Reflected materials on reflected scene graph mesh components are incorrectly initialized

Velocity_Zero · March 10, 2025, 11:40am

Summary

Reflected materials on reflected mesh components (scene graph) cannot be casted to the expted material subclass.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Other

Steps to Reproduce

Create a custom material like m_custom_material (with at least one parameter) and a custom mesh like sm_custom_mesh.

Configure the material slot of the mesh to be m_custom_material.

Compile verse in a SG project to reflect them.
Create a custom component like the following:

using { /UnrealEngine.com/Temporary/SceneGraph }
using { /Verse.org/Simulation }

vz_test_reflected_material_component := class<final_super>(component) {
  OnBeginSimulation<override>(): void = {
    (super:)OnBeginSimulation()

    if (MeshComponent := Entity.GetComponent[mesh_component]) {
      if (ReflectedMeshComponent := sm_custom_mesh[MeshComponent]) {
        Print(ToDiagnostic(ReflectedMeshComponent.CustomMaterial))
        if (CustomMaterial := m_custom_material[ReflectedMeshComponent.CustomMaterial]) {
          Print("Material can be casted")
        } else {
          Print("Material can NOT be casted")
          Print("Overriding the material manually")
          set ReflectedMeshComponent.CustomMaterial = m_custom_material {}
        }
        Print(ToDiagnostic(ReflectedMeshComponent.CustomMaterial))
      } else {
        Print("Wrong mesh component")
      }
    }
  }
}

Add an entity to the scene that uses the custom mesh and add the custom component to it.

Run the simulation.

Here are the logs:

Assets_material /...-c1ab874f1c0b/vz_experiments_LevelInstance_3.vz_experiments:PersistentLevel.LevelEntity.LevelEntity.Entity.experiment_6-sm_custom_mesh_0.__verse_0x793F222D_CustomMaterial ❌UNEXPECTED
Material can NOT be casted ❌UNEXPECTED
Overriding the material manually
experiment_6-m_custom_material /...-c1ab874f1c0b/vz_experiments_LevelInstance_3.vz_experiments:PersistentLevel.LevelEntity.LevelEntity.experiment_6-m_custom_material_2147482645

Expected Result

The cast should succeed.

Observed Result

The cast should not fail.

Platform(s)

UEFN (v34.00)