Actor Component properties can become "linked" across multiple Blueprints after a hot reload

UE - Gameplay - Components - Dec 3, 2018

If code in an Actor Component class is changed (eg. a new UPROPERTY is added) and a hot reload is performed to implement the changes, the properties in the component can become linked across any Blu ...

When very far out from the map origin, large static mesh is not streaming in until player is close in world partition even though it's within loading range.

UE - World Creation - Worldbuilding Tools - World Partition - May 7, 2025

Context World Partition has a distance-based level streaming system that provides a complete solution for large world management. Problem The problem is that when the player and large static mesh a ...

Costs of Static Lights on Render Thread

UE - Graphics Features - Jun 9, 2016

A Japanese developer's making a scene that has over 4000 static point lights. They thought the lights don't affect rendering in runtime. But they realized the RenderThread's costs become bigger. I ...

Vulkan leaks memory when opening and closing windows

UE - Rendering - Architecture - RHI - Nov 22, 2019

As described here: https://udn.unrealengine.com/questions/532725/index.html (1) Start Prebuilt Vanilla 4.23.1. with Vulkan enabled (2) Create a new project (3) Drag and drop the Sphere from “modes ...

Plane Constraint Normal is not Properly Reset

UE - Simulation - Physics - Jan 26, 2016

In the Character Movement Component, setting the Plane Constraint Normal to a value other than default, and then attempting to change the value back to the default does not revert to the default val ...

Android compile failure with GearVR

UE - Platform - XR - Jul 11, 2017

Compiling failure from several compile errors in the output log. They're of same type like this:UATHelper: Packaging (Android (ETC2)): xgConsole: In file included from D:\Streams\UE4_Release\Engine\ ...

Package build fails after disabling VR plugins

UE - Platform - XR - Mar 27, 2017

Package build fails after disabling VR plugins and launching the project The error message that pops up is: Fatal error: [Link Removed] [Line: 353] Missing global shader FPixelShaderDeclaration, P ...

FDetailGroup::AddGroup does not correctly apply the default expansion state for DetailGroups

UE - Editor - Verse Class Editor - Feb 10, 2026

There is a bug affecting DetailGroups in the engine. When adding child DetailGroups to a parent DetailGroup, the expansion state does not behave as expected and ignores the flags intended to control ...

Light function does not work with volumetric fog when not compatible with light atlas

UE - Graphics Features - Mar 28, 2025

Light functions do not work as intended with volumetric fog when using clamped mask textures which are not compatible with the light function atlas. In light functions materials, when using any UV ...

[CrashReport] Crash related to looped Reroute nodes

UE - Gameplay - Blueprint - Jul 14, 2017

This is a common crash affecting users in 4.15 and 4.16. User DescriptionsI connected two reroute nodes together in a circle. And well it brought me here.I connected a reroute node with a reroutnod ...