Behaviour Tree is Inactive (instead of Simulating)

I have created a new project with a new Pawn actor, controlled by a controller derived from AiController. I also created a BT actor and a blackboard. The BT itself is empty, ie. it only contains the default root node.

In the pawn’s controller actor, event BeginPlay, I call the RunBehaviourTree node on “self”. Now when I play the game in the editor the BT editor shows a big “Inactive” instead of “Simulating”. The debug filter drop down also shows no suitable actor.

Any ideas what I might be missing here?
Are BTs only applicable to Characters?!

Empty BT is “invalid”, and a BT with only the default root node (which is in fact a fake, editor-only node) is invalid. Try adding a composite node and some wait tasks if you want to see if it runs at all.

Also, do not call RunBehaviorTree on BeginPlay. OnPossess is a lot better place of it.



Thanks for the quick reply. After adding a wait task it’s working fine now.

My BT is not empty, and running on OnPossess doesn’t work either, it still says “Steps back: -1”
I’m in version 4.23