# RayTracingSubGeometryDesc

> Struct describing a single ray tracing geometry using spans of memory in the common vertex and index buffer.

## Definition

* **Type:** Struct
* **Namespace:** [UnityEngine.Rendering](/engine/6000.3/script-reference/unityengine/rendering.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public struct RayTracingSubGeometryDesc
```

## Remarks

When using index buffers, you can specify the sub-geometry range using [RayTracingSubGeometryDesc.indexStart](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/indexstart.md) and [RayTracingSubGeometryDesc.indexCount](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/indexcount.md) with [RayTracingSubGeometryDesc.vertexStart](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/vertexstart.md) being 0 and [RayTracingSubGeometryDesc.vertexCount](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/vertexcount.md) being the total amount of vertices in the vertex buffer.

Additional Resources: [RayTracingMultiGeometryInstanceConfig](/engine/6000.3/script-reference/unityengine/rendering/raytracingmultigeometryinstanceconfig.md).

## Properties

| Property                                                                                                      | Description                                                                                                                                           |
| ------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- |
| [flags](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/flags.md)             | Flags that determine the ray-geometry intersection behavior relative to a material used together with this geometry configuration during ray tracing. |
| [id](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/id.md)                   | An optional identifier for the ray tracing geometry.                                                                                                  |
| [indexCount](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/indexcount.md)   | The amount of indices from an index buffer that defines a ray tracing geometry.                                                                       |
| [indexStart](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/indexstart.md)   | The first index from an index buffer that defines a ray tracing geometry.                                                                             |
| [vertexCount](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/vertexcount.md) | The amount of vertices from a vertex buffer that defines a ray tracing geometry.                                                                      |
| [vertexStart](/engine/6000.3/script-reference/unityengine/rendering/raytracingsubgeometrydesc/vertexstart.md) | The index of the first vertex from a vertex buffer that defines a ray tracing geometry.                                                               |