If you use an object that has media as a light source's looks_like argument, and
then translate the light source, the media doesn't get translated with it.

Here's a little sample to show it.  Render it as is to see it as normal, then
change it to translate it in some direction and you'll see the media doesn't
move along with it:

background { rgb .35 }

camera { location <0, 0, -10> look_at <0,0,0> }

#declare Plasma = cylinder {
    <0,-3,0> <0,3,0>, 1
    pigment { color rgbt <1,1,1,.85> }
    finish { ambient .5 }
    interior {
        media {
            emission 0.95
            method 3
            intervals 2
            samples 10,30
            density {
                cylindrical
                turbulence 0.375
                omega 1.3
                lambda 4.5
                color_map {
                    [0.0 color rgb <0.0,0.0,0.0>]
                    [0.5 color rgb <1.0,0.8,0.0>]
                    [1.0 color rgb <1.0,1.0,0.0>]
                }
                frequency 1
                scale .5
            }
        }
    }
    hollow
    no_shadow
}

light_source {
    <0,0,0> rgb <0.98824,0.78039,0.20451>
    area_light <-2,-2,-2><2,2,2>
    2,2
    adaptive 1
    circular
    orient
    media_attenuation on
    fade_power 1.2
    fade_distance 45
    projected_through { cylinder { <0,3.1,0> <0,-3.1,0>, 1.1 } }
    looks_like { Plasma }
    translate <0,0,0>
}

These are the INI settings I'm using:

Antialias_Depth=3
Antialias=On
Antialias_Threshold=0.02
Bounding=On
Bounding_Threshold=5
Display=On
Display_Gamma=1.0
File_Gamma=1.0
Height=240
Jitter_Amount=1
Jitter=On
Light_Buffer=On
Quality=9
Remove_Bounds=On
Sampling_Method=2
Split_Unions=Off
Verbose=On
Vista_Buffer=On
Width=320

----
Michael Nickerson

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Darkshadow nous illumina en ce 2009-06-05 15:17 -->
> If you use an object that has media as a light source's looks_like argument, and
> then translate the light source, the media doesn't get translated with it.
> 
> Here's a little sample to show it.  Render it as is to see it as normal, then
> change it to translate it in some direction and you'll see the media doesn't
> move along with it:
> 
I can comfirm.
Note that rotate works as expected.
If the LOCATION of the light_source is changed, the media follows.

Just like that, you should use intervals 1, or NOT specify intervals at all and 
instead increase the samples. It renders faster that way. Also, ONLY the first 
samples parameter is ever used.

Antialias_Depth=3 Default. Don't need to set.
Antialias=On
Antialias_Threshold=0.02
Bounding=On Default.
Bounding_Threshold=5
Display=On Default
Display_Gamma=1.0
File_Gamma=1.0
Height=240
Jitter_Amount=1
Jitter=On
Light_Buffer=On Default
Quality=9 Default
Remove_Bounds=On
Sampling_Method=2 Useless as you explicitely set it to 3 in your scene
Split_Unions=Off
Verbose=On
Vista_Buffer=On Default
Width=320

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Alain <ele### [at] netscapenet> wrote:
> I can comfirm.
> Note that rotate works as expected.
> If the LOCATION of the light_source is changed, the media follows.
>

Oh yes, I meant to mention that rotating and scaling the light source works
correctly.

> Just like that, you should use intervals 1, or NOT specify intervals at all and
> instead increase the samples. It renders faster that way. Also, ONLY the first
> samples parameter is ever used.
>

Thanks for the tip.  As to the INI settings, I just used the Write Ini File
setting.  I did take out some of the defaults, as well as the Library Paths,
but I wasn't particularly trying to make sure I took out all of the default
settings.

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Alain wrote:
> Sampling_Method=2 Useless as you explicitely set it to 3 in your scene 

Uhh no. Sampling_Method is about antialias subsampling, not media. You can't
set antialias sampling method in a scene file.

I think there isn't even a Sampling_Method=3, unless 3.7 added a new one.

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