Unfocused Standalone window has reduced performance

UE - Rendering Architecture - RHI - Aug 25, 2020

User description: When I run two windowed standalone instances to test multiplayer, the unfocused window gets about 2-5 fps...but if I focus on it, smooth 120fps, yet the opposite screen is now onl ...

Crash when spawning actor with no viewport initialized

UE - Editor - Workflow Systems - Nov 22, 2023

If an attempt to spawn an actor is made before the Level Editor Viewport is fully initialized (i.e. before it has had a chance to get rendered at least once), and that actor has no specific Factory ...

Crash when a subsystem calls GetSubsystemArray() on its owner while engine code is iterating on subsystems also obtained through GetSubsystemArray()

UE - Gameplay - Aug 6, 2024

In some occasions, engine code iterates over a certain subsystem type by calling FSubsystemCollection::GetSubsystemArray() and then calling some method on all subsystems of the returned array. This ...

"FVector contains NaN" on packaged builds for Debug configuration

UE - Graphics Features - Lumen - May 6, 2022

Customer Provided Description:This was experienced in UE 5.01 - custom installed engine (No changes to UE code, simply added the Debug build configuration, see the following command): "c:%ue_dire ...

TeleportTo result with Chaos is different from PhysX

UE - Simulation - Physics - Jun 25, 2021

The result with Chaos is not wrong, rather it returns a correct correction vector, that vector is perfectly horizontal to the teleport buried against the landscape mesh. Therefore, teleportation wil ...

Expose light depth and position to Light Functions

UE - Graphics Features - Oct 14, 2019

Users have requested that light depth and light position are made available to Light Function Materials.Light Depth We seem to be calculating the per-pixel distance from the light to the surface in ...

Gauntlet test warnings in QAGame Win64 Development BootTest

UE - Rendering Architecture - RHI - Sep 6, 2023

QAGame Win64 Development BootTest: * Ensure: Ensure condition failed: oldValue == newValue [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\HAL\ThreadingBase.cpp] [Line: 311] oldVal ...

Prevent unnecessary rebuilds of windows resource files

UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 20, 2023

How Necessary are BUILT_FROM_CHANGELIST and BUILD_VERSION in Resource Files? We've been investigating ways to improve the speed of our iterative engine builds, and have found that the vast, vast maj ...

[CrashReport] UE4Editor_Engine!FTextureCacheDerivedDataWorker::BuildTexture() [texturederiveddata.cpp:772]

UE - Graphics Features - Feb 20, 2017

Error message: Access violation - code c0000005 (first/second chance not available) Source Context:757 if (SourceMips.Num()) 758 { 759 FFormatNamedArguments Args; ...

Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI

UE - Simulation - Physics - Destruction - Apr 22, 2025

Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI. The licensee noticed that the Trailing event is not available to BPs. It's expected that the same data avail ...