# indexBuffer

> The index buffer that Unity uses to define the ray tracing geometry instance.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine.Rendering](/engine/6000.0/script-reference/unityengine/rendering.md)
* **Assembly:** UnityEngine.CoreModule

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

### Remarks

You can use a common index buffer and vertex buffer to define multiple geometry instances with different properties (for example different materials).

Use `GraphicsBuffer.Target.Index | GraphicsBuffer.Target.Raw` for the [GraphicsBuffer.Target](/engine/6000.0/script-reference/unityengine/graphicsbuffer/target.md) parameter when creating the index buffer from scripts.