For the first issue I guess I installed a more outdated version of the package and it was easily fixable anyway.
For the second issue I just used the code on the API Documentation in the Rendering Orbital Motion.
Code here:
-- Import OrbitLib
local CelestialBody = require(game.ReplicatedStorage.OrbitLib.CelestialBody)
local Orbit = require(game.ReplicatedStorage.OrbitLib.Orbit)
-- Convert from Roblox coordinates to OrbitLib coordinates.
function RobloxToOrbitLib(x: number, y: number, z: number)
return x, -z, y
end
-- Convert from OrbitLib coordinates to Roblox Coordinates.
function OrbitLibToRoblox(i: number, j: number, k: number)
return i, k, -j
end
-- Conversion Factors
local oneStudEqualsKilometers = 1000
local oneKilometerEqualsStuds = 1/oneStudEqualsKilometers
-- Time Values
local timeAcceleration = 10000 -- How many times normal speed
local currentTime = 0
-- Prediction constants
local TOLERANCE = 0.0008 -- A constant used for calculating precision of prediction
-- See Orbital Prediction for documentation.
-- Parent body and orbit
local earth = CelestialBody.new("Earth", 5.972e24, 6378.1)
local orbit = Orbit.fromKeplerianElements(
earth, 0.3, 22000, 1, 0, 0, 0, 0
)
-- Makes a part to show the spacecraft's position.
function CreateSpacecraftPart()
-- Create part to match
local part = Instance.new("Part")
part.Anchored = true
part.Color = Color3.new(1,0,0)
part.Name = "Spacecraft"
part.Size = Vector3.new(1, 1, 1)
part.Shape = Enum.PartType.Ball
part.TopSurface = Enum.SurfaceType.Smooth
part.BottomSurface = Enum.SurfaceType.Smooth
part.Position = Vector3.new(0,0,0)
part.Parent = game.Workspace
return part
end
-- Part for spacecraft
local spacecraftPart = CreateSpacecraftPart()
-- Positions the spacecraft based on the current time.
function PositionPartBasedOnPrediction(orbit: table, part: BasePart, currentTime: number)
-- Get the predicted true anomaly
local trueAnomaly = orbit:UniversalPrediction(currentTime, TOLERANCE)
print(trueAnomaly)
-- Get ECI position from true anomaly
local currentPosXEci, currentPosYEci, currentPosZEci =
orbit:GetPositionVelocityECI(trueAnomaly)
-- Convert ECI position from OrbitLib reference vectors
-- to Roblox reference vectors
currentPosXEci, currentPosYEci, currentPosZEci =
OrbitLibToRoblox(currentPosXEci, currentPosYEci, currentPosZEci)
-- Convert from kilometers to Roblox studs from
-- our arbitrary conversion factor
currentPosXEci = currentPosXEci * oneKilometerEqualsStuds
currentPosYEci = currentPosYEci * oneKilometerEqualsStuds
currentPosZEci = currentPosZEci * oneKilometerEqualsStuds
-- Position part
part.Position = Vector3.new(currentPosXEci, currentPosYEci, currentPosZEci)
end
-- A handler for the Heartbeat event. The argument step contains the time since the last frame.
function OnHeartbeat(step: number)
currentTime += step * timeAcceleration
PositionPartBasedOnPrediction(orbit, spacecraftPart, currentTime)
end
game:GetService("RunService").Heartbeat:Connect(OnHeartbeat)
Here’s a low quality screenshot of my output currently.
