Stephen nous illumina en ce 2008-05-23 15:14 -->
> On 23 May 2008 11:28:34 -0400, Warp <war### [at] tagpovrayorg> wrote:
> 
>> Stephen <mcavoysAT@aoldotcom> wrote:
>>>         I was just wondering. I am using a large sphere for a
>>> skysphere as I want a planet to be obscured slightly by clouds and a
>>> skysphere will not do this.
>>  Btw, a layer of clouds is never a sphere centered at the camera.
Unless you are at the center of a free floating bubble of air.
>> If you are making a huge sphere to work as a sky sphere centered at
>> the origin (or the camera), that won't really work as realistic clouds.
> 
> Drat! Would you expand a little, please?
> At the moment I'm just using the sphere as a means of having a sky for
> reflections on the sea and I will start working on the textures soon.
> So any help will be appreciated.
You can flatten the sphere with an uneven scaling and shift it down 
(scale<1,0.5,1> translate -Radius/4*y). You'd still get the reflections.
The sky_sphere will also get reflected. Good for the background of the sky.
Remember that a sky_sphere never interact with any light and never cast any 
shadow. It's a unit sphere centered on the camera, whose pigment get returned 
whenever a ray is not stopped by an object.
> 
>>  The sky_sphere is not even intended to be used for clouds (never mind
>> what the documentation and example scenes claim). It's intended for the
>> change in coloration of the sky which depends on the angle of incidence
>> (sky usually looks whiter closer to the horizon). Clouds should usually
>> be added as a plane or similar object.
> 
> Interesting, would you suggest a sky_sphere for the air with a "cloud
> plane" in front of my background planet?
That's the general idea. The cloud plane is transparent exept for the clouds 
that will have various levels of opacity.
The sky_sphere hold the background pigment that is beyong everything else.
You can then add some fog or media.

-- 
Alain
-------------------------------------------------
Please hassle me, I thrive on stress.

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