Bug Report: Runtime Actor Creation Issue in Unreal Engine 5.3.2
Description:
There is a bug affecting the creation of Actors with Mesh components at runtime in Unreal Engine 5.3.2. This issue only occurs in the Packaged version of the project. The same functionality works perfectly in the Editor.
Details:
The issue arises when using C++ code to dynamically create and configure Actors during runtime. Specifically:
- I have an
ExternalCommunicationManagerthat is responsible for creating drawable entities. - These entities are selected based on a category provided by external input.
- The system assigns an appropriate Mesh and materials to the Actor based on this category.
In the Editor version, this process works as intended, and the Actors are created and rendered correctly. However, in the Packaged version of the project, the Mesh components fail to display and seems not in the game.
I added some UE_LOG to trace everithing in the packaged version of the App and seems that the execution goes into it.
Steps to Reproduce:
- Use C++ to implement an Actor creation system at runtime.
- Assign Mesh components and materials to the Actors based on an external category.
- Run the project in the Editor – the Actors are created and rendered correctly.
- Package the project and run the executable – the issue with the Actors occurs.
Expected Behavior:
The Actors should be created with their Mesh components and materials correctly assigned and displayed, both in the Editor and in the Packaged version of the project.
Actual Behavior:
In the Packaged version, the Actors are not displayed as expected, indicating that the Mesh components or materials are not being set up properly.
Additional Notes:
- This issue seems specific to the runtime behavior in the Packaged version.
- There are no errors or warnings during the packaging process or runtime.
- The Meshes and materials are properly referenced and loaded in the Editor.
Environment:
- Unreal Engine Version: 5.3.2
- Platform: Windows 11 (Packaged build)
Some code of my class that i’m currently using.
void AExternalCommunicationManager::instanceDrawableEntity(ADrawableEntity* elem) {
UStaticMesh ** mesh = staticMeshesTable.Find(elem->category); //UStaticMeshComponent **scene_meshComponent = meshLookUpTable.Find(elem->category);
// TODO: to add the "debug label".
//need to create the Actor into the game
FString id_actor = FString::FromInt(elem->tracking_id);
FName name_in_game = FName(*id_actor);//elem->tracking_id+"";// + " Actor";
AUActorDrawable* new_object = ref_to_world->SpawnActor<AUActorDrawable>(AUActorDrawable::StaticClass(), FVector::ZeroVector, FRotator::ZeroRotator);
new_object->Tags.Add(FName(*id_actor));
#if WITH_EDITOR
new_object->SetActorLabel(name_in_game.ToString());
#else
#endif
if (!mesh)
{
// Not implemented model:
//elem->MeshComponent = NewObject<UStaticMeshComponent>(elem->MeshActorInGame->GetRootComponent(), "SMComp_Ale_NotImpModel", EObjectFlags::RF_Public); //*meshLookUpTable.Find(managerSmooth->c_exclamation_mark_ERRORS)
mesh = staticMeshesTable.Find(this->c_exclamation_mark_ERRORS);
// elem->MeshComponent->SetStaticMesh((*meshLookUpTable.Find(managerSmooth->c_exclamation_mark_ERRORS))->GetStaticMesh());
UE_LOG(LogTemp, Warning, TEXT("ALLERT, an object arrived without the correct C_Category!!! (Arrived %d for composed_id: %d"), elem->category,elem->tracking_id);
}
FName name_mesh = FName("Mesh " + id_actor);
UMaterialInstanceDynamic ** fadeMatr = MaterialMeshesTable.Find(elem->category);
if (!fadeMatr)
{
// Not Implemented Material
fadeMatr = MaterialMeshesTable.Find(this->c_exclamation_mark_ERRORS);
}
if(fadeMatr)
{
new_object->instanceMeshAndGeorefAndOthers(*mesh,cesium_georeference_actor,name_mesh, *fadeMatr);
UE_LOG(LogTemp, Warning, TEXT("Instance MeshAndGeorefAndOthers with fade matr | cat: %d for composed_id: %d"), elem->category, elem->tracking_id);
}
else
{
new_object->instanceMeshAndGeorefAndOthers(*mesh, cesium_georeference_actor, name_mesh, NULL);
UE_LOG(LogTemp, Warning, TEXT("Instance MeshAndGeorefAndOthers without fade matr | cat: %d for composed_id: %d"), elem->category, elem->tracking_id);
}
//NewObject<UStaticMesh>(elem->MeshActorInGame,UStaticMesh::StaticClass(), "Mesh", RF_Public | RF_ArchetypeObject | RF_Transactional, *mesh,true);// NewObject<UStaticMesh>(elem->MeshActorInGame, *mesh, "StaticMesh", RF_NoFlags, *mesh, true, nullptr, true);//
//elem->MeshComponent->GetStaticMesh() = static_Mesh;
//elem->MeshComponent->SetStaticMesh(static_Mesh);
elem->MeshComponent = new_object->MeshComponent;
if (!new_object->MeshComponent->GetStaticMesh())
{
UE_LOG(LogTemp, Warning, TEXT("Tried to set the created static mesh, but nope."));
}
elem->CesiumGlobeAnchor_var = new_object->CesiumGlobeAnchor_var;
elem->ActorInGame = new_object;
elem->can_use_every_objects = true;
ActorsInGameDrawableEntity.Add(new_object);
UE_LOG(LogTemp, Warning, TEXT("ExternalCommManager MeshAndGeorefAndOthers being added to ActorsInGameDrawableEntity | cat: %d for composed_id: %d"), elem->category, elem->tracking_id);
The instanceMeshAndGeorefAndOthers() method:
void AUActorDrawable::instanceMeshAndGeorefAndOthers(UStaticMesh* Mesh, ACesiumGeoreference* cesium_georeference_act,FName name_mesh, UMaterialInterface* matr)
{
if (Mesh != NULL)
{
UStaticMesh * mesh_instance = DuplicateObject<UStaticMesh>(Mesh, this, name_mesh);
this->MeshComponent->SetStaticMesh(mesh_instance);
this->MeshComponent->SetVisibility(true);
//this->MeshComponent->RegisterComponent();
}
if (cesium_georeference_act != NULL)
{
...
...
...
if (matr != NULL)
{
this->fade_material = DuplicateObject<UMaterialInterface>(matr, this, "fade_material"); //TO TEST
MaterialInstance = Cast<UMaterialInstanceDynamic>(this->fade_material);
}
}
}
// Called when the game starts or when spawned
void AUActorDrawable::BeginPlay()
{
Super::BeginPlay();
// attach each single component to this one.
if (RootComponent != MeshComponent)
RootComponent = MeshComponent;
}
// Called every frame
void AUActorDrawable::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
Could you please help me? I have been struggling for days to figure out the issue on my own, but it seems to be a problem with the Engine itself.