# OnContactBegin2D(ContactBeginEvent)

> Called when a PhysicsEvents.ContactBeginEvent 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/6000.5/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

```csharp
void OnContactBegin2D(PhysicsEvents.ContactBeginEvent beginEvent)
```

### Parameters

**** (\[ContactBeginEvent]\(/engine/6000.5/script-reference/unity/u2d/physics/physicsevents/contactbeginevent)): The event that occurred.