Writing a script to play an additive animation when a character is controlled by timeline.

That question is better asked on the Timeline forum: https://forum.unity.com/forums/timeline.127/

 

Yes, it is possible, although it's not possible to do on the animation track itself. But you can do it by manipulating the underlying playable graph once it is created.

Here's a sample that should help you get started. It adds an additive layer to a timeline animation track via script that attaches to a playable director.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.Animations;
5. using UnityEngine.Playables;
6.  
7. [ExecuteInEditMode]
8. [RequireComponent(typeof(PlayableDirector))]
9. public class PlayAdditive : MonoBehaviour
10. {
11.     private AnimationClipPlayable clipPlayable;
12.  
13.     public AnimationClip clip;
14.     public AvatarMask mask;
15.     public Animator who;
16.  
17.     private double startTime;
18.  
19.  
20.     void Update()
21.     {
22.         if (clip == null || who == null)
23.             return;
24.  
25.         if (!clipPlayable.IsValid())
26.         {
27.             var graph = GetComponent<PlayableDirector>().playableGraph;
28.             if (graph.IsValid())
29.             {
30.                 startTime = graph.GetRootPlayable(0).GetTime(); // capture the current time
31.             }
32.  
33.             for (int i = 0; i < graph.GetOutputCount(); i++)
34.             {
35.                 var output = (AnimationPlayableOutput) graph.GetOutputByType<AnimationPlayableOutput>(i);
36.                 if (output.GetTarget() == who)
37.                 {
38.                     // get the root of the playable graph
39.                     var outputPlayable = output.GetSourcePlayable().GetInput(output.GetSourceOutputPort());
40.  
41.                     // search the subgraph for the layer mixer
42.                     while (outputPlayable.GetInputCount() > 0 && !outputPlayable.IsPlayableOfType<AnimationLayerMixerPlayable>())
43.                         outputPlayable = outputPlayable.GetInput(0);
44.  
45.                     if (outputPlayable.IsValid())
46.                     {
47.                         var layerMixer = (AnimationLayerMixerPlayable) outputPlayable;
48.                         clipPlayable = AnimationClipPlayable.Create(graph, clip);
49.                         var inputIndex = layerMixer.AddInput(clipPlayable, 0, 1);
50.  
51.                         layerMixer.SetLayerAdditive((uint) inputIndex, true);
52.                         layerMixer.SetLayerMaskFromAvatarMask((uint)inputIndex, mask);
53.  
54.                         startTime = GetComponent<PlayableDirector>().time;
55.                     }
56.                 }
57.             }
58.         }
59.  
60.         if (clipPlayable.IsValid())
61.         {
62.             clipPlayable.SetTime(GetComponent<PlayableDirector>().time - startTime);
63.         }
64.  
65.     }
66. }