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Cant create blackboard key on new blackboard

I created a new blackboard asset and a new behaviour tree asset, the first ones created for this project. I dont remember if it automatically opened, or I double-clicked. Pretty sure I went into the blackboard first, then swiched tabs to the behaviour tree to set the blackboard asset, and it was already set. I went back to the blackboard and clicked on the NewKey button, and clicking on any of the options didnt do anything, wouldnt even close the dropdown. I SavedAll, and still nothing.

I then looked at the output log, and it was spammed with this error:

LogBlackboardEditor:Error: Trying to delete an entry from a blackboard while no Blackboard Asset is set!

I closed both the behaviour tree and blackboard, and then reopened the blackboard, and was able to make new keys. I remember having this issue in previous versions as well. So not sure whats going on, but was pretty irritating at 4:30am :(

Product Version: UE 4.14
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asked Dec 18 '16 at 11:34 AM in Bug Reports

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avatar image Sean L ♦♦ STAFF Dec 22 '16 at 03:51 PM


After attempting to reproduce this issue, I haven't seen the same behavior occurring on my end. Is this occurring for you in a clean project as well?

avatar image Interitus384 Dec 23 '16 at 01:59 AM

Yes! woah.
Ok, new blueprint project on first person template. In blueprint folder, I created a behaviour tree, then a blackboard.

I opened the blackboard, and was able to create a new key, but the behaviour tree was greyed out, I closed the blackboard.

I opened the behaviour tree, and was able to switch to the blackboard. The key I had previously created was not there, and I was unable to make a new key. I closed the tree.

Opening the blackboard, I could see the previous key, but the behaviour tree was greyed out again.

I checked the output log, and the error was there. At this point, I have not saved the new assets!

Closed the blackboard, saved all. Reopened behaviour tree, switched to blackboard and was able to see the key, and create new ones.

However, If i just open the blackboard, the tree is still greyed out.. Is this part intended? as many trees can use the same blackboard? Anyways, yes I was able to reproduce on a new project. My guess is something to do with it all still being a 'temporary' asset and needing to be saved.

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Thanks for providing your full steps. I've seen the same issue as you after testing, but I do not believe that this is a bug. The reason behind this is because the asset needs to be saved before the added keys will show up.

Having the Behavior Tree be grayed out also seems like intended behavior to me, because the Blackboard can be linked to several Behavior Trees, so if you tried to switch over it wouldn't be possible to determine which of the BT's you wanted to access.

I hope that makes sense, and let me know if you have further questions regarding this issue.

Have a great day

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answered Dec 23 '16 at 03:08 PM

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Sean L ♦♦ STAFF
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