Line Trace Null Pointer Issue or Destructible Mesh Issue

I updated to 4.18 from 4.16 and now I’m getting editor crashes that didn’t happen before the update.

Fatal error!

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x000002e0

0x00000000E8DFA64F UE4Editor-Engine.dll!SetHitResultFromShapeAndFaceIndex() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\collision\collisionconversions.cpp:379]
0x00000000E8DC9189 UE4Editor-Engine.dll!ConvertQueryImpactHit() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\collision\collisionconversions.cpp:518]
0x00000000E8DD846A UE4Editor-Engine.dll!GeomSweepSingle() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\collision\physxcollision.cpp:1079]
0x00000000E8DFDC8E UE4Editor-Engine.dll!UWorld::SweepSingleByChannel() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\collision\worldcollision.cpp:131]
0x00000000E8E17C74 UE4Editor-Engine.dll!UCharacterMovementComponent::FloorSweepTest() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\charactermovementcomponent.cpp:5925]
0x00000000E8E13049 UE4Editor-Engine.dll!UCharacterMovementComponent::ComputeFloorDist() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\charactermovementcomponent.cpp:5689]
0x00000000E8E17425 UE4Editor-Engine.dll!UCharacterMovementComponent::FindFloor() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\charactermovementcomponent.cpp:5800]
0x00000000E8E262B7 UE4Editor-Engine.dll!UCharacterMovementComponent::PhysWalking() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\charactermovementcomponent.cpp:4531]
0x00000000E8E36F20 UE4Editor-Engine.dll!UCharacterMovementComponent::StartNewPhysics() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\charactermovementcomponent.cpp:2586]
0x00000000E8E220B2 UE4Editor-Engine.dll!UCharacterMovementComponent::PerformMovement() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\charactermovementcomponent.cpp:2121]
0x00000000E8E39054 UE4Editor-Engine.dll!UCharacterMovementComponent::TickComponent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\charactermovementcomponent.cpp:1143]
0x00000000E8DA4B97 UE4Editor-Engine.dll!FActorComponentTickFunction::ExecuteTickHelper<<lambda_a8128609955b5bb0ccb5da311e0c1d1a> >() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\classes\gameframework\actor.h:3100]
0x00000000E8DD12A4 UE4Editor-Engine.dll!FActorComponentTickFunction::ExecuteTick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\components\actorcomponent.cpp:794]
0x00000000E9A0946B UE4Editor-Engine.dll!FTickFunctionTask::DoTask() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:273]
0x00000000E9A0D59B UE4Editor-Engine.dll!TGraphTask<FTickFunctionTask>::ExecuteTask() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:784]
0x00000000006A4825 UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:651]
0x00000000006A4E0A UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:560]
0x00000000006C587E UE4Editor-Core.dll!FTaskGraphImplementation::WaitUntilTasksComplete() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:1330]
0x00000000E9A276A1 UE4Editor-Engine.dll!FTickTaskSequencer::ReleaseTickGroup() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:542]
0x00000000E9A2BEC2 UE4Editor-Engine.dll!FTickTaskManager::RunTickGroup() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:1454]
0x00000000E931CC54 UE4Editor-Engine.dll!UWorld::RunTickGroup() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\leveltick.cpp:760]
0x00000000E9325F98 UE4Editor-Engine.dll!UWorld::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\leveltick.cpp:1408]
0x00000000E7506783 UE4Editor-UnrealEd.dll!UEditorEngine::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1659]
0x00000000E7DB4316 UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:396]
0x000000007A335A26 UE4Editor.exe!FEngineLoop::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3296]
0x000000007A345430 UE4Editor.exe!GuardedMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
0x000000007A3454AA UE4Editor.exe!GuardedMainWrapper() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
0x000000007A352379 UE4Editor.exe!WinMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
0x000000007A353D57 UE4Editor.exe!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253]
0x000000003C932774 KERNEL32.DLL!UnknownFunction []
0x000000003D4D0D51 ntdll.dll!UnknownFunction []
0x000000003D4D0D51 ntdll.dll!UnknownFunction []

I do a couple of traces, but the crash always happens when I apply damage to a destructible mesh and there’s an enemy actor next to it. I’ve noticed that the destructible mesh components hit the enemy actor and push it backwards and the crash happens when the actor lands. I first assumed it must be because of that, but the call stack would suggest otherwise.

The crash does happen if I use my player actor and run into the rubble, too. So, maybe it is a destructible mesh issue? Although, if I tick Enable Impact Damage from the destructible mesh and just run into it, then no crash. It’s gotta have something to do with the line trace.

Ok, as a workaround I messed with the collision settings of the destructible mesh component of my blueprint and now it doesn’t bother any pawns and thus seems to be harmless for now. Not an ideal solution, but I can’t figure out why this was crashing the editor.

Thanks for the reply jimd667!

I’ve tried this, but I haven’t been able to change the destructible mesh collision via blueprint. I assume it would happen something like in the picture below (obviously the exe pin was connected) but this had no effect to the gameplay.

That is strange, maybe have the destructible mesh actors ignore the enemy actors either through collision presets or blueprint. I assume the pieces that fly off the destructible mesh and hit the enemy actor are still bound to the collision set to it when its a whole mesh.

Yeah that’s the way I would do it, what about the other way around? Enemies ignore the breakable mesh, instead of what you have now with the mesh ignoring the enemy, maybe try both at the same time? Hoping someone else can chime in and help cause it might be an issue with 4.18

Hmm, yeah, perhaps that would work, but I’d have to also set it for the player and any future enemies. I’m mainly just wondering what the crash is all about. Why am I getting a null pointer exception? At least there’s a workaround in place at the moment so I don’t need the answer right now, but it would be nice to know what I did wrong if anything.

Hello Ianuarius,

I have a few questions for you that will help narrow down what issue it is that you are experiencing.

Quick questions:

  1. Can you reproduce this issue in a clean project?
  2. If so, could you provide a detailed list of steps to reproduce this issue on our end?
  3. Could you provide screen shots of any settings/blueprints that may be involved (with the reproduction steps)?

Hey Q, thanks for the reply.

I’m going to have to give the clean project a try. That being said, unfortunately I can’t say when I’ll have the time to do that, but I’ll give you an update when I do. :slight_smile:

When you have more information feel free to update the thread and we will be happy to follow up.

Hello Ianuarius,

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will follow up.

Thanks,