# PolygonId

> Represents a compact identifier for the data of a NavMesh node.

## Definition

* **Type:** Struct
* **Namespace:** [UnityEngine.Experimental.AI](/engine/6000.5/script-reference/unityengine/experimental/ai.md)
* **Assembly:** UnityEngine.AIModule
* **Implements:** [IEquatable\<PolygonId>](https://learn.microsoft.com/dotnet/api/system.iequatable-1)

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

```csharp
public struct PolygonId : IEquatable<PolygonId>
```

## Remarks

It is used in [NavMeshQuery](/engine/6000.5/script-reference/unityengine/experimental/ai/navmeshquery.md) operations for pinpointing and getting access to relevant nodes in the NavMesh. Each node can be used by only one type of agent.

This identifier becomes invalid once the node gets removed from the NavMesh, either by completely removing the surface or by modifying the surface in the node's immediate vicinity.

Additional Resources: html, [NavMeshQuery.IsValid](/engine/6000.5/script-reference/unityengine/experimental/ai/navmeshquery/isvalid.md)

## Methods

| Method                                                                                              | Description                                                                                                                                                                          |
| --------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [Equals](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid/equals.md)           | Returns `true` if two [PolygonId](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid.md) objects refer to the same NavMesh node.                                  |
| [GetHashCode](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid/gethashcode.md) | Returns the hash code for use in collections.                                                                                                                                        |
| [IsNull](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid/isnull.md)           | Returns `true` if the [PolygonId](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid.md) has been created empty and has never pointed to any node in the NavMesh. |

## Operators

| Operator                                                                                              | Description                                                                                                                                                                          |
| ----------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [operator ==](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid/op-equality.md)   | Returns `true` if two [PolygonId](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid.md) objects refer to the same NavMesh node or if they are both null.         |
| [operator !=](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid/op-inequality.md) | Returns `true` if two [PolygonId](/engine/6000.5/script-reference/unityengine/experimental/ai/polygonid.md) objects refer to different NavMesh nodes or if only one of them is null. |