# Collision2D

> Collision details returned by 2D physics callback functions.

## Definition

* **Type:** Class
* **Namespace:** [UnityEngine](/engine/6000.0/script-reference/unityengine.md)
* **Assembly:** UnityEngine.Physics2DModule

```csharp
public class Collision2D
```

## Remarks

The collisions details are returned by [MonoBehaviour.OnCollisionEnter2D(Collision2D)](/engine/6000.0/script-reference/unityengine/monobehaviour/oncollisionenter2d.md), [MonoBehaviour.OnCollisionStay2D(Collision2D)](/engine/6000.0/script-reference/unityengine/monobehaviour/oncollisionstay2d.md) and [MonoBehaviour.OnCollisionExit2D(Collision2D)](/engine/6000.0/script-reference/unityengine/monobehaviour/oncollisionexit2d.md) callbacks. It details which [Collider2D](/engine/6000.0/script-reference/unityengine/collider2d.md) and [Rigidbody2D](/engine/6000.0/script-reference/unityengine/rigidbody2d.md) pairs are involved in the collision as well as contact points where the [Collider2D](/engine/6000.0/script-reference/unityengine/collider2d.md) meet. **Note:** During the `OnCollisionExit2D` event, there are no contacts to be retrieved.

## Properties

| Property                                                                                        | Description                                                                                                                                                                                                                                                                                                                               |
| ----------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [collider](/engine/6000.0/script-reference/unityengine/collision2d/collider.md)                 | The incoming [Collider2D](/engine/6000.0/script-reference/unityengine/collider2d.md) involved in the collision with the [Collision2D.otherCollider](/engine/6000.0/script-reference/unityengine/collision2d/othercollider.md).                                                                                                            |
| [contactCount](/engine/6000.0/script-reference/unityengine/collision2d/contactcount.md)         | Gets the number of contacts for this collision.                                                                                                                                                                                                                                                                                           |
| [contacts](/engine/6000.0/script-reference/unityengine/collision2d/contacts.md)                 | The specific points of contact with the incoming Collider2D. You should avoid using this as it produces memory garbage. Use [Collision2D.GetContact](/engine/6000.0/script-reference/unityengine/collision2d/getcontact.md) or [Collision2D.GetContacts](/engine/6000.0/script-reference/unityengine/collision2d/getcontacts.md) instead. |
| [enabled](/engine/6000.0/script-reference/unityengine/collision2d/enabled.md)                   | Indicates whether the collision response or reaction is enabled or disabled.                                                                                                                                                                                                                                                              |
| [gameObject](/engine/6000.0/script-reference/unityengine/collision2d/gameobject.md)             | The incoming GameObject involved in the collision.                                                                                                                                                                                                                                                                                        |
| [otherCollider](/engine/6000.0/script-reference/unityengine/collision2d/othercollider.md)       | The other [Collider2D](/engine/6000.0/script-reference/unityengine/collider2d.md) involved in the collision with the [Collision2D.collider](/engine/6000.0/script-reference/unityengine/collision2d/collider.md).                                                                                                                         |
| [otherRigidbody](/engine/6000.0/script-reference/unityengine/collision2d/otherrigidbody.md)     | The other [Rigidbody2D](/engine/6000.0/script-reference/unityengine/rigidbody2d.md) involved in the collision with the [Collision2D.rigidbody](/engine/6000.0/script-reference/unityengine/collision2d/rigidbody.md).                                                                                                                     |
| [relativeVelocity](/engine/6000.0/script-reference/unityengine/collision2d/relativevelocity.md) | The relative linear velocity of the two colliding objects (Read Only).                                                                                                                                                                                                                                                                    |
| [rigidbody](/engine/6000.0/script-reference/unityengine/collision2d/rigidbody.md)               | The incoming [Rigidbody2D](/engine/6000.0/script-reference/unityengine/rigidbody2d.md) involved in the collision with the [Collision2D.otherRigidbody](/engine/6000.0/script-reference/unityengine/collision2d/otherrigidbody.md).                                                                                                        |
| [transform](/engine/6000.0/script-reference/unityengine/collision2d/transform.md)               | The Transform of the incoming object involved in the collision.                                                                                                                                                                                                                                                                           |

## Methods

| Method                                                                                | Description                                                                                                                                                                                                                                              |
| ------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [GetContact](/engine/6000.0/script-reference/unityengine/collision2d/getcontact.md)   | Gets the contact point at the specified index.                                                                                                                                                                                                           |
| [GetContacts](/engine/6000.0/script-reference/unityengine/collision2d/getcontacts.md) | Retrieves all contact points for contacts between [Collision2D.collider](/engine/6000.0/script-reference/unityengine/collision2d/collider.md) and [Collision2D.otherCollider](/engine/6000.0/script-reference/unityengine/collision2d/othercollider.md). |