Importing through Python fails

UE - Editor - Content Pipeline - Import and Export - Feb 20, 2019

Version 4.21:The script result in popping the Alembic Import windows instead of a silent importThe provided options are ignored by the importer.  Version 4.22: Results in the provided callstack wi ...

Replicated component destruction not reaching client

UE - Networking - Aug 31, 2021

See the attached UDN for more information and a sample project reproducing the issue. This issue seems to happen due to a specific order of events. First, the component is destroyed, and garbage col ...

Packed Level Actors will create ISMs with inverted normals when a portion of static meshes have negative scales. This is apparent with two-sided materials.

UE - World Creation - Worldbuilding Tools - Feb 17, 2025

Packed level actors will create ISM instances with inverted normals when the selection of meshes used to create the packed level actor contains a subset of meshes with negative scales. This is the ...

Performance slowdown when ray tracing is disabled due to SetResidencyPriority

UE - Rendering Architecture - RHI - Jul 17, 2025

When a game is compiled with ray tracing disabled (D3D12_RHI_RAYTRACING=0) and the GPU the game is running on becomes low on VRAM, frame time is negatively impacted and doesn't recover. The D3D12_RH ...

LIVE: Setting sg.EffectsQuality between values will reset Destructible meshes if they have fractured

UE - Simulation - Physics - Destruction - Nov 14, 2014

DESCRIPTION: Using the command line sg.EffectsQuality and setting a value will reset a destructible mesh if it has already been fractured. AH Post: https://answers.unrealengine.com/questions/12850 ...

C# UHT fails to recognize delegates declared in another class's namespace

UE - Foundation - Cpp Tools - UnrealHeaderTool - Dec 14, 2022

Repro Rate: 3/3 This issue occurs in the live build //UE5/Release-5.1 at CL 23058290. This issue has also been regression tested against //UE5/Release-5.0 at CL 20979098 and is confirmed to be a r ...

Crash when duplicating component with Instanced property initialized with CreateDefaultSubobject

UE - Framework - Feb 2, 2024

An editor crash can be observed when copy-pasting an actor with an actor component with an instanced object property when set to a non-default value. Detailed steps to reproduce are provided below. ...

Crash on Mac when adding Convex Collision to a mesh converted from a brush

UE - Platform - Apple - Jun 6, 2017

This is one of the top Mac crashes occurring in 4.16. Caused by adding Auto Convex Collision to a mesh converted from a brush. Does not occur on Windows. User DescriptionsI was trying to add a conv ...

Skeletal Meshes have physics collisions lag

UE - Simulation - Physics - Oct 2, 2019

Skeletal mesh's physics collision lag behind the actual mesh. It didn't matter if there was just a root bone or multiple bones/constraints. This doesn't happen when using static meshes. The effect ...

[Interchange][gltf] Imported animation are all 1 frame long.

UE - Editor - Content Pipeline - Import and Export - Jan 27, 2025

All the imported animation only contain one frame. If the file contains in archive are imported in a gltf web viewer we can see animation are playing.  [Link Removed] [Link Removed] https://foru ...