Bug AnimationScriptPlayable cannot strip the velocity of its input

I tried to input an

AnimationClipPlayable

into an

AnimationScriptPlayable

and set the

AnimationStream.velocity

to

Vector3.zero

in the

AnimationScriptPlayable.ProcessRootMotion

method to remove the displacement in the AnimationClip. However, this approach did not work as expected. Although

AnimationStream.velocity

did become

Vector3.zero

, the character still moved, and in the

OnAnimatorMove

method,

Animator.velocity

was also not

Vector3.zero

.

Why are

AnimationStream.velocity

and

Animator.velocity

not equal (without any animation blending)?

What is the relationship between the RootMotion generated in the AnimationClip and

AnimationStream.velocity

? Is it that the RootMotion in the clip is converted to velocity and carried by

AnimationStream

to be passed up the Playable tree? Or is there additional data that caused me to change

AnimationStream.velocity

but not affect the final RootMotion?

If the approach of handling RootMotion with

AnimationScriptPlayable

does not work, do I need to handle RootMotion in

OnAnimatorMove

instead? In this case, should I directly extract

Animator.velocity

, multiply it by

deltaTime

, and add it to the Transform? If our character uses

Rigidbody

, should we modify

Rigidbody.velocity

instead of modifying Transform?

Here is the test code (also attached by file):

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Animations;
3. using UnityEngine.Playables;
4. using UnityEngine.UI;
5.  
6. // AnimationScriptPlayable cannot strip the velocity and angularVelocity of its input
7. // See comment in `AnimJobTest.OnAnimatorMove`
8.  
9. [RequireComponent(typeof(Animator))]
10. public class AnimJobTest : MonoBehaviour
11. {
12.     public AnimationClip clip;
13.     public Text text;
14.  
15.     private Animator _animator;
16.     private PlayableGraph _graph;
17.     private Vector3 _prevPos;
18.  
19.  
20.     // Window/Analysis/PlayableGraph Monitor
21.     // https://github.com/SolarianZ/UnityPlayableGraphMonitorTool
22.  
23.     private void Start()
24.     {
25.         _animator = GetComponent<Animator>();
26.         _graph = PlayableGraph.Create(nameof(AnimJobTest));
27.         _graph.SetTimeUpdateMode(DirectorUpdateMode.GameTime);
28.  
29.         var animClipPlayable = AnimationClipPlayable.Create(_graph, clip);
30.  
31.         var animScriptPlayableA = AnimationScriptPlayable.Create(_graph, new MyAnimJobA());
32.         animScriptPlayableA.AddInput(animClipPlayable, 0, 1f);
33.  
34.         var animScriptPlayableB = AnimationScriptPlayable.Create(_graph, new MyAnimJobB());
35.         animScriptPlayableB.AddInput(animScriptPlayableA, 0, 1f);
36.  
37.         var animOutput = AnimationPlayableOutput.Create(_graph, "AnimOutput", _animator);
38.         animOutput.SetSourcePlayable(animScriptPlayableB);
39.  
40.         _graph.Play();
41.     }
42.  
43.     // private void OnAnimatorMove()
44.     // {
45.     //     // Theoretically, the `FINAL_VEL` should be zero, because it has been stripped in `MyAnimJobA.ProcessRootMotion`,
46.     //     // and in `MyAnimJobB.ProcessRootMotion` , the `JOB_B_VEL_0` is indeed zero.
47.     //     // However, the `FINAL_VEL` is actually a non-zero value, close to the `JOB_A_VEL_1`.
48.     //
49.     //     // Only used to view values during breakpoint debugging
50.     //     var velocity = _animator.velocity; // FINAL_VEL
51.     //     var deltaPosition = _animator.deltaPosition;
52.     //     var rootPosition = _animator.rootPosition;
53.     //     var targetPosition = _animator.targetPosition;
54.     //     var pivotPosition = _animator.pivotPosition;
55.     //     // var bodyPosition = _animator.bodyPosition;
56.     //
57.     //     _animator.ApplyBuiltinRootMotion();
58.     // }
59.  
60.     private void LateUpdate()
61.     {
62.         var currPos = transform.position;
63.         var posChanged = (_prevPos - currPos).sqrMagnitude > Mathf.Epsilon;
64.         _prevPos = currPos;
65.  
66.         text.text = posChanged ? "Has Motion" : "No Motion";
67.         text.color = posChanged ? Color.red : Color.green;
68.     }
69.  
70.     private void OnDestroy()
71.     {
72.         if (_graph.IsValid()) _graph.Destroy();
73.     }
74. }
75.  
76. public struct MyAnimJobA : IAnimationJob
77. {
78.     public void ProcessRootMotion(AnimationStream stream)
79.     {
80.         // var input = stream.GetInputStream(0);
81.         // var inputVelocity = input.velocity;
82.         // var inputPosition = input.rootMotionPosition;
83.  
84.         // Only used to view values during breakpoint debugging
85.         var velocity = stream.velocity; // JOB_A_VEL_0
86.         var position = stream.rootMotionPosition;
87.  
88.         stream.velocity = Vector3.zero;
89.         stream.angularVelocity = Vector3.zero;
90.  
91.         // Only used to view values during breakpoint debugging
92.         var newVelocity = stream.velocity; // JOB_A_VEL_1
93.         var newPosition = stream.rootMotionPosition;
94.     }
95.  
96.     public void ProcessAnimation(AnimationStream stream)
97.     {
98.     }
99. }
100.  
101. public struct MyAnimJobB : IAnimationJob
102. {
103.     public void ProcessRootMotion(AnimationStream stream)
104.     {
105.         // var input = stream.GetInputStream(0);
106.         // var inputVelocity = input.velocity;
107.         // var inputPosition = input.rootMotionPosition;
108.  
109.         // Only used to view values during breakpoint debugging
110.         var velocity = stream.velocity; // JOB_B_VEL_0
111.         var position = stream.rootMotionPosition;
112.     }
113.  
114.     public void ProcessAnimation(AnimationStream stream)
115.     {
116.     }
117. }

 

The topology of the PlayableGraph:

 

A possable solution: https://forum.unity.com/threads/how...ut-affecting-the-characters-position.1408411/

 

Unity has confirmed that this is a bug: https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-36098