Question Adding Animation Track\Clip at Runtime

Hello!

I have a timeline that is part of an in-game tutorial sequence. It has numerous tracks, one of which moves an object from point A (off-screen) to point B (any given point on-screen)

This is currently achieved by parenting the object in question and animating that over a fixed distance, but that approach has numerous drawbacks.

I considered moving the object in code whilst also playing the timeline, but this just didn't feel right.

So I've been experimenting with creating a timeline track dynamically, but am struggling to get it working.

Currently I have this (excuse the rough code, I'll tidy\refactor after)...

Code (CSharp):

1. TimelineAsset asset = <Timeline>.playableAsset as TimelineAsset;
2.  
3. TrackAsset existingTrack = <Timeline>.FindTrack("Animation Track (5)");
4. if (existingTrack != null)
5.   asset.DeleteTrack(existingTrack);
6.  
7. AnimationTrack newTrack = asset.CreateTrack<AnimationTrack>("Animation Track (5)");
8.  
9. <Timeline>.SetGenericBinding(newTrack, <TargetGameObject>);
10.  
11. TimelineClip clip = newTrack.CreateClip<AnimationPlayableAsset>();
12. clip.start = 0;
13. clip.duration = 3;
14. clip.CreateCurves("Test");
15.  
16. AnimationCurve xCurve = new AnimationCurve();
17. xCurve.AddKey(n, n);
18. xCurve.AddKey(n, n);
19. clip.curves.SetCurve(String.Empty, typeof(RectTransform), "m_AnchoredPosition.x", xCurve);
20.  
21. AnimationCurve yCurve = new AnimationCurve();
22. yCurve.AddKey(n, n);
23. yCurve.AddKey(n, n);
24. clip.curves.SetCurve(String.Empty, typeof(RectTransform), "m_AnchoredPosition.y", yCurve);
25.  
26. <Timeline>.RebuildGraph();
27.  
28. <Timeline>.Play();

It adds the track to the timeline, but does not animate the object. The timeline track shows a yellow warning triangle and the object inspector reports "No animation clip assigned" (even though double-clicking the track opens up the animation with the correct key frames)

I know it's me doing something silly so any help would be greatly appreciated.

 

When using AnimationTrack, it's better to use

AnimationTrack.CreateClip(AnimationClip clip)

or

AnimationTrack.CreateInfiniteClip(string infiniteClipName)

. In your case, it may be CreateInfiniteClip() I think.
However, is this only an editor thing, or will this also be executed in runtime? The problem is, you can't create an non-legacy animation clip in runtime, after you build the game (the SetCurve() will throw errors).

 

Thanks @tsukimi

I did some more research over the weekend (based on your feedback) and yes, it seems there are numerous limitations and gotchas with the timeline (and my approach)

I eventually came across a custom track sample that Unity bundles with timeline, that is doing exactly what's needed...

https://docs.unity3d.com/Packages/com.unity.timeline@1.6/manual/smpl_custom_tween.html

https://docs.unity3d.com/Packages/com.unity.timeline@1.8/manual/samp-custom-samples.html

I imported the sample and managed to get it working with the tutorial timeline, which is good news. But it's made me re-think my entire approach, so may end up re-designing this anyway.

Thanks again for the info & feedback, it definitely helped.