Specular Scale 0 on Light still affects Groom asset

UE - Rendering Architecture - Jul 30, 2025

When a light's Specular Scale is set to 0, the specular still affects hair / groom assets. The specular of other assets (like a shiny static mesh in the scene) is properly affected by the change.  ...

Crash when changing parent of Material Instance with Layered Materials and viewing Layer Parameters

UE - Rendering Architecture - Materials - Aug 1, 2025

Reparenting a MaterialInstance that uses Material Layers to another instance with a different layer configuration can cause the editor to crash when opening the Layer Parameters tab. This appears to ...

Typo in GetAsBoundsArray() from file AABBTree.h on Chaos module

UE - Simulation - Core - Jul 30, 2025

From file [Engine\Source\Runtime\Experimental\Chaos\Public\Chaos\AABBTree.h], function Chaos::TAABBTree<>::GetAsBoundsArray(): bool GetAsBoundsArray(TArray<TAABB<T, 3>>& AllBounds, int32 NodeIdx, i ...

FNiagaraScalabilityManager incorrectly reactivates a NiagaraComponent that was deactivated by runtime user code

UE - Niagara - Scalability - Oct 1, 2025

Context: The Niagara System is the primary tool to do visual effects inside Unreal. Niagara systems can be culled due to distance. Problem: Once a deactivated Niagara System is culled due to distan ...

In the GameUserSettings class, Landscape quality is not taken into account by GetOverallScalabilityLevel, but is changed by SetOverallScalabilityLevel.

UE - Gameplay - Oct 17, 2025

Context: GameUserSettings stores user settings for a game, for example graphics and sound settings. The Scalability settings provide a way for to adjust the quality of various features in order to m ...

OverrideVertexColor causes a crash on mobile renderer

UE - Platform - Mobile - Jan 8, 2026

Setting Allow CPU Access on the mesh, or setting bSupportsManualVertexFetch=1 in Engine.ini, avoids the crash. ...

Structure variables in Child Blueprints do not maintain the default values set in their Parent Blueprints

UE - Gameplay - Blueprint - Jan 12, 2015

Values changed to an inherited Struct variable in a Child Blueprint will be kept after compile, but any not changed will be set to 0s. ...

After compile, spawnable actor is stuck in spawned state

UE - Anim - Sequencer - Jun 3, 2016

After compile, spawnable actor is stuck in spawned state ...

Lock Actor Movement doesn't prohibit rotating an object by turning the viewport while piloting it.

Tools - Jun 12, 2015

If you pilot an object and wish for it not be moved, such as a camera, you can use the Lock Actor Movement option. This will stop the object from moving, but it will not stop the object from being r ...

Performance will drop in PIE if simulate physics is toggled rapidly on an actor with attached components

UE - Gameplay - Nov 3, 2015

Performance will drop in PIE if simulate physics is toggled rapidly on an actor with attached components User Description: Simulating physics for Primitive components causes severe performance dr ...