Light Leak Issue in Modular Buildings (Lumen HZBTraversal)

UE - Rendering - Graphics Features - Lumen - Oct 14, 2025

Starting in Unreal Engine 5.6, disabling "r.Lumen.ScreenProbeGather.ScreenTraces.HZBTraversal" can lead to light leaking between adjacent or overlapping meshes. Also tested on Release-5.6, CL: 4523 ...

Multi Sphere Trace is not returning the correct Impact Location

UE - Simulation - Physics - Jan 19, 2015

Multi Sphere Trace is not returning the correct Impact Location. Other AnswerHub Report:https://answers.unrealengine.com/questions/30952/multisphere-trace-fhitresult-location-same-as-impa.html ...

Integrity of AnimSyncMarkers compromised while playing AnimMontage with root motion in server side

UE - Anim - Gameplay - Jan 11, 2023

Reference UDN as it explains well the cause of the issue. ...

Crash can occur in the Ansel plugin when setting Use Client Side Camera Updates to false in Player Camera Manager

UE - Graphics Features - Apr 18, 2017

Setting the `bUseClientSideCameraUpdates` property in a `PlayerCameraManager` class to false can result in a crash in the Ansel plugin because `GEngine->GameViewport` may be NULL. Another user has ...

UE 5.4 - Specular/reflection disappears above 4096 resolution render

UE - Rendering - Architecture - Aug 1, 2024

After a viewport is more than 4096 pixels wide, Lumen's specular reflections buffer cuts its width off at 4096 pixels. It appears that the affected buffer is "Lumen.Reflections.ResolvedSpecularIndi ...

Creating a new Physics Asset will override the behavior of the previous Physics Asset inside the Phat Editor

UE - Gameplay - Aug 11, 2016

Creating a new Physics Asset will override the behavior of the previous Physics Asset inside the Phat Editor. This seems to be linked to which physics asset is currently assigned to the skeletal me ...

Translucent User Interface materials do not have a thumbnail preview

Tools - Feb 15, 2018

Translucent User Interface materials do not have a thumbnail preview. I do not see this issue with Translucent Surface materials. REGRESSION: No, this issue also occurs as far back as 4.17.2 ...

Inclusive Nativized Blueprints slower than Non Nativized Blueprints in packaged project

UE - Gameplay - Jul 1, 2019

When nativizing blueprints the packaged build of the project runs slower than a non-nativized version of the packaged project. Found in 4.22 CL#7053642 Reproduced in 4.21 CL#4753647, 4.24Main CL#7 ...

Distant mesh / vista have visible Lumen bounces

UE - Rendering - Architecture - Jun 15, 2024

Objects far outside of the Lumen Scene don't temporally accumulate screen traces, leading to heavy flickering. It appears that the temporal reprojection is failing when comparing the depth in "Scree ...