Simulation example · Chapter 8

mdi-nbody

An interactive two-dimensional N-body application showing how MDI connects a numerical simulation to editable scientific items, linked views, and live diagnostics.

github.com/heddle/mdi-nbody · v1.0.0 release

What It Demonstrates

mdi-nbody builds a complete scientific application around MDI’s simulation and view architecture:

A worker-owned gravitational model publishing immutable snapshots to Swing views
Start, pause, resume, stop, reset, and single-step lifecycle control
Masses represented as selectable MDI items that can be dragged, edited, or deleted while the simulation is not running
Interactive construction of custom systems, including graphical velocity editing and versioned JSON save and open
Linked sPlot views for energy and angular-momentum error, plus a selected-body inspector
Reproducible presets ranging from stable two-body motion to chaotic multi-star systems

Gallery

MDI N-body application showing three massive suns, a small planet, orbital trails, energy, angular-momentum error, and selected-body diagnostics — An educational interpretation of the Trisolaris system from Cixin Liu’s acclaimed trilogy beginning with *The Three-Body Problem*, rather than a claim about canonical initial data.

Try It

git clone https://github.com/heddle/mdi-nbody.git
cd mdi-nbody
mvn clean verify
mvn compile exec:java

Dependency

mdi-nbody requires Java 17 or newer and MDI 1.2.3, which Maven resolves automatically from Maven Central; no local MDI installation is required.