Having tried to deal with the problem, I can appreciate your progress.
I am trying to illuminate a geographic heightfield with an overhead view
in such a way as to achieve the yellow of sunlight with the blue/purple
shadows common to the outdoors. My best effort so far is front illumination
with a yellow light source and back (shadows) illumination with a blue light
source.
   Any suggestion?
                                 Thanks,
                               Jim Julian
   Below is a sample script.
------------------------------
#include "colors.inc"
camera{
    orthographic
    location <0, .275, 0>
    right<3.65, 0, 0>
    up <0, 3.65, 0>
    look_at 0
    angle 0
  }
  light_source { < -30, 30, 1> color rgb < 1.35, 1.35, 1.05 >  }  /*  light
 */
  light_source { <  30, 30, 1> color rgb < 0.75, 0.75, 1.00 >  }  /*  shadow
  */
  height_field {
    tiff "c:\Temp\Eliz_Povray\rgbimg1-vf.tif"
    pigment { White}
    translate <-.5, -.5, -.5>
    scale <1, 0.05, 1>
    rotate <0, 0, 0>
  }
----------------------------




Abe wrote:
>> First of all: What exactly did you do? Did you use fog, or
>> media to create that atmosphere effect?
>
>My methods are patented and top secret. But if you promise not to
>tell...
>The atmosphere is an additive combination of a blue scattering media and
>a blueish absorption media. The goal was to produce a blue-ing of the
>shadow elements in the scene and a reddening of the light elements as a
>function of distance. Ultimately the red and blue would merge in a
>neutral gray.
>
>> If you'll take a look into my gallery, you'll find an image in the
>> widescreen section "featuring" a silver woman statuette with
>> a red heart in her hand.
>>
>> If you look closely at the horizon, the clouds do "haze away".
>>
>> I did it using several ground-fogs with different fog_alt
>> settings. The color was adjusted to fit the actual color of the
>> horizon, and using some transmit (or filter, depends) helps
>> a lot to take care of the radioactive horizon. When using several
>> ground-fogs and high transmit values, you can get certain colors,
>> objects fading into that color when very distant, and eliminate
>> the glowing horizon to some degree.
>
>I appreciate the manner of control you exhibit in that scene, but
>I couldn't get the particular effect of coloration on light and dark
>areas I was after with fog.
>
>Abe
>


Jim Julian

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