mtxcoll nous apporta ses lumieres en ce 2007/08/13 16:16:
> Hi, I'm experimenting on POV-Ray trying to make a realistic Earth-like sky
> using scattering media and need help finding a place to start. I haven't
> found any good tutorials on how to accomplish this, and my own attempts
> always seem to make the atmosphere look too dark or too bright.
There is no absolute settings. You need to adjust your media acording to your 
scene. Try adjusting the color value by small steps. Try using another 
scattering model until you are satisfied.
> 
> Also, I'm trying to use realistic proportions for the Sun in my scene,
> placing it at a distance of about 1 AU (1.5e11 m) from the observer and
> using a sphere of radius 7.0e8 m. However, the sphere isn't visible in my
> scene when I do this, even when I scale the units to 1.5e4 and 7.0
> respectively. Is the Sun really that small  in the sky, or am I doing
> something wrong?
> 
> 
You have to large scale variations.
If using a 1 meter = 1POV unit scale, and your objects scale down to about 1mm, 
you have a scale range of 1 500 000 000 000 to 0.001! You just can't have such a 
range with any kind of acuracy using floating point values.
The best you can do is to fake the huge proportions of the solar system. Make 
your sun about 1 000 000 000 times closer and smaller. Scale down any area_light 
array extent by the same amount. Add parallel to that light to beter simulate an 
extremely distant light source.
You may have to adlust the positioning, the down scaling may make your sun drift 
away from the visible area of your scene.

-- 
Alain
-------------------------------------------------
Keep your eyes wide open before marriage, half shut afterwards.
Benjamin Franklin

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