Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...

Collision of child actor doesn't rotate if the parent is simulating physics

UE - Simulation - Physics - Aug 11, 2015

Collision of child actor doesn't rotate if the parent is simulating physics. This was an old bug that an AnswerHub user reported back in 4.9 but now a licensee is reporting this same behavior in 4.1 ...

Hidden enumerator variables can cause the enumerator to become broken with the Select node in blueprints

UE - Gameplay - Blueprint - May 26, 2015

If a user makes an enumerator in C++ and sets one of the variables to Hidden and doesn't make it the last variable of the enum, it will cause issues with the numbering of the enum when using the Sel ...

ChaosCacheManager is not properly recording the state of each particle when toggling Fields and Anchor Fields in the scene.

UE - Simulation - Physics - Destruction - Oct 22, 2024

ChaosCacheManager is not properly recording the state of each particle when toggling Fields and Anchor Fields in the scene. During my investigations I've noticed that ChaosCacheManager does not reco ...

Internal Compiler error when calling a custom enum in a struct from a blueprint macro

UE - Gameplay - Blueprint - Aug 6, 2015

If a macro is referencing a custom enum within a struct and compiled after another output pin is removed, an internal compiler error will appear and the blueprint will not compile. ...

The Remove-On-Break feature, set on Fracture Mode on Geometry Collections, stops shrinking and shows strange behaviors

UE - Simulation - Physics - Destruction - Oct 15, 2024

The Remove-On-Break (ROB) feature, set on Fracture Mode on Geometry Collections (GC), was supposed to make the particle shrink until it vanishes. When the GC goes to sleep the shrinking stops and sh ...

Crash with for loop and TArray in constructor to generate multiple StaticMeshComponents

UE - Foundation - Core - Apr 20, 2015

Using a TArray to store multiple components being setup inside a for loop of a constructor will crash on project open. Crash Reporter: [Link Removed] ...

Changing the “show mouse cursor” variable of PlayerController with a mouse button input does not work the same as with a keyboard input

UE - Editor - UI Systems - Slate - Oct 6, 2020

Using the mouse input to show the mouse cursor acts like an Alt+Tab. When clicking the mouse input again to no longer show the cursor, the camera controls stop at the edge of the screen. Reported i ...

Max Pitch Angle does not correctly apply when utilized in procedural foliage volumes

UE - World Creation - Worldbuilding Tools - Foliage - Aug 27, 2015

Random Pitch Angle does not properly apply when called within a procedural foliage volume. ...

Make Bitmask node returns incorrect value when using custom Enum

UE - Gameplay - Blueprint - Jul 5, 2016

When a custom enum is used as the Bitmask Enum of a Make Bitmask node, the value returned does not match the expected value ...