POV-Ray : Newsgroups : povray.newusers : Sunbeam effect Server Time
29 Jul 2024 14:26:03 EDT (-0400)
  Sunbeam effect (Message 1 to 4 of 4)  
From: Neil Fraser
Subject: Sunbeam effect
Date: 12 Jan 2006 12:15:01
Message: <web.43c68d4e1bf62e8dc5c410000@news.povray.org>
I've got a set of strong lights behind a shape, and I'd like to add some
atmosphere so that the beams of light are visible in mid-air.

Here's the scene at the moment:
  http://neil.fraser.name/exit.png
As one can see, the beams which happen to hit the floor look great.  But I
want to see them in the air.

I've tried placing a transparent hollow box in the foreground which is
filled with everything I can think of, but I've never found the desired
effect.
box {
  <50, 50, 0>, <-50, -50, -50>
  texture { pigment { color rgbf <1,1,1, 1> } }
  hollow
  interior {
    media {
      emission 0.01
    }
  }
}

Any suggestions would be appreciated.  Thank you.


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From: Roman Reiner
Subject: Re: Sunbeam effect
Date: 12 Jan 2006 13:15:01
Message: <web.43c69b7b3689a52f1d8bf38d0@news.povray.org>
You might want to use scattering media. emission media is not being
influenced by any lightsources. neither is absorbing media. But with
scattering media you should get your desired effect. I would recommend
looking up section 2.3.6.3.3 (tutorial) or section 3.6.2.1.3 (reference) in
the docs.

Hope this helpes
Regards Roman

"Neil Fraser" <pov### [at] neilfrasernameNOSPAM> wrote:
> box {
>   <50, 50, 0>, <-50, -50, -50>
>   texture { pigment { color rgbf <1,1,1, 1> } }
>   hollow
>   interior {
>     media {
>       emission 0.01
>     }
>   }
> }
>
> Any suggestions would be appreciated.  Thank you.


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From: Tim Nikias
Subject: Re: Sunbeam effect
Date: 12 Jan 2006 16:47:52
Message: <43c6ce88@news.povray.org>
> You might want to use scattering media. emission media is not being
> influenced by any lightsources. neither is absorbing media. But with
> scattering media you should get your desired effect. I would recommend
> looking up section 2.3.6.3.3 (tutorial) or section 3.6.2.1.3 (reference)
in
> the docs.

After you've read through that, here's a hint: inside the
scattering-brackets (where you set the type and color of the scattering
media), use "extinction 0". That way, the media won't swallow any light, so
things might get very bright, but at least you see if everything is running
fine. Then slowly crank extinction back up to 1 to see if you like it. 1 is
realistic, but I personally often resort to using scattering and absorbing
media together to have full control of the scattering color, and the color
the media gets when the light is absorbed.

Regards,
Tim

-- 
aka "Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: Neil Fraser
Subject: Re: Sunbeam effect
Date: 13 Jan 2006 01:40:00
Message: <web.43c74a333689a52fc5c410000@news.povray.org>
"Roman Reiner" <lim### [at] gmxde> wrote:
> You might want to use scattering media.

Thanks Roman, I'd tried a bit of everything, but without knowing where to
concentrate it was difficult to narrow in on the correct strategy.

"Tim Nikias" <JUSTTHELOWERCASE:timISNOTnikias(at)gmx.netWARE> wrote:
> inside the scattering-brackets [...], use "extinction 0".

Thanks Tim, that's what had made me abandon scattering earlier.

It took a lot of tinkering (thank goodness for fast processors), but I'm
very happy with the result.
  http://neil.fraser.name/exitdone.png


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