Let AI move in the last known target's movement direction

Development Programming & Scripting AI
, , , ,
1

Hi, I am kind of stuck with my behavior tree. I’m using an advanced version of the Quick Start behavior tree guide (https://docs.unrealengine.com/latest/INT/Engine/AI/BehaviorTrees/QuickStart/11/index.html). I want the AI controlled pawn to move in the direction of the last known player’s movement direction when the player gets out of sight. The right end of my AggroCheck service looks like:

84382-aggrocheck.png
84382-aggrocheck.png1867×607 205 KB

Each 11 Event Receive Ticks I’m storing the targets location and each Tick with the target in line of sight I am storing a vector to a location where the player seems to go. When I move close to the AI controlled pawn and then directly towards the left the output is the following: (deleted all irrelevant X and Z values)

LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3133.347
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=0.000 
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3322.593 
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3133.347 
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3322.593
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3322.593
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3028.659 
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3322.593 
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3028.659 
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3028.659 
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=2717.122 
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=3028.659 
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=2717.122 
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=2717.122 
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=2393.226 
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=2717.122 
LogBlueprintUserMessages: [AggroCheck_C_1] --------------------
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=2393.226 
LogBlueprintUserMessages: [AggroCheck_C_1]  Y=2393.226

So I can’t see why sometimes in both TargetLastKnownLocations the same value is stored, I never stopped. This would only makes sense to me when the player controlled actor’s location, updated by InputAxis events of the WASD keys, would be less frequently changed than the Event Receive Tick in the AggroCheck Service is called. Beside my try to let the AI move in the last known targets location the behavior tree is working as intended.

2

So i ‘fixed’ this by removing my timer with a condition that checks if the targets location changed and only updates TargetLastKnownLocations when thats true. But I’m still wondering what caused the behavior in the above post.