Double Properties break reset to default and inherited value propagation

UE - Gameplay - LWC - Apr 13, 2022

This is an issue with how FPropertyValueImpl::ResetToDefault works: it uses GetDefaultValueAsString to reset the default value. This is problematic because the LexToString function that is eventuall ...

Many native-only interfaces incorrectly appear as implementable by blueprints

UE - Gameplay - Blueprint - Sep 14, 2020

Right now, any UINTERFACE that is not marked as CannotImplementInterfaceInBlueprint is shown as implementable in blueprint. If these functions have BlueprintCallable functions or related things then ...

Changing the name of a variable that references a Blackboard Key inside a Task removes the Key reference inside the Task's node in the Behavior Tree

UE - Gameplay - Blueprint - Oct 5, 2015

Changing the name of a variable that references a Blackboard Key inside a Task removes the Key reference inside the Task's node in the Behavior Tree. Clicking on the Behavior Tree's Task node that r ...

FBX export from UE4 with multiple materials the UV is corrupted

Tools - Apr 18, 2016

When exporting a Static Mesh from within UE4 that has multiple materials, some of the material IDs will be condensed into a single ID which will mess up how the material assignment for that part of ...

Lightmaps on Mobile Devices Appear Dirtied and Pixelated

UE - Platform - Mobile - Jun 19, 2015

Baked lighting on mobile has dirtied or pixelated lightmaps. When testing this issue I attempted to change various settings within the 'Lightmass' section and the changes made did not have much effe ...

The "Random Integer in Range from Stream" returns the same value if the seed is power of 2 of anything above 22.

UE - Foundation - Core - Aug 7, 2019

When using the "Random Integer in Range from Stream" where the seed is a power of 2 after a certain point (2^22) the random integer that is returned is the always the same. If the seed is 2^23 + 1 i ...

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 ...

Child actor passes a string to it's parent's overloaded constructor the incorrect string is received

UE - Gameplay - Sep 24, 2019

When a child actor passes a string to it's parent's overloaded constructor using an overridden function that returns a string it won't receive the correct string. I have verified that the correct fu ...

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 ...

Instigator is no longer automatically set when spawning actors from blueprint

UE - Gameplay - Blueprint - Aug 20, 2024

Actors that are spawned from blueprints will no longer have their instigator automatically set to the instigator that spawned them. This is a regression in 5.5, because in 5.4 and earlier a null Ins ...