# init(weightNames:name:from:to:by:duration:timing:isAdditive:bindTarget:blendLayer:repeatMode:fillMode:trimStart:trimEnd:trimDuration:offset:delay:speed:) Creates an animation that blends between a configuration of blend targets. ``` init(weightNames: [String], name: String = "", from: Value? = nil, to: Value? = nil, by: Value? = nil, duration: TimeInterval = 1.0, timing: AnimationTimingFunction = .linear, isAdditive: Bool = false, bindTarget: BindTarget? = nil, blendLayer: Int32 = 0, repeatMode: AnimationRepeatMode = .none, fillMode: AnimationFillMode = [], trimStart: TimeInterval? = nil, trimEnd: TimeInterval? = nil, trimDuration: TimeInterval? = nil, offset: TimeInterval = 0, delay: TimeInterval = 0, speed: Float = 1.0) ``` ## Parameters `weightNames` The names of the weights in the animated blend shape. `name` A unique name for the animation. `from` The state of the target object’s weights before the animation starts. `to` The state of the target object’s weights after the animation finishes. `by` An amount that increments the animated weights during the animation. `duration` The total playback time. `timing` An option that determines the animation’s pace over time. `isAdditive` A Boolean value that indicates whether the animation blends additively with concurrent animations. `bindTarget` A textual name that identifies the particular property that animates. `blendLayer` The order in which the framework composites the animation into the view. `repeatMode` An option that determines how the animation repeats. `fillMode` The playback behavior outside of the normal duration. `trimStart` The optional time, in seconds, at which the animation plays. `trimEnd` The optional time, in seconds, at which the animation stops. `trimDuration` An optional duration that overrides the calculated duration. `offset` The time, in seconds, at which the animation begins within the duration. `delay` An amount of time that elapses before the animation plays. `speed` A factor that increases or decreases the animation’s rate of playback. --- 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)