State of Child Actor Component in UE 5.7.2

Development Platform & Builds
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Hello,

We are currently working on a new multiplayer project where using Child Actor Components is very useful for building more complex actors. Think something the lines of building a large ship based on smaller actors, each supporting a component hierarchy.

We have previously encountered issues in earlier versions of UE (4.27, if I remember correctly), and the general sentiment online is to avoid using them. However, given the large amount of updates to the engine, I wonder if this is still the case, or if it these issues have been addressed, making the use of Child Actors as a core part of our game viable.

Any insight would be appreciate before we invest too many resource going in this direction

Thanks

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Steps to Reproduce

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Child Actor Components have not been a high priority throughout UE5. I’ve gather a couple of the known, unresolved bugs with CAC that you can have a look at on the public issue tracker: UE-243412, UE-349951, UE-229282, UE-221432, UE-215536, UE-199646, UE-149185. There are more.

CACs are still usable, but with a lot of caution. For example:

  • There are issues around cooking, while having a different mobility than the parent components
  • There are issues around attaching an actor to a child actor in the map
  • There is an experimental feature cac.ExperimentalAllowPerInstanceChildActorProperties which allows you to select and modify child actors in the level editor. You shouldn’t use it currently, there is a regression since UE 5.6 that we haven’t addressed yet, making the overrides not apply in PIE (even though they apply in standalone and cooked builds).

From my point of view, they are okay to use as long as the child actor itself:

  • Is just a collection of visuals, or the only overrides are property overrides via the ChildActorTemplate property. Construction script can utilize those property overrides.
  • You don’t attach anything to the child actor at editor-time (on the map).
  • They’re not part of a runtime spawned Level Instance.

Those are a lot of caveats though. For other cases, forget about editor-time convenience and spawn the actor hierarchies at runtime.