# indexCount

> The amount of indices from RayTracingGeometryInstanceConfig.indexBuffer that defines this ray tracing geometry instance.

## Definition

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

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

### Remarks

Use -1 to instruct Unity to use all the indices from [RayTracingGeometryInstanceConfig.indexBuffer](/engine/6000.0/script-reference/unityengine/rendering/raytracinggeometryinstanceconfig/indexbuffer.md) when building the acceleration structure associated with the ray tracing instance. If the value is positive, it must be a multiple of 3 and together with [RayTracingGeometryInstanceConfig.indexStart](/engine/6000.0/script-reference/unityengine/rendering/raytracinggeometryinstanceconfig/indexstart.md) it must define a valid range into [RayTracingGeometryInstanceConfig.indexBuffer](/engine/6000.0/script-reference/unityengine/rendering/raytracinggeometryinstanceconfig/indexbuffer.md).