Can Replication Lists of Extended Classes Be Triggered Individually? What is Max Actor Channel Rep Count?

Dear Friendst at Epic,

I am loving UE4, thanks so much!

My first question:

Let’s say I have a reaally big replication list including static arrays and ustructs as well as simple data types (below code is just a theoretical example)

//							Replication List
int32* AVictoryPower::GetReplicationList(uint8* Recent, FPropertyRetirement* Retire, int32* Ptr, UPackageMap* Map, UActorChannel* Channel, FReplicationFlags RepFlags)
	Ptr = Super::GetReplicationList(Recent, Retire, Ptr, Map, Channel, RepFlags);

	//~~~~~~~~~~~~~~~~~~~~~ Landscapes ~~~~~~~~~~~~~~~~~~~~~~
	//Triggers Rep
        //this is a single boolean value
	DOREP(AVictoryPower, LandscapeVisibility_DoRepEverything); 
	//~~~ Static Arrays ~~~
	DOREPARRAY(AVictoryPower, LandscapeHidden);
	DOREPARRAY(AVictoryPower, MoreData);
    DOREPARRAY(AVictoryPower, MoreData2);

	//~~~ UStructs ~~~
	DOREPSTRUCT(AVictoryPower, LandscapeHidden2);
	DOREPSTRUCT(AVictoryPower, Morestructs1);
    DOREPSTRUCT(AVictoryPower, Morestructs2);
    DOREPSTRUCT(AVictoryPower, Morestructs3);
	return Ptr;

Is it true

that if I manage to dirty the single value of LandscapeVisibility_DoRepEverything, which is a boolean, by writing

LandscapeVisibility_DoRepEverything = !LandscapeVisibility_DoRepEverything;

that everything else in the entire replication list will always be replicated?

My Conclusion if The Above Is True

If it is true that the dirtying of a single value causes whole replication list to be sent across network


I assume it is to my advantage to separate out the replication list into different replicating actors

so that there is a minimal chance of an excess of data being sent across the network just because 1 value got dirtied.


Obviously there’d have to be a balance between the number of actors used to separate out a big replication list as there is a limit to how many actor can be replicated simultaneously

Actor Replication Limit

Speaking of which

what is the Actor channel / simultaneous Actor replication limit in UE4?

Replication Lists of Extended Classes

Let’s say I have class like this Character->MyCharacterBase->MyCharacterFinal

each of these classes has a replication list

In relation to all my above questions, you can see why I’d like to know if each replication list gets treated separately!

specifically I am asking

If the replication list of MyCharacterFinal gets triggered by a dirty boolean value

does it also trigger MyCharacterBase and Character’s replication lists?

I see the super:: call, but I am hoping for some sort of magic regarding the replication of alllll data if a single value gets altered :slight_smile:

My Point!

If the replication lists of each superclass are OR CAN BE triggered individually, then I can avoid the actor channel limit and the excessive replication for a single value by separating my actor out into subclasses with individual replication lists depending on the purpose that actor is playing with the particular data is replicating.

Why I am so focused on all this

I need to replicate a looot of info for my game, since it has a built in multiplayer level editor where multiple people can edit the world at the same time.

Tutorial Coming

I will be writing up a tutorial on all this info once you help me get it all sorted out :slight_smile:



The replication system is pretty robust. Only the dirty properties are sent on an actor channel. 1 property being dirty does not force every other property to replicate. GetReplicationList only builds a list of properties to potentially replicate (if they are dirty).

The max actor channel is something ridiculously high, like 10240 channels.

Improving documentation is something we plan to do for networking/replication. I don’t have an estimate for this though.

"GetReplicationList only builds a list of properties to potentially replicate (if they are dirty).

The max actor channel is something ridiculously high, like 10240 channels."


10240 Channels!

And thanks for the explanation of GetReplicationList!

Thanks Dave!