# PhysicsCallbacks.ITriggerCallback

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

## Definition

* **Type:** Interface
* **Namespace:** [Unity.U2D.Physics](/engine/6000.5/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

```csharp
public interface PhysicsCallbacks.ITriggerCallback
```

## Methods

| Method                                                                                                                      | Description                                                                                                                                                                                                                                   |
| --------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [OnTriggerBegin2D](/engine/6000.5/script-reference/unity/u2d/physics/physicscallbacks/itriggercallback/ontriggerbegin2d.md) | Called when a [PhysicsEvents.TriggerBeginEvent](/engine/6000.5/script-reference/unity/u2d/physics/physicsevents/triggerbeginevent.md) for the object occurs. This will always be called on the main-thread after the simulation has finished. |
| [OnTriggerEnd2D](/engine/6000.5/script-reference/unity/u2d/physics/physicscallbacks/itriggercallback/ontriggerend2d.md)     | Called when a [PhysicsEvents.TriggerEndEvent](/engine/6000.5/script-reference/unity/u2d/physics/physicsevents/triggerendevent.md) for the object occurs. This will always be called on the main-thread after the simulation has finished.     |