# CubicKeyframe A keyframe that uses a cubic curve to smoothly interpolate between values. ``` struct CubicKeyframe where Value : Animatable ``` ## Overview If you don’t specify a start or end velocity, SwiftUI automatically computes a curve that maintains smooth motion between keyframes. Adjacent cubic keyframes result in a Catmull-Rom spline. If a cubic keyframe follows a different type of keyframe, such as a linear keyframe, the end velocity of the segment defined by the previous keyframe will be used as the starting velocity. Likewise, if a cubic keyframe is followed by a different type of keyframe, the initial velocity of the next segment is used as the end velocity of the segment defined by this keyframe. ## Topics ### Creating the keyframe [`init(_:duration:startVelocity:endVelocity:)`](/documentation/SwiftUI/CubicKeyframe/init(_:duration:startVelocity:endVelocity:)) Creates a new keyframe using the given value and timestamp. --- 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)