Bug What is the relationship between Animator.velocity and AnimationStream.velocity?

Recently, I have been using Playable to create a new animation controller, and I am using AnimationScriptPlayable (ASP for short) to perform some motion corrections. However, I have noticed that in some cases, the corrections made by ASP do not take effect, and the values of Animator.velocity and AnimationStream.velocity are inconsistent.

For example, I have created a PlayableGraph with the following connections (→ represents the direction of Playable output):

AnimationClipPlayable → ASP → AnimationPlayableOutput


When no AnimationClip is assigned to the AnimationClipPlayable , the motion corrections made by ASP will take effect. However, when an AnimationClip is assigned to the AnimationClipPlayable , the motion corrections made by ASP will not take effect.

There is more information in these two posts:

• https://forum.unity.com/threads/ani...nnot-strip-the-velocity-of-its-input.1410405/
• https://forum.unity.com/threads/how...ut-affecting-the-characters-position.1408411/

 

Sample code:

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Animations;
3. using UnityEngine.Playables;
4.  
5. public struct ModifyMotionJob : IAnimationJob
6. {
7.     public void ProcessAnimation(AnimationStream stream) { }
8.  
9.     public void ProcessRootMotion(AnimationStream stream)
10.     {
11.         stream.velocity = Vector3.zero; // force zero velocity
12.         //stream.angularVelocity += Vector3.up * 180 * Mathf.Deg2Rad;
13.     }
14. }
15.  
16. [RequireComponent(typeof(Animator))]
17. public class Test : MonoBehaviour
18. {
19.     public AnimationClip clip;
20.  
21.     private Animator _animator;
22.     private PlayableGraph _graph;
23.  
24.  
25.     private void Awake()
26.     {
27.         _animator = GetComponent<Animator>();
28.         _graph = PlayableGraph.Create("ASP Test");
29.         _graph.SetTimeUpdateMode(DirectorUpdateMode.GameTime);
30.  
31.         var acp = AnimationClipPlayable.Create(_graph, clip);
32.         var asp = AnimationScriptPlayable.Create(_graph, new ModifyMotionJob());
33.         asp.AddInput(acp, 0, 1f);
34.         var output = AnimationPlayableOutput.Create(_graph, "Animation", _animator);
35.         output.SetSourcePlayable(asp);
36.  
37.         _graph.Play();
38.     }
39.  
40.     private void OnDestroy()
41.     {
42.         _graph.Destroy();
43.     }
44.  
45.     private void OnAnimatorMove()
46.     {
47.         //_animator.velocity is not zero
48.         transform.rotation *= _animator.deltaRotation;
49.         transform.position += _animator.deltaPosition;
50.     }
51. }

 

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