WorldCoordinate3Way produces Incorrect Axis Lerps

UE - Graphics Features - May 18, 2016

The Material Function WorldCoordinate3Way seems to incorrectly perform the Lerps from the axis contributions of the normals. An example is show here, with the left objects using the version that com ...

Foliage experiences odd culling when world origin is changed

UE - Graphics Features - Sep 13, 2017

There is an odd issue occurring when the world origin is changed, changing the world origin causes the foliage to cull in unexpectred ways. The issue can be solved by using the console command "r.Al ...

When running multiple clients in PIE the second player's inputs become toggled every tick when setting Input mode Game only on tick

UE - Editor - UI Systems - Slate - Jul 9, 2015

A user has found that setting input mode to game only on tick will cause the client in PIE to toggle their inputs on and off every tick. If this test is run with a single player the inputs are const ...

Sound Track in Matinee Ignoring Track Location and Playing Audio at Beginning of Sound Wave/Cue

Tools - Sep 22, 2015

When scrubbing the Matinee handle with a Sound Track added, no matter the location of the handle, the sound wave associated will play from the beginning of the audio file. Tested in 4.8.3 - 2634408 ...

Null Material Layers in Material Instances cause Opacity Mask and WPO to break on Nanite Meshes

UE - Rendering - Architecture - Materials - Oct 31, 2024

When a Material Instance is loaded that has a nullptr layer in StaticParametrs.Materiallayers.  The Material Instance will create it's own CachedExpressionData but the ConnectedParameterMask will be ...

Swarm Agent Binaries Missing in Launcher 5.7 Preview

UE - Foundation - Build - Rocket (Installed Engine) - Oct 23, 2025

The Swarm binaries are missing from Engine\Binaries\DotNET in the 5.7 Preview launcher version of the engine. This causes any lighting build or precomputed static visibility builds to fails due to t ...

Visual Studio opens unnecessary windows when adding a new C++ class via the editor's interface

Tools - Oct 25, 2017

When adding a new C++ class to a project via the editor's interface, Visual Studio is opened but it ends up opening more than is necessary. Firstly, Visual Studio is opened without focus on the two ...

[CrashReport] UE4Editor_LevelEditor!FMulticastDelegateBase<FWeakObjectPtr>::RemoveAll() [multicastdelegatebase.h:81]

Tools - Oct 26, 2017

This is a trending crash in 4.18.0. One case of this callstack occurred in 4.17.1, but then numerous have occurred in 4.18. Users have not provided any descriptions of their actions when the crash ...

Tabbing out of exclusive fullscreen leaves the window & backbuffer in an incorrect state

UE - Editor - UI Systems - Apr 24, 2020

With windows 10 there has come some new swap chains, which unfortunately messes some things with regards to fullscreen up. We've fixed a bunch in the renderer (which would downright cause crashes), ...

SetActorLabel resets components when run outside main editor process

Tools - Mar 30, 2015

Calling SetActorLabel causes an actor's components to return to default states when called from a client accessing a listen server outside of main editor process. Note: User posted code linked to ...