Import then cancel while file is read leads to potential crash

TM - Interoperability - Oct 6, 2025

1/ Import a file with mootools such as an fbx 2/ while the file is still read, cancel the import Result : may crash few times after (when theoretically the file has finished being read) - not repr ...

Illegal reference to private object when cooking a child level sequence with a time warp track

zComponent - Archive - Apr 28, 2025

Slack: [Link Removed] Another Slack: [Link Removed] Cook error:UATHelper: Cooking (Windows): LogSavePackage: Warning: UATHelper: Cooking (Windows): Referencers of MovieSceneTimeWarpSection /Gam ...

D3D12 uses a lot more memory than D3D11

UE - Graphics Features - Nov 4, 2015

We’re aware of some extra memory usage in the DX12, but 100% more is more than we’ve seen! I think it’s multiple sources that is causing the increase in usage but not all are known. For example, I’v ...

FStateTreeExecutionContext::GetDebugInfoString() outputs wrong info and crashes when using linked state trees

UE - AI - Debugging - Apr 17, 2025

When using State Trees, the AI Debugger can be accessed during play to show information about their current execution state. If a behavior tree is currently in a state that references a linked tree, ...

When PCH is Disabled, Error Occurs in VulkanGenericPlatform.h at Android Build

UE - Graphics Features - Dec 6, 2018

If disable PCH in Target.cs, an error will occur when building for Android. The log is as follows. LogPlayLevel: Error: D:/Build/Release-4_21_0/Engine/Source/Runtime/VulkanRHI/Private/Android/../Vu ...

Vive Trackpad X and Y always return 0

UE - Platform - XR - Feb 3, 2020

Platform-specific input for pad axis in 4.24 leads to missing value in VIVE. in 4.23.1 this is not reproduced. ...

Blueprint processing is heavy in PIE since 4.26

UE - Gameplay - Blueprint - Feb 17, 2021

As the attached image shows, there is no problem in 4.25.4, and the process is noticeably slower in 4.26.1. Also, there is no problem in Standalone. The problem occurs only in PIE. ...

Volumetric Clouds High Quality Aerial Perspective Issue

UE - Rendering - Architecture - Oct 19, 2023

There is a workaround to set r.VolumetricRenderTarget.Mode=1. The lines appear to be coming from the temporal component of the Volumetric Clouds. Each frame, the lines are merged in from the previou ...

Assets on paths with speed parameters are sped up in Path Tracer exports

TM - Rendering - Jul 18, 2025

Reported in SF [Link Removed] In Path Tracer renders, all paths with a speed component (vehicles, bicycles, custom) will render at an increased speed than specified in the exported render. This is ...

Division by zero in FAnimNode_StrideWarping::EvaluateSkeletalControl_AnyThread

UE - Characters - Animation - Sep 29, 2025

When an Actor's CustomTimeDilation is 0.0, functions FActorTickFunction::ExecuteTick() and FActorComponentTickFunction::ExecuteTickHelper() will call AActor::TickActor() and UActorComponent::TickCom ...