# buildFlags

> The build flags Unity uses to build a RayTracingAccelerationStructure.

## Definition

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

```csharp
public RayTracingAccelerationStructureBuildFlags buildFlags { readonly get; set; }
```

### Remarks

For acceleration structure implementations that use a two-level hierarchy, for example DirectX Raytracing (DXR), Unity uses these flags to build the top-level acceleration structure (TLAS).

To customize the flags Unity uses to build the bottom-level acceleration structures (BLAS), use [Renderer](/engine/6000.3/script-reference/unityengine/renderer.md) settings or the parameters in the [RayTracingAccelerationStructure.AddInstance](/engine/6000.3/script-reference/unityengine/rendering/raytracingaccelerationstructure/addinstance.md) method.