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# CHHapticParameterCurve

A curve that you send to a haptic pattern player to alter a property value gradually during playback.

```
class CHHapticParameterCurve
```

## Overview

Parameter curves serve the same purpose as dynamic parameters in that they alter a property value during playback. Unlike dynamic parameters, which change a property value instantaneously, parameter curves interpolate linearly between parameter values to ensure a smooth transition.

![A rising blue line represents how a parameter curve changes the parameter’s value gradually over time, while an orange line shows how dynamic parameters change the parameter’s value immediately.](images/com.apple.corehaptics/media-3197275@2x.png)

For example, a parameter curven’tr haptic intensity modulates the intensity over time, ensuring a smooth transition between the current intensity and the upcoming one. Parameter curves apply to all events in a pattern; it isn’t possible to apply one to only a single event.

## Topics

### Creating a Curve

[`-  initWithParameterID:controlPoints:relativeTime:`](/documentation/CoreHaptics/CHHapticParameterCurve/init(parameterID:controlPoints:relativeTime:))

Creates a parameter curve from its parameter ID, control points, and start time.

[`ControlPoint`](/documentation/CoreHaptics/CHHapticParameterCurve/ControlPoint)

A single control point in a parameter curve.

### Describing the Curve

[`controlPoints`](/documentation/CoreHaptics/CHHapticParameterCurve/controlPoints)

An array containing the curve’s control points.

[`parameterID`](/documentation/CoreHaptics/CHHapticParameterCurve/parameterID)

The parameter ID defining the type of parameter that the curve represents.

[`relativeTime`](/documentation/CoreHaptics/CHHapticParameterCurve/relativeTime)

The time at which this parameter curve is applied, relative to the start time of the pattern.

## Relationships

### Conforms To

[`CVarArg`](/documentation/Swift/CVarArg)

[`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible)

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

[`Equatable`](/documentation/Swift/Equatable)

[`Hashable`](/documentation/Swift/Hashable)

[`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible)

### Inherits From

[`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class)

---

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