Unreal Engine Issues
Unreal Engine Issues
[CrashReport] Assertion failed: Array index out of bounds - GetPhysicsTriMeshData() [modelcomponent.cpp:688]
UE - Simulation - Physics - Oct 30, 2017This is a semi-common crash that has occurred since at least 4.17.1. The callstack is nearly identical to [Link Removed], which was fixed in 4.18.0, however the error message and source context are ...
[CrashReport] UE4Editor_CoreUObject!FScriptArrayHelper::EmptyAndAddUninitializedValues() [unrealtype.h:2703]
UE - Gameplay - Blueprint Compiler - Aug 15, 2017This is a trending crash coming out of the 4.17.0 release. Based on user descriptions, this crash occurs on Play or Compile for affected users. User DescriptionsAgain crashing when I hit playIF I C ...
Add Submix Effect Blueprint Does Not Have Any Effect
UE - Audio - Dec 11, 2020Adding a second effect to the Submix Effect Chain on a Submix works as expected, but when trying to add a Submix Effect via Blueprint, there is no effect. This also applies to "Add Master Submix Ef ...
[CrashReport] Mac crash - TArray<FDeferredMacEvent, FDefaultAllocator>::ResizeGrow
UE - Platform - Apple - Sep 14, 2017This is a somewhat common crash on Mac that has affected users since 4.16. Users have not provided any descriptions of their actions when the crash occurred. Callstack from Log [2017.09.08-05.17. ...
Get Mouse Position Blueprint node returns different values outside of viewport depending on whether it was called from Event Tick, or within an Actor function
UE - Gameplay - Nov 15, 2018There seems to be a discrepancy between the output of Get Mouse Position node depending on whether the node is inside an Actor function or called from Event Tick. If the node is present inside a fun ...
A chaos vehicle that moves at very high speeds with CCD enabled on the vehicle sometimes has a collision response that is abnormal where the vehicle loses a significant amount of speed when colliding with dynamic objects configured as One Way Interaction
UE - Simulation - Gameplay - Dec 16, 2025Context: Continuous Collision Detection (CCD) is being used on a Chaos Vehicle to avoid tunneling issues with certain surfaces as it prevents any missed collisions between fast moving particles and ...
Wrong WPO motion vectors due to Periodic World Space node
UE - Rendering - Graphics Features - May 13, 2026We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...
Control Rig parameters don't function in the AnimBP after the Editor restarts
UE - Anim - Rigging - Control Rig - Jun 14, 2020Control Rig parameters don't function after editor restarts. Also the default values don't function and you need to use an input instead of directly editing the values of the pins. You can work aro ...
Crash when casting to owner from AnimGraph
OLD - Anim - Sep 6, 2016Crash occurs when casting back to the pawn owner from the Anim Graph. In this case, it is being used for "Copy Pose from Mesh" Workaround: Cast to Owner from Event Graph, defining variable as the ...
Race condition in full builds of UE4 engine source
UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 26, 2019This is a race condition caused by how "Clean.bat", a batch file used during rebuilds, tries to manually rebuild the UnrealBuildTool project when it runs. This causes a spam of UnrealBuildTool build ...