"Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> wrote in message 
news:web.466d0ae043579e8de8ba46670@news.povray.org...
> Depending on the effect I want it may be from <0.1, 0.2, 1> to <0.4, 0.6, 
> 1>

ahhh .... fairly close to what I'm using.

> or so (normalized afterwards). I first tweak the atmosphere, more 
> sensitive
> for low elevations where the blue component is more scattered by the
> thickness of the media, leading to reddening sky), then I tweak the clouds
> density function and the light power.

sounds like we are going at this with simular methodology :-)

> Here is another try with 2 layers. But I am absolutely not satisfied:
> turbulence and thresholds not very good.

I'm using 3 layers and the sun (lightsource) is at the back of the scene 
that is to say I'm looking east at sunset. I have a rising moon and a 
shooting star that have a media componet to them .... I'm thinking about 
loosing the shooting star. anyway I'm feeling like I'm 70% there and at 
~6hrs render time progress is slow. As you mentioned earlier that allows 
only one many two tests per day (and I'm not the only one using this 
machine). Please .... do post the results if you come up with something you 
like .... I'll do the same.

Jim

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"Jim Holsenback" <jho### [at] hotmailcom> wrote:
> "Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> wrote in message
> news:web.466d0ae043579e8de8ba46670@news.povray.org...
> > Depending on the effect I want it may be from <0.1, 0.2, 1> to <0.4, 0.6,
> > 1>
>
> ahhh .... fairly close to what I'm using.
>
> > or so (normalized afterwards). I first tweak the atmosphere, more
> > sensitive
> > for low elevations where the blue component is more scattered by the
> > thickness of the media, leading to reddening sky), then I tweak the clouds
> > density function and the light power.
>
> sounds like we are going at this with simular methodology :-)
>
> > Here is another try with 2 layers. But I am absolutely not satisfied:
> > turbulence and thresholds not very good.
>
> I'm using 3 layers and the sun (lightsource) is at the back of the scene
> that is to say I'm looking east at sunset. I have a rising moon and a
> shooting star that have a media componet to them .... I'm thinking about
> loosing the shooting star. anyway I'm feeling like I'm 70% there and at
> ~6hrs render time progress is slow. As you mentioned earlier that allows
> only one many two tests per day (and I'm not the only one using this
> machine). Please .... do post the results if you come up with something you
> like .... I'll do the same.
>
> Jim


Hi Jim!

Here are two versions of the same scene, with different elevation and
settings. Both use radiosity, and have a sun aperture twice the real one (1
deg instead of 0.5). For the first image, the elevation was 5 degrees, the
second was 2.5 and You can notice that some sampling artifacts begin to
show in the latter (some kind of horizontal bandings).

    Bruno

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Attachments:
Download 'atmo_wip_1.jpg' (36 KB)

Preview of image 'atmo_wip_1.jpg'

Keep up the good work, guys!! And keep us informed! When you are done, I/we 
would certainly much appreciate some kind of tutorial to make all our 
outdoor scenes better!!!

Thomas

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"Thomas de Groot" <t.d### [at] internlDOTnet> wrote:
> Keep up the good work, guys!! And keep us informed! When you are done, I/we
> would certainly much appreciate some kind of tutorial to make all our
> outdoor scenes better!!!
>
> Thomas

I can't imagine I can do something you can't Thomas :o)! Seeing your latest
scenes and your latest entries, you are at pre-guru state and speeding very
fast!! YOU could tell us so much! But if this study leads me (or us, Jim and
I, if we can share and dig) to something reasonably usable and
determinitstic, I will be proud of telling the way I proceed. As I already
told here, I try to imitate nature.

To be honest, I have a wider goal, but it is too early now.

Attached: a dense cloud cover with 5 degrees sun elevation.


    Bruno

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Attachments:
Download 'cloud_cover_8.jpg' (26 KB)

Preview of image 'cloud_cover_8.jpg'

"Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> wrote in message 
news:web.466d3d0c43579e8de8ba46670@news.povray.org...
> Here are two versions of the same scene, with different elevation and
> settings. Both use radiosity, and have a sun aperture twice the real one 
> (1
> deg instead of 0.5). For the first image, the elevation was 5 degrees, the
> second was 2.5 and You can notice that some sampling artifacts begin to
> show in the latter (some kind of horizontal bandings).

Wow .... I like the first image! I think you've mastered the dark clouds. 
Very nice! Last evening we had a rather nice sunset here and I sat out on 
the deck and admired it for as long as it lasted. I think I'll need a few 
more tweeks to get the effect you've achieved. I'm in the process of 
incorprating the radiosity settings that I used in the courtyard scene I did 
some months ago. Perhaps I'll let it run overnight and dare anyone to go 
near the computer ..... yikes Bruno you've raised the bar .... nice work.

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"Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> schreef in bericht 
news:web.466d742a43579e8de8ba46670@news.povray.org...
>
> I can't imagine I can do something you can't Thomas :o)! Seeing your 
> latest
> scenes and your latest entries, you are at pre-guru state and speeding 
> very
> fast!! YOU could tell us so much!

Thanks Bruno, but I disagree  :-)
I am fairly good at a couple of things, but there are vast territories that 
I find very difficult and this is one of them. I have been playing awhile 
with Abe's code (in 2006 I think) which addressed essentially the same 
question, but I think that you are already farther in the development.


But if this study leads me (or us, Jim and
> I, if we can share and dig) to something reasonably usable and
> determinitstic, I will be proud of telling the way I proceed. As I already
> told here, I try to imitate nature.

I follow the thread with great attention!!

> To be honest, I have a wider goal, but it is too early now.

<grin> Of course! I could tell!! :-)

>
> Attached: a dense cloud cover with 5 degrees sun elevation.

Looks very natural!

Thomas

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Here's what I've got so far .....

3 layers concentric sphere's gradiant sky_sphere as outer most layer. By far 
Bruno has done a MUCH better job. I wondering if the approach of looking 
east at sunset is my problem. The darker clouds are supposed to give the 
clouds a look of depth ..... still my setup tends to look more like a 
painting than realistic. A little more thought into my setup seems to be in 
order. I seem to have a fairly tight and low camera angle on my terrain, and 
I'm noticing the curve of my "sky dome". Anything special about your camera 
setup?

Jim

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Attachments:
Download 'scratch1.jpg' (15 KB)

Preview of image 'scratch1.jpg'

"Jim Holsenback" <jho### [at] hotmailcom> wrote:
> Here's what I've got so far .....
>
> 3 layers concentric sphere's gradiant sky_sphere as outer most layer. By far
> Bruno has done a MUCH better job. I wondering if the approach of looking
> east at sunset is my problem. The darker clouds are supposed to give the
> clouds a look of depth ..... still my setup tends to look more like a
> painting than realistic. A little more thought into my setup seems to be in
> order. I seem to have a fairly tight and low camera angle on my terrain, and
> I'm noticing the curve of my "sky dome". Anything special about your camera
> setup?
>
> Jim



I fear that they would both distract from the rest of the scene. That is,
you

Is that the moon? If so, is the phase right or is it just a marker for
interest?



Stephen

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> "Mike the Elder" <zer### [at] wyanorg> wrote:
>
> > Only one criticism... not big enough to swipe and use for wallpaper ;-)
> >
>
> Next one will be 1024*768, promess...
>

Hello Mike.

The 1024*768 image I promessed is currently rendering. I made it good
quality (I hope!!!) and it will be ready tomorrow morning (it's 14:36 in
France).

    Bruno

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"Stephen" <mcavoys_AT_aolDOT.com> wrote in message 
news:web.466e8ea143579e8dc4e49fa40@news.povray.org...
> I've seen skies like that and I like your image. I must say that I like
> Bruno's as well. Both of the methods give very desirable results, although

two simular but slightly different approaches .... kind of funny 
(coincidence) that we both were working on skies at the same time. Thats why 
I joined in on this thread. This is a pretty good group of folks and it's 
nice to be able to bounce ideas and techniques around. I really respect the 
talents and approaches of some of the folks here .... math, logic .... etc. 
I'm kind of a trial and error guy, so I'm constantly blown away at some of 
the stuff I seen over the past couple of years.

> I fear that they would both distract from the rest of the scene. That is,
> you wouldn't want to use them where they weren't the focal point of the 
> image.

hmmmm .... I guess I see your point. I think I've always seen the sky as 
dressing around the scene. I'm working on shore grass, a fishing dory and 
some other ground cover for this scene.

> Is that the moon? If so, is the phase right or is it just a marker for
> interest?
>
 yep .... it's the moon although a rough draft version. I have a shooting 
star that I used Nathan Kopp's Lens Flare include to put a sparkle on the 
head of the star trail .... that's a work in progress too.

Jim

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