---
title: stiffness
framework: realitykit
role: symbol
role_heading: Instance Property
path: realitykit/clothbodycomponent/targetshape/positionconstraint/stiffness
---

# stiffness

The stiffness by which the particle is pulled towards the position.

## Declaration

```swift
var stiffness: Float { get set }
```

## Discussion

Discussion In the context of a target shape, this gets multiplied by the weight of the target shape. A stiffness of 0 will effectively inactivate the position constraint. The valid range is [0.0, 1.0], both included. Values outside the valid range are clamped.