# DynamicGeometryManualUpdate

> Use this mode when the associated geometry or transformation can change. Call RayTracingAccelerationStructure.UpdateInstanceGeometry to mark the geometry as dirty.

## Definition

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

```csharp
DynamicGeometryManualUpdate = 4
```

### Remarks

If you add a ray tracing instance that uses this mode to a [RayTracingAccelerationStructure](/engine/6000.6/script-reference/unityengine/rendering/raytracingaccelerationstructure.md) and its geometry is dirty, Unity updates the associated geometry acceleration structure (BLAS) when [RayTracingAccelerationStructure.Build](/engine/6000.6/script-reference/unityengine/rendering/raytracingaccelerationstructure/build.md) or [CommandBuffer.BuildRayTracingAccelerationStructure](/engine/6000.6/script-reference/unityengine/rendering/commandbuffer/buildraytracingaccelerationstructure.md) is invoked. After invoking one of these functions, the geometry isn't considered dirty anymore.

Additional Resources: [RayTracingAccelerationStructure.UpdateInstanceGeometry](/engine/6000.6/script-reference/unityengine/rendering/raytracingaccelerationstructure/updateinstancegeometry.md), [RayTracingAccelerationStructure.AddInstance](/engine/6000.6/script-reference/unityengine/rendering/raytracingaccelerationstructure/addinstance.md), [RayTracingAccelerationStructure.CullInstances](/engine/6000.6/script-reference/unityengine/rendering/raytracingaccelerationstructure/cullinstances.md).