# IsNull()

> Returns true if the PolygonId has been created empty and has never pointed to any node in the NavMesh.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine.Experimental.AI](/engine/6000.7/script-reference/unityengine/experimental/ai.md)
* **Assembly:** UnityEngine.AIModule

> **Warning:**
>
> **Deprecated.** The experimental PolygonId struct has been deprecated. Use NavNode instead.

```csharp
public bool IsNull()
```

### Returns

| Type                                                          | Description |
| ------------------------------------------------------------- | ----------- |
| [bool](https://learn.microsoft.com/dotnet/api/system.boolean) |             |