' (387 KB)

Bald Eagle wrote on 26/05/2021 03:39:
> Paolo Gibellini <p.g### [at] gmailcom> wrote:
>> Bald Eagle wrote on 28/04/2021 19:50:
>>> I know I have it ... somewhere.
> 
> 
> Found it.
> No idea when it's from, who made it, or where I got it.
> 

It looks great,
   Paolo

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