---
title: SCNQuaternion
framework: scenekit
role: symbol
role_heading: Type Alias
path: scenekit/scnquaternion
---

# SCNQuaternion

A representation of a quaternion.

## Declaration

```swift
typealias SCNQuaternion = SCNVector4
```

## Discussion

Discussion A quaternion is a mathematical construct useful for describing rotations in three-dimensional space. Although its implementation differs from that of a 4-component vector, you specify a quaternion value using the same fields as an SCNVector4 structure. SceneKit uses unit quaternions (those whose components satisfy the equation x*x + y*y + z*z + w*w == 1) for the orientation property of nodes.

## See Also

### Transforms and Rotations

- [SCNMatrix4](scenekit/scnmatrix4-swift.struct.md)
- [SCNMatrix4](scenekit/scnmatrix4-swift.typealias.md)