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# ringRadius

The major radius of the torus, defining a circle in the x- and z-axis dimensions. Animatable.

```
var ringRadius: CGFloat { get set }
```

## Discussion

In the definition of a torus as a surface of revolution, the ring radius is the distance from the center of a circle (defined by the [`pipeRadius`](/documentation/SceneKit/SCNTorus/pipeRadius) property) to the axis of revolution (the y-axis of the torus’s local coordinate space). Rotating the circle around the axis forms a pipe that follows a ring-shaped path.

The default ring radius is `0.5`. A ring radius of zero or less creates an empty geometry.

You can animate changes to this property’s value. See [Animating SceneKit Content](/documentation/SceneKit/animating-scenekit-content).

---

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