# PhysicsEvents.PreSimulateEventHandler

> Event handler for a pre-simulate event callback. This is called prior to the simulation running and is always called on the main-thread. See PhysicsWorld and PhysicsEvents.PreSimulate.

## Definition

* **Type:** Delegate
* **Namespace:** [Unity.U2D.Physics](/engine/6000.7/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

```csharp
public delegate void PhysicsEvents.PreSimulateEventHandler(PhysicsWorld world, float deltaTime)
```