# layerMask

> A 32-bit mask that specifies which layers a ray tracing instance must be on in order to be added to the RayTracingAccelerationStructure.

## Definition

* **Type:** Field
* **Namespace:** [UnityEngine.Rendering](/engine/6000.3/script-reference/unityengine/rendering.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public int layerMask
```

### Remarks

Unity interprets the mask as binary. So a mask value of -1 allows you to add objects from all layers to the structure, a value of 1 only allows objects on layer 0, and a value of 2 only allows objects on layer 1, for example.