Crash when exporting static mesh actor to FBX (Array index out of bounds)

UE - Editor - Content Pipeline - FBX - Apr 25, 2025

I set the Forced LOD Model on the mesh component > 1, then tried to export, this is what causes the crash. Here is my suggested fix, we just don't use Git or I'd do a PR: In the else() branch of FF ...

5.5 Static Mesh Import Pipeline Regression

UE - Editor - Content Pipeline - Import and Export - Apr 25, 2025

This question was created in reference to: [Link Removed] This post references the first post because this problem was not discovered till now. I think it was masked because the issue appears to be ...

Engine no longer compiles after backporting RHI thread improvements and crash fix

UE - Rendering Architecture - RHI - Apr 24, 2025

Unreal Engine 5.4 code will no longer compile after applying both the RHI improvement code changes as described in [Link Removed] and the fix for the crash described in [Link Removed]. The compilati ...

Divergent group barriers in Lumen

UE - Graphics Features - Lumen - Apr 23, 2025

Intel reported GPU crashes on their hardware caused by divergent group barriers in ScreenProbeConvertToIrradianceCS:[numthreads(THREADGROUP_SIZE, THREADGROUP_SIZE, 1)] void ScreenProbeConvertToIrra ...

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 ...

FStateTreeExecutionContext::GetDebugInfoString() outputs wrong info and crashes when using linked state trees

UE - AI - Debugging - Apr 17, 2025

When using State Trees, the AI Debugger can be accessed during play to show information about their current execution state. If a behavior tree is currently in a state that references a linked tree, ...

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 ...

[Interchange] Import Material flag ignored for MaterialInstances

UE - Editor - Content Pipeline - Import and Export - Apr 15, 2025

When Import Materials flag is disabled we still import MaterialInstances currently. If the flag is disabled we should leave out Materials and MaterailInstances on import. ...

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 ...