No communication from Blueprint to Child Actor Blueprint


I have two BPs (A and B) which are communicating fine via Custom Events. In both BPs I have created a variable which I assigned the other BP to. If I add both to the scene the communication works fine.

Now I add BP A as a child component to a third BP (C) and the Trigger I used in BP A to trigger BP B returns: “Accessed None trying to read property … from function”.

Any Ideas?

My guess: Usually in my details panel of BP A under “Default” I have to assign BP B. Now, if I open BP C and select the child actor BP A in the details panel under Child Actor Component - Child Actor Template - Default I can see my BP B variable but I cant assign anything. It says “Editing this value in a class Default Object is not allowed”. But not sure if my guess is even close to what Im looking for.

Also tried Interfaces with different problems but als no solution.

If you define a Blueprint as a ChildActor component the Parent spawns the child instance of that class. It is the purpose of a ChildActor component to spawn a specific Blueprint and sort of glue two Blueprints together in a Parent Child relationship.
It sounds like you are calling a function on an orphaned child.

To keep things simple you should try to keep the communication going in one direction so e.g. from Parent to the child, however the child can talk to the parent with “GetParentActor”.

If you want to glue two specific instances of Actors together at run-time you could use the Blueprint node “AttachToActor”.

Thanks. Thats it. In my Child BP I do GetParentActor and have now access to the variable in my Parent BP. My third BP (C) can now CastTo my Parent BP and that particular variable.

I tried to reduce the step going through the Parent BP and cast directly to BP C but that didnt work.

But it works this way as well.