Editor crash when playing Montage after using Motion Warping (with Smart Object)

[carrot_soup (carrot stew)]

(edits for clarity)

Looking for help trouble shooting why I can’t get Motion Warping to work and why it causes a crash upon exiting PIE after attempting to play an Animation Montage (the pawn appears to be deleted from the world).

I am following this video tutorial on setting up a simple Smart Object where the NPC approaches a chair (or in my case, a bench) and sits down in it.

So far I have working:

• Set up a Smart Object that consists of 1 static mesh (a bench) and one Smart Object “slot”
• NPC can scan area for this object, approach one, and then play the desired animation montage (Sit Down, and then loops a sitting Idle).

Now I need the NPC to rotate and orient itself to sit on the bench more naturally facing outward. The video solves this with the Motion Warping feature (starts around 2:17).

I’ve set up everything identically, but after approaching the smart object, my NPC pawn disappears from the world, and the editor crashes.

Here is my blueprint setup inside the event graph of the “sit behavior”:

Things I tried that didn’t help:

• Using transforms from other objects (e.g. Target Point placed in world) and swapping out other static meshes, to rule out an issue with the original bench mesh

• Turning off collision on the bench

• double checked warp point spelling

If I remove all logic related to motion warping and just call the Play Montage directly from the event, everything works fine again.

FWIW, here’s the transform info being passed through. Doesn’t look like anything weird like trying to teleport the pawn to (0,0,0).

I’m running out of ideas of how else to trouble shoot this, any help is appreciated!

[carrot_soup (carrot stew)]

Adding that I believe the crash itself is due to the NPC Pawn getting completely deleted from the world/game. If I use F8 after it disappears from view to check the world outliner without exiting PIE, it is nowhere to be found in the list.

So possibly the montage is bugging out because it has nothing to play itself on, which makes sense. There have also been some cases where the crash did not occur until exiting PIE.

The pawn does not disappear if I remove all Motion Warping logic from the blueprint.

[carrot_soup (carrot stew)]

I think my issue is actually the same as in this post:

End simulation during "Use Claimed Gameplay Behavior Smart Object" Node crashes editor

Go to Epic Games\UE_5.2\Engine\Plugins\Runtime and move the “GameplayBehaviorSmartObjects” to your Plugins project folder. If you don’t have the Plugins folder, create one in the project root folder. Go to GameplayBehaviorSmartObjectsModule\Private\AI\AITask_UseGameplayBehaviorSmartObject.cpp - UAITask_UseGameplayBehaviorSmartObject::Abort, comment out check(OwnerController->GetPawn()); and add if (OwnerController->GetPawn()) check before the AbortBehavior. [image] Do the same in UA…

Would delete this post to avoid redundancy but it’s locked for some reason.

[Panos98]

did this solve your issue ? i tried but with no luck

[carrot_soup (carrot stew)]

I didn’t personally implement the solution in that link from earlier, as I ended up avoiding the crash another way. That said, seems like it should work in theory, as the root issue for me was the same – my Pawn object disappearing.

I never figured out the nuts-and-bolts code reason why my pawn was getting deleted, but I did narrow it down to an issue with my character asset. I am using a pack obtained online, and it had something to do with the import settings on the skeletal mesh (or skeleton, or rig, I’m not sure, unfortunately these aren’t my area of expertise). Something was getting borked during the import process that set the bones’ scales weirdly large (or, the mesh weirdly small?).

For whatever reason, this had not affected anything else so far, such as setting up the animation BP, playing montages, etc. So the issue remained hidden until I began working on the motion warping.

Therefore my theory is it was something to do with the bad data in the skeleton/rig/mesh resulting in some weird/bad math results during the Motion Warping process that for whatever reason led to the pawn getting yeeted from existence.

I experimented with reimporting my meshes under different settings until I found something that now works (i.e. no crash, motion warping works with the model). These are the settings that worked for me:

However, I can’t say whether these settings would necessarily work for anyone else, as it may have to do with the way the models were originally created in Blender. I cracked open one of the .fbx files in Blender, but the scaling and unit proportions all seemed reasonable in there. However, I am not a modeler/animator by trade, so there could be something I was missing.

Anyway, hope this further information is helpful to someone. I am going to relink the post about how to edit the C++ to avoid the crash here so that I can mark this reply as a tentative answer with all the info in one spot.

End simulation during "Use Claimed Gameplay Behavior Smart Object" Node crashes editor

Go to Epic Games\UE_5.2\Engine\Plugins\Runtime and move the “GameplayBehaviorSmartObjects” to your Plugins project folder. If you don’t have the Plugins folder, create one in the project root folder. Go to GameplayBehaviorSmartObjectsModule\Private\AI\AITask_UseGameplayBehaviorSmartObject.cpp - UAITask_UseGameplayBehaviorSmartObject::Abort, comment out check(OwnerController->GetPawn()); and add if (OwnerController->GetPawn()) check before the AbortBehavior. [image] Do the same in UA…

[Panos98]

Thanks for your reply, but unfortunately, it did not work. I am also following the tutorial and don’t understand why this is happening. Probably unreal being unreal, but still does not make sense.