Legacy Documentation: Version 5.0
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Collider.OnCollisionEnter(Collision)

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Description

OnCollisionEnter is called when this collider/rigidbody has begun touching another rigidbody/collider.

In contrast to OnTriggerEnter, OnCollisionEnter is passed the Collision class and not a Collider. The Collision class contains information about contact points, impact velocity etc. If you don't use collisionInfo in the function, leave out the collisionInfo parameter as this avoids unneccessary calculations. Notes: Collision events are only sent if one of the colliders also has a non-kinematic rigidbody attached. Collision events will be sent to disabled MonoBehaviours, to allow enabling Behaviours in response to collisions.

#pragma strict
var audio;
function Start() {
	audio = GetComponent.<AudioSource>();
}
function OnCollisionEnter(collision) {
	for (var contact in collision.contacts) {
		Debug.DrawRay(contact.point, contact.normal, Color.white);
	}
	if (collision.relativeVelocity.magnitude > 2)
		audio.Play();
}

Another example:

// A grenade
// - instantiates a explosion prefab when hitting a surface
// - then destroys itself

using UnityEngine; using System.Collections;

public class ExampleClass : MonoBehaviour { public Transform explosionPrefab; void OnCollisionEnter(Collision collision) { ContactPoint contact = collision.contacts[0]; Quaternion rot = Quaternion.FromToRotation(Vector3.up, contact.normal); Vector3 pos = contact.point; Instantiate(explosionPrefab, pos, rot); Destroy(gameObject); } }