I cannot get a pointlight to interact with atmospheric media. What's up?

When I put a spotlight here, it looks cool.  The pointlight, however,
doesn't do a thing....

light_source{<0.005,0.00081,0.00081>  color White*14
media_interaction on}
  /*
  light_source {  <0,0,0>
    color White*14
    spotlight
    radius 90
    falloff 89//28
    tightness 1
    point_at x

  }
    */
media {                         //media scattering
  intervals 10
  scattering { 2, red 0.05 blue 0.001 green 0.02}
  samples 1, 10
  confidence 0.9999
  variance 1/1000
  ratio 0.9
}

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"Greg M. Johnson" wrote:
> 
> I cannot get a pointlight to interact with atmospheric media. What's up?
> 
> When I put a spotlight here, it looks cool.  The pointlight, however,
> doesn't do a thing....
> 
> light_source{<0.005,0.00081,0.00081>  color White*14
> media_interaction on}
>   /*
>   light_source {  <0,0,0>
>     color White*14
>     spotlight
>     radius 90
>     falloff 89//28
>     tightness 1
>     point_at x
> 
>   }
>     */
> media {                         //media scattering
>   intervals 10
>   scattering { 2, red 0.05 blue 0.001 green 0.02}
>   samples 1, 10
>   confidence 0.9999
>   variance 1/1000
>   ratio 0.9
> }

	Is there anything else in the scene besides the media and the light? If
not, that's because when you use a spotlight, the samples get
concentrated in the lighted cone so the effect is visible, whereas for a
pointlight they are distributed along the whole ray and if there's
nothing to stop it, the ray goes to infinity... (in fact that's why
rather than using atmospheric media, I usually use object media in a
very large container: it's easier to tune)

		Jerome

-- 
*******************************

* they'll tell you what can't * mailto:ber### [at] inamecom
* be done and why...          * http://www.enst.fr/~jberger
* Then do it.                 *
*******************************

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Okay, thanks for the suggestion.  However, I already tried the "container media"
and the effect was not nearly as cool as that for the spotlight and atmospheric
media.


Jerome M. BERGER wrote:

>         Is there anything else in the scene besides the media and the light? If
> not, that's because when you use a spotlight, the samples get
> concentrated in the lighted cone so the effect is visible, whereas for a
> pointlight they are distributed along the whole ray and if there's
> nothing to stop it, the ray goes to infinity... (in fact that's why
> rather than using atmospheric media, I usually use object media in a
> very large container: it's easier to tune)
>
>                 Jerome
>
> --
> *******************************

> * they'll tell you what can't * mailto:ber### [at] inamecom
> * be done and why...          * http://www.enst.fr/~jberger
> * Then do it.                 *
> *******************************

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On second thought, I will repeat my complaint that point lights DO NOT WORK with
atmospheric media. This is either a bug or a design flaw.

I wanted the effect of a light bulb inside a wiffle ball in the fog.  I set up a
porous object (based on 3d noise), but a point light inside, and had NO effect.  I
removed my porous object.  There was still no effect.  Thus, I conclude that point
lights do not interact with atmospheric media.

Greg M. Johnson wrote:

> Okay, thanks for the suggestion.  However, I already tried the "container media"
> and the effect was not nearly as cool as that for the spotlight and atmospheric
> media.
>
> Jerome M. BERGER wrote:
>
> >         Is there anything else in the scene besides the media and the light? If
> > not, that's because when you use a spotlight, the samples get
> > concentrated in the lighted cone so the effect is visible, whereas for a
> > pointlight they are distributed along the whole ray and if there's
> > nothing to stop it, the ray goes to infinity... (in fact that's why
> > rather than using atmospheric media, I usually use object media in a
> > very large container: it's easier to tune)
> >
> >                 Jerome
> >
> > --
> > *******************************

> > * they'll tell you what can't * mailto:ber### [at] inamecom
> > * be done and why...          * http://www.enst.fr/~jberger
> > * Then do it.                 *
> > *******************************

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"Greg M. Johnson" wrote:
> 
> I cannot get a pointlight to interact with atmospheric media. What's up?
> 
> When I put a spotlight here, it looks cool.  The pointlight, however,
> doesn't do a thing....
> 
> light_source{<0.005,0.00081,0.00081>  color White*14
> media_interaction on}
>   /*
>   light_source {  <0,0,0>
>     color White*14
>     spotlight
>     radius 90
>     falloff 89//28
>     tightness 1
>     point_at x
> 
>   }
>     */
> media {                         //media scattering
>   intervals 10
>   scattering { 2, red 0.05 blue 0.001 green 0.02}
>   samples 1, 10
>   confidence 0.9999
>   variance 1/1000
>   ratio 0.9
> }


This works for me using your media and my camera. Turn the media_interaction
off and the media dissappears. Turn the media_interaction on and the media
appears. I don't know what your problem is but it's not Pov's fault.

#include "colors.inc"

  camera {
    location <0, 0, -1>
    look_at <0, 0, 0>
    angle 75
    }
    

 light_source{<0.005,0.00081,0.00081>  color White*14
 media_interaction on}

 media {                         //media scattering
   intervals 10
   scattering { 2, red 0.05 blue 0.001 green 0.02}
   samples 1, 10
   confidence 0.9999
   variance 1/1000
   ratio 0.9
 }


-- 
Ken Tyler
1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html

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They worked for me. They've always worked. I suggest you add fade_power and
fade_distance. And media_interaction on.

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Greg M. Johnson wrote in message <37FC9CD6.9B9261F4@my-dejanews.com>...
>On second thought, I will repeat my complaint that point lights DO NOT WORK
with
>atmospheric media. This is either a bug or a design flaw.


Having gone through the source code for media, I have determined that media
DOES work with point lights.

Mark

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Ken's code works in pov 3.1g, but not in the superpatch for 3.1e.

And as I complained in p.b.i.,   a spotlight looks so much cooler. WHY?

Ken wrote:

>
> This works for me using your media and my camera. Turn the media_interaction
> off and the media dissappears. Turn the media_interaction on and the media
> appears. I don't know what your problem is but it's not Pov's fault.
>
> #include "colors.inc"
>
>   camera {
>     location <0, 0, -1>
>     look_at <0, 0, 0>
>     angle 75
>     }
>
>
>  light_source{<0.005,0.00081,0.00081>  color White*14
>  media_interaction on}
>
>  media {                         //media scattering
>    intervals 10
>    scattering { 2, red 0.05 blue 0.001 green 0.02}
>    samples 1, 10
>    confidence 0.9999
>    variance 1/1000
>    ratio 0.9
>  }
>
> --
> Ken Tyler
> 1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html

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