Thanks, I'll give this a try.



"Kenneth" <kdw### [at] earthlinknet> wrote in message
news:web.443f549b58ac26787e0dcd410@news.povray.org...
> "Bryan Valencia" <pov### [at] spamgourmetcom> wrote:
>
> > I have an outdoor night city scene and I have placed spotlights on the
> > ground and I want the media to do 2 things.
> > 1. show the light being cast upwards through the city
> > 2. make the distant buildings less clear.
>
> Here's one solution to problem #1 (I'm asuming that your spotlights on the
> ground are pointing up):
>
> Start with a media sphere of unit size (I find that this makes
media-filled
> objects more understandable as to how they behave)...
>
> sphere{0,1 hollow
>  pigment {rgbt 1}
>
> interior{
>  media{
>   scattering{1, <...color...>*2 // or whatever multiplier looks
appropriate
>    extinction 0
>    method 3 // the default
>    intervals 1 // the default for method 3...the POV docs are incorrect
here
>    samples 100,100 // or even higher
>     }
>                       }
>              }
>  scale 10 // or whatever
>         }
>
> The extinction 0 value makes the media disappear EXCEPT where the
spotlights
> hit it. (The spotlights should probably have some fade distance/fade power
> as well, to look more realistic.) Depending on how big your media sphere
> ends up being, the samples values may need tweaking. If they're too low,
> you'll see "discontinuities" in the illuminated media.
>
> Hope this helps.
>
> Ken W.
>
>

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