# OnGUI()

> Implement IMGUI controls and logic in this method.

## Definition

* **Type:** Method
* **Namespace:** [UnityEditor.Overlays](/engine/6000.6/script-reference/unityeditor/overlays.md)
* **Assembly:** UnityEditor.CoreModule

```csharp
public abstract void OnGUI()
```

### Remarks

This function is invoked by the IMGUI event loop. It is the only method required to implement an IMGUIOverlay.