GAS: DefaultSubobject AttributeSet becomes invalid on duplicated blueprint

UE - Gameplay - Gameplay Ability System - Apr 22, 2025

When a native actor 'AMyActorClass' creates AttributeSets as a default subobject via CreateDefaultSubobject, duplicating an actor blueprint based on AMyActorClass will result in a blueprint with an ...

Map placed actor binding to another actor's Event Dispatcher (multicast delegate) results in duplicate bindings after blueprint recompile

UE - Framework - Blueprint - Apr 17, 2025

Context Blueprint actors placed on the map can bind to another actor's event. If an ActorB has a reference to ActorA, it can bind to an event dispatcher in A by creating an event node in ActorB's e ...

Change of rotation axis when switching solver

UE - Simulation - Physics - Apr 17, 2025

This alteration was introduced in the 'Found CL' field - and is likely an unintentional side effect of adding SIMD to the solver. There is a repro project attached, open up 'TestMap' and run to see ...

Niagara Position Mode Unset results in World Space rather than Local Space

UE - Niagara - Scripting - Apr 16, 2025

When an emitter's Position Mode is Unset, the particles spawn in World Space 0,0,0. This is unexpected. If the Position Mode is Unset in 5.4, the particles remain in Local Space, which is the inten ...

Navigation mesh is generated ignoring collision for ISM added by construction script

UE - AI - Navigation - Apr 15, 2025

When opening a map with ISM in place, NavOctree is not updated because the ISM bounds are assumed invalid and the geometry is not taken into account in the navmesh build.  The following log output i ...

FName no longer equals FName_None when constructed with a trailing underscore and digits in range of 1-9

UE - CoreTech - Apr 15, 2025

When an FName is created with a trailing underscore and any number of digits in the range of 1-9 the trailing digits are used as the internal number value for the FName lookup. This results in the F ...

Nanite TwoSidedSign is backwards

UE - Graphics Features - Nanite - Apr 10, 2025

The value of MaterialExpressionTwoSidedSign is flipped when calculating the Opacity Mask for Nanite meshes. This seems to be a regression in 5.5. ...

XR - Volumetric Clouds - VM Clouds appear overtop of meshes in the right-eye

UE - Graphics Features - Apr 10, 2025

When the user changes the Volumetric Render Target Mode, the Volumetric clouds in a scene will render in front of Static Meshes in the Right-Eye. ...