M_Volumetric_Sky_Prototype Material has compile errors

UE - Content - Engine - Mar 17, 2020

The material "M_Volumetric_Sky_Prototype" has numerous compile errors that prevent it from being used. This was reported and tested in 4.25 Preview 2 (CL-12055273) and reproduced in 4.26 (CL-121923 ...

Duplicating BP actors reset edited Variables to Default Value if Variables name start with Chinese Character

UE - Foundation - Core - Jul 29, 2020

Hints: It has no problem in 4.24, only happening in 4.25 It has no problem as long as the Variable name is contained with Alphabat(English characters) fully; or start with Alphabat(A_变量 is fine) ...

Problems in skeletal mesh merge

UE - Editor - Content Pipeline - Asset Build - May 10, 2021

There are a few issues a licensee has found with the skeletal mesh merge operation. See the UDN for more details and the proposed fixes. Note, the issue with the cloth merge is already logged in a ...

bIgnoreAllPressedKeysUntilRelease only applies to keys in the previous mapping

UE - Gameplay - Input - Jun 16, 2022

This is because the RebuildControlMappings function only checks this flag when you have a mapping that was already added, we should apply this for any new mappings as well.  I'll update the repro s ...

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

UE - Graphics 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 ...

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

UE - Anim - Rigging - 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 copying Geometry Cache Track in Sequencer

UE - Anim - Sequencer - Aug 6, 2020

Geometry cache section  will crash in PostLoad when track is copied. See UDN for alternative repro steps and more info on attached repro project. ...

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 ...