UAIPerceptionSystem::Tick() has a chance of not being called after level reloading

UE - AI - Dec 16, 2019

UAIPerceptionSystem::Tick() is not called after level reloading. When Debugging, UAIPerceptionSystem::CurrentTime is always 0, and UAIPerceptionSystem::SourcesToRegister always contains sources to ...

Compile on load crashes for classes within an abstract class

UE - Gameplay - Blueprint Compiler - Feb 20, 2021

When compiling on load in -game, a blueprint class that inherits from a native class that is marked within and the class that it is within is abstract, a crash will occur when FBlueprintCompilationM ...

LOD dithered fade-out transition does not work since UE5.4

UE - Rendering Architecture - Aug 7, 2024

When DitheredLODTransition is enabled for HierarchicalInstancedStaticMesh, in the previous version (5.1.1), dithering was applied during fade-in/fade-out, but in 5.4.3, dithering is not applied duri ...

Crash Occurs When Actors are Attached Across Persistent and Sublevels When Levels are Saved

UE - Anim - Sequencer - Dec 12, 2017

Can attach actors to each other through the use of sequencer even though actors are in different levels which leads to crashing when saving and changing levels F3DAttachTrackEditor::IsActorPickabl ...

FBX Transform does not scale skeletal mesh with multiple pieces properly using the Import Uniform Scale option

UE - Editor - Content Pipeline - Import and Export - Aug 15, 2016

Importing a skeletal mesh fbx from blender and setting the Import Uniform Scale option for the mesh to a higher value, like 100, results in only one of the meshes being scaled while the other is lef ...

Certain combined Linear/Angular movements cause Client to freeze for several seconds

UE - Simulation - Physics - May 24, 2019

When using Replicated Movement, certain combined linear/angular movements cause the client to freeze for several seconds and then catch up to the server. This is a regression from 4.21.2 (CL-4753647 ...

NavModifierVolume's FailsafeExtent is applied to the wrong area

UE - AI - Apr 16, 2020

The FailsafeArea of NavModifierVolume is generated at a different location from the center of the actor when it rotated. This means that the effect of rotation is incorrect. (see attached file) W ...

BuiltData is saved alongside it's map, even if lighting hasn't changed

Tools - Jun 25, 2021

Saving a map will always resave the map's BuiltData, even if the BuiltData hasn't been marked dirty. Changes were made to avoid marking it dirty for [Link Removed], but the call to SaveWorld in FEdi ...

Behavior of reparenting Component on UE5 is different from UE4

UE - Gameplay - Blueprint Editor - Mar 29, 2022

In UE4, Reparenting the Child Component did not update it on the screen, but the Relative Transform was updated. However, UE5 now retains Relative Transform, so there are on-screen updates. This is ...

Crash in Retarget Manager with Humanoid Rig when trying to re-assign a bone to a node

OLD - Anim - May 26, 2015

Crash in the Retarget Manager with Humanoid Rig when trying to re-assign a bone to a node. Happens particularly when there is already a bone selected and you want to select a new one. [Link Remove ...