FStateTreeExecutionContext::GetDebugInfoString() outputs wrong info and crashes when using linked state trees

UE - AI - Debugging - Apr 17, 2025

When using State Trees, the AI Debugger can be accessed during play to show information about their current execution state. If a behavior tree is currently in a state that references a linked tree, ...

When PCH is Disabled, Error Occurs in VulkanGenericPlatform.h at Android Build

UE - Graphics Features - Dec 6, 2018

If disable PCH in Target.cs, an error will occur when building for Android. The log is as follows. LogPlayLevel: Error: D:/Build/Release-4_21_0/Engine/Source/Runtime/VulkanRHI/Private/Android/../Vu ...

Vive Trackpad X and Y always return 0

UE - Platform - XR - Feb 3, 2020

Platform-specific input for pad axis in 4.24 leads to missing value in VIVE. in 4.23.1 this is not reproduced. ...

Blueprint processing is heavy in PIE since 4.26

UE - Gameplay - Blueprint - Feb 17, 2021

As the attached image shows, there is no problem in 4.25.4, and the process is noticeably slower in 4.26.1. Also, there is no problem in Standalone. The problem occurs only in PIE. ...

Volumetric Clouds High Quality Aerial Perspective Issue

UE - Rendering Architecture - Oct 19, 2023

There is a workaround to set r.VolumetricRenderTarget.Mode=1. The lines appear to be coming from the temporal component of the Volumetric Clouds. Each frame, the lines are merged in from the previou ...

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 ...

Instanced Static Mesh does not apply World Aligned Material correctly

UE - Graphics Features - Aug 22, 2016

If you apply a material that uses World Aligned Blend to an instanced static mesh, it will display differently than an non-instanced static mesh with identical settings. They only look identical if ...

mobile DOF setting is not applied when play on standalone mode

UE - Platform - Mobile - Feb 20, 2023

In 5.0, the mobile depth of field settings were correctly reflected when running standalone. However, in 5.1, the DOF doesn't appear to be working correctly and the focus is off, causing a blurry im ...

FX.TestGPUSort fails on Vulkan

UE - Niagara - May 5, 2025

“FX.TestGPUSort” fails on both PC Editor and Android with Vulkan RHI. ...

Fringe Saturation in Post Process Volume not functioning

UE - Graphics Features - Jul 27, 2015

Setting the values for Fringe Saturation within the Post Process Volume does not seem to have any visual change. The documentation suggests that changing the Fringe Saturation will either increase ...