On Fri, 15 Jan 1999 12:06:11 -0600, Bob Hughes <inv### [at] aolcom> wrote:

>First of all, you should not have thrown P-R 3.0* away. 

Actually, I recently immigrated, and didn't take my old computer along...
Had to download/install everything from scratch, and ended up with
POV 3.1 instead.

>Anyway, here's my attempt at equalization of this halo using media, for
>this example anyhow.

Thanks, that'll give me something to work with.
Unfortunately, it's still quite different: After replacing the outside
pigment with something transparent, the 'flame' itself turns out to be blue
on the inside, and white on the outside, which is the opposite of what it
should be. When I try to change the density map to reverse this, the white
is gone completely, and I end up with a 100% blue 'flame'.

I think I liked halo's better... :-)

>//BEGIN
> #declare Exhaust = intersection {
> box { <-2,0,-2>,<2,10,2>
> pigment { rgb 0 }
> }
>     sphere { 0, 2
>         pigment { color rgbf <1, 1, 1, 1> }
>         interior {
>          media { //as-is below this is 4X slower than halo
>             emission <.4,.4,2> //half red&green? double blue? +??
>             intervals 12 //lower grainy (3 equals speed of halo)
>             samples 1,1 //higher slower if intervals is high too
>    scattering {4,<2.4,2.4,.5> extinction .25} //3X and 1/2? type 4
>           density {
>             spherical
>              density_map {  //see the emission and scattering vectors
>                 [ 0 rgb <0,0,1> ] //same
>                 [ 1 rgb <.8,.8,1>*1.5 ] //one and a half times original
>             }
>             scale 2.0
>             turbulence sin(clock*2*pi)/4
>         }
>       }} //media&interior
>         hollow
>         scale <.3, 2, .1>
>     } //sphere
> }
>//END

>> //--------------------------------------------------------
>> 
>> #declare Exhaust = intersection {
>> box { <-2,0,-2><2,10,2>
>> pigment { Black }
>> }
>>     sphere { 0, 2
>>         pigment { color rgbt <1, 1, 1, 1> }
>>         halo {
>>             emitting
>>             spherical_mapping
>>             linear
>>             color_map {
>>                 [ 0 color rgbt <0, 0, 1,  1> ]
>>                 [ 1 color rgbt <.8, .8, 1, -1> ]
>>             }
>>             samples 10
>>             scale 2.0
>>             turbulence sin(clock*2*pi)/4
>>         }
>>         hollow
>>         scale <.3, 2, .1>
>>     }}
>> 
>> //--------------------------------------------------------

-- 
Marc van den Dikkenberg
--
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