Actor Hidden in Game does not take lighting into account any longer

UE - Graphics Features - Jul 13, 2016

Using indirect lighting from bounce cards that are set to Actor Hidden in Game no longer generate indirect lighting for the scene. This is a regression of 4.11.2 where this worked but is no longer ...

Having "Accurate velocities from vertex deformation" enables causes extreme blur on skeletal meshes

UE - Graphics Features - Jan 4, 2016

Having accurate velocities from vertex deformation enabled and a SceneCapture2D in the same project will create blurry skeletal meshes. I am unable to reproduce this with an Nvidia graphics card. T ...

BulkDataManifest asset is non-deterministic

UE - Core - Data Pipeline - Cooker - Jan 11, 2022

FPackageStoreBulkDataManifest:: Data ** is not sorted. It generates a difference, Here's a workaround void FPackageStoreBulkDataManifest::Save() { TUniquePtr<FArchive> BinArchive(IFileManager:: ...

Non-determinism when cooking a UProceduralMeshComponent

UE - Framework - Components - May 21, 2026

We received a report from a licensee that UProceduralMeshComponent cook is not deterministic. This is related to the ProcMeshBodySetup member and the fact the UProceduralMeshComponent code changes t ...

DFAO in 4.9 has significant artifacts on some machines

UE - Graphics Features - Jul 30, 2015

Reported in this threadhttps://forums.unrealengine.com/showthread.php?78320-4-9-Horrible-DFAO-artifacts This looks to be a machine specific issue. I'd like to get some testing on different video c ...

Vulkan leaks memory when opening and closing windows

UE - Rendering - Architecture - RHI - Nov 22, 2019

As described here: https://udn.unrealengine.com/questions/532725/index.html (1) Start Prebuilt Vanilla 4.23.1. with Vulkan enabled (2) Create a new project (3) Drag and drop the Sphere from “modes ...

Unable to run UE4Editor using the -SM4 commandline argument

UE - Graphics Features - Nov 16, 2018

Attempting to run the UE4 Editor using SM4 causes an error to popup stating that "A Feature Level 5 video card is required to run to Editor. AvailableFeatureLevel = SM4, ShaderPlatform = PCD3D_SM4" ...

Virtualized Silent Sounds "Pop" When Played With New Mixer

UE - Audio - Sep 27, 2017

-Could not reproduce and only happens in the project linked below -Tested in 4.16 and Preview 4.18 and this can not be heard -Does not look like the .ini file is the cause of the issue -Other soun ...

Unable to open UE4Editor on Linux - Bad hlslcc header found

UE - Platform - Linux - Nov 4, 2015

UE4Editor does not open on Ubuntu 15.10 due to the following error: [2015.11.04-16.19.35:974][ 0]LogOpenGLShaderCompiler:Error: Bad hlslcc header found! Missing '#'!Error in `./UE4Editor': free(): ...

Projects crashing on launch after converting from 4.7.3 to 4.7.4

UE - Gameplay - Blueprint - Apr 3, 2015

A couple users have reported a crash when opening their 4.7.3 project in 4.7.4. From MikeB:https://answers.unrealengine.com/questions/205043/473-to-474-project-crash-on-startup.html The guy is hit ...