Data loss caused by C++ Child Actor Component when compiling Child BP

UE - Gameplay - Blueprint - Dec 22, 2016

Having Child Actor Components that are set in code can cause data loss upon compiling the blueprint. In this particular scenario, there are two custom Actor classes involved, MainActor and SubActo ...

Landscape Shaders Unknown by Landscape Thumbnail: Add to AllowedShaderTypes or ExcludedShaderTypes

UE - LD & Modeling - Terrain - Landscape - Oct 12, 2017

When packaging Elemental Demo and Vehicle Game for Linux from Windows, multiple Landscape Shader warnings are encountered complaining that the shader is unknown by the landscape thumbnail material a ...

Null Material Layers in Material Instances cause Opacity Mask and WPO to break on Nanite Meshes

UE - Rendering Architecture - Materials - Oct 31, 2024

When a Material Instance is loaded that has a nullptr layer in StaticParametrs.Materiallayers.  The Material Instance will create it's own CachedExpressionData but the ConnectedParameterMask will be ...

[CrashReport] FMaterialEditor::NotifyPostChange()

UE - Rendering Architecture - Materials - Aug 29, 2017

This is a trending crash in the 4.17 release. Update: also trending in the 4.18 release User DescriptionsImporting new charactertogled lighting modes on shadersChanging attriubtes on a materialWa ...

Crash adding a C++ First Person feature pack to a project

UE - Foundation - Core - Oct 2, 2017

Result: Crash while compiling modules for the projectFatal error: [File:d:\Builds\Release-4.18\Engine\Source\Runtime\CoreUObject\Private\Templates\Casts.cpp] [Line: 10] Cast of nullptr to Package fa ...

Crash launching ES31 app on Android

UE - Platform - Mobile - Apr 9, 2018

This has occurred so far using ES31 with Launch On to Android. It didn't occur with ES2 or Vulkan.Error: === Critical error: === Error: Error: Fatal error: [File:D:\Streams\Fortnite_Staging\Engin ...

Staging Directory in Project Packaging Settings should not be saved as absolute path

UE - Foundation - Data Pipeline - Cooker - Jun 8, 2021

When you package a project via the editor, it updates the ProjectPackagingSettings to set the StagingDirectory to the specific one chosen by the user. However, it saves this path as an absolute path ...

[UDN-19505621] Hide Selected At Startup Issue

UE - Editor - Workflow Systems - Jun 10, 2025

From [Link Removed]: 你好,我发现这里的选项有一些工作逻辑不一致,提一个改进建议: ​ 当手动隐藏Actor小眼睛图标的时候,设置Hide Selected At Startup 是无效的,这具有很大的误导性,而其他任何情况下,工作都是正常的,比如: 1.小眼睛隐藏+Show All At Startup 2.小眼睛隐藏+Show Selected At Startup ...

[AI] Changing NavMesh Resolution in config file does not update the quantFactor of existing navmesh

UE - AI - Navigation - Aug 6, 2025

When we changed the resolution in the config, if you open a map and then look at the navmesh, the resolution it shows is the updated one from the config (assuming you haven't overridden anything) ...

NPC - Does not get updates from Material Parameter Collection changes in the editor

UE - Niagara - Sep 30, 2024

When an MPC is selected as the Source Material Collection for an NPC, all of its current parameters are carried over to the NPC with their current values. After that, if parameters are added to, rem ...