N-body simulation

= Godot N-body simulation

A Godot-Plugin for simulating gravitational attraction between bodies in 3D-Space.
Any class that inherits from Spatial can be added to the simulation.

== Usage

1. Add NBodySimulation3D-node to your scene.
2. Add all Elements that should attract each other as children of the simulation node.
   ** every node that should be affected needs the properties mass: float and velocity,
   so make sure to add those to their scripts.
3. Modify the parameters of the NBodySimulation3D to fit your case.

• G: The gravity constant. This determines how much the planets attract each other
• Time Multiplier: Slows or speeds up the simulation time.
• Theta: Threshold for the octant-size / distance ratio.
  The higher the value the simulation can be calculated but the less accurate it gets.
  See http://arborjs.org/docs/barnes-hut[The Barnes-Hut Algorithm] for reference.

4. Start the scene and the simulation will automatically compute die forces and move the bodies.

NOTE: If you use RigidBody-nodes inside the N-body simulation,
make sure to set physics/3d/default_gravity to 0 in your project settings.
Otherwise the bodies will still be affected by the linear gravity of the world.