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

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

### Parameters

**** (\[TriggerBeginEvent]\(/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsevents/triggerbeginevent)): The event that occurred.