On Enter
Fires a pulse when something enters a trigger volume — the checkpoint, doorway and pressure-plate node.
Output: event (wire into a Particles trigger, a Counter, a Set Color, or an Object Selector)
Setting up a trigger volume
A trigger volume is an object whose collider is a sensor: things pass straight through it, but overlaps are reported. Two ways to make one:
- Inspector ▸ Physics ▸ Sensor on the object, or
- a Collider node with sensor on, wired to the object.
Scale a box over your doorway, make it a sensor, and hide it (Inspector ▸ visibility) if you don't want it seen.
How it works
While a simulation runs, the peer stepping the physics detects the overlap starting and pulses the node for everyone (the same replicated trigger stamp On Click uses). Each pair fires once per entry — re-entering fires again.
Parameters
| Parameter | Default | Meaning |
|---|---|---|
| pulse | 0.3 | how long the pulse stays high (seconds) |
Targeting
Like On Click, the node acts on the object it reaches in the graph: wire it into an Object Selector, or drop it unwired inside an object's own flow to target that object.
Practical example
A checkpoint that celebrates:
- Add a box over your track, scale it into a gate, tick Physics ▸ Sensor.
- In its flow: On Enter → Particles (
triggerinput, emission burst, preset Confetti) and On Enter → Counter to count laps. - Press P and drive or throw something through the gate.
Tip
Pair with On Exit to know when the object leaves again — e.g. a door that opens on enter and closes on exit.