Crash upon using marquee selection in Anim Graph while debugging

UE - Gameplay - Blueprint - Apr 20, 2016

A user reported a crash that occurs only in Debug Editor, related to the Anim Graph of an Animation Blueprint. The issue involves marquee selecting multiple nodes inside of a State Machine transitio ...

Ledge Movement Stuck (CheckLedgeDirection is always returning true)

UE - Gameplay - Nov 20, 2023

The issue appears to that CheckLedgeDirection almost always returns true, which returns the leftward side step. This is correct for the leftward direction, but is not valid for the rightward directi ...

Rebuild (with hot reload) fails on newly-created projects

UE - Foundation - Cpp Tools - Hot Reload - Jan 18, 2018

Performing a Rebuild with a hot reload on a brand new code project will fail unless both the Editor and Visual Studio have first been closed and then re-opened. The same result occurs if a Clean is ...

LightMap is created exceeding [Packed Light and Shadow Map Texutre Size]

UE - Graphics Features - Lumen - Oct 3, 2019

When LightBuild is performed with CornTestBox.umap of EngineTest, 4096 light maps are generated even though [Packed Light and Shadow Map Texutre Size] is 1024. The reason is that the asset's LightMa ...

Landscape LOD behaviours is not working as expected (Its Calculation is not based on Sections anymore)

UE - Graphics Tools - Terrain - Landscape - Apr 10, 2024

"Components can optionally be divided into either 1 or 4 (2x2) subsections to increase the resolution of the Landscape. These subsections are the base unit of Landscape LOD calculation." From Doc ...

Blueprint actor reference breaks after hot reload

UE - Gameplay - Blueprint - Apr 21, 2016

Reference to a blueprint based on a custom class will break if changes are made to the parent class and a hot reload is performed. Error Displayed added to Callstack section. Workaround: Compiling ...

Permanent FPS Drop After Using High Resolution Screenshot With Planar Reflections

UE - Graphics Features - Mar 9, 2017

After taking a high res screenshot with a planar reflection actor in the scene the engine will experience a permanent performance hit relative to the resolution of the screenshot. For example if you ...

PrepareTextureResources is being called repeatedly (on commandlets and potentially other cases)

UE - Graphics Tools - Terrain - Landscape - May 28, 2026

Implement a commandlet that renders (with `-AllowCommandletRendering`) and frequently calls `CommandletHelpers::TickEngine()`.Have the commandlet load a map containing a world-partitioned landscape. T ...

Non-Nanite meshes not being correctly cleared from all levels of VSMs on actor destruction when r.Shadow.Virtual.NonNanite.IncludeInCoarsePages=0

UE - Rendering - Graphics Features - Shadows - Jun 15, 2026

When using the r.Shadow.Virtual.NonNanite.IncludeInCoarsePages=0 to optimize VSM performance there are errors in how the VSM is invalidated when actors are destroyed with non-Nanite meshes. The curr ...

A packaged game that includes a code class that references a widget Blueprint will display an error on launch stating that the widget blueprint cannot be found.

UE - Editor - UI Systems - Sep 24, 2015

If a widget Blueprint is referenced in code, an error is displayed when the packaged game is launched stating that the widget could not be found (in 4.11 the widget still appears to be successfully ...