How to animate a transform in RealityKit

问题

In my previous question I already found how to put a rotation transform over only one axis on an object, now I want this to be animated.

Is there a way to do this in RealityKit?

回答1:

Here's how you can animate object in RealityKit (for simplicity I made it using macOS app):

import RealityKit

class ViewController: NSViewController {

    @IBOutlet var arView: ARView!
    let boxAnchor = try! Experience.loadBox()

    override func awakeFromNib() {

        boxAnchor.steelBox?.scale = [10, 10, 10]

        let rotation = Transform(pitch: 0, yaw: 0, roll: .pi)

        boxAnchor.steelBox?.orientation = rotation.rotation

        arView.scene.anchors.append(boxAnchor)

        boxAnchor.steelBox?.move(to: rotation,
                         relativeTo: boxAnchor.steelBox,
                           duration: 5.0,
                     timingFunction: .linear)
    }
}

Or you can use an animationPlaybackController to play a ready animation made in 3D app:

import RealityKit

class ViewController: NSViewController {

    @IBOutlet var arView: ARView!

    override func awakeFromNib() {

        do {
            let robot = try ModelEntity.load(named: "drummer")

            let anchor = AnchorEntity(world: [0, -0.7, 0])

            anchor.transform.rotation = simd_quatf(angle: .pi/4, 
                                                    axis: [0, 1, 0])
            arView.scene.anchors.append(anchor)

            robot.scale = [1, 1, 1] * 0.1

            anchor.children.append(robot)

            robot.playAnimation(robot.availableAnimations[0].repeat(), 
                                transitionDuration: 0.5, 
                                      startsPaused: false)
        } catch {
            fatalError("Cannot load USDZ asset.")
        }
    }
}

回答2:

Rotation with animation:

copy the box's current transform

var rotationTransform = boxAnchor.steelBox?.transform

set the box to rotate 90 degrees over z-axis

rotationTransform?.rotation = simd_quatf(angle: .pi/2, axis: [0,0,1])

move the box to the new transform over 10s

boxAnchor.steelBox?.move(to: rotationTransform!, relativeTo: boxAnchor.steelBox?.parent, duration: 10, timingFunction: .easeInOut)

Translation with animation:

var translationTransform = boxAnchor.steelBox?.transform

translationTransform?.translation = SIMD3<Float>(x: 5, y: 0, z: 0)

boxAnchor.steelBox?.move(to: translationTransform!, relativeTo: boxAnchor.steelBox?.parent, duration: 10, timingFunction: .easeInOut)

Scale with animation:

var scaleTransform = boxAnchor.steelBox?.transform

scaleTransform?.scale = SIMD3<Float>(x: 1, y: 1, z: 1)

boxAnchor.steelBox?.move(to: scaleTransform!, relativeTo: boxAnchor.steelBox?.parent, duration: 10, timingFunction: .easeInOut)

来源：https://stackoverflow.com/questions/59335075/how-to-animate-a-transform-in-realitykit

标签

swift

xcode

animation

transform

realitykit