JR Orrery - 2D & 3D Orbital Mechanics 1.0 Tools 4.7 Community

Submitted by user MasterGrunt06; MIT; 2026-11-11

JR Orrery is an orbital mechanics, multi-body spacecraft trajectory, and multi-scale visualization plugin for Godot 4.7+ that drives 2D scenes, 3D scenes, or both simultaneously from a single simulation.

Space games normally struggle with astronomical distances breaking 32-bit floating-point precision and camera clipping planes. JR Orrery solves this by separating orbital physics from visual gameplay nodes: simulation nodes compute accurate orbits in real-world astronomical units (such as Kilometers, Astronomical Units, Solar Masses, Earth Masses, Days, and Seconds) relative to local parent bodies, while JrOrbiter3D and JrOrbiter2D scale positions down into comfortable Godot scene coordinates without distorting child mesh or sprite scales.

Custom Nodes:
- JrOrbitDriver: Root controller for simulation time, time warp, physical units, 2D ecliptic lock, and active scene-origin perspective.
- JrRailOrbiter: Analytical Keplerian body supporting circular, elliptical, parabolic, and hyperbolic orbits, nested moon/submoon hierarchies, axial tilt, sidereal spin, and coupled binary star barycenters.
- JrBallisticOrbiter: Free-flying N-body physics body stepped via GPU GLSL compute shaders (with automatic CPU fallback), featuring continuous thrust in inertial, body-local, or orbital frames, instant delta-v impulses, automatic sphere-of-influence handoffs, drift-free time-warp conics, and live flight-path forecasting.
- JrOrbiter3D and JrOrbiter2D: Visual follower nodes that move and rotate 3D and top-down 2D nodes in either nested local or flat system-wide scene trees.

Editor & Demo Features:
- Interactive 2D and 3D viewport gizmos with Undo/Redo for dragging periapsis, apoapsis, semi-parameter, inclination, ascending node, axial tilt, epoch anomaly, and ballistic state vectors, plus animated editor trajectory ghosts.
- Dynamic reference frames on JrOrbitDriver: re-center the scene origin (0, 0, 0) on any star, planet, moon, or spacecraft at runtime in Inertial, Body Spin (surface-locked), or Synodic Orbital (co-rotating L1-L5 Lagrange) views.
- Includes an interactive showcase (res://addons/jr_orrery/demo/demo.tscn) featuring five scenarios: planetary systems with submoons, real-scale 1 AU + 400 km Low Earth Orbit and ion-drive spirals, stable L4/L5 Lagrange points, coupled binary stars, and a 256-body GPU asteroid swarm.