Instanced Actors: Editor preview don't show correct relative mesh transforms

UE - Engine Scaling - Mass - May 30, 2026

Context Actors can be converted into Instanced Actors via the IA plugin. During runtime and in the editor, an instanced actor’s visual is generated from the collection of StaticMeshComponents on th ...

Mutable Chaos Cloth breaks when culling mesh affects mesh sections with cloth

UE - Runtime - Mutable - Sep 29, 2026

Encountering an issue since we updated to UE5.8 where characters whose cloth mesh sections have vertices culled will cause mesh degradation in editor and crashes in packaged builds. There are two i ...

Bone names of ~100 characters or longer crash the editor when baking to control rig

UE - ACT Character - Control Rig - May 15, 2025

This is an issue with inconsistencies over rig names and how control names are generated. We expect that a control name will be appended with _CONTROL or _CURVE_CONTROL. But because URigHierarchy: ...

Split Struct pins cause errors when a project is converted to 4.17

UE - Gameplay - Aug 11, 2017

Split Struct pins cause errors when a project is converted to 4.17. You are still unable to split struct pins even if a new variable is created for the struct. Only adding a new variable to the st ...

Unreal Remote 2 does not send information about motion control

UE - Platform - Mobile - Aug 25, 2018

Unreal Remote 2 does not give information on motion control to PC. This is different from the description of the application. Use this application alongside Unreal Engine to view and control the de ...

OSS Steam: SteamSocket listen connections do not work after poll group changes

UE - Online - Oct 25, 2021

In 4.27 the logic in SteamSocket.cpp which is part of the SteamSockets plugin was changed to use Poll Groups instead of a removed API function that checked all children of a listen socket. However,  ...

Animation attributes - user defined structs containing types defined in plugins cannot be registered

UE - Runtime - Animation - Dec 18, 2023

This issue is caused by us forcing user defined structs to be loaded as part of AttributeTypes::Initialize.  That is called after at the ObjectSystemReady run phase during engine initialization howe ...

Packed Level Actors will create ISMs with inverted normals when a portion of static meshes have negative scales. This is apparent with two-sided materials.

UE - World Creation - Worldbuilding Tools - Feb 17, 2025

Packed level actors will create ISM instances with inverted normals when the selection of meshes used to create the packed level actor contains a subset of meshes with negative scales. This is the ...

Volumetric clouds are jagged along mesh edges when Fog Height Falloff is 0

UE - Rendering - Jul 27, 2026

Volumetric clouds are composited against opaque mesh silhouettes at a reduced resolution. A blocky and jagged edge appears along the silhouette. The fog brightness of the clouds also changes abruptl ...

Check() crash in merge tool when using SVN

UE - Gameplay - Blueprint Editor - Oct 21, 2015

A UDN user found a crash in the merge tool when using SVN. https://udn.unrealengine.com/questions/265740/crashbug-with-svn-merging.html The failing check() crash occurs in LoadBaseRev (Merge.cpp): ...