Motion blur does not work with ray traced translucency enabled

UE - Graphics Features - Lumen - Jun 1, 2021

Refraction of Ray Traced Translucency in Path Trace View is Incorrect

UE - Graphics Features - Lumen - Apr 8, 2019

Refraction of Ray Traced Translucency in Path Trace View is Incorrect. Found in 4.22 CL# 5660361 and 4.23 CL# 5779284 ...

Memory leak when rendering some meshes with ray tracing enabled

UE - Graphics Features - Jul 19, 2021

This memory leak seems to be caused by the TMemStackAllocator of FRayTracingMeshCommandOneFrameArray. Using the FDefaultAllocator for FRayTracingMeshCommandOneFrameArray works as a workaround. // ...

Media Plate Actor becomes blacked out when set to Spawnable in a Level Sequencer

UE - Virtual Production - Rendering - Jun 7, 2023

saving a media plate actor set to spawnable in a level sequence causes the media plate actor to become black. there are two known workarounds 1. toggling the Media plate to Possessable, and Spawnabl ...

New VR-Basic level triggers Metal validation layer assertion

UE - Platform - Apple - Mar 16, 2020

This was discovered externally and reported on UDN here: https://udn.unrealengine.com/questions/563268/mac-editor-crash-when-disable-ambient-occlusion.html ...

Ray Traced Translucency Option Doesn't Function in Post Process Volume

UE - Graphics Features - Lumen - Aug 16, 2019

Ray Traced Translucency Option Doesn't Work in Post Process Volume. Found in 4.23 Preview 6 CL# 7848402, and 4.24 CL# 8074192 Working as expected in 4.22 CL# 7053642 This is a regression. ...

Lumen reflection distortion

UE - Graphics Features - Lumen - May 30, 2024

Lumen reflections appear distorted depending on the camera orientation. ...

Crash when DFAO is disabled and a lower scalability is used while Distance Field Shadowing is enabled.

UE - Graphics Features - Feb 2, 2016

When enabling Distance Fields for a project and adjusting the cvars to disable DFAO and set a lower Detail Mode will result in a crash. Using the console commands outlined in the steps will work. ...

Translucent Water renders dark with Lumen enabled.

UE - Graphics Features - Ray Tracing - May 30, 2023

Regression tested in 5.1 at CL 23901901 where the issue still occurs. The material will still have the normal and reflective properties. ...

Ray tracing scene doesn't reflect WPO with instance custom data

UE - Graphics Features - Ray Tracing - Sep 19, 2025

When custom instance data is used to calculate WPO in a Material and applied to an ISM the WPO value in the Lumen scene (ray tracing scene) is different than the visible scene resulting in incorrect ...