---
title: geometryDescriptors
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtl4primitiveaccelerationstructuredescriptor/geometrydescriptors
---

# geometryDescriptors

Associates the array of geometry descriptors that comprise this primitive acceleration structure.

## Declaration

```swift
var geometryDescriptors: [MTL4AccelerationStructureGeometryDescriptor]? { get set }
```

## Discussion

Discussion If you enable keyframe motion by setting property motionKeyframeCount to a value greater than 1, then all geometry descriptors this array references need to be motion geometry descriptors and have a number of primitive buffers equals to motionKeyframeCount. Example of motion geometry descriptors include: MTL4AccelerationStructureMotionTriangleGeometryDescriptor, MTL4AccelerationStructureMotionBoundingBoxGeometryDescriptor, MTL4AccelerationStructureMotionCurveGeometryDescriptor.