MonoBehaviour.OnParticleCollision(GameObject)

Description

OnParticleCollision is called when a particle hits a Collider.

This can be used to apply damage to a GameObject when hit by particles.

Legacy Particle System:
This message is sent to all scripts attached to the WorldParticleCollider and to the Collider that was hit. The message is only sent if you enable sendCollisionMessage in the Inspector of the WorldParticleCollider.

// Legacy Particle System example
// Applies a force to all Rigidbody components that are hit by the particle.

function OnParticleCollision (other : GameObject) {
    var body : Rigidbody = other.GetComponent.<Rigidbody>();
    if (body) {
        var direction : Vector3 = other.transform.position - transform.position;
        direction = direction.normalized;
        body.AddForce (direction * 5);
    }
}

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void OnParticleCollision(GameObject other) {
        Rigidbody body = other.GetComponent<Rigidbody>();
        if (body) {
            Vector3 direction = other.transform.position - transform.position;
            direction = direction.normalized;
            body.AddForce(direction * 5);
        }
    }
}

Shuriken Particle System:
This message is sent to scripts attached to Particle Systems and to the Collider that was hit.

When OnParticleCollision is invoked from a script attached to a GameObject with a Collider, the GameObject parameter represents the ParticleSystem. The Collider receives at most one message per Particle System that collided with it in any given frame even when the Particle System struck the Collider with multiple particles in the current frame. To retrieve detailed information about all the collisions caused by the ParticleSystem, the ParticlePhysicsExtensions.GetCollisionEvents must be used to retrieve the array of ParticleSystem.CollisionEvent.

When OnParticleCollision is invoked from a script attached to a ParticleSystem, the GameObject parameter represents a GameObject with an attached Collider struck by the ParticleSystem. The ParticleSystem receives at most one message per Collider that is struck. As above, ParticlePhysicsExtensions.GetCollisionEvents must be used to retrieve all the collision incidents on the GameObject.

Messages are only sent if you enable Send Collision Messages in the Inspector of the Particle System Collision module.

The OnParticleCollision can be a co-routine. Simply use the yield statement in the function.

var part: ParticleSystem;
var collisionEvents: ParticleCollisionEvent[];

function Start() {
    part = GetComponent.<ParticleSystem>();

    collisionEvents = new ParticleCollisionEvent[16];
}

function OnParticleCollision(other: GameObject) {

    // adjust array length
    var safeLength = part.GetSafeCollisionEventSize();

    if (collisionEvents.Length < safeLength) {
        collisionEvents = new ParticleCollisionEvent[safeLength];
    }

    // get collision events for the gameObject that the script is attached to
    var numCollisionEvents = part.GetCollisionEvents(other, collisionEvents);

    // apply some force to Rigidbody components
    var rb = other.GetComponent.<Rigidbody>();

    for (var i = 0; i < numCollisionEvents; i++) {
        if (rb)
        {
            var pos = collisionEvents[i].intersection;
            var force = collisionEvents[i].velocity * 10;
            rb.AddForce(force);
        }
    }
}

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

public class ExampleClass : MonoBehaviour
{
    public ParticleSystem part;
    public List<ParticleCollisionEvent> collisionEvents;

    void Start()
    {
        part = GetComponent<ParticleSystem>();
        collisionEvents = new List<ParticleCollisionEvent>();
    }

    void OnParticleCollision(GameObject other)
    {
        int numCollisionEvents = part.GetCollisionEvents(other, collisionEvents);

        Rigidbody rb = other.GetComponent<Rigidbody>();
        int i = 0;

        while (i < numCollisionEvents)
        {
            if (rb)
            {
                Vector3 pos = collisionEvents[i].intersection;
                Vector3 force = collisionEvents[i].velocity * 10;
                rb.AddForce(force);
            }
            i++;
        }
    }
}