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.

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 ParticleSystem, per frame, even if multiple particles from the same ParticleSystem collide with it in that frame. To retrieve detailed information about all the collisions in that frame, use ParticlePhysicsExtensions.GetCollisionEvents to retrieve the array of ParticleCollisionEvent.

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, per frame, even if multiple particles strike the same Collider in that frame. As in the previous case, use ParticlePhysicsExtensions.GetCollisionEvents to retrieve all collision incidents for the GameObject.

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

OnParticleCollision can be a coroutine.

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++;
        }
    }
}