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# update(parameters:)

Defines how the custom force effect computes forces at each physics simulation step.

```
func update(parameters: inout ForceEffectParameters)
```

## Parameters

`parameters`

On input, the rigid body parameters declared in [`parameterTypes`](/documentation/RealityKit/ForceEffectProtocol/parameterTypes).
On output, the computed forces and torques.

---

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