How do I use the timeline feature?

[PlutonianEmpire]

I know that timelines were implemented in the ssc codes for the default spacecraft in the default Celestia installations.

My question is, is it possible to use it for planets and moons as well, beyond orbital and rotational mechanics?

I have a planet, and I want to implement changes in the planet itself, such as losing its rings when it gets too close to its sun, and its moons losing their ices (going from an icy appearance to a rocky appearance, possibly shrinking in the process), or a moon being terraformed over time, and so forth....

[selden]

Sorry: a quick test reveals that Timeline works only for orbit and orientation, not for the other SSC parameters.

When apparent shape changes are needed, you'll have to use separate objects with their own Beginning and Ending statements for those different objects.

p.s. I've used ScriptedOrbit to cause periodic changes in appearance. Separate object definitions are still needed, but it reduces the number of objects to just those needed to define the different shapes.

[selden]

Here's an example using Timeline to change a moon's apparent size.

Code: Select all

"InflatingMoon" "Sol/Earth"
{

   Radius 1
   Mesh "invisible.cmod"
   Color [ 0 0 1 ]
        OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   EllipticalOrbit { SemiMajorAxis 30000 Period 1 }
        FixedRotation { Inclination 270 AscendingNode 90 }
}

"BigMoon" "Sol/Earth"
{
        Radius 0.9
   Color [ 0 1 0 ]
    Timeline [
      # Phase 1: small -- invisible inside planet
      {
        Ending    "2010 3 12 15:30"
        OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   EllipticalOrbit { SemiMajorAxis 0 Period 1 }
        FixedRotation { Inclination 90 AscendingNode 90 }
      }

      # Phase 2: inflated -- on orbit
      {
        Ending    "2010 3 13 15:30"
        OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   EllipticalOrbit { SemiMajorAxis 30000 Period 1 }
        FixedRotation { Inclination 270 AscendingNode 90 }

      }
      # Phase 3: small
      {
        OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   EllipticalOrbit { SemiMajorAxis 0 Period 1 }
        FixedRotation { Inclination 90 AscendingNode 90 }
      }

    ]
}
"SmallMoon" "Sol/Earth"
{
        Radius 0.1
   Color [ 1 1 0 ]
    Timeline [
      # Phase 1: small -- on orbit
      {
        Ending    "2010 3 12 15:30"
        OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   EllipticalOrbit { SemiMajorAxis 30000 Period 1 }
        FixedRotation { Inclination 90 AscendingNode 90 }
      }

      # Phase 2: inflated -- invisible inside planet
      {
        Ending    "2010 3 13 15:30"
        OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   EllipticalOrbit { SemiMajorAxis 0 Period 1 }
        FixedRotation { Inclination 270 AscendingNode 90 }

      }
      # Phase 3: small
      {
        OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   EllipticalOrbit { SemiMajorAxis 30000 Period 1 }
        FixedRotation { Inclination 90 AscendingNode 90 }
      }

    ]
}


[John Van Vliet]

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