# indexBuffer

> The index buffer that Unity uses to define geometries used by ray tracing instances.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine.Rendering](/engine/6000.6/script-reference/unityengine/rendering.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public GraphicsBuffer indexBuffer { readonly get; set; }
```

### Remarks

You can use a common index buffer as a pool to define multiple geometries used by ray tracing instances that have different properties (for example different materials). Use [RayTracingMultiGeometryInstanceConfig.subGeometries](/engine/6000.6/script-reference/unityengine/rendering/raytracingmultigeometryinstanceconfig/subgeometries.md) array to configure index ranges for each geometry.

Specify `GraphicsBuffer.Target.Raw` for the [GraphicsBuffer.Target](/engine/6000.6/script-reference/unityengine/graphicsbuffer/target.md) parameter when you create the index buffer from scripts. If the buffer is also used in rasterization, then add the `GraphicsBuffer.Target.Index` flag.