Extend AnimationPlayableAsset

AnimationPlayableAsset wasn't originally intended to be extended, although that seems like a something that has been requested by several people.

There are plans to give users more control over animation in general, and that will extend to timeline. The ground work for that is just starting now.

As for worries that timeline will never be "finished", it has a dedicated team at Unity. It is actively being worked on and we are always looking for feedback to make it better.

 

The ability to extend AnimationPlayableAsset hasn't explicitly been worked on, but there are several things that have landed since the last post, or will land soon that will help.

• Animation Events are now supported in timeline.
• Animation C# Jobs were recently introduced. We are currently looking at integrating those into timeline. Not quite the callback mechanism, but it would be a way to inject into existing animation tracks.
• You can create your own simple animation tracks. It can be useful where root motion and offsets that typically are needed with character animation aren't needed (UI for example). There you would have fully control over the resulting graph produced.
• Playable Notifications in 2018.3 let you send notifications to a binding. This is a precursor to timeline events.

I quickly tried extending AnimationTrack and AnimationPlayableAsset and injecting a simple script playable into the graph to get a clearer picture of what worked and what didn't, and on the surface it's possible to get something working. But the extended classes don't properly inherit a lot of the customization done for Animation Tracks, so they are more difficult to use (for example, the matching options aren't available and the inspector is not inherited).

I'll post it here if you want to look at the methodology. I built it with 2018.3 (which has improved Animation Tracks).

 

Sorry, no way around that one 2018.2 has better drag and drop support and recognizes ExtendedAnimationPlayableAsset, but it prioritizes AnimationPlayableAsset over ExtendedAnimationPlayableAsset.

 

Yes, it is. Here's an example that replaces them all.

Code (CSharp):

1. var timeline = (TimelineAsset) playableDirector.playableAsset;
2. foreach (var track in timeline.GetOutputTracks().OfType<AnimationTrack>()
3. {
4.      foreach (var clip in track.GetClips())
5.      {
6.            var animPlayableAsset = (AnimationPlayableAsset) clip.asset;
7.            animPlayableAsset.clip = myAnimationClip;
8.      }
9. }
10.  
11. playableDirector.RebuildGraph();

Note that you are modifying the asset in this case, which even in playmode may get saved.