Problem with cooking assets with conditionals in nested subsequences

Development Cinematics & Media
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1

Background

For our UE 5.5.4-based project, we are utilizing Subsequences. We have noticed a strange behavior.

If you have a Sequence which has Subsequence tracks with Scene conditions on them, the sequence asset cooks just fine.

If you have a Sequence which has a subsequence track which also has subsequence tracks and THOSE tracks in the nested sequence have conditionals, the cook fails with the following message:

LogWindows: Error: appError called: Can't save 'TopLevelSequence.uasset': Illegal reference to private object: 'MovieSceneSubTrack SubSequence0.SubSequence0: MovieScene_0.MovieSceneSubTrack_1' referenced by 'CompiledData' (at 'TopLevelSequence.TopLevelSequence') in its 'Condition' property.

I’ve replaced project-specific names with generic names.

I have noticed that this error is really similar to this change in github, related to Timewarp tracks.

We are seeing the same cook error when cooking via the editor and on our CI solution.

I may have missed a separate post, but I tried looking about the forum before making this post, to try to avoid potentially duplicating the issue.

Are we abusing Subsequences, or is this a bug?

Thanks so much in advance for your help!

2

Steps to Reproduce

  • Create a LevelSequence, SequenceA.
    • Add Sub Sequence tracks, reference other LevelSequences and add Scene conditions to those tracks.
  • Create yet another Level Sequence, MainSequence
    • Add a SubSequence Track and reference SequenceA.
  • Try to cook your assets. The error shared above ought to show when the cook operation fails.
3

Hey there,

Apologies for the delay in response, Epic was on a summer break. There is a bug that we have logged internally for the one you noted, but it is the same issue.

There isn’t really a way to get around it at the moment.

Dustin

4

Unfortunately, we don’t have too much in terms of guidance here at the moment. It’s possible that the track or conditionals would need to be checked that they are being constructed and saved as weak pointers. The only work around suggestion I have is not to have have conditional tracks nested at the moment, knowing that could be deeply inconvenient for you.

Dustin

5

Due to the nature of this bug, I wouldn’t expect it to be included in a 5.6.x release. However, after discussing this bug with the development team, I believe they are interested in addressing it as soon as possible.

6

Thanks, we ended up moving the project to 5.6 in the meantime.

7

Updating: We are still encountering this issue in 5.6 specifically with scene conditions on subsequence tracks of subsequences.

8

Would you be able to advise on what needs to be solved, and where? I can take a stab at getting this addressed for us in the short term.

9

Thanks for the quick and honest reply and no worries at all. We’re thinking the same, in terms of your suggested workaround. It at least will get us to a good place.

I’ll be interested to hear when a solution does come in!

Really appreciate the help!

10

One more question for right now:

What is the priority of the internally tracked bug? Is this something we could hope to see in any upcoming 5.6.x release?

B