Atmosphere not working well on model (Celestia 1.5.0)

[Cham]

I'm unable to reproduce a proper atmosphere on models, with Celestia 1.5.0, like what Chris has shown before. Here's what I get on a simple disk shaped 3ds model :



Here's the SSC code I'm using for this :

Code: Select all

"External Accretion Disk" "PSR J0142+61"
{
   Mesh "torus.3ds"
   Radius 1.8E6
   Emissive true

   EllipticalOrbit {
      Period               9E10
      SemiMajorAxis        1E-10
   }

   Atmosphere {
      Height 200000
      Lower [ 0.8 0.9 1 ]
      Upper [ 0.2 0.2 0.4 ]
      }

   Orientation      [90 1 0 0]
   RotationPeriod       4.5
   Albedo               0.01
}



If I rise up the atmosphere height by a factor of 10 or 100, I get some weird rendering, like this :



I strongly suspect it isn't a bug in my video card drivers. I strongly feel it's a bug in Celestia, (Mac version ?) .

Maybe this bug is related to the fact that there's a star at the center of the mesh ?

[chris]

There are two sets of parameters for atmospheres: the old ones that you're using, and the new ones for 1.5.0 that do a simple scattering simulation. Only the new ones give a volumetric effect, and even then they're really designed to be used with spheres (or ellipsoids), not just any old mesh.

--Chris

[Cham]

Chris,

then, can you give an explicit example of code that defines a volumetric atmosphere ? What did you used, in your example around an asteroid (the model wasn't exactly spherical, if I remember !).