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From: Bruno Cabasson
Subject: Cloudscape experiment.
Date: 15 May 2007 04:15:02
Message: <web.46496bd58b4e344ab227a3bb0@news.povray.org>
Hello folks!

Experimenting lately with atmospheres and clouscapes, I got this render
quite satisfactory, though you can notice some little under-sampling
artifacts. Instead of faking the Nature, I tried to follow the laws of
physics and let them do the job.

The ground is basic and has a white pigment. The light is white. This render
does not use radiosity, thus all turns very red, but it is a normal
behaviour. With radiosity, I guess the red color coming from the white sun
(after Rayleigh scattering of the atmosphre) would participate less to
illumination, and the lighting of objects would be more realistic. I'll
experiment soon with radiosity on those scenes.

Comments welcome.

    Bruno


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Preview of image 'sc7_1.png'
sc7_1.png


 

From: Mike the Elder
Subject: Re: Cloudscape experiment.
Date: 15 May 2007 09:50:02
Message: <web.4649ba402a123e1266debb60@news.povray.org>
"Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> wrote:
> Hello folks!
>
> Experimenting lately with atmospheres and clouscapes, I got this render
> quite satisfactory...

> Comments welcome.
>
>     Bruno

IMHO, much better than just satisfactory.  From a purely subjective point of
view, I respond to nine out of ten landscapes (digital and painted) with a
yawn.  This one is "number ten". It has real power and drama. Excellent
work!

regards,
Mike C.


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From: Thomas de Groot
Subject: Re: Cloudscape experiment.
Date: 15 May 2007 10:00:29
Message: <4649bcfd@news.povray.org>
"Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> schreef in bericht 
news:web.46496bd58b4e344ab227a3bb0@news.povray.org...
> Hello folks!
>
> Experimenting lately with atmospheres and clouscapes, I got this render
> quite satisfactory, though you can notice some little under-sampling
> artifacts. Instead of faking the Nature, I tried to follow the laws of
> physics and let them do the job.
>
> The ground is basic and has a white pigment. The light is white. This 
> render
> does not use radiosity, thus all turns very red, but it is a normal
> behaviour. With radiosity, I guess the red color coming from the white sun
> (after Rayleigh scattering of the atmosphre) would participate less to
> illumination, and the lighting of objects would be more realistic. I'll
> experiment soon with radiosity on those scenes.
>
> Comments welcome.
>

I am really impressed by this. Very natural looking. In the line of Abe 
Madey's work. How long did the render take?

Thomas


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From: Florian Brucker
Subject: Re: Cloudscape experiment.
Date: 15 May 2007 10:10:25
Message: <4649bf51$1@news.povray.org>
Wow! Artifacts aside, this looks very good, both in terms of realism and
artistic means. I'm looking forward to more of this!


Keep up the good work,
Florian


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From: Bruno Cabasson
Subject: Re: Cloudscape experiment.
Date: 15 May 2007 18:40:01
Message: <web.464a35952a123e12386fe4280@news.povray.org>
"Thomas de Groot" <t.d### [at] internlDOTnet> wrote:
> "Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> schreef in bericht
> news:web.46496bd58b4e344ab227a3bb0@news.povray.org...
> > Hello folks!
> >
> > Experimenting lately with atmospheres and clouscapes, I got this render
> > quite satisfactory, though you can notice some little under-sampling
> > artifacts. Instead of faking the Nature, I tried to follow the laws of
> > physics and let them do the job.
> >
> > The ground is basic and has a white pigment. The light is white. This
> > render
> > does not use radiosity, thus all turns very red, but it is a normal
> > behaviour. With radiosity, I guess the red color coming from the white sun
> > (after Rayleigh scattering of the atmosphre) would participate less to
> > illumination, and the lighting of objects would be more realistic. I'll
> > experiment soon with radiosity on those scenes.
> >
> > Comments welcome.
> >
>
> I am really impressed by this. Very natural looking. In the line of Abe
> Madey's work. How long did the render take?
>
> Thomas

For this 1024*768 render, it took a bit more than one day on my Athlon
XP3000+. But most of the image is occupied by the clouds. I noticed that
with clouds, the  finest the resolution, the more samples you need. Here I
used 60 samples for 1 interval and method 3 for Mie scattering. I think I
should have set it up to 100 to avoid some artifacts when the media is thin
(sampling must 'hit' the media) or near the horizon with low sun (the light
makes a long path through the container - differenced spheres).

I am currently rendering a smaller 512*384 with 2 layers of clouds and a
more red light. I'll post the result tomorrow if you are interrested. I am
focusing on sunsets because they are much more difficult than daylight
clouds: needs more samples due to the longer distance the light traverses.

    Bruno


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From: Bruno Cabasson
Subject: Re: Cloudscape experiment.
Date: 15 May 2007 18:55:01
Message: <web.464a391f2a123e12386fe4280@news.povray.org>
Florian Brucker <tor### [at] torfboldcom> wrote:
> Wow! Artifacts aside, this looks very good, both in terms of realism and
> artistic means. I'm looking forward to more of this!
>
>
> Keep up the good work,
> Florian

Thanks for encouragements. I'll keep on this track until I get something
satisfactory yet versatile and user-friendly. The fact that POV lacks
specific features for clouds (we must use the general-purpose media feature
with user-specified density) forces us to use either a built in pattern and
make a heavy trial/fail process to get acceptable results, or find a
magical function{} for the density (which I can imagine for single clouds,
but wich cannot in no case be suitable for entire cloudscapes).

Whatever you can do, good clouds = many samples = looooooooong render time
(I usually get between 5 and 30 pps). But until some specialized shader is
build-in, this is the price to pay for near-realistic results. We must do
with what we have, and with POV we have a lot, a big lot. Thanks again to
all contributors and all talented people here who spend time for us to
learn and improve.

    Bruno


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From: Bruno Cabasson
Subject: Re: Cloudscape experiment.
Date: 15 May 2007 19:05:01
Message: <web.464a3c3e2a123e12386fe4280@news.povray.org>
"Mike the Elder" <zer### [at] wyanorg> wrote:
> "Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> wrote:
> > Hello folks!
> >
> > Experimenting lately with atmospheres and clouscapes, I got this render
> > quite satisfactory...
>
> > Comments welcome.
> >
> >     Bruno
>
> IMHO, much better than just satisfactory.  From a purely subjective point of
> view, I respond to nine out of ten landscapes (digital and painted) with a
> yawn.  This one is "number ten". It has real power and drama. Excellent
> work!
>
> regards,
> Mike C.

Thanks Mike!

I must confess this one is my best result so far. When I see sunsets in RL,
the vast diversity and the beauty of what I sometimes see, I know I have
still a long way to go. The problem is that rendering good clouds takes
ages, and I would need a large array of meteorological computers for me
alone - lol <:O). Thanks anyway to my brave and courageous Athlon.

   Bruno

PS: I am waiting for the next quad-core systems be affordable. I think
dual-core is just transitional.


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From: William Tracy
Subject: Re: Cloudscape experiment.
Date: 15 May 2007 19:44:17
Message: <464a45d1$1@news.povray.org>
Mike the Elder wrote:
> IMHO, much better than just satisfactory.

The words "freaking amazing" come to mind. :-)

-- 
William Tracy
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|a|f|i|s|h|i|o|n|a|d|o|@|g|m|a|i|l|.|c|o|m|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|w|t|r|a|c|y|@|c|a|l|p|o|l|y|.|e|d|u|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

You know you've been raytracing too long when you think you can do 
better than reality.


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From: aaglo
Subject: Re: Cloudscape experiment.
Date: 16 May 2007 05:55:01
Message: <web.464ad44e2a123e125de33b630@news.povray.org>
"Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> wrote:
> Hello folks!
> The ground is basic and has a white pigment. The light is white. This render
> does not use radiosity, thus all turns very red, but it is a normal
> behaviour. With radiosity, I guess the red color coming from the white sun
> (after Rayleigh scattering of the atmosphre) would participate less to
> illumination, and the lighting of objects would be more realistic. I'll
> experiment soon with radiosity on those scenes.
>
> Comments welcome.
>
>     Bruno

I wonder how that pic can be made more realistic! I'll be waiting your
"experiments soon with radiosity".

It looks stunning already.


My civ3-units - modelled and animated with pov-ray:
http://forums.civfanatics.com/showpost.php?p=2036938&postcount=4


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From: Bruno Cabasson
Subject: Re: Cloudscape experiment.
Date: 16 May 2007 18:10:02
Message: <web.464b80042a123e12709516bb0@news.povray.org>
Florian Brucker <tor### [at] torfboldcom> wrote:
> Wow! Artifacts aside, this looks very good, both in terms of realism and
> artistic means. I'm looking forward to more of this!
>
>
> Keep up the good work,
> Florian

Here is today's render (not the one I was talking about in my previous
post), using radiosity. I can't explain the strange look of the sphere
(everyone recognized it). I used quite fine settings for radiosity. I'll
investigate.

    Bruno


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Attachments:
Download 'sc9_2_rad.png' (208 KB)

Preview of image 'sc9_2_rad.png'
sc9_2_rad.png


 

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