Actors can be attached to multiple actors at the same time bug

Development World Creation
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1

To recreate:

  1. Place a empty actor in the world (Actor A), select it, in the details panel in the components list drag and drop any amount of actors

  2. Place another empty actor in the world (Actor B)

  3. Make any blueprint logic that does something like: get all attached actors of Actor A, attach actors to Actor B

  4. Simulate Play

  5. In the World Outliner you will see that it seems to work correctly but when you select Actor A you will see outlines of the child actors even though Actor A has those child actors not anymore as you can see in the world outliner

  6. Now if you destroy Actor A all childs of Actor B will be destroyed!

  • Detaching a actor before attaching it to a new actor does not fix it either

  • Another Bug might be that actors placed in the world that then get attached through blueprint and and then their parent actor deleted does not delete its childs. Well, I don’t know which way should be correct, should the destroying of a parent actor delete also its child or do not delete the childs. Currently there are the 2 ways.

2

Hey Davision,

I attempted to reproduce this but I’m not getting your results. I would like to clarify a couple things.

  • Where are you creating the blueprint setup for attaching? The Event Graph or Construction Script of one of the bps? Or the Level Blueprints?

  • Could you post some screenshots of steps 5-6?

3

Hi Davision,

We haven’t heard back from you in a few days, so we are marking this post as resolved for tracking purposes. If you’re still experiencing this issue, please feel free to post back here with additional information to reopen the post.

Cheers,

TJ

4

It has happened to me that an actor is attached to two other actors at the same time… Everything happens in the BeginOverlap function…

Everything happens very fast. There are several actors (at least three) who are capable of attaching another type of actor…

One of them has the object attached. Then he detaches it.

At that moment there are several actors very close together and overlapping that actor that everyone wants to attach.

The overlap event gets a reference and several actors get to attach the object at the same time.

It’s a multiple overlapping problem.
And it’s a headache to solve.