# Update(ref SystemState)

> When a TransformLookup is cached by a system across multiple system updates, calling this function inside the system's OnUpdate() method performs the minimal incremental updates necessary to make the lookup safe to use.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Entities](/engine/7000.0/script-reference/unity/entities.md)
* **Assembly:** UnityEngine.EntitiesModule

## Update(SystemState)

```csharp
public void Update(ref SystemState systemState)
```

### Parameters

**** (\[SystemState]\(/engine/7000.0/script-reference/unity/entities/systemstate)): The [SystemState](/engine/7000.0/script-reference/unity/entities/systemstate.md) of the system on which this lookup is cached.