# OnEnterToolMode()

> Called when the tool is activated.

## Definition

* **Type:** Method
* **Namespace:** [UnityEditor.TerrainTools](/engine/6000.5/script-reference/unityeditor/terraintools.md)
* **Assembly:** UnityEditor

```csharp
public virtual void OnEnterToolMode()
```

### Remarks

Unity calls this method when the tool becomes the active tool.