I'm now working hard on my assignment for my CG class at college, in which I'm
trying to make a realistic earth animation.
I used "difference" to create something like atmosphere right outside earth, and
in which I also used emission for making the atmosphere glow. And this is where
I'm facing a problem.

When I set a light_source from a distance, there is no shadow cast on earth.
Here I paste the source code:

light_source {
 <100, 0, 50>
 color White
 spotlight
 fade_distance 100
 fade_power 10
 point_at <0, 0, 0>
}

// earth
sphere {
    <0, 0, 0>, 3.5
    texture {
        pigment {
      image_map {
                jpeg "textures/earth.jpg"
                map_type 1
            }
            scale 3.5
        }

        finish {
            ambient 1
            diffuse 3
        }

        rotate y*-135
        rotate x*35
    }
    // rotation
    rotate <0, 360*clock, 0>
}

// atmosphere emission
difference {
  sphere { <0, 0, 0>, 3.54 }
  sphere { <0, 0, 0>, 3.0 }

  material {
   texture{
   pigment { rgbt 1 }
   }

   interior {
     media {
       emission 0.5
       //scattering { 5 color rgb 0.01 eccentricity 0.56 }
       density {
         spherical density_map {
       [ 0.0  rgb 0.0 ]
          [ 0.5294*0.25e-6  rgb <0.02, 0.05, 0.2>*0.07 ]
          [ 0.5294*0.4e-6   rgb <0.02, 0.07, 0.3>*0.32 ]
          [ 0.5294*0.5e-6   rgb <0.08, 0.18, 0.4>*0.5 ]
          [ 0.5412*0.6e-6   rgb <0.08, 0.18, 0.4>*0.9 ]
          [ 0.5471*0.65e-6  rgb <0.08, 0.18, 0.4>*1.5 ]
          [ 0.5471*0.675e-6 rgb <0.08, 0.18, 0.4>*4.5 ]
          [ 0.5471*0.71e-6  rgb <0.08, 0.18, 0.4>*12 ]
         }
     scale 100
       }
     }
   }
  }

  hollow on
}

And below I attach the rendered result for now.

How can I solve this problem? I'd appreciate it if someone could help.
I'm not a native English speaker, so I'm very sorry for my poor English... I
really wish I didn't use impolite expressions!

Thanks.

Post a reply to this message

Attachments:
Download 'earth.png' (584 KB)

Preview of image 'earth.png'