Components tree is ending up with duplicate entries (same pointer added to the list view more than once), causing an assert

UE - Gameplay - Blueprint Editor - Jul 19, 2017

This is a common crash affecting users in 4.15 and 4.16. Over 200 unique users have been affected. User DescriptionsCamera Component Drag Drop Error 카메라 컴포넌트를 이벤트 그래프에 드래그 하는 도중 에러 발생 Creating a ne ...

Morph Targets flicker Randomly in Slave Mesh

OLD - Anim - Oct 1, 2015

When a mesh is slave to a master mesh, its morph targets will flicker when Played in Editor. This does not occure with the same assets in 4.8. This has been reported by at least two different use ...

NavLinkProxy potentially causing extra Character Movement

UE - AI - Feb 12, 2020

The user is using a Nav Mesh Bounds Volume and a Nav Link Proxy. They are calling AI Move To to navigate to the point, but the Character reproduces extra movement and goes a bit past it. For debuggi ...

Crash when rendering cinematic in a Separate Process without "-NoLoadingScreen" cmd argument

UE - Anim - Sequencer - Jul 5, 2016

Crash when rendering cinematic in a Separate Process without "-NoLoadingScreen" cmd argument. Occurs in 4.12 and 4.13 in both Matinee and Sequencer Error message: Assertion failed: SizeX > 0 && S ...

Rarely, unmodified Niagara will cause diffs and bloat the patch.

UE - Niagara - May 3, 2022

Attached is a project that picks up Niagara from the content sample. The probability of reproduction is about 1/10. The simpler the project, the lower the reproduction probability. I am attaching ...

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 ...

Crash when using Mesh Reduction on ScotsPine_01 for LOD3

UE - Graphics Features - Jan 30, 2017

A crash occurs when trying to use the Mesh Reduction tool for the ScotsPine_01 static mesh from the Open World Demo collection. The assets from this project are usually very processor heavy due to ...

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 ...

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 ...