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14 Apr 2024 07:39:18 EDT (-0400)
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From: Thomas de Groot
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 24 Sep 2012 04:02:16
Message: <50601388$1@news.povray.org>
On 24-9-2012 9:24, Thomas de Groot wrote:
The problem is the gold.

Well, I seem to have been wrong with that too. A new test shows that the 
finish can nicely be used. It was probably in an earlier stage of scene 
building.

I shall make an update of the scene.

Thanks for pushing me :-)

Thomas


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From: Stephen
Subject: Re: Spectral Rendering with POV-Ray
Date: 24 Sep 2012 04:35:00
Message: <web.50601a068647b6fff2eb76540@news.povray.org>
Ive <ive### [at] lilysoftorg> wrote:
> Am 22.09.2012 21:00, schrieb Stephen:
> >
> > Thank you for that. I have just spent about an hour listening to Marika
> > Rökk. I loved this clip on you tube:
> > http://www.youtube.com/watch?v=NOc8zFCzxno
> >
> Wow. Marika Rökk, thats a surprise ;)


Well I did enjoy jazz and blues at one time and I can listen to it occasionally.

> Note that this video is part of a documentary and those NS "Kraft durch
> Freude" scenes are not part of the movie.

The last scene being in colour was a bit of a giveaway. :-)

> Personally I do not like this
> kind of editing as especially this movie cannot be considered as NS
> propaganda flick - after all it features American jazz and tap-dance!

I understand you not liking it as it does hark back to those days. But for me it

clothes on. Although Jazz was banned in Germany during the NS years. I believe
that Goebbels encouraged a home grown film industry which included  German


> But on the other hand she did participate in 3rd Reich propaganda movies
> and - like Leni Riefenstahl - always claimed that she was just and
> artist and did know nothing ...
>
I do sympathise in a way. It is not as if she were pitchforking babies into a
truck, just keeping up moral of the folk at home.
Anyway I cannot get that tune out of my head. I am sure that I have heard it in
English from about the same period.

Stephen


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From: Thomas de Groot
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 24 Sep 2012 10:02:36
Message: <506067fc$1@news.povray.org>
Done a new render with finish{} added to the gold.

Thomas


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From: Stephen
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 24 Sep 2012 10:30:01
Message: <web.50606d9631d3852af2eb76540@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Done a new render with finish{} added to the gold.
>

How about a bit more red and a couple of small lens flares?

Stephen


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From: Thomas de Groot
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 25 Sep 2012 02:51:38
Message: <5061547a$1@news.povray.org>
On 24-9-2012 16:26, Stephen wrote:
>
> How about a bit more red and a couple of small lens flares?
>

As far as the texture is concerned, I just took one of the golds 
available in the golds.inc. Possibly others contain more or less red. I 
think I shall keep it as is.

I am not too keen on lens flares, especially in this context. I have 
been musing about some blooming or even stars, but in the end abandoned 
the idea as a bit too artificial.

Thomas


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From: Ive
Subject: Re: Spectral Rendering with POV-Ray
Date: 25 Sep 2012 12:40:19
Message: <5061de73$1@news.povray.org>
Hi all,

following Thomas' advice I have rewritten the "Spectral Rendering" page 
and hope it is now more comprehensive.
As soon as I'll find the time there is more to come ...

-Ive


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From: Ive
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 25 Sep 2012 14:10:05
Message: <5061f37d@news.povray.org>
Am 24.09.2012 16:02, schrieb Thomas de Groot:
> Done a new render with finish{} added to the gold.
>
Hm, I fail to notice any improvement :(

Having not used any of the standard texture include files myself since 
decades I took a quick look at golds.inc and assume you did replace the 
P_Gold statements by
#declare P_Gold1 = srgb CVect1;
...and so on, right?

Well, I have sworn to keep my mouth shut on this topic but I simply 
can't help it. As I have stated multiple times all "color math" works 
only as expected within a linear color space (and doing this kind of 
math myself very often is one of the reasons I advocate for 
assumed_gamma 1.0 since decades).
Now the author of golds.inc does apply a lot of mathematical operations 
on this declared color vectors afterwards - but when this vectors are 
already defined as non-linear srgb values all these operations are 
pretty pointless and the final textures will never look like expected.

And to get even a bit on topic ;) you might find the M_Gold macro with 
its sub-macro calls that are used for *Preview* rendering useful (and 
with a high reflective value like M_Gold(0.9) ) as they give under all 
lighting conditions fairly realistic results.

-Ive


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From: Thomas de Groot
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 26 Sep 2012 03:52:18
Message: <5062b432$1@news.povray.org>
On 25-9-2012 20:08, Ive wrote:
> Hm, I fail to notice any improvement :(

Well, I did, some... :-)

>
> Having not used any of the standard texture include files myself since
> decades I took a quick look at golds.inc and assume you did replace the
> P_Gold statements by
> #declare P_Gold1 = srgb CVect1;
> ...and so on, right?

Yep.

>
> Well, I have sworn to keep my mouth shut on this topic but I simply
> can't help it. As I have stated multiple times all "color math" works
> only as expected within a linear color space (and doing this kind of
> math myself very often is one of the reasons I advocate for
> assumed_gamma 1.0 since decades).
> Now the author of golds.inc does apply a lot of mathematical operations
> on this declared color vectors afterwards - but when this vectors are
> already defined as non-linear srgb values all these operations are
> pretty pointless and the final textures will never look like expected.

In fact, I do not see any difference, but I see your point.

>
> And to get even a bit on topic ;) you might find the M_Gold macro with
> its sub-macro calls that are used for *Preview* rendering useful (and
> with a high reflective value like M_Gold(0.9) ) as they give under all
> lighting conditions fairly realistic results.

So... where is this M_Gold() located? I cannot find it  :-(


Thomas


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From: Thomas de Groot
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 26 Sep 2012 04:13:36
Message: <5062b930$1@news.povray.org>
On 26-9-2012 9:52, Thomas de Groot wrote:
> So... where is this M_Gold() located? I cannot find it  :-(

OK. Found it. My brain is sluggish (it's Wednesday, don't ask me why).

Thomas


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From: Thomas de Groot
Subject: Re: Spectral Rendering with POV-Ray: comments on the tutorial
Date: 28 Sep 2012 04:05:15
Message: <50655a3b$1@news.povray.org>
On 25-9-2012 20:08, Ive wrote:
> And to get even a bit on topic ;) you might find the M_Gold macro with
> its sub-macro calls that are used for *Preview* rendering useful (and
> with a high reflective value like M_Gold(0.9) ) as they give under all
> lighting conditions fairly realistic results.

I patched in an updated gold nugget bowl with M_Gold(0.9). I first tried 
a reflectance of 0.5 to see the difference.

Thanks for pointing me to the macros. I shall return to them in future 
scenes I am sure.

Thomas


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