# PhysicsCallbacks.IContactCallback

> An interface that when implemented by a Object, can be called as a target by PhysicsWorld.SendContactCallbacks.

## Definition

* **Type:** Interface
* **Namespace:** [UnityEngine.LowLevelPhysics2D](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d.md)
* **Assembly:** UnityEngine.Physics2DModule

```csharp
public interface PhysicsCallbacks.IContactCallback
```

## Methods

| Method                                                                                                                                  | Description                                                                                                                                                                                                                                               |
| --------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [OnContactBegin2D](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicscallbacks/icontactcallback/oncontactbegin2d.md) | Called when a [PhysicsEvents.ContactBeginEvent](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsevents/contactbeginevent.md) for the object occurs. This will always be called on the main-thread after the simulation has finished. |
| [OnContactEnd2D](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicscallbacks/icontactcallback/oncontactend2d.md)     | Called when a [PhysicsEvents.ContactEndEvent](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsevents/contactendevent.md) for the object occurs. This will always be called on the main-thread after the simulation has finished.     |