"Thomas de Groot" <t.d### [at] internlDOTnet> wrote:
> "Bruno Cabasson" <bru### [at] alcatelaleniaspacefr> schreef in bericht
> news:web.47302f5d7579baf9e8ba46670@news.povray.org...
> > Kyle <hob### [at] gatenet> wrote:
> >> These are all very nice.  What method are you using to produce them?  Are
> >> you planning to post the code?
> >
> > I am experimenting an approach. I wait until I have acceptable results
> > before
> > publishing. If this approach is judged OK by the community, I'll try to
> > write
> > something about it (paper, tutorial or so).
> >
> > BTW, I was already working on skyscapes a few moths ago, and if I remember
> > well,
> > I promised one to Steve. I dedicate this one (sky_7.png) to him.
> >
> > Bruno
> >
>
> This one is spectacular indeed! I think that you are on the same line with
> Abe Madey who experimented with similar skies about a year and a half ago.
>
> Thomas

I searched for Abe Madey on the web and found this site:
http://www.fairpoint.net/~bullfrog/sky/index.html

I do not use the same technique. All is volumetric and media (atmosphere &
clouds). The lighting is done only with media behaviour: Rayleigh (type 4) for
atmosphere, Mie (type 3, sometimes 2) & absorption for cloud layers. I use a
few parameters that are a bit delicate to tweak, but I obtain those results
with a little perseverence and patience. The renders can be quite long,
depending on the quality I want and on the sun elevation (the lower the longer,
due to adaptive method). My skies also cast shadows on the ground.

Tweaking for high elevations is easy and the results are quite good and fast. I
am mainly experimenting sunsets, with all the variety of colors they produce in
real life, including negative elevations for the sun (below the horizon). I want
acceptable behaviour at low elevations and near the horizon. In CG, beauty has a
price....

Once I get good results, I plan to render with a hemispherical camera in order
to map the resulting image on the sphere, provided no shadows are necessary for
the given scenes. Maybe there is a technique for that.

Thanks for the feedback, Thomas.

    Bruno.

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