>
>> of course if anyone has some knowledge of the "real" mathematical model for a
>> twilight sky sphere (and an approximative function) , i ll be glad to hear it !
>
> I looked into this a couple of years ago.  If I recall correctly, a good
> approximation can be made by combining a ground fog (Copper can work well) with
> a regular gradient on the sky_sphere oriented in the same direction as the sun.
>   The gradient's scale and wave form pick the first color in the color_map for
> the sky right behind the sun, while the last color shows up on the opposite side
> of the sky_sphere (usually below the horizon).  The color_map for the gradient
> will vary with the time of day.
>
> The sky sphere simulates the molecular (Raleigh) scattering, while the ground
> fog approximates lower-atmosphere aerosol (water and solid particle) scattering.
>
>

You can combine that with some layered pigments on your sky_sphere.
A gradient with a bright spot where the sun is located, then, a mostly 
transparent, filtering, vertical gradient used to tint the "sun" spot.
Then, you can use some fog or even media in a container some distance up 
to make your clouds.



Alain

Post a reply to this message