Physics Constraint returns incorrect values for Swing1, Swing2, and Twist

UE - Runtime - Simulation - Jul 7, 2022

Tested in //UE5/Main CL#20966071 Tested in //UE4/Release-4.27 CL#18319896 Physics Constraint returns incorrect values for Swing1, Swing2, and Twist. ...

Disabling bLerpUVs in Nanite Settings of Static Mesh causes texture warping in clusters

UE - Rendering - Features - Nanite - Jan 21, 2025

The licensee has identified a potential fix by changing if( Settings.bLerpUVs ) to if( Settings.bLerpUVs || UVIndex == 0 ) On line 389 of NaniteBuilder\Private\Cluster.cpp in UE 5.5 ...

Poor Vulkan RHIThread performance in Development builds on some Android

UE - Platform - Mobile - Systems - Dec 10, 2024

Community-attempted workaround received in [Link Removed] Closed Correct fix submitted to 5.6 FNMain in [Link Removed] whic ...

Copy-pasting custom property nodes (ControRig etc.) results in invalid bindings, perf issues

UE - ACT Character - Control Rig - Jul 28, 2025

From this UDN: [Link Removed] Suggested fix:Override PostPasteNode to perform the GUID update andAdd validation on load to strip 'invalid' copies that do not correspond to a valid pin input ...

Crash when changing shadow scalability settings to low, then clicking in the viewport

UE - Graphics Features - Jun 9, 2016

A crash occurs after setting the shadow scalabilty settings to "low" then clicking on an item in the viewport. The issue also occurs when setting all of the scalabilty settings to low at one time as ...

Geometry Material Alignment not functioning in 4.8

Tools - Jun 15, 2015

Material Alignment on BSPs are not functioning in 4.8.0 Release. This is a regression from 4.7.6. The issue does appear to be fixed and functional in 4.9 (Promotable-CL-2581018) ...

GameMode::StartNewPlayer calls RestartPlayer() without checking PlayerCanRestart()

UE - Gameplay - Nov 11, 2015

Bug report from UDN thread. https://udn.unrealengine.com/questions/266937/gamemodestartnewplayer-calls-restartplayer-without.html#answer-268579 His point seems sound, we should fix it. ...

[CrashReport] FBX import crash - UE4Editor_UnrealEd!TSet<TPair<unsigned int,FMeshSectionInfo>

Tools - Jan 12, 2017

This crash was introduced in 4.14.2, and is very similar to [Link Removed], however it is still occurring in 4.14.3 (after that fix) According to submitted crash reports, this one is not very wides ...

Editor crash with Japanese ATOK input(candidate list related)

UE - Editor - UI Systems - Localization - Jul 5, 2017

This is probably a continuation from [Link Removed]. [Link Removed] fixed the crash with MS-IME input, but crash/instability can still happen with another Japanese input system, ATOK. ...

Missing some UBX collisions after imported from FBX

Tools - May 15, 2018

If move those UBX collision closer to the visual mesh, it kind could fix the problem, but still wondering if it's a bug or limitation; what's the reason behind it and how artist could avoid those pr ...