Sampling textures with bias in the path of a custom data pin causes derivative operations when avoidable

UE - Rendering Architecture - Materials - Apr 8, 2025

Materials that make use of the analytical derivatives path to avoid hardware derivatives can still generate derivative operations on texture samples when the shading model has a custom data pin and ...

Using xcode-select to switch between Xcode 10 and Xcode 11 beta can cause Xcode 11 to be unrecognized by the editor

UE - Platform - Apple - Jul 16, 2019

After switching from Xcode 11.0 Beta 3 (11M362v) to Xcode 10 (10A255) and then back to Xcode 11, the editor no longer recognized that Xcode was installed on my machine when trying to use Xcode 11 as ...

[CrashReport] Assertion failed: Array index out of bounds - GetPhysicsTriMeshData() [modelcomponent.cpp:688]

UE - Simulation - Physics - Oct 30, 2017

This is a semi-common crash that has occurred since at least 4.17.1. The callstack is nearly identical to [Link Removed], which was fixed in 4.18.0, however the error message and source context are ...

Printing the result of the 'Get Move Ignore Actors' node will crash the editor

UE - Gameplay - Blueprint - May 6, 2015

Printing the result of the 'Get Move Ignore Actors' node will crash the editor. The Licensee found the issue while exploring a workaround for this JIRA:https://jira.ol.epicgames.net/browse/UE-14734 ...

Editor crashes when child blueprint uses billboard in construction script

UE - Gameplay - Blueprint - Jun 24, 2015

The editor is crashing when a child blueprint uses a billboard in the construction script after hovering over 'apply instance changes to blueprint' from the details panel. ...

UE4 Crashes if multiple Vive Trackers or Lighthouses are used

UE - Platform - XR - Jan 24, 2018

User reports that if more than 5 trackers are connected, UE4 crashes Suggested fix: Root cause of bug is related to the fact that UE has no setup to receive input events from Vive Trackers. (we ha ...

Crash Occurs When Generated Item Type Doesn't Match Return Type

UE - AI - Jan 7, 2016

After creating the example generator that is displayed at the bottom of the documentation linked below, a crash will occur if the Generated Item Type is set to EnvQueryItemType_Actor (which is the d ...

Make Writable button does not work as intended when using Subversion

Tools - Oct 22, 2015

When using the Make Writable button, it is intended to make the file editable without the prompt to check an asset out popping up on subsequent attempts to save the asset. This does not work for Sub ...

Movie playback doesn't work on Mac and iOS the way it did before

Tools - Aug 5, 2016

New media framework is making Mac/iOS not render ...

Lightmass: Blocky lightmap artifacts appears on the Mesh Actor which is shadowing by a single face mesh

UE - Graphics Features - Lumen - Jun 9, 2020

Begin Map Begin Level Begin Actor Class=/Script/Engine.StaticMeshActor Name=Plane_2 Archetype=/Script/Engine.StaticMeshActor'/Script/Engine.Default__StaticMeshActor' Begin Object Class=/Script/En ...