Hi(gh)!

As I mentioned in my posting before, with my Earth model I now use a 
separate sphere for the cloud-only texture. The original cloud-only 
testure bitmap was black to white; to get the cloud-free portions 
transparent, I used the GIMP's Layer/Transparency/Colour to Transparency 
feature.

But obviously, the eastern hemisphere of that bitmap seems to be 
somewhat lighter than the western one; however, when I render a view of 
the North Pole (see below), the clouds-only texture covering the eastern 
hemisphere is not entirely transparent even in its cloud-free parts. 
And, very strangely, this effect does not disappear when I darken the 
eastern portion of the original map!

Here is the code:

union
{
   sphere // Earth, surface
   {
     0, 1
     texture
     {
       pigment
       {
         image_map
         {
           png "solarsys/ev5826_land_ocean_ice_lights_8192.png"
           map_type 1
           interpolate 2
         }
       }
       finish
       {
	ambient 1
	diffuse 0
       }
     }
     texture
     {
       pigment
       {
         image_map
         {
           png "solarsys/ev11612_land_ocean_ice_8192_POV.png"
           map_type 1
           interpolate 2
         }
       }
       finish { F_Standard_Planetary_Surface }
     }
   }
   sphere // Earth, clouds
   {
     0, 1.000783928 // clouds 5 kms above surface
     texture
     {
       pigment
       {
	image_map
	{
	  png "solarsys/cloud_combined_8192a_alpha.png"
	  map_type 1
	  interpolate 2
	}
       }
       finish { F_Standard_Planetary_Surface }
     }
   }
   rotate -y*clock
   SetAxis(bodies[3][10], bodies[3][11])
   scale <bodies[3][1], bodies[3][2], bodies[3][3]>/sc
   translate Pos_Earth/sc
}


What went wrong?

See you in Khyberspace!

Yadgar

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