Collision Meshes Are Ignored Until FBX Is Reimported

Tools - Feb 20, 2017

When importing a mesh with it's collision geometry and its LOD meshes all contained within the same group it won't import the collision geometry correctly. This can be fixed by simply right clicking ...

Material Slot Names Get Replaced With "None" After Merge Actors Operation

Tools - Mar 23, 2017

After merging two actors the resulting merged actor's slot names will be replaced with "none". Fixing this is a very tedious process for our licensee since there usually is a large amount of slot ...

Build fails when using the Windows 10 SDK

UE - Foundation - Build - Farm - Aug 14, 2017

Attempting to build the Engine using the Windows 10 SDK currently fails. This was tested on both a Windows 7 and Windows 10 machine using both Visual Studio 2015 and Visual Studio 2017. ...

Private lobbies cannot be invited to on Steam

UE - Online - May 13, 2019

The old method doesn't work with private match invites as it doesn't have the right security permissions. It's still valid for dedicated servers. It also doesn't work properly with lobbies on VR eit ...

Montage Root Motion does not work from sub anim instances

UE - Anim - Gameplay - Oct 25, 2019

Root motion from sub instances is not used when the parent instance is marked as 'Root Motion from Montages Only'. Proposed fix is to modify USkeletalMeshComponent::IsPlayingNetworkedRootMotionMo ...

ISM Component in an instanced BP does not take into account changes to NumCustomDataFloats from the BP class

UE - Graphics Features - Sep 16, 2022

PerInstanceSMCustomData is bulk serialized and doesn't get changed on the BP instance when changing NumCustomDataFloats, possibly causing out of bounds array access leading to a crash. Possible sol ...

FMaterialResource::IsDualBlendingEnabled bug

UE - Rendering Architecture - Materials - Jul 24, 2023

The user has a proposed fix for this in the case. FMaterialResource::IsDualBlendingEnabled needs the following modification that includes MaterialInstance check: bool bMaterialRequestsDualSourceBle ...

Auto Exposure Compensation Curve issue when switching from Histogram to Manual

UE - Rendering Architecture - Feb 21, 2024

When switching the Camera's Exposure Metering Mode from Histogram to Manual, there is a single-frame flash. The Licensee has a proposed code change that would fix this issue. Also found in 5.4, CL 3 ...

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 ...

FFieldPath resolution doesn't handle redirection

UE - CoreTech - Feb 16, 2022

A licensee has found that redirectors don't apply to FFieldPath. We should integrate it with the following changes:It needs better error handling (looks like it could infinitely recurse),The change ...