The AABBTree spatial acceleration structure goes off-sync when physics substepping is enabled in a "low" framerate environment.

UE - Simulation - Physics - Mar 15, 2024

When you enable the physics substepping, if you run the console command p.Chaos.Solver.DebugDrawSpatialAccelerationStructure 1, you can see how does not follow the physical object. The user that rep ...

Compiler error after changing the class in a Spawn Actor from Class node, undoing with Ctrl + Z, refreshing the node, and reconnecting exposed variables

UE - Gameplay - Blueprint - May 26, 2015

Compiler error after changing the class in a Spawn Actor from Class node, undoing with Ctrl + Z, refreshing the node, and reconnecting exposed variables. "Error Internal compiler error inside Creat ...

Setting a parent and child static mesh scale to negative effects the rotation on child movement

UE - Gameplay - Jun 1, 2016

Setting a parent and child static mesh scale to negative effects the rotation on child movement This is a regression. Worked in 4.11.2. User Description: We have a simple project example (see att ...

Assertion failed: (Index >= 0) & (Index < ArrayNum) when importing large Alembic file

UE - Editor - Content Pipeline - Datasmith - Importer - May 3, 2022

Regression testing done on //UE4/Release-4.27.2 CL-18427296 and this issue did occur. [Link Removed] [Link Removed] Below is snips of customers description and proposed workaround:Importing alembi ...

Blurry textures on BSP geometry when a very small static mesh using the same texture is in the same scene (standalone game)

UE - Graphics Features - Mar 9, 2020

The texture streamer does not appear to take into consideration the size on screen of any BSP brushes, only static meshes. When a large brush, and a very small static mesh, both using the same textu ...

Children of editor-only actors do not maintain correct transforms when placed inside level instances for PIE and cooked builds

UE - World Creation - Worldbuilding Tools - Level Instances - Oct 20, 2025

We have found an issue where children of editor-only actors get wrong transforms in PIE and cooked builds when placed inside level instances. This affects both engine version 5.5 and 5.6. The issue ...

Incorrect behavior after attaching an actor to a non-root component of another actor in the Editor

UE - Editor - Workflow Systems - Jul 3, 2024

UE allows actors to be attached to other actors. More precisely, it allows the root component of an actor (child) to be attached to any component of another actor (parent). From now on, "parent" and ...

LIVE: EDITOR: SPEEDTREE: CRASH: When using SpeedTree with Fracture Tool editor crashes

UE - Graphics Features - Aug 11, 2014

Crash Reporter information added for 4.7.2 - 4.7.6 Also Reproduced in Main Promotable-CL-2527312 Crashes from current engine seem to be predominately from Open World Content Assets. including Rep ...

NDisplay hangs and stops responding on cluster event send

UE - Virtual Production - nDisplay - Nov 12, 2019

"The test event is set up using the default CE port, but every time an event is sent through the launcher the display receives the input and processes it, however the launcher will "hang" and stop ...

Physics enabled Child Actor components that spawn with with a delay, always spawns at world origin

UE - Gameplay - Jun 3, 2016

Physics enabled Child Actor components that spawn with with a delay, always spawns at world origin **This is a regression. It was working in 4.11.2 Could also be related to: [Link Removed] User D ...