Crash After Reimporting Static Mesh With Added Material Slot

Tools - Jan 12, 2017

After importing a mesh without any materials assigned, if you add a material slot and save the material. Reimporting this mesh will cause a crash. The only way to avoid this crash is to import a me ...

Switchboard Unable to Launch Multi-User Slate Server in Launcher Builds

UE - Virtual Production - Tools - Switchboard - Jan 14, 2023

Switchboard is unable to launch the Multi-User Slate Server in launcher builds.  This is because the default install location has "Program Files and "Epic Games" in the path (aka folders with spaces ...

IsOverlappingActor is always returning false

UE - Gameplay - Sep 23, 2015

When you use the IsOverlappingActor node to determine whether or not something is overlapping another actor, it returns false regardless of whether or not you're actually overlapping another actor. ...

Path Tracing denoiser is not stable in animation

UE - Graphics Features - Nov 30, 2021

When rendering an animation with the path tracer through MovieRenderQueue, at low sampling rates the denoiser produces splotchy results that flicker from frame to frame. The current denoiser (Ope ...

Swarm: Not able to set number of processors to use for Swarm from the UI

UE - Graphics Features - Aug 25, 2015

There is a setting called "LocalJobsDefaultProcessorCount" in the Developer Settings tab in Swarm. After the change to make Lightmass build asynchronously while the user keeps working, this set ...

Frequent ensure opening meshes on Mac, locks up AMD machines

UE - Graphics Features - Jun 6, 2017

REGRESSION No, I was able to reproduce the hard lock in 4.16.1. A frequent ensure occurs when opening static or skeletal meshes on Mac. Doesn't reproduce 100% of the time, but I've gotten it about ...

Navmesh seems to have buggy behavior when interacting with HISMCs that programmatically set mesh via SetStaticMesh.

UE - AI - Mar 6, 2020

Both versions works correctly if HISMC is pre-placed (generated in ConstructionScript). Only when generated dynamically does it fails. The Navmesh isn't being updated after SetStaticMesh and AddInst ...

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 ...

WindDirectionalSourceComponent.h has a meta edit condition that, by referencing an undefined property (bSimulatePhysics), throws an error

UE - Framework - Apr 15, 2025

WindDirectionalSourceComponent.h has a meta edit condition that, by referencing an undefined class property (bSimulatePhysics), throws an error in the logs: LogEditCondition: Error: EditCondition pa ...

Cloth Simulation Doesn't Work When Clothing Data Is Applied Before Being Painted

UE - Simulation - Physics - Character - Jan 17, 2020

When clothing data is applied before painting the influence on the section the cloth doesn't simulate. I tested this using the Paragion: Twinblast actionhero skeletal mesh asset. Found in 4.24.1 C ...