# PreSimulate

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

## Definition

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

```csharp
public static event PhysicsEvents.PreSimulateEventHandler PreSimulate
```