# filteringAtrousPositionSigmaAO

> Specifies the threshold the Progressive Lightmapper uses to filter direct light stored in the lightmap when using the A-Trous filter. (Editor only).

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.7/script-reference/unityengine.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public float filteringAtrousPositionSigmaAO { get; set; }
```

### Remarks

The range is 0 through 2. The default value is 0.5. A higher value will increase the threshold, which reduces the amount of noise in the direct lighting component of the lightmap. Too high of a value can cause a loss of detail in the lightmap.

This setting affects lightmaps generated by the Baked Global Illumination system. It only applies to the the Progressive Lightmapper.

When Unity serializes this `LightingSettings` object as a [Lighting Settings Asset](/engine/6000.7/manual/lighting-overview/lighting-reference/class-lighting-settings.md), this property corresponds to the **Filtering > Direct Filter > Sigma** property in the Lighting Settings Asset Inspector.

Additional Resources: [Lighting Settings Asset](/engine/6000.7/manual/lighting-overview/lighting-reference/class-lighting-settings.md).