Adding virtual bones causes the engine to crash using Synty characters

Development Character & Animation
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1

I’m trying to properly convert my Synty assets to work with ALS (Advanced Locomotion System).

I can successfully add virtual bones to other skeletons I have in my project, such as the UE5 mannequin and another skeleton from an animation asset.

However, when tying to add a virtual bone with the Synty skeleton, the engine crash with the following error message:

Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:C:\Program Files\Epic Games\UE_5.1\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 763] Array index out of bounds: 56 from an array of size 56

I’m pretty sure it’s because the Synty skeleton has a few missing bones (it has only 3 fingers instead of 5).
Is there a fix, workaround or anything else I could do to help?

Thanks!

1 Like
2

same issue

3

If you are using “retarget pose from mesh” in your animation blueprint (you probably are with ALS), disconnect that node, compile anim blueprint and then add virtual bones to your skeleton. Worked for me with the same issue.

1 Like
4

I do not have a retarget pose in my ALS BP, but still getting a crash with the error:
Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 771] Array index out of bounds: 342 from an array of size 342

EDIT. I simply unhooked it at the end to the output block…

5

I simply reopened the project into an empty map and made sure not to reopen previous animBP tabs, that fixed it for me