# scheduleParameterCurve(_:atTime:) Schedules a parameter curve to begin transitioning a parameter at a certain time. ``` func scheduleParameterCurve(_ parameterCurve: CHHapticParameterCurve, atTime time: TimeInterval) throws ``` ## Parameters `parameterCurve` The curve along which to vary the parameter. `time` The time at which to begin applying the parameter curve. ## Discussion Scheduling a parameter curve tells the haptic pattern player to vary a parameter gradually along the curve. For example, if the intensity of a haptic pattern is `0` at the time of application, then a curve created to set the haptic intensity to `1` will smoothly hit every single continuous value between `0` and `1` during the transition.  Scheduling a parameter curve is analogous to sending a dynamic parameter with [`sendParameters(_:atTime:)`](/documentation/CoreHaptics/CHHapticPatternPlayer/sendParameters(_:atTime:)); the only difference is that the curve transitions the parameter gradually, whereas the dynamic parameter changes the parameter immediately at a certain time. ```objc CHHapticParameterCurveControlPoint* intensityControlPoint = [[CHHapticParameterCurveControlPoint alloc] initWithRelativeTime:0.1 value:intensity]; CHHapticParameterCurve* intensityCurve = [[CHHapticParameterCurve alloc] initWithParameterID:CHHapticDynamicParameterIDHapticIntensityControl controlPoints:@[intensityControlPoint] relativeTime:0]; NSError* intensityCurveError; [continuousPlayer scheduleParameterCurve:intensityCurve atTime:0 error:&intensityCurveError]; ``` Schedule a parameter curve for one parameter at a time, and specify control points to characterize the curve’s shape. For more information on creating or specifying a parameter curve, see [`CHHapticParameterCurve`](/documentation/CoreHaptics/CHHapticParameterCurve). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)