# smoothnessSource

> Choose the source for smoothness value.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.0/script-reference/unityengine.md)
* **Assembly:** UnityEngine.TerrainModule

```csharp
public TerrainLayerSmoothnessSource smoothnessSource { get; set; }
```

### Remarks

Used for choosing where smoothness value comes from when [TerrainLayer.diffuseTexture](/engine/6000.0/script-reference/unityengine/terrainlayer/diffusetexture.md) has an alpha channel. Setting to [TerrainLayerSmoothnessSource.Constant](/engine/6000.0/script-reference/unityengine/terrainlayersmoothnesssource/constant.md) results in using the smoothness value set in [TerrainLayer.smoothness](/engine/6000.0/script-reference/unityengine/terrainlayer/smoothness.md). Setting to [TerrainLayerSmoothnessSource.DiffuseAlphaChannel](/engine/6000.0/script-reference/unityengine/terrainlayersmoothnesssource/diffusealphachannel.md) results in using smoothness value set from alpha channel of [TerrainLayer.diffuseTexture](/engine/6000.0/script-reference/unityengine/terrainlayer/diffusetexture.md).