---
title: instanceDescriptorBuffer
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtl4indirectinstanceaccelerationstructuredescriptor/instancedescriptorbuffer
---

# instanceDescriptorBuffer

Assigns a reference to a buffer containing instance descriptors for acceleration structures to reference.

## Declaration

```swift
var instanceDescriptorBuffer: MTL4BufferRange { get set }
```

## Discussion

Discussion This buffer conceptually represents an array of instance data. The specific format for the structs that comprise each entry depends on the value of the  instanceDescriptorType property. You are responsible for ensuring the buffer address the range contains is not zero.