# Custom

> Use the assigned PhysicsWorld.transformPlaneCustom to allow transformation writing and reading to/from a custom 2D plane.

## Definition

* **Type:** Field
* **Namespace:** [Unity.U2D.Physics](/engine/7000.0/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

```csharp
Custom = 3
```