# timingFunctions An optional array of `CAMediaTimingFunction` objects that define the pacing for each keyframe segment. ``` var timingFunctions: [CAMediaTimingFunction]? { get set } ``` ## Discussion You can use this array to apply ease-in, ease-out, or custom timing curves to the points that lie between two keyframe values. If the number of keyframes in the values property is *n*, then this property should contain *n*`-1` objects. If you provide timing information in the [`keyTimes`](/documentation/QuartzCore/CAKeyframeAnimation/keyTimes) property, the timing functions you specify using this property further modify the timing between those values. If you do not assign a value to the [`keyTimes`](/documentation/QuartzCore/CAKeyframeAnimation/keyTimes) property, the timing functions modify the default timing provided by the animation object. If you also specify a timing function in the animation object’s [`timingFunction`](/documentation/QuartzCore/CAAnimation/timingFunction) property, that function is applied first followed by the timing function for the specific keyframe segment. For information on how to create a timing function, see [`CAMediaTimingFunction`](/documentation/QuartzCore/CAMediaTimingFunction). --- 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)