# TerrainLayerSmoothnessSource

> Source of smoothness value used in the underlying splat material of a TerrainLayer when TerrainLayer.diffuseTexture has an alpha channel.

## Definition

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

```csharp
public enum TerrainLayerSmoothnessSource
```

## Remarks

When [TerrainLayer.diffuseTexture](/engine/6000.0/script-reference/unityengine/terrainlayer/diffusetexture.md) has an alpha channel, you can set smoothness by [TerrainLayer.smoothness](/engine/6000.0/script-reference/unityengine/terrainlayer/smoothness.md) or through the alpha channel of the diffuse texture.

## Fields

| Value                                                                                                                  | Description                                                                                                                                                 |
| ---------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [Constant](/engine/6000.0/script-reference/unityengine/terrainlayersmoothnesssource/constant.md)                       | Smoothness value comes from [TerrainLayer.smoothness](/engine/6000.0/script-reference/unityengine/terrainlayer/smoothness.md).                              |
| [DiffuseAlphaChannel](/engine/6000.0/script-reference/unityengine/terrainlayersmoothnesssource/diffusealphachannel.md) | Smoothness value comes from the alpha channel of [TerrainLayer.diffuseTexture](/engine/6000.0/script-reference/unityengine/terrainlayer/diffusetexture.md). |