---
title: MTLAccelerationStructureInstanceDescriptor
framework: metal
role: symbol
role_heading: Structure
path: metal/mtlaccelerationstructureinstancedescriptor
---

# MTLAccelerationStructureInstanceDescriptor

A description of an instance in an instanced geometry acceleration structure.

## Declaration

```swift
struct MTLAccelerationStructureInstanceDescriptor
```

## Topics

### Creating an instance descriptor

- [init()](metal/mtlaccelerationstructureinstancedescriptor/init().md)
- [init(transformationMatrix:options:mask:intersectionFunctionTableOffset:accelerationStructureIndex:)](metal/mtlaccelerationstructureinstancedescriptor/init(transformationmatrix:options:mask:intersectionfunctiontableoffset:accelerationstructureindex:).md)

### Specifying the instance

- [accelerationStructureIndex](metal/mtlaccelerationstructureinstancedescriptor/accelerationstructureindex.md)

### Specifying the instance transform

- [transformationMatrix](metal/mtlaccelerationstructureinstancedescriptor/transformationmatrix.md)

### Customizing intersection and hit tests for the instance

- [intersectionFunctionTableOffset](metal/mtlaccelerationstructureinstancedescriptor/intersectionfunctiontableoffset.md)
- [options](metal/mtlaccelerationstructureinstancedescriptor/options.md)
- [mask](metal/mtlaccelerationstructureinstancedescriptor/mask.md)

## Relationships

### Conforms To

- [Sendable](swift/sendable.md)

## See Also

### Instance descriptors

- [MTLAccelerationStructureUserIDInstanceDescriptor](metal/mtlaccelerationstructureuseridinstancedescriptor.md)
- [MTLAccelerationStructureMotionInstanceDescriptor](metal/mtlaccelerationstructuremotioninstancedescriptor.md)
- [MTLAccelerationStructureInstanceOptions](metal/mtlaccelerationstructureinstanceoptions.md)
- [MTL4IndirectInstanceAccelerationStructureDescriptor](metal/mtl4indirectinstanceaccelerationstructuredescriptor.md)
- [MTLIndirectInstanceAccelerationStructureDescriptor](metal/mtlindirectinstanceaccelerationstructuredescriptor.md)
- [MTLIndirectAccelerationStructureInstanceDescriptor](metal/mtlindirectaccelerationstructureinstancedescriptor.md)
- [MTLIndirectAccelerationStructureMotionInstanceDescriptor](metal/mtlindirectaccelerationstructuremotioninstancedescriptor.md)