Animation blueprint children causing editor crash

I am working on a multiplayer game, and recently decided to make a parent animation blueprint to handle the shared functions between the characters, with child classes to specify animations per character. This setup works great, and would surely save me a lot of time. The issue is that once I switch a character blueprint to use one of the child animation blueprints, I can no longer compile my character blueprints without crashing the editor.

My class hierarchy works like this:

For character blueprints:
MyGameCharacter → PlayerCharacter → SamuraiCharacter

For animation blueprints:
MyPlayer → Samurai

Using the MyPlayer parent animation blueprint causes no issues. All my blueprints can compile and the game simulates without error. However, switching SamuraiCharacter to use the Samurai animation blueprint instantly causes the MyGameCharacter and PlayerCharacter classes to crash the editor if they are compiled for any reason, with or without changes. The SamuraiCharacter blueprint can still be modified without issues, but all other character classes will crash the editor.

The Samurai animation blueprint is completely empty (besides running parent update animation) and contains no overrides for testing purposes. Using this child blueprint anywhere causes crashes.

I had gotten to this point earlier in the week and experienced the exact same problem. I reverted my project to before I started messing with animation blueprints, figuring that there was probably a reference error somewhere I couldn’t trace. Starting from the beginning, I was able to produce an identical scenario, and have now isolated the problem to be something with animation child blueprints.

The error message is below:

Assertion failed: ((UObject*)ContainerPtr)->IsA((UClass*)GetOuter()) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.9\Engine\Source\Runtime\CoreUObject\Public\UObject\UnrealType.h] [Line: 308]
‘AnimBP_SequoiaSamurai_C_4’ is of class ‘AnimBP_SequoiaSamurai_C’ however property ‘StructProperty_203’ belongs to class ‘TRASHCLASS_AnimBP_PlayerCharacter_104’

Hi bitvain,

Can you provide your project in a zip file to test here? If small enough you can add as an attachment here. Otherwise you can provide a Dropbox link here or in a private message to me on the forums.

Thanks

Hello Steve,

The Dropbox link is below. It is currently semi-stable, but if you switch the anim blueprint on Char_Sequoia_Samurai to AnimBP_SequoiaSamurai the problems I mentioned will occur.

Thanks

Hi bitvain,

Thank you for sending a sample file, however, I have not been able to reproduce the crash on this end. Here is a picture of how I’ve set up the character per your instructions:

As you can see, I set the Animblueprint to AnimBP_SequoiaSamurai in the Char_Sequoia_Samurai Character Blueprint, compile, and play in editor. If you can think of any other repro steps that I am missing or some additional steps I can take to cause the crash, please let me know.

Thanks

Steve,

Your setup is correct. The Char_Sequoia_Samurai blueprint will compile just fine. The parent classes (PlayerCharacter and MySequoiaCharacter) will not compile without crashing the editor on my end.

Hi Bitvain,

Thank you for supplying the sample project and additional information needed to cross reference this bug with our existing data. After testing with the characters “PlayerCharacter” and “MySequoiaCharacter” I was able to recreate the crash and found that this has been experienced by a few other users as well and has already been reported as a bug: JIRA [20068].

When this issue has been corrected and released, we will notify you with an update to this post.

-Steve H.

Hi Steve,

I was going to post this exact same bug when I saw this… I’m also getting this in the promoted Branch CL2713796 on version 4.11

will the fix make it here also?

Stu

The status of this report is “In progress” and, hence, no Changelist can be determined. When completed, I will update this post and will include the changelist.

Here is the GitHub commit for this fix: https://github.com/EpicGames/UnrealEngine/commit/ad72b1fbaffa3ed732dba14554da8f2c98d21775

This issue has been marked fixed for the 4.10 official release; CL2719945.