---
title: axis
framework: simd
role: symbol
role_heading: Instance Property
path: simd/simd_quatd/axis
---

# axis

The normalized axis about which the quaternion’s action rotates.

## Declaration

```swift
var axis: SIMD3<Double> { get }
```

## See Also

### Querying a quaternion’s properties

- [angle](simd/simd_quatd/angle.md)
- [conjugate](simd/simd_quatd/conjugate.md)
- [imag](simd/simd_quatd/imag.md)
- [real](simd/simd_quatd/real.md)
- [inverse](simd/simd_quatd/inverse.md)
- [length](simd/simd_quatd/length.md)
- [normalized](simd/simd_quatd/normalized.md)
- [vector](simd/simd_quatd/vector.md)