# JointTransforms A set of animatable transform values for joints that collectively represent a single skeletal pose. ``` struct JointTransforms ``` ## Overview This structure provides a template that informs an animation on how to animate a character. The resulting movement bases on the *from* ([`fromValue`](/documentation/RealityKit/FromToByAnimation/fromValue-6msd)) , *to* ([`toValue`](/documentation/RealityKit/FromToByAnimation/toValue-813jk)) , or *by* values ([`byValue`](/documentation/RealityKit/FromToByAnimation/byValue-3bp3q)) you supply for a [`FromToByAnimation`](/documentation/RealityKit/FromToByAnimation). The animation determines which joints take on the movement through its [`jointNames`](/documentation/RealityKit/FromToByAnimation/jointNames) property. ## Animate an Entity’s Skeleton The following code moves the joints of a 3D asset by specifying the joint, `joint1`, beginning, and ending values. ```swift // Define the joint's pose at the start of the animation. let fromTransforms: [Transform] = [Transform(scale: SIMD3(1, 2, 3), rotation: simd_quatf(ix: 5.0, iy: 6.0, iz: 7.0, r: 8.0), translation: SIMD3(10, 20, 30))] let fromPose = JointTransforms(fromTransforms) // Define the joint's pose at the end of the animation. let toTransforms: [Transform] = [Transform(scale: SIMD3(10, 20, 30), rotation: simd_quatf(ix: 50.0, iy: 60.0, iz: 70.0, r: 80.0), translation: SIMD3(100, 200, 300)) ] let toPose = JointTransforms(toTransforms) // Indicate that the animation applies to the joint named 'joint1'. let jointNames = ["joint1"] // Configure the animation specifics. var fromToBy = FromToByAnimation() fromToBy.name = "anim" fromToBy.blendLayer = 100 fromToBy.duration = 10.0 fromToBy.fillMode = .forwards fromToBy.jointNames = jointNames fromToBy.fromValue = fromPose fromToBy.toValue = toPose fromToBy.bindTarget = .transform // Generate a resource from the animation. let animationResource = fromToBy.create() ``` To run the animation on an entity and animate the joints, call `playAnimation(_:transitionDuration:startsPaused:)`. Optionally, you can control the animation’s playback by storing the returned controller object. ```swift // Play the animation on an entity. let entity = AnchorEntity(...) let controller = entity.playAnimation(animationResource) // Optionally control playback using the returned controller. controller.pause() ``` ## Topics ### Creating joint transforms [`init()`](/documentation/RealityKit/JointTransforms/init()) Initializes a collection of animatable transforms for a single skeletal pose. [`init(_:)`](/documentation/RealityKit/JointTransforms/init(_:)) Initializes a collection of transforms of a specific type for a single skeletal pose. [`init(arrayLiteral:)`](/documentation/RealityKit/JointTransforms/init(arrayLiteral:)) Initializes a collection of animatable transforms using the argument elements for a single skeletal pose. ### Identifying joint transforms [`JointTransforms.Index`](/documentation/RealityKit/JointTransforms/Index) A position of an individual joint transform in the collection. ### Inspecting joint transform details [`startIndex`](/documentation/RealityKit/JointTransforms/startIndex) An index to the first joint transform in the collection. [`endIndex`](/documentation/RealityKit/JointTransforms/endIndex) An index to the last joint transform in the collection. ### Accessing joint transforms [`subscript(_:)`](/documentation/RealityKit/JointTransforms/subscript(_:)) Accesses a single joint transform in the collection at the given index. [`index(after:)`](/documentation/RealityKit/JointTransforms/index(after:)) Returns the position in the sequence of the joint that follows the given position. [`index(before:)`](/documentation/RealityKit/JointTransforms/index(before:)) Returns the position in the sequence of the joint that preceeds the given position. --- 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)