Particle Encounter Lab

Parameters

Particles N Speed v Hit radius r Near-miss radius m Total time T Box side L Time step dt Direction range Δθ Random seed

Correlated walk Turn off for a fresh random heading every step

Near misses0

Active pairs0

Time0.0

Contacts are sampled at each step; a large v × dt can miss an encounter between steps.

Start with the defaults, then change one setting at a time.

N Particles: Number of moving points. More particles create more encounters and require more processing.
v Speed: Distance travelled per time unit. Each simulation step moves a particle by v × dt.
r Hit radius: Two particles register a hit when their distance becomes smaller than this value.
m Near-miss radius: Starts and ends an encounter. It must be greater than r.
T Total time: Length of the simulated period. The run ends after approximately T ÷ dt steps.
L Box side: Width and height of the square domain. A smaller box increases particle density.
dt Time step: Time between position checks. Smaller values improve contact detection but run more steps.
Δθ Direction range: Maximum heading change in radians per step. Smaller values produce straighter paths.
Random seed: Use the same whole number to repeat a run. Leave it blank for a new random run.
Correlated walk: On perturbs the current heading; off chooses an entirely new heading each step.

AccuracyKeep v × dt small compared with r.

DensityIncrease N or decrease L for more encounters.

PlaybackChanges viewing speed only; it does not change the model.