# Update

> Use this enumeration to specify to Unity that it should execute the physics simulation immediately after MonoBehaviour.Update().

## Definition

* **Type:** Field
* **Namespace:** [UnityEngine](/engine/6000.7/script-reference/unityengine.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
Update = 1
```

### Remarks

Executing the physics simulation during [MonoBehaviour.Update()](/engine/6000.7/script-reference/unityengine/monobehaviour/update.md) provides a less stable and deterministic physics simulation due to the unpredictable fluctuations in framerate that can arise. However, the physics simulation is always synchronized each frame, including contacts between [Collider2D](/engine/6000.7/script-reference/unityengine/collider2d.md). Using this mode, [Rigidbody2D](/engine/6000.7/script-reference/unityengine/rigidbody2d.md) interpolation is not required as the simulation is updated per-frame.

Additional Resources: [Physics2D.simulationMode](/engine/6000.7/script-reference/unityengine/physics2d/simulationmode.md).