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 ...

Crash when calling FillDataTableFromCSVString() while viewing the contents of the data table

When the function UDataTableFunctionLibrary::FillDataTableFromCSVString() is used from Editor Utility Blueprints or Python Scripts, and the contents of the affected Data Table are currently being vi ...

[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 ...

Control Rig - Undo doesn't function correctly with proxy and multi bone controls

UE - Anim - Rigging - Control Rig - Oct 26, 2025

Issue from my Technical Animator where the undo operation in Control Rig doesn't work as expected on Proxy Controls. He has recreated the issue using the "Control Rig Samples Pack" and recorded a vi ...

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 ...

A physics actor will still bounce if the Restitution of a Physical Matieral is set to 0

UE - Gameplay - Oct 6, 2016

A physics actor will still bounce if the Restitution of a Physical Matieral is set to 0 User Description: Explanation : I am trying to create a Badminton Game for fun and while I was trying to han ...

Using Execute Console Command in a custom Game Instance causes Standalone Game to crash

UE - Gameplay - Blueprint - Jan 15, 2015

Using Execute Console Command in a custom Game Instance causes Standalone Game to crash. Also occurs in 4.6.1: CL-2386410 and 4.7 Preview: CL-2403078 Crash Report: [Link Removed] Call Stack:UE4Ed ...

Crash related to Vertex Painting - MeshPaint!CastChecked<AActor,UObject>()

Tools - May 23, 2016

This crash was reported on the UDN. Upon further investigation it has been experienced by a handful of different users throughout 4.11 and 4.12. JIRA logged for tracking despite unknown repro steps ...