---
title: roll
framework: vision
role: symbol
role_heading: Instance Property
path: vision/vnfaceobservation/roll
---

# roll

The roll angle of a face in radians.

## Declaration

```swift
var roll: NSNumber? { get }
```

## Discussion

Discussion This value indicates the rotational angle of the face around the z-axis. If the request doesn’t calculate the angle, the value is nil.

## See Also

### Determining Facial Orientation

- [yaw](vision/vnfaceobservation/yaw.md)
- [pitch](vision/vnfaceobservation/pitch.md)