Unreal Engine Issues
Unreal Engine Issues
Integer overflow in NaniteBuilder can lead to an editor crash on certain meshes
UE - Graphics Features - Nanite - Jul 10, 2024NaniteBuilder uses an int8 type for ExternalEdges and counts adjacency with a int32. The bug stems for the cast to int8 when adding the adjacency count into the ExternalEdges array. The precision l ...
Indirect lighting cache generates points inside interpenetrating static meshes
UE - Graphics Features - Jun 10, 2015Seems to be an issue with the indirect lighting cache where if you have interpenetrating static meshes (for example static mesh rocks that make up the ground), there are cases where the cache points ...
Material Compile Error [SM5]
UE - Graphics Features - Jun 8, 2016There is an material compile error when using a TexCoord node shared between two Texture samples. The user provided a number of ways to work around the issue, but this issue becomes more problemati ...
Blueprint inheritance can cause dangling references to stale UProperties across compiles
UE - Gameplay - Blueprint Compiler - Jun 6, 2017A number of places in the code rely on raw UProperty pointers to track properties they care about. This can present issues when BPs inherit from other BPs, because the parent's class may be Purged / ...
Vector VM - Crash / memory stomp when using > 255 external function calls
UE - Niagara - Aug 12, 2025The Vector VM has only every supported a byte's worth of external function calls, when we blew the limit it would index into the incorrect VM call. The new VM will also overwrite memory when exceed ...
GAS: Double attributes not shown GameplayDebugger
UE - Gameplay - Gameplay Ability System - Aug 27, 2025Context The Gameplay Ability System lets devs specify numerical attribute properties in UAttributeSet subclasses. Although the preferred attribute property type is FGameplayAttributeData, GAS has l ...
Exposed Niagara User Parameter Enums are displayed as Integers
UE - Niagara - Sep 29, 2022(Note: all enums seem to fail when exposed as a user parameter and changing the exposed int does not impact the result of the simulation) Add a rigid mesh collision query di to a scratch module pe ...
Ctrl+Alt selection drag inside to outside of Matinee window will crash the editor
Tools - May 18, 2016Ctrl+Alt selection drag inside to outside of Matinee window will crash the editor Reproduced in Releases stream 2982080 as well, to verify that this wasn't the same bug as https://jira.ol.epicgames ...
Plugin Warden entitlement check "timing out" error
UE - Editor - Content Pipeline - Datasmith - Importer - Dec 28, 2017A growing number of users are reporting the Plugin Warden entitlement check timeout error while attempting to import datasmith files. Some users have been able to resolve the issue, some have not. ...
Granular Synth stays silent since it cannot load the sound with Stream Caching enabled
UE - Audio - Jun 1, 2020Using Granular Synth with Stream Cache enabled, Granular Synth will stay silent since it cannot load the sound with Stream Caching turned on. This was reported and tested in 4.25 (CL-13144385). Thi ...