(Scene Graph) Descendant mesh components cannot be disabled when a duplicate entity ID exists in the entity hierarchy of the mesh component

[Snowfall_Jaden (JadenH)]

Summary

Descendant mesh components cannot be disabled when a duplicate entity ID exists in the entity hierarchy of the mesh component.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Stability

Steps to Reproduce

1. Create an entity prefab component

2. Copy the entities until your hierarchy contains 2 entities, in sequence, with the same ID.

3. Place an entity with a mesh as a descendant of these 2 entities. The outliner should look like this:

   P_NAME
     entity_id_duplicate
       entity_id_duplicate
         mesh_entity
   

4. Add the following component to P_NAME that disables descendant mesh components at game start.

   using { /Verse.org/SceneGraph }
   using { /Fortnite.com/Game }
   
   test_child_mesh_visible_component<public> := class<final_super>(component):
     OnBeginSimulation<override>():void =
       (super:)OnBeginSimulation()
       if:
         FortRoundManager := Entity.GetFortRoundManager[]
       then:
         FortRoundManager.SubscribeRoundStarted(OnRoundStarted)
   
     OnRoundStarted():void =
       for (DescendantMesh : Entity.FindDescendantComponents(mesh_component)):
         Print("Disable Descendant Mesh")
         DescendantMesh.Disable()
   

5. Run the game

Expected Result

The descendant mesh component on mesh_entity should be disabled (not visible).

Observed Result

The descendant mesh component is visible.

Platform(s)

PC

Video

UEFN Scene Graph Duplicate Entity ID Bug

[Rodney_Houle]

I haven’t been able to get two entities with the same ID in the prefab editor. I tried Ctrl + C & Ctrl V, Ctrl D, and Alt Drag with no luck. Do you have any additional information how you got the duplicate IDs? Thanks

[Snowfall_Jaden (JadenH)]

I walk through how to get the duplicate ID in the hierarchy in the video at 54 seconds! https://youtu.be/mAf-o46Yh6s?t=54

Written Steps:

1. Create a hierarchy of entities:

   entity_1
     entity_2
        mesh_entity
   

2. Duplicate entity_1

   entity_1
     entity_2
        mesh_entity
   
   entity_1 <--- The New Copy
     entity_2 <---
        mesh_entity
   

3. Take the descendant entity_2 from the new copy and move it into the original entity_1

   entity_1
     entity_2 <--- MOVE IT UNDER THIS ONE
        mesh_entity
   
   entity_1 <--- The New Copy
     entity_2 <--- MOVE THIS
        mesh_entity
   

Expected:
All entities in the hierarchy should be unique.

Actual:
Entities have the same ID in the hierarchy.

---

NOTE: I suspect the duplicate ID is the cause of the mesh component not being disabled, but it could be a red herring. Regardless, something is causing the mesh component to remain visible when it should not be.

[Rodney_Houle]

Thank you! I was able to reproduce this issue. We will get someone on this.

[ArcaneStudio]

I’m curious how such a critical bug could go unfixed for a month and a half?

[Bug-Reporter]

FORT-945452 has been ‘Closed’. We’re unable to reproduce this issue.