Regression: "Play particle effect" anim notifies are not seen in the editor playing level sequence/matinee when Attached is set to false

UE - Graphics Features - Dec 21, 2017

Not Attached particle system is not seen in the viewport of the editor. This particle will be seen normally when PIE.  Regression? Yes. This issue is not reproduced in 4.17 version. You can simply ...

Gameplay Ability Component Montage Replication incorrectly handles cyclic animation sections

UE - Gameplay - Gameplay Ability System - Dec 4, 2023

In AbilitySystemComponent_Abilities.cpp, the check for the client being on a different section on line 3059 checks that the RepNextSectionID is not the current section. One would assume this is beca ...

Null Material Layers in Material Instances cause Opacity Mask and WPO to break on Nanite Meshes

UE - Rendering Architecture - Materials - Oct 31, 2024

When a Material Instance is loaded that has a nullptr layer in StaticParametrs.Materiallayers.  The Material Instance will create it's own CachedExpressionData but the ConnectedParameterMask will be ...

Duplicated TextureLoadVirtualPageTable in GetCustomData functions in generated HLSL add to the total instruction count due to TextureLoad having side effects

UE - Rendering Architecture - Materials - Dec 4, 2024

When using materials with CustomData inputs, such as the Eye material with Iris Distance and Mask, Virtual Texture samples will increase the instruction count for each unique VTPageResult. Each cus ...

Blueprint Library plugin set to 'Runtime' doesn't work in Standalone/packaged builds if used inside of the 1st Person Character BP

UE - Foundation - Cpp Tools - UnrealBuildTool - Nov 18, 2016

Blueprint Library plugin set to 'Runtime' doesn't work in Standalone/packaged builds if used inside of the 1st Person Character BP. User Description: Blueprint libraries are still broken in the fi ...

Staging Directory in Project Packaging Settings should not be saved as absolute path

UE - Foundation - Data Pipeline - Cooker - Jun 8, 2021

When you package a project via the editor, it updates the ProjectPackagingSettings to set the StagingDirectory to the specific one chosen by the user. However, it saves this path as an absolute path ...

Updating Material does not update platform stats in derived Instance

UE - Rendering Architecture - Materials - Nov 26, 2024

It would seem that updating a material does not update the associated platform stats in a material instance editor, only the parameters. Can workaround by manually invoking shader compile in the ma ...

ChaosCacheManager is not reproducing Trailing Events

UE - Simulation - Physics - Mar 28, 2025

ChaosCacheManager (CCM) is not reproducing Trailing Events. Particles set to track Trailing Events correctly follow the position of the trailing event when the Geometry Collection (GC) is physically ...

GetRefBonePose doesn't return the correct location if the mesh has been switched to another mesh of the same skeleton

OLD - Anim - Sep 10, 2015

When using GetRefBonePose() on a USkeletalMesh's RefSkeleton, the given location is incorrect if the SkeletalMesh has been changed from one to another where both meshes share the same skeleton. Als ...

Packaging a project to HTML5 and opening the project disables mouse over events

UE - Platform - Mobile - Dec 24, 2015

Packaging a game to HTML5 disables the mouse and mouse over events on local host, which prevents any mouse functionality from working in a packaged project. ...