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# accelerationStructureSizes(descriptor:)

Returns the buffer sizes the GPU device needs to build, refit, and store an acceleration structure.

```
func accelerationStructureSizes(descriptor: MTLAccelerationStructureDescriptor) -> MTLAccelerationStructureSizes
```

## Parameters

`descriptor`

An [`MTLAccelerationStructureDescriptor`](/documentation/Metal/MTLAccelerationStructureDescriptor) instance.

## Return Value

A new [`MTLAccelerationStructureSizes`](/documentation/Metal/MTLAccelerationStructureSizes) instance.

## Discussion

---

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