Download

UNREAL UE4 - What is BTree flow control & why makes error logs, when set observers to both?

Hi, I followed this tutorial: Digital Tutors - Introduction to AI and Navigation Systems.

It sets the Behaviour Tree´s Flow control options for every decorator to “observer aborts: both”, this, creates hudge error logs (no crashing but I still get errors), if i choose “self” i get less errors, but still … I could not find any tutorial that explains how to use decorators “Flow control”, then i have no idea what that is or how to avoid this errors. I only discovered many people with the same problems, unsolved, like: (exactly the same error) https://forums.unrealengine.com/deve…rt-both-option

The only solution i have found its, from my Decorator (see image below) disconnect everything from “AND”, if i do that, no errors… BUT i canot set the “attack range” variable at the BTree, so its never true…

What can i do? What Flow Control´s options are? (none, self, lower priority, both), please share BP images for help.

Error logs (repeating multiple times):
Blueprint Runtime Error: Accessed None trying to read property CallFunc_GetBlackboardValueAsActor_ReturnValue from function: ‘PerformConditionCheck’ from node: Print String in graph: PerformConditionCheck in object: BTDecorator_Isinattackrange with description: Accessed None trying to read property CallFunc_GetBlackboardValueAsActor_ReturnValue
Blueprint Runtime Error: Accessed None trying to read property CallFunc_GetBlackboardValueAsActor_ReturnValue from function: ‘PerformConditionCheck’ from node: Return Node in graph: PerformConditionCheck in object: BTDecorator_Isinattackrange with description: Accessed None trying to read property CallFunc_GetBlackboardValueAsActor_ReturnValue