# TerrainLayerSmoothnessSource

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

## Definition

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

```csharp
public enum TerrainLayerSmoothnessSource
```

## Remarks

When [\_diffuseTexture](/engine/6000.7/script-reference/unityengine/terrainlayer/diffusetexture.md) has an alpha channel, you can set smoothness by [\_smoothness](/engine/6000.7/script-reference/unityengine/terrainlayer/smoothness.md) or through the alpha channel of the diffuse texture.

## Fields

| Value                                                                                                                                            | Description                                                                                                                                                                                                                                         |
| ------------------------------------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [ConstantMultipliedByDiffuseAlpha](/engine/6000.7/script-reference/unityengine/terrainlayersmoothnesssource/constantmultipliedbydiffusealpha.md) | Smoothness value comes from a mix of [\_smoothness](/engine/6000.7/script-reference/unityengine/terrainlayer/smoothness.md) and the alpha channel of [\_diffuseTexture](/engine/6000.7/script-reference/unityengine/terrainlayer/diffusetexture.md) |
| [ConstantOnly](/engine/6000.7/script-reference/unityengine/terrainlayersmoothnesssource/constantonly.md)                                         | Smoothness value comes from [\_smoothness](/engine/6000.7/script-reference/unityengine/terrainlayer/smoothness.md).                                                                                                                                 |
| [DiffuseAlphaChannel](/engine/6000.7/script-reference/unityengine/terrainlayersmoothnesssource/diffusealphachannel.md)                           | Smoothness value comes from the alpha channel of [\_diffuseTexture](/engine/6000.7/script-reference/unityengine/terrainlayer/diffusetexture.md).                                                                                                    |