---
title: "accelerationStructureSizes(descriptor:)"
framework: metal
role: symbol
role_heading: Instance Method
path: "metal/mtldevice/accelerationstructuresizes(descriptor:)"
---

# accelerationStructureSizes(descriptor:)

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

## Declaration

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

## Parameters

- `descriptor`: An doc://com.apple.metal/documentation/Metal/MTLAccelerationStructureDescriptor instance.

## Return Value

Return Value A new MTLAccelerationStructureSizes instance.

## See Also

### Creating acceleration structures for ray tracing

- [makeAccelerationStructure(descriptor:)](metal/mtldevice/makeaccelerationstructure(descriptor:).md)
- [makeAccelerationStructure(size:)](metal/mtldevice/makeaccelerationstructure(size:).md)
- [MTLAccelerationStructureSizes](metal/mtlaccelerationstructuresizes.md)