OnParticleTrigger runs every frame?

I’m having some difficulty understanding Particle System triggers. I want to have the “Inside” callback only execute when my Collider is inside the particle system.

My initial idea was just to throw a print statement into the OnParticleTrigger() function, but this seems to run the print statement every frame:

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class ParticleTriggers : MonoBehaviour
	ParticleSystem ps;

	void OnEnable()
		ps = GetComponent<ParticleSystem>();

	void OnParticleTrigger()
		print ("inside"); // why does this run every frame?

I then thought maybe there’s a problem with my collider and particle system and they’re always colliding, but this isn’t the case. If I change the color of the affected particles (see this page) then the particles only change colors once I’m inside the particle system.

So am I misunderstanding OnParticleTrigger? Does it run every frame? This seems to defeat the purpose of calling this feature a “callback”.

The documentation for OnParticleTrigger says it “is called when any particles in a particle system meet the conditions in the trigger module.”

I’m experiencing the same issue. Maybe a bug with Unity?
You could use “ps.GetTriggerParticles(ParticleSystemTriggerEventType.Inside, enter);” as a work around, but I agree, it would defeat the purpose of being a callback.

I have the same issue. The whole thing feels janky af. Hopefully some one can answer this.

Still happening as of Unity 2018.3.0f2. It even happens for me if I mark all events as ‘Ignore’ and delete the assigned collider.

Same issue here, callback every frame even when all events set to Ignore. Any workarounds?