Playing USDZ skeletal animation in RealityKit from a separate file

Question

I am trying to play a specific skeletal animation on my 3D object (loaded from a USDZ file). The animation file is also in format of USDZ.

I tried the following:

Entity.loadAsync(contentsOf: Bundle.main.url(forResource: "Character", withExtension: "usdz")!)
            .append(Entity.loadAsync(contentsOf: Bundle.main.url(forResource: "Animation", withExtension: "usdz")!))
            .collect()
            .sink(receiveCompletion: {
                if case .failure(let error) = $0 {
                    print(error)
                }
            }, receiveValue: { data in
                let character = data[0]
                self.anchorEntity?.addChild(character)

                DispatchQueue.main.asyncAfter(deadline: .now() + 5) {
                    let animationEntity = data[1]
                    animationEntity.transform.matrix = character.transform.matrix
                    if let animation = animationEntity.availableAnimations.first {
                        character.playAnimation(animation, startsPaused: false)
                    }
                }
            })
            .store(in: &self.cancellables)

I am seeing these in the console:

[Animation] Invalid bind path: Ann_Body_anim_Neutral.RootNode.root.Root_M_bnd.Spine1_M_bnd.Spine2_M_bnd.Spine3_M_bnd.Chest_M_bnd.Scapula_R_bnd.Shoulder_R_bnd.Elbow_R_bnd.Transform.transform

 [Animation] Invalid bind path: Ann_Body_anim_Neutral.RootNode.root.Root_M_bnd.Spine1_M_bnd.Spine2_M_bnd.Spine3_M_bnd.Chest_M_bnd.Scapula_R_bnd.Shoulder_R_bnd.ShoulderPart1_R_bnd.Transform.transform

[Animation] Invalid bind path: Ann_Body_anim_Neutral.RootNode.root.Root_M_bnd.Spine1_M_bnd.Spine2_M_bnd.Spine3_M_bnd.Chest_M_bnd.Scapula_R_bnd.Shoulder_R_bnd.ShoulderPart2_R_bnd.Transform.transform
 ...

It seems that the transform is different between the animation file joints/nodes and the character ones.

Is there any way to fix this in code? If not, how I can make it work?

I am receiving the animation as FBX file and then I am converting it into gtlf using the fbx2gltf tool, then I am converting the gltf into usdz using usdzconvert.

let task = Process()
        task.executableURL = Self.fbx2gltfBinURL
        task.arguments = [
            "-i",
            url.path,
            "-o",
            temporaryURL.path,
            "-b",
            "--blend-shape-normals",
            "--blend-shape-tangents",
            "--fbx-temp-dir",
            temporaryDirectory.path,
        ]
        
        try task.run()

Playing USDZ skeletal animation in RealityKit from a separate file

0 Answers0