UE 5.4.1 Crash on PIE

Development Programming & Scripting
1

Hello,

i have a problem updating my Project from 5.2.1 to 5.4.1
Everything works so far, but as i try to PIE it crashes with this error.

Assertion failed: DispatchData.PreviousPositionBuffer != DispatchData.PositionBuffer [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\GPUSkinCache.cpp] [Line: 2056] 



UnrealEditor_Engine!FGPUSkinCache::PrepareUpdateSkinning() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\GPUSkinCache.cpp:2056]
UnrealEditor_Engine!FGPUSkinCache::DoDispatch() [D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Private\GPUSkinCache.cpp:1325]
UnrealEditor_Renderer!TSparseArray<TSetElement<FPrimitiveComponentId>,TSparseArrayAllocator<TSizedDefaultAllocator<32>,FDefaultBitArrayAllocator> >::operator=() [D:\build\++UE5\Sync\Engine\Source\Runtime\RenderCore\Public\RenderGraphBuilder.inl:646]
UnrealEditor_Renderer!UE::Tasks::Private::FTaskBase::TryExecuteTask() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Tasks\TaskPrivate.h:504]
UnrealEditor_Renderer!LowLevelTasks::TTaskDelegate<LowLevelTasks::FTask * __ptr64 __cdecl(bool),48>::TTaskDelegateImpl<`LowLevelTasks::FTask::Init<`UE::Tasks::Private::FTaskBase::Init'::`2'::<lambda_1> >'::`13'::<lambda_1>,0>::CallAndMove() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\Fundamental\TaskDelegate.h:171]
UnrealEditor_Core!LowLevelTasks::FTask::ExecuteTask() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\Fundamental\Task.h:627]
UnrealEditor_Core!LowLevelTasks::FScheduler::ExecuteTask() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Async\Fundamental\Scheduler.cpp:155]
UnrealEditor_Core!LowLevelTasks::FScheduler::WorkerMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Async\Fundamental\Scheduler.cpp:397]
UnrealEditor_Core!UE::Core::Private::Function::TFunctionRefCaller<`LowLevelTasks::FScheduler::CreateWorker'::`2'::<lambda_1>,void __cdecl(void)>::Call() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Templates\Function.h:406]
UnrealEditor_Core!FThreadImpl::Run() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\HAL\Thread.cpp:69]
UnrealEditor_Core!FRunnableThreadWin::Run() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsRunnableThread.cpp:149]

If i remove the Player Skeletons it works fine again.
Does someone have a idea how to solve this issue ?

Greez DarkSoe

2

If this is blocking you, for now you could try going into the Config/DefaultEngine.ini file and setting r.SkinCache.DefaultBehavior=0 and see if it bypasses the assert in the SkinCache.

That would only be a temporary workaround if that prevents the assert as it would impact performance. It would probably be best to get Unreal QA a copy of your skeleton so they could have someone investigate it on their end. I don’t see any recent bugs related to the SkinCache in their bug tracker.

3

Thank you for your reply, we are using Epics UE4 Default Skeletan with own Meshes, but it also happens with the Maniquen so it would not make sense to send this Skeleton Mesh.

And yes i also dont saw any report about a bug, thats why i hope someone has a idea what could cause this issue.

4

I have the exact same issue did you manage to find a solution ?

5

No sorry, the issue still is not solved.

6

So I had the exact same issue, this issue was after I added a body I created in blender, I imported the body from UE5 into blender, changed the mesh and imported it into unreal engine, I also changed the torso for a blouse and a skirt that was high polygon. Anyways, when I reserve engineered the problem I learned that the problem was with that specific metahuman, so I went into the folder that contained it and deleted it and UE5 opened like normal so I would recommend you think back to when the error started happening and what you did right before the error started, you might find your answer

7

the issue does not apear when opening the editor, it happens when you start PIE.
And it does not only happen with custom bodys, it happens also with Manny from EPIC.
And what i did right before it happend, i upgraded from 5.2.1 to 5.4.1.
With 5.2.1 everything still works fine, so i current continue with that engine untill i find a solution.

8

Okay. issue solved by removing all Project Settings that are set besides stuff we are realy sure that cant be the issue like Settings for EOS, Collision or Physics Materials. Now it works.
So it seems to be caused by a setting we did in a previewes Engine version that does not work correctly in 5.4.