Changing MaterialQualityLevel causes a crash due to a ShaderMap mismatch in UniformExpressionCache

UE - Rendering - Architecture - Materials - Nov 26, 2025

A crash may occur when changing the MaterialQualitylevel via Scalability due to a race condition. The issue occurs because in ScalabilityCVarsSinkCallback(), when it creates the FGlobalComponentRec ...

Cones for angular constraints not visible is Separate Translucency is disabled

UE - Graphics Features - Apr 14, 2016

A user reported an issue where the cones that represent angular constraints in the PHAT editor are not rendered if Separate Translucency is disabled. This may be related to another issue with Separa ...

[CrashReport] UE4Editor_MeshPaint!MeshPaintHelpers::FillVertexColors()

OLD - Anim - Jun 27, 2017

This is a common crash in the 4.16 release. Users have not provided any descriptions, so additional information is currently unavailable. Source Context 804 elseif (USkeletalMeshComponent ...

Moving a Copy of an Actor from Persistent to Sublevel Dirties Persistent Level

Tools - Aug 18, 2017

Using Alt-Drag to move a copy of an actor from the persistent level to a sublevel (when the sublevel is selected as the current level in the Levels window), the persistent level is getting marked as ...

PostProcessSettings no longer has the Post Process Materials option

UE - Gameplay - Blueprint - Aug 29, 2017

In engine version 4.17 and later the Post Process Materials node is not present. This option allowed for custom Post Process Settings. Other nodes are still present and working as intended. This iss ...

SceneColor in surface material ignores translucent objects

UE - Graphics Features - Sep 22, 2017

Translucent meshes and particles behind an actor who's surface material uses SceneColor node are not rendered properly. Changing the view angle of the camera causes the translucent meshes to "pop" ...

Building lighting after map data is built dirties level

UE - Graphics Features - Oct 5, 2017

There is an issue occurring where after the map built data is made building lighting on a level causes the level to become dirty. this occurs even if anything in the level has not been changed excep ...

Crash Occurs When Attempting to Resume Execution After Hitting a Breakpoint in a BT Task

UE - Gameplay - Oct 6, 2017

When a breakpoint is hit in a BT Task, if you attempt to use CTRL+P to search for and open the BT the task is being run in, try to resume execution, and then return to the original BT Task Blueprint ...

[CrashReport] UE4Editor_Kismet!FQuatRotationMatrix::FQuatRotationMatrix() [quatrotationtranslationmatrix.h:43]

UE - Gameplay - Aug 31, 2018

User comment in crash group:Please Contact me to help fix this. I don't know what else to do. 41 FQuatRotationMatrix(const FQuat& Q) 42 ***** : FQuatRotationTranslationMatrix(Q, FVect ...

Push based fast array with net.PushModelSkipUndirtiedFastArrays not replicating across multiple PIE sessions

UE - Framework - Networking - Sep 19, 2022

The conditions for this bug are fairly specific. The actor must be statically placed, with its only replicated property being the fast array, and net.PushModelSkipUndirtiedFastArrays must be enabled ...