POV-Ray : Newsgroups : povray.general : How can I create cloud shadows in the atmosphere? Server Time
6 Aug 2024 06:18:16 EDT (-0400)
  How can I create cloud shadows in the atmosphere? (Message 1 to 6 of 6)  
From: Jeff Nighbert
Subject: How can I create cloud shadows in the atmosphere?
Date: 20 May 2002 15:00:54
Message: <3CE947DD.842B5AEF@or.blm.gov>
Hi folks--
Does anyone have an example of clouds casting shadows in the atmosphere?

Any help here would be appreciated.

Thank you,
Jeff


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From: Slime
Subject: Re: How can I create cloud shadows in the atmosphere?
Date: 20 May 2002 18:54:07
Message: <3ce97e8f@news.povray.org>
> Does anyone have an example of clouds casting shadows in the atmosphere?

Do you mean with fog? Shadows (and beams of light) can only be seen in fog
if the fog is modelled using scattering media.

 - Slime
[ http://www.slimeland.com/ ]


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From: Tom Melly
Subject: Re: How can I create cloud shadows in the atmosphere?
Date: 21 May 2002 04:57:42
Message: <3cea0c06$1@news.povray.org>
"Slime" <slm### [at] slimelandcom> wrote in message news:3ce97e8f@news.povray.org...
> > Does anyone have an example of clouds casting shadows in the atmosphere?
>
> Do you mean with fog? Shadows (and beams of light) can only be seen in fog
> if the fog is modelled using scattering media.
>

...and that's "fog" as in RealLife(tm) fog, not pov-fog, which never shows
beams. As slime says, you need scattering media underneath the clouds.


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From: Jeff Nighbert
Subject: Re: How can I create cloud shadows in the atmosphere?
Date: 21 May 2002 10:26:35
Message: <3CEA5919.71893438@or.blm.gov>
Hi folks-
In regards to fog or media and creating sun streaks:

At this point I am willing to use either but media is probably what I want.
I was just looking for a sample where this phenomena happens.

The other day I was driving up a mountain side and in the trees along the
road  I could see the morning sun streaking through trees into the light fog
that was present.  I thought it was a neat effect.  Also later that day I
could see sun streaks created by clouds at the horizon as they illuminated
the dust and thin clouds that were present.  So I was wondering if anyone
else had seen similar effects and was a sample program available, so I could
create these real-world effects in my renderings.

So any help or advice to create these effects would be greatly appreciated
by all.
Jeff


Jeff Nighbert wrote:

> Hi folks--
> Does anyone have an example of clouds casting shadows in the atmosphere?
>
> Any help here would be appreciated.
>
> Thank you,
> Jeff


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From: Slime
Subject: Re: How can I create cloud shadows in the atmosphere?
Date: 21 May 2002 15:09:46
Message: <3cea9b7a@news.povray.org>
> The other day I was driving up a mountain side and in the trees along the
> road  I could see the morning sun streaking through trees into the light
fog
> that was present.  I thought it was a neat effect.  Also later that day I
> could see sun streaks created by clouds at the horizon as they illuminated
> the dust and thin clouds that were present.  So I was wondering if anyone
> else had seen similar effects and was a sample program available, so I
could
> create these real-world effects in my renderings.


I *love* those two effects you mentioned, they're beautiful. And you
certainly do need scattering media to model them. I don't have any really
good examples for you; just look up "media" and then "scattering" in the
documentation.

It takes lots of practice to get it to look right.

 - Slime
[ http://www.slimeland.com/ ]


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From: Timothy R  Cook
Subject: Re: How can I create cloud shadows in the atmosphere?
Date: 21 May 2002 15:22:32
Message: <3CEA9E76.79B493D8@bellsouth.net>
Slime wrote:
> > So I was wondering if anyone else had seen similar effects
> > and was a sample program available, so I could create these
> > real-world effects in my renderings.

> I *love* those two effects you mentioned, they're beautiful.
> And you certainly do need scattering media to model them. I
> don't have any really good examples for you; just look up
> "media" and then "scattering" in the documentation.
> It takes lots of practice to get it to look right.

I'm currently doing an underwater scene, but the effect is
the same.  How I accomplish it is follows: scattering media
of desired flavour in hollow scene-containing primitve,
point or area light to taste, sphere around light with noisy
colourmap with one of the areas with transmit of 1 or higher.
Of course, if you're wanting the camera to be pointing at
the lightsource and you want clouds, those would replace
the sphere for accomplishing the effect.  I just used the
sphere 'cuz it was a quick way of getting what I wanted.
Image to follow in p.b.i as soon as it finishes.

-- 
Tim Cook
http://empyrean.scifi-fantasy.com
mirror: http://personal.lig.bellsouth.net/lig/z/9/z993126

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