---
title: indexType
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtlaccelerationstructuretrianglegeometrydescriptor/indextype
---

# indexType

The data type of indices in the index buffer.

## Declaration

```swift
var indexType: MTLIndexType { get set }
```

## Discussion

Discussion The index type needs to be MTLIndexType.uint16 or MTLIndexType.uint32. The default is MTLIndexType.uint32.

## See Also

### Configuring index data

- [indexBuffer](metal/mtlaccelerationstructuretrianglegeometrydescriptor/indexbuffer.md)
- [indexBufferOffset](metal/mtlaccelerationstructuretrianglegeometrydescriptor/indexbufferoffset.md)