# BlendIndices

> The indices that map a vertex to specific bones in skinning calculations.

## Definition

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

```csharp
BlendIndices = 13
```

### Remarks

This attribute is optional. Up to four indices can be included in the vertex stream.

Blend weights are commonly represented using integers.

This attribute corresponds to the `BLENDINDICES` semantic in the HLSL shading language.

You can set blend indices for vertices using methods such as [Mesh.SetBoneWeights](/engine/6000.7/script-reference/unityengine/mesh/setboneweights.md).

For more information, refer to [mesh vertex data](/engine/6000.7/manual/assets-and-media/asset-types/mesh/get-started-with-meshes/anatomyofa/vertex-data.md).