Clear Blackboard Value node doesn't seem to function

Development Programming & Scripting AI
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1

Hey there,

I’m working on making a behaviour tree and added a new custom task that I’ve named BTTask_ResetBBValue. After finding the Clear Blackboard Value node I was hoping I could use this general node/task to clear any BB value that I needed. But it doesn’t seem to be working at all no matter which Blackboard value I have it hooked up to, the value never resets or gets cleared.

The task itself is a really easy set up, but for testing you’ll obviously need someway to input a value through a behaviour tree yourself.

Am I missing something here? Or is it a bug.

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1 Like
2

Hi there,

Which UE4 version are you using? Can you try promoted binaries from the UE4’s github repo? I’ve just gave it a try and it worked like a charm, but I did some changes in the related code two weeks ago and I might have fixed a bug accidentally :smiley:

Cheers,

–mieszko

3

Please let me know. If it still doesn’t work spare as many details as possible so I can nail it down. Thanks!

4

I was in 4.6 from the launcher at the time. I can try your suggestion once I get back home. Thanks!

5

Doesn’t work for me either in 4.6, I’m using set BB value and set it to null instead.

6

Doesn’t work for me as well in UE4 promoted 2b8bd07e0ec73c55dd00de541825c76ea5a0649d

CodeSpartan’s solution is ok, but it doesn’t work with vectors unfortunately.

7

I found that
in this file: Engine\Source\Runtime\AIModule\Private\BehaviorTree\BlackboardComponent.cpp
in this function:

 void UBlackboardComponent::ClearValue(FBlackboard::FKey KeyID)

there’s this line:

const bool bHasData = EntryInfo->KeyType->WrappedIsEmpty(*this, RawData);

I changed it to

const bool bHasData = !EntryInfo->KeyType->WrappedIsEmpty(*this, RawData);

and the ‘Clear Blackboard Value’ node started working.

8

You’re totally right - it’s a bug! Fixed it. Thanks for pointing it out! Keep it coming :smiley:

Cheers,

–mieszko