# vertexCount

> Number of vertices used by the index buffer of this sub-mesh.

## Definition

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

```csharp
public int vertexCount { readonly get; set; }
```

### Remarks

Together with [SubMeshDescriptor.firstVertex](/engine/6000.7/script-reference/unityengine/rendering/submeshdescriptor/firstvertex.md), this defines the range of vertices that are possibly used by this sub-mesh. You must set the vertex count so that `firstVertex+vertexCount` encompasses the whole range of vertices referenced by the index buffer. For example, if the index buffer contains vertex indices `5,6,100`, then the `firstVertex` needs to be `5`, while `vertexCount` needs to be `96` (100-5+1).

These values are important for any CPU-based mesh processing, for example dynamic batching or CPU skinning.

The [SubMeshDescriptor.bounds](/engine/6000.7/script-reference/unityengine/rendering/submeshdescriptor/bounds.md), [SubMeshDescriptor.firstVertex](/engine/6000.7/script-reference/unityengine/rendering/submeshdescriptor/firstvertex.md) and [SubMeshDescriptor.vertexCount](/engine/6000.7/script-reference/unityengine/rendering/submeshdescriptor/vertexcount.md) values are calculated automatically by [Mesh.SetSubMesh](/engine/6000.7/script-reference/unityengine/mesh/setsubmesh.md), unless [MeshUpdateFlags.DontRecalculateBounds](/engine/6000.7/script-reference/unityengine/rendering/meshupdateflags/dontrecalculatebounds.md) flag is passed.

Additional Resources: [SubMeshDescriptor.firstVertex](/engine/6000.7/script-reference/unityengine/rendering/submeshdescriptor/firstvertex.md).