How can I limit fog to a certain area or volume without visibility of the
limiting shape?
e.g. I like to fill up one single pit with ground-fog without the infinite
fog area around that pit.

Thanks, Wulf

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<wul### [at] compuservede> wrote:

> How can I limit fog to a certain area or volume without visibility of the
> limiting shape?
> e.g. I like to fill up one single pit with ground-fog without the infinite
> fog area around that pit.

You would be better off with scattering media for this. It is much more 
flexible, and is usually used confined to a certain area.
However, you will probably want to use MegaPOV for its sampling methods 
2 and 3, otherwise it will take a long time to render if you want smooth 
results.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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> How can I limit fog to a certain area or volume without visibility of the
> limiting shape?
> e.g. I like to fill up one single pit with ground-fog without the infinite
> fog area around that pit.

Make a big solid shape and add the fade_distance and fade_power keywords (and
hollow if the camera is inside it, I think...).

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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"David Fontaine" wrote:
> Make a big solid shape and add the fade_distance and
> fade_power keywords (and hollow if the camera is
> inside it, I think...).

Fog and fading are two entirely different things as you can se if you render
the code
below (requires MegaPov).
(It simulates interior fog by using an inverted object.)
You could say that if fog is like transmit, fade_color is like filter.

#default {finish {ambient 1 diffuse 0}}
box {<-3,0,7>, <3,-2,8> pigment {color <1,1,1>}}
box {<-3,0,7>, <3,+1,8> pigment {color <1,0,0>}}
box {<-3,1,7>, <3,+2,8> pigment {color <0,1,0>}}
difference {
   sphere {5*z-x, 1 inverse}
   sphere {0, 0.00001}
   pigment {color rgbt 1}
}
fog {
   fog_type 1
   distance 1
   color rgb <0.0,0.0,1.0>
}
sphere {
   5*z+x, 1
   pigment {color rgbf 1}
   interior {fade_power 1 fade_distance 0.6 fade_color <0,0,1>}
   hollow
}

Rune
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