Unreal Engine 5.1 ReplicateSubobjectList Not Working

[BeijingDiana]

I’m trying to use the new subobject replicate system,but it’s doesn’t work.

according to documentation (虚幻引擎中的复制子对象 | 虚幻引擎5.1文档)

In constructor

In BeginPlay

Call

engine crashed

I also try to Override IsSupportNetworking() in UObject derived class,return true.
engine stop crash,but RPC and Property replicate not work.

sorry for my poor English,if anyone can help me,really thanks

[IrSoil]

Raw UObjects can’t be replicated by default. For the first thing you can check your logic with AActor class as a base. upd: or just as a struct inside of a character

If it’s works fine (and i guess it is), and you really sure you need custom uobject replication then here is a kind of a guide:

Copypaste of code from related guide

Guide source (ru)
In short:

//myobject.h
// object itself
UCLASS(Blueprintable)
class MYPROPJECT_API UMyObject : public UObject
{
	GENERATED_BODY()
public:
	UMyObject();
	virtual bool IsSupportedForNetworking () const override { return true; };
	void GetLifetimeReplicatedProps (TArray<FLifetimeProperty>& OutLifetimeProps) override;

	UPROPERTY(Replicated, BlueprintReadWrite, Category="Object")
	int MyInteger;
}

//myobject.cpp
UMyObject ::UMyObject ()
{
	bReplicates = true;
}
void UMyObject ::GetLifetimeReplicatedProps (TArray<FLifetimeProperty>& OutLifetimeProps)
{
	Super::GetLifetimeReplicatedProps(OutLifetimeProps);

	DOREPLIFETIME(UMyObject, MyInteger);
}

//myactor.h
// replicateable owner of your object
class MYPROPJECT_API AMyActor : public AActor
{
	GENERATED_BODY()

public:

	AMyActor();

	virtual bool ReplicateSubobjects (class UActorChannel *Channel, class FOutBunch *Bunch, FReplicationFlags *RepFlags) override;

	void GetLifetimeReplicatedProps (TArray<FLifetimeProperty>& OutLifetimeProps) const override;

	virtual void BeginPlay ();

	UPROPERTY(Replicated, BlueprintReadOnly, Category="Object")
	class UMyObject* MyObject;
}

//myactor.cpp
#include "MyActor.h"
#include "Net/UnrealNetwork.h"
#include "Engine/World.h"
#include "Engine/ActorChannel.h"
#include "PATH_TO_YOUR_UObject/MyObject.h"

AMyActor::AMyActor()
{
	bReplicates = true;
}

void AMyActor::GetLifetimeReplicatedProps (TArray<FLifetimeProperty>& OutLifetimeProps)
{
	Super::GetLifetimeReplicatedProps(OutLifetimeProps);

 
	DOREPLIFETIME(AMyActor, MyObject);
}

bool AMyActor::ReplicateSubobjects(UActorChannel * Channel, FOutBunch * Bunch, FReplicationFlags * RepFlags)
{
	bool WroteSomething = Super::ReplicateSubobjects(Channel, Bunch, RepFlags);

	if (MyObject ) WroteSomething |= Channel->ReplicateSubobject(MyObject , *Bunch, *RepFlags);

	return WroteSomething;
}

AMyActor::BeginPlay()
{
	if(HasAuthority()) 
	{
	MyObject = NewObject<UMyObject>(this);
	if(MyObject) UE_LOG(LogTemp, Log, TEXT("%s created"), *MyObject->GetName());
	}
}

But realistically there is a chances there are already a place in engine for handling data you need, like GameState, PlayerState, etc. I suggest checking this guide first before diving into custom uobjects.

Fyi in my project i’m also started from custom uobjects, but after all 95% of code was moved back into engine-provided classes

[BeijingDiana]

Thanks,that’s work.recently I use this method to implement uobject replicate,but UE5.1 add a new system"Subobject Replicate List" according to document,they say you no longer to need override some functions to implement UObject replicate;you can directly use built-in system to replicate uobject derived class.but the new system not work for me.sad thing is,your method will DEPRECATED at next engine update.

sorry for my poor English

[IrSoil]

UE5.1 add a new system

oh, i’m still on 5.0.3 and seems i’m out of the loop, sorry then. Will read about it later

[BeijingDiana]

Solved,I just need Add UPROPERTY(Replicated) Specifier.like property rep