# timingFunction The timing function used for all animations within this animation proxy group. ``` var timingFunction: CAMediaTimingFunction? { get set } ``` ## Discussion The NSAnimationContext timing function is analogous to the CATransaction method. Animations initiated through the “animator” proxy syntax, that do not have an explicitly specified timing functions, will inherit the enclosing `NSAnimationContext` instance’s [`timingFunction`](/documentation/AppKit/NSAnimationContext/timingFunction) if it is not `nil` (which is the default). As with the existing [`duration`](/documentation/AppKit/NSAnimationContext/duration) property, changing a timing function causes the same change in the underlying CATransaction instance’s . Also as with the [`duration`](/documentation/AppKit/NSAnimationContext/duration) property, you may change the timingFunction any number of times within a given NSAnimationContext [`beginGrouping()`](/documentation/AppKit/NSAnimationContext/beginGrouping()) and [`endGrouping()`](/documentation/AppKit/NSAnimationContext/endGrouping()) block. Changes to the `timingFunction` will apply to any animations that are subsequently initiated in that NSAnimationContext grouping, until the `timingFunction` is possibly changed again. --- 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)