Niagara GPU particles will always have a lifetime of one second if they use a Collision Module

UE - Niagara - May 2, 2019

GPU Particles will always have a lifetime of one second when using a collision module. This is a result of an issue with how off screen timing is handled. GPU particles that are off screen should on ...

Crash when duplicating the Child Actor Component class

UE - Gameplay - Components - Jun 3, 2019

Creating a blueprint class with a child actor component and setting its actor class to Point Light, then copying and pasting it causes the editor to crash. Tested in 4.21.2 (CL - 4753647), 4.22.1 ...

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 ...

The default scene root of an blueprint actor is not removed after adding a static mesh component via C++ until after restarting the project

UE - Gameplay - Jun 27, 2019

The default scene root of an blueprint actor is not removed after adding a static mesh component via C++ until after restarting the project (or reloading the blueprint asset) Found in 4.22 CL#70536 ...

Editor Crashes when Isolating a Material Element on Skeletal Meshes with Ray Tracing Enabled

UE - Graphics Features - Lumen - Jul 3, 2019

With ray tracing turned on, clicking on the isolate material option next to a material slot on a skeletal mesh with more than one material slot, causes the editor to crash. Found in 4.22 CL# 7053647 ...

Material Parameter Collection Values not Updating in Simulate if "Run Dedicated Server" is Checked

UE - Networking - Jul 15, 2019

Material Parameter Collection Values not Updating if "Run Deadicated Server" is Checked Working as expected in 4.21 CL# 4753647 Found in 4.22 CL# 7053642, 4.23 Preview 1 CL# 7236301, and 4.24 CL# ...

Sorting a Blueprint variable into a subcategory separates variables into separate category structures

UE - Gameplay - Blueprint - Oct 14, 2019

Within the Blueprint Editor, it is possible to create subcategories for variables to be sorted into. Doing so separates variables not nested into subcategories out into standalone, top-level structu ...

Inventor Assembly imports incomplete or missing geometry

UE - Editor - Content Pipeline - Datasmith - Importer - May 22, 2020

It seems that UE4 has a problem with importing Inventor Assemblies and Subassemblies. Files are either the wrong orientation or missing their geometry completely. This was reported and tested in 4 ...

Naming a variable 'LifeSpan' causes the default value to be reset after closing the editor

UE - Gameplay - Blueprint - Nov 3, 2020

Customer reported this issue in Salesforce. I repro'd this issue in 4.25.3, 4.25.4, and 4.26. Therefore marking it as not a regression. Renaming the variable something like "LifeTimer" does not res ...

RGB/UINT10 HDR Format not using ST.2084

UE - Rendering Architecture - RHI - Aug 23, 2021

Specification here: [Link Removed] Which is mirrored in engine in FD3D12DynamicRHI::Init (for example): [Image Removed] However, FWindowsPlatformMisc::ChooseHDRDeviceAndColorGamut always returns ...