Physics Constraint Actor: When plasticity is enabled, Drive Position Target is reset to zero on constraint initialization

UE - Runtime - Simulation - Mar 5, 2026

When a Chaos joint constraint is first created, having linear/angular plasticity enabled will unexpectedly force its linear/angular drive position target to zero on initialization, disregarding the ...

Physics Constraint Component loss of accuracy

UE - Runtime - Simulation - Mar 6, 2025

Physics Constraint Component has lost accuracy between Unreal versions 5.2 and 5.4 (and up). When measuring the exact distance between rigid bodies constrained by a Physics Constraint Component, the ...

Converting BSP to static mesh on Linux causes the editor to crash

UE - Platform - Linux - Mar 11, 2016

Converting a BSP to a static mesh will freeze and crash the editor when done on Linux. Windows does not exhibit the same conversion crash. ...

[WorldPartition][CellTransformer] ISM Cell Transformer breaks component hierarchy when child component are transformed

UE - World Creation - Worldbuilding Tools - World Partition - Dec 15, 2025

This case is related to [Link Removed] Closed but is not a duplicate.  Please make sure to download the attached project a ...

Interchange framework is bypassed on the second attempt after a failed import

UE - Editor - Content Pipeline - Import and Export - Jul 14, 2025

Hello! We have encountered a bug with the Interchange pipeline. When an interchange texture import is cancelled due to non-power of 2, and then the same texture is imported again without any change ...

r.MobileContentScaleFactor appears to be ignored defaulting to 1 on Mobile Devices

UE - Platform - Mobile - Feb 28, 2022

r.MobileContentScaleFactor = 0 should return Native Resolution; 1 should return Standard definiton; 2 shold return an High Definition Resolution. It seems that r.MobileContentScaleFactor is being i ...

Crash when duplicating component with Instanced property initialized with CreateDefaultSubobject

UE - Framework - Feb 2, 2024

An editor crash can be observed when copy-pasting an actor with an actor component with an instanced object property when set to a non-default value. Detailed steps to reproduce are provided below. ...

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 ...

Crash when starting PIE on a World Partition level with a Niagara Component inside nested Child Actor Components

UE - Niagara - Jun 25, 2024

Consider an actor containing a Niagara Particle System Component, which is instantiated from another actor's Child Actor Component. When initializing PIE on a World Partition level containing this s ...

Landscape Splines in Partially Loaded World Partition Levels Can Cause Nanite Landscape Invalidation

UE - Graphics Tools - Terrain - Nov 7, 2025

Certain placements of landscape splines in world partition levels can cause Nanite landscape proxies to invalidate, and switch back to their non-nanite version. This happens when specific regions of ...