Changes in C++ are not reflected in BP as expected

Development Programming & Scripting C++
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1

I encounter weird behavior in UE5.2 when using a mix of C++ and BP. This behavior makes BP unusable for me. Am I doing something wrong? How is this possible?

Steps to reproduce:

(0. Clear Binaries/Intermediate etc if you want)

  1. Create AIController C++ class with this constructor:
AMyAIController::AMyAIController(const FObjectInitializer& ObjectInitializer)
    : Super(ObjectInitializer)
{
    PerceptionComponent = CreateDefaultSubobject<UAIPerceptionComponent>(TEXT("PerceptionComponent"));
    SetPerceptionComponent(*PerceptionComponent);
	
	SightConfig = CreateDefaultSubobject<UAISenseConfig_Sight>(TEXT("SightConfig"));
    SightConfig->SightRadius = 5.0f;
    SightConfig->LoseSightRadius = 1200.0f;
    SightConfig->PeripheralVisionAngleDegrees = FieldOfViewAngle;
    SightConfig->SetMaxAge(0.0f);
    SightConfig->AutoSuccessRangeFromLastSeenLocation = -1.0f;   
    SightConfig->DetectionByAffiliation.bDetectEnemies = true;
    SightConfig->DetectionByAffiliation.bDetectFriendlies = true;
    SightConfig->DetectionByAffiliation.bDetectNeutrals = true;
	
    HearingConfig = CreateDefaultSubobject<UAISenseConfig_Hearing>(TEXT("HearingConfig"));
    HearingConfig->HearingRange = 10000.0f;
    HearingConfig->DetectionByAffiliation.bDetectEnemies = true;
    HearingConfig->DetectionByAffiliation.bDetectFriendlies = true;
    HearingConfig->DetectionByAffiliation.bDetectNeutrals = true;
    HearingConfig->SetMaxAge(0.0f);
	
    GetPerceptionComponent()->ConfigureSense(*SightConfig);
    //GetPerceptionComponent()->ConfigureSense(*HearingConfig);
}

  1. Create BP for this class, save it and close editor

  2. In C++ rename the perception component (from TEXT(“PerceptionComponent”) to TEXT(“AbcPerceptionComponent”))

  3. Build, open editor and try to open Details panel for this perception component in BP. In my case the details panel is empty.

  4. Go back to C++ and rename the perception component back to TEXT(“PerceptionComponent”)

  5. Build, open editor and open Details panel for the perception component. In my case the details panel is not empty anymore.

(Worse:)

  1. Uncomment the line //GetPerceptionComponent()->ConfigureSense(*HearingConfig);

  2. Build, open editor and check the Details panel. Do you find the hearing sense in the configs array? In my case it does not exist.

  3. Create a new BP for the same C++ class. Check the Details panel. The hearing config is included.

This behavior will force me to recreate the BP each time I change the component configuration.

2

While I can’t help with the perception display issues, I will say that it’s a well known issue that renaming components is not well supported and something to avoid (at least when they are default subobjects).

The issue is that when you create the blueprint and save it, that component is “baked” into the blueprint. When you rename it in code and open up the blueprint, it doesn’t create those subobjects again. It just loads them from the file. But because you messed with the defaults, there’s now a mismatch between the components from native and the components on the blueprint which is why it stops showing in the details panel.

1 Like
3

Thanks for the input. Good to know.