Kepler Translation

In order to implement a Kepler Translation, you will need to obtain the following values:

Eccentricity, SemiMajorAxis, Inclination, AscendingNode, ArgumentOfPeriapsis, MeanAnomaly, Epoch, Period (values for this example were taken from here: https://www.princeton.edu/~willman/planetary_systems/Sol/Pluto)

You will create an asset file to draw a trail, the trail will use the KeplerTranstion to decide where its points are. Once you have created the file, you will add the asset to OpenSpace.

Create an Asset File

For this example, you will create a file and put it at data/assets/keplertranslation.asset in the OpenSpace directory structure. This asset file will create a renderable trail displaying the orbit.

--keplertranslationexample.asset
local assetHelper = asset.require('util/asset_helper')
local sunTransforms = asset.require('scene/solarsystem/sun/transforms')

local PlutoKeplerTrail = {
  Identifier = "PlutoKeplerTrail",
  Parent = sunTransforms.SolarSystemBarycenter.Identifier,
  Renderable = {
    Type = "RenderableTrailOrbit",
    Translation = {
      Type = "KeplerTranslation",
      Eccentricity = 0.24883,
      SemiMajorAxis = 5906438091.0,
      Inclination = 17.14001,
      AscendingNode = 110.30,
      ArgumentOfPeriapsis = 113.76,
      MeanAnomaly = 0.003973966,
      Epoch = "2000 01 01 00:00:00",
      Period = 7821583948.8,
    },
    Color = { 0.00, 0.62, 1.00 },
    Period = 7821583948.8,
    Resolution = 86000
  },
  GUI = {
    Name = "Pluto Kepler Trail",
    Path = "/Solar System/Dwarf Planets/Pluto"
  }
}

assetHelper.registerSceneGraphNodesAndExport(asset, { PlutoKeplerTrail })

Add the Asset to OpenSpace

The final step is to simply add this asset to OpenSpace for rendering. This can be done by either:

1. Including the asset in a .scene file before starting OpenSpace: asset.require('keplertranslationexample')

2. Typing in the ` console while OpenSpace is running: openspace.asset.add('keplertranslationexample')