Unreal Engine Issues
Unreal Engine Issues
Previous Tangent Recalc` and Size by Life misbehave at low FPS
UE - Niagara - Jun 18, 2019At low FPS particle systems with "Previous Tangent Recalculation" enabled in the Ribbon Data result in messy mesh generation. Found in 4.21 CL# 4753647, 4.22 CL# 6574378, 4.23 CL# 6925347, and 4.24 ...
Unable to save a map file when editing a LevelInstance by placing multiple LevelInstances on a PersistentLevel
UE - World Creation - Worldbuilding Tools - Level Instances - Mar 17, 2023Can not save the map file, if trying to edit a LevelInstance in a PersistentLevel where multiple LevelInstances are placed. The workaround is to open and edit the LevelInstance as PersistentLevel. ...
Lumen indirect lighting artifacts when far from world origin
UE - Graphics Features - Lumen - Feb 6, 2024Lumen seems to not be using Large World Coordinates somewhere. The Lumen Scene develops artifacts at large distances (5000 KM) from the world origin. ...
UV Offset Effect Material in RetainerBox Causes Visual Artifacts in Editor Preview
UE - Editor - UI Systems - UMG - Apr 22, 2025When a UV Offset is applied in a RetainerBox effect material, visual artifacts appear only in the editor — not at runtime — if a widget with a dotted preview outline (like CanvasPanel) is placed dir ...
20 FPS performance drop between 4.7.6 and 4.8 on devices rendering Metal only
UE - Platform - Mobile - Jun 22, 2015User reported a considerable performance drop on iOS between versions 4.7.6 and 4.8. I was able to reproduce this perf drop using the steps he provided. ...
Rotated component made into root displays incorrectly in the blueprint editor
UE - Gameplay - Blueprint - Jan 25, 2017Rotated component made into root displays incorrectly in the blueprint editor. Closing and reopening the BP editor corrects the displayed root component. ...
Mobile Preview - Custom Stencil 4.23 Regression
UE - Platform - Mobile - Oct 25, 2019Regression when using custom stencil with in-editor mobile preview. This does NOT reproduce in MAIN at CL 9730599 ...
Depth Not Rendered Correctly When Using CustomProjectionMatrix in SceneCaptureComponent2D
UE - Graphics Features - Apr 15, 2020The depth is rendered incorrectly when using a custom projection matrix in SceneCaptureComponent2D. You can find an example project at [Link Removed]. You can find where the CustomProjectionMatrix ...
Skeleton mesh with hair strands material will lead to unnecessary draw call submissions
UE - Graphics Features - Mar 27, 2025Materials with "Used With Hair Strands" enabled will cause Skeletal Meshes to draw twice in the Base Pass. ...
Editor vs Runtime: Inconsistent data layer behavior when attaching actors
UE - World Creation - Worldbuilding Tools - World Partition - Jun 5, 2025In editor, data layer system respects the data layer settings for each actor, but at runtime, the condition check is made collectively for each actor cluster, resulting in differences in behavior. ...