Pressing the "Show Inactive" button in the material instance editor did not display groups that did not contain the active parameter

UE - Rendering Architecture - Materials - Aug 1, 2024

When pressing the "Show Inactive" button in the material instance editor, all material parameters are supposed to be displayed in the EditorUI. This is not the case, only some of the parameters are ...

Incremental GC vs Loading Screens deadlock

UE - CoreTech - Sep 5, 2024

A licensee is reporting that using a loading screen with the incremental garbage collector can result in a dead lock when a loading screen is displayed. The licensee found out that:  -------------- ...

Material Emissive Color not working with SkyAtmosphereIlluminance Material Expression

UE - Graphics Features - Jan 9, 2025

A licensee has reported that they are unable to use an emissive material utilizing the SkyAtmosphereLightIlluminance material expression together with Nanite and Lumen. The linked UDN has some more ...

Virtual Bone caused nanite skinned mesh crash

UE - Graphics Features - Nanite - May 31, 2025

When a Nanite skeletal mesh has a virtual bone the engine can crash when changing LODs ...

Performance hitch from RemoveGeometryCache flushing the render thread

UE - Editor - Content Pipeline - Alembic - Jun 12, 2025

FGeometryCacheStreamingManager::RemoveGeometryCache calls FlushRenderingCommands which shows up as a hitch when profiling. [Link Removed] Ideally the flush added in CL#23782411 to fix a rare deadl ...

If 'Enable Physics Interaction' is disabled, the player can still interact with physics objects

UE - Gameplay - Oct 22, 2015

If 'Enable Physics Interaction' is disabled, the player can still interact with physics objects User Description: I have a Bus Vehicle with custom physics (skeletal mesh). So I can walk through th ...

Distance Fields no longer work with instances when PIE/Simulate

UE - Graphics Features - Apr 20, 2015

When using distance fields with instance meshes from the foliage tool everything works correctly, however, when simulating or PIE the distance fields will be removed. This working correctly in 4.7.5 ...

Editor movement control regression

Tools - Jul 8, 2015

Using Ctrl+Drag in 4.8 will not affect the location of selected actor if the viewport camera is facing away from selected actor. In 4.7.6 the actor would travel along the X axis even if the camera ...

Game sounds only play during first PIE editor session for Linux project

UE - Platform - Linux - May 11, 2015

Games sounds will play as appropriate during first PIE session but subsequent PIE sessions have no sound until editor is closed / reopened. ...