# Collision

> Describes a collision.

## Definition

* **Type:** Class
* **Namespace:** [UnityEngine](/engine/6000.7/script-reference/unityengine.md)
* **Assembly:** UnityEngine.PhysicsModule

```csharp
public class Collision
```

## Remarks

Collision information is passed to MonoBehaviour.OnCollisionEnter(Collision), MonoBehaviour.OnCollisionStay(Collision) and MonoBehaviour.OnCollisionExit(Collision) events.

**Note**: The contact points are in world-space.

Additional Resources: [ContactPoint](/engine/6000.7/script-reference/unityengine/contactpoint.md)

## Properties

| Property                                                                                              | Description                                                                                                                                                                                                                                                                                                                                                                                               |
| ----------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [angularVelocity](/engine/6000.7/script-reference/unityengine/collision/angularvelocity.md)           | The angular velocity of the [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) or [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) that belong to the collider that your [Component](/engine/6000.7/script-reference/unityengine/component.md) collides with (Read Only).                                                                           |
| [articulationBody](/engine/6000.7/script-reference/unityengine/collision/articulationbody.md)         | The [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) of the collider that your GameObject collides with (Read Only).                                                                                                                                                                                                                                                   |
| [body](/engine/6000.7/script-reference/unityengine/collision/body.md)                                 | The [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) or [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) of the collider that your [Component](/engine/6000.7/script-reference/unityengine/component.md) collides with (Read Only).                                                                                                               |
| [collider](/engine/6000.7/script-reference/unityengine/collision/collider.md)                         | The [Collider](/engine/6000.7/script-reference/unityengine/collider.md) we hit (Read Only).                                                                                                                                                                                                                                                                                                               |
| [contactCount](/engine/6000.7/script-reference/unityengine/collision/contactcount.md)                 | Gets the number of contacts for this collision.                                                                                                                                                                                                                                                                                                                                                           |
| [contacts](/engine/6000.7/script-reference/unityengine/collision/contacts.md)                         | The contact points generated by the physics engine. You should avoid using this as it produces memory garbage. Use [Collision.GetContact](/engine/6000.7/script-reference/unityengine/collision/getcontact.md) or [Collision.GetContacts](/engine/6000.7/script-reference/unityengine/collision/getcontacts.md) instead.                                                                                  |
| [gameObject](/engine/6000.7/script-reference/unityengine/collision/gameobject.md)                     | The [GameObject](/engine/6000.7/script-reference/unityengine/gameobject.md) whose collider you are colliding with. (Read Only).                                                                                                                                                                                                                                                                           |
| [impulse](/engine/6000.7/script-reference/unityengine/collision/impulse.md)                           | The total impulse applied to this contact pair to resolve the collision.                                                                                                                                                                                                                                                                                                                                  |
| [linearVelocity](/engine/6000.7/script-reference/unityengine/collision/linearvelocity.md)             | The linear velocity of the [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) or [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) belonging to the collider that your [Component](/engine/6000.7/script-reference/unityengine/component.md) collides with (Read Only).                                                                              |
| [relativeVelocity](/engine/6000.7/script-reference/unityengine/collision/relativevelocity.md)         | The relative linear velocity of the two colliding objects (Read Only).                                                                                                                                                                                                                                                                                                                                    |
| [rigidbody](/engine/6000.7/script-reference/unityengine/collision/rigidbody.md)                       | The [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) we hit (Read Only). This is `null` if the object we hit is a collider with no rigidbody attached.                                                                                                                                                                                                                               |
| [thisAngularVelocity](/engine/6000.7/script-reference/unityengine/collision/thisangularvelocity.md)   | The angular velocity of the [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) or [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) belonging to the collider of the [Component](/engine/6000.7/script-reference/unityengine/component.md) that received the collision event (Read Only).                                                            |
| [thisArticulationBody](/engine/6000.7/script-reference/unityengine/collision/thisarticulationbody.md) | The [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) of the collider of the GameObject which received the [Collision](/engine/6000.7/script-reference/unityengine/collision.md) event (Read Only).                                                                                                                                                                     |
| [thisBody](/engine/6000.7/script-reference/unityengine/collision/thisbody.md)                         | The [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) or [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) of the collider that received the [Collision](/engine/6000.7/script-reference/unityengine/collision.md) event (Read Only).                                                                                                               |
| [thisCollider](/engine/6000.7/script-reference/unityengine/collision/thiscollider.md)                 | The [Collider](/engine/6000.7/script-reference/unityengine/collider.md) that received the [Collision](/engine/6000.7/script-reference/unityengine/collision.md) event (Read Only).                                                                                                                                                                                                                        |
| [thisGameObject](/engine/6000.7/script-reference/unityengine/collision/thisgameobject.md)             | The [GameObject](/engine/6000.7/script-reference/unityengine/gameobject.md) that received the [Collision](/engine/6000.7/script-reference/unityengine/collision.md) event (Read Only).                                                                                                                                                                                                                    |
| [thisLinearVelocity](/engine/6000.7/script-reference/unityengine/collision/thislinearvelocity.md)     | The linear velocity of the [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) or [ArticulationBody](/engine/6000.7/script-reference/unityengine/articulationbody.md) belonging to the collider of the [Component](/engine/6000.7/script-reference/unityengine/component.md) that received the [Collision](/engine/6000.7/script-reference/unityengine/collision.md) event (Read Only). |
| [thisRigidbody](/engine/6000.7/script-reference/unityengine/collision/thisrigidbody.md)               | The [Rigidbody](/engine/6000.7/script-reference/unityengine/rigidbody.md) of the collider of the GameObject which received the [Collision](/engine/6000.7/script-reference/unityengine/collision.md) event (Read Only).                                                                                                                                                                                   |
| [thisTransform](/engine/6000.7/script-reference/unityengine/collision/thistransform.md)               | The [Transform](/engine/6000.7/script-reference/unityengine/transform.md) of the [GameObject](/engine/6000.7/script-reference/unityengine/gameobject.md) that received the [Collision](/engine/6000.7/script-reference/unityengine/collision.md) event (Read Only).                                                                                                                                       |
| [transform](/engine/6000.7/script-reference/unityengine/collision/transform.md)                       | The [Transform](/engine/6000.7/script-reference/unityengine/transform.md) of the object we hit (Read Only).                                                                                                                                                                                                                                                                                               |

## Methods

| Method                                                                              | Description                                      |
| ----------------------------------------------------------------------------------- | ------------------------------------------------ |
| [GetContact](/engine/6000.7/script-reference/unityengine/collision/getcontact.md)   | Gets the contact point at the specified `index`. |
| [GetContacts](/engine/6000.7/script-reference/unityengine/collision/getcontacts.md) | Retrieves all contact points for this collision. |