# OnTriggerBegin2D(TriggerBeginEvent)

> Called when a PhysicsEvents.TriggerBeginEvent for the object occurs. This will always be called on the main-thread after the simulation has finished.

## Definition

* **Type:** Method
* **Namespace:** [Unity.U2D.Physics](/engine/6000.6/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

```csharp
void OnTriggerBegin2D(PhysicsEvents.TriggerBeginEvent beginEvent)
```

### Parameters

**** (\[TriggerBeginEvent]\(/engine/6000.6/script-reference/unity/u2d/physics/physicsevents/triggerbeginevent)): The event that occurred.