MonoBehaviour.OnParticleCollision(GameObject)

Description

OnParticleCollision is called when a particle hits a collider.

This can be used to apply damage to a game object 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 rigid bodies 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. In order to retrieve detailed information about all the collisions caused by the ParticleSystem 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 will receive at most one message per Collider that is struck. As above ParticlePhysicsExtensions.GetCollisionEvents must be used to retrieve all the collisions incident 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;

public class ExampleClass : MonoBehaviour {
    public ParticleSystem part;
    public ParticleCollisionEvent[] collisionEvents;
    void Start() {
        part = GetComponent<ParticleSystem>();
        collisionEvents = new ParticleCollisionEvent[16];
    }
    void OnParticleCollision(GameObject other) {
        int safeLength = part.GetSafeCollisionEventSize();
        if (collisionEvents.Length < safeLength)
            collisionEvents = new ParticleCollisionEvent[safeLength];
        
        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++;
        }
    }
}