Collision Problems on Meshes with Collision Complexity Setting UseComplexAsSimple

UE - Simulation - Physics - Dec 20, 2018

Collision does not appear to work properly on a static mesh that is set up with UseComplexCollisionAsSimple. ...

Previous Tangent Recalc` and Size by Life misbehave at low FPS

UE - Niagara - Jun 18, 2019

At 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, 2023

Can 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, 2024

Lumen 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, 2025

When 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, 2015

User 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, 2017

Rotated 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, 2019

Regression 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, 2020

The 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, 2025

Materials with "Used With Hair Strands" enabled will cause Skeletal Meshes to draw twice in the Base Pass. ...