Renaming a Blackboard Key removes it's references in the Behavior Tree

UE - AI - Jan 27, 2015

Renaming a Blackboard Key removes it's references in the Behavior Tree ...

Parent component visibility in a child blueprint isn't reflected in a launched project.

UE - Gameplay - Blueprint - Mar 5, 2015

Parent component visibility in a child blueprint isn't reflected in a launched/packaged project. ...

After breaking a level instance without Actor Folders, moving its actors between folders of the world-partition map does not work correctly

UE - World Creation - Worldbuilding Tools - World Partition - Jan 29, 2024

If a standard level (without Actor Folders enabled) is added to a world-partition map (with Actor Folders enabled) as a Level Instance, and then that instance is "broken" so that its actors are inco ...

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 ...

Sampling textures with bias in the path of a custom data pin causes derivative operations when avoidable

UE - Rendering Architecture - Materials - Apr 8, 2025

Materials that make use of the analytical derivatives path to avoid hardware derivatives can still generate derivative operations on texture samples when the shading model has a custom data pin and ...

[CrashReport] UE4Editor_UnrealEd!UEditorEngine::TeardownPlaySession() [playlevel.cpp:595]

Tools - Aug 30, 2016

This Jira was created from CrashReports submitted by the public due to the high number of occurrences. Descriptions from users are provided below. Error message: Assertion failed: EditorWorld == G ...

Exponential Editor Slate Performance Cost When Editing An Asset With Nested Instanced Structs

UE - Editor - Workflow Systems - Feb 20, 2024

UDN Issue: [Link Removed] ...

Physics Constraints do not have the same values if they are part of an 'Always Loaded' level

UE - Gameplay - Dec 3, 2014

Physics Constraints do not have the same values if they are part of an 'Always Loaded' level. They will work correctly in the Persistent level and a level that is Streamed in. This becomes problem ...

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 ...

In Editor, Blueprint resources are not freed up when the Blueprint is closed

UE - Framework - Blueprint - Feb 16, 2024

It appears that the preview scene used to render thumbnails is not destroyed after a thumbnail is rendered, even after the blueprint editor is closed and GC is run. Also found in Release-5.4, CL: 31 ...