Pasting an instanced subobject property into a Blueprint prevents that Blueprint from being added to level

UE - Framework - Blueprint Editor - Nov 17, 2022

Copying and pasting an array of nested instanced subobjects from a level instance into a Blueprint's defaults and adding that Blueprint to the level will prevent the actor instance from saving. ...

Fix primitive uniform buffer validation.

UE - Rendering Architecture - RHI - Jul 31, 2020

GPUScene primitive validation is currently busted and asserts. It looks like there are two problems: 1) NaN's in the entries can cause comparison issues, so a MemCmp would be better. 2) There's a ...

PythonScriptPlugin: UE_LOG Format Changed to Unicode after Redirection

UE - Editor - Workflow Systems - Feb 15, 2023

PythonScriptPlugin sets std output mode to _O_BINARY but fails to restore it to the previous state afterwards because cached StdOutMode is already _0_TEXT, hence _setmode returns -1. See PythonScri ...

Static Mesh Only enabled Foliage Actor causes serialization error in packaged game

UE - World Creation - Worldbuilding Tools - Nov 24, 2023

The crash can be worked around by modifying FFoliageISMActor::Serialize as following code : void FFoliageISMActor::Serialize(FArchive& Ar) { #if WITH_EDITORONLY_DATA     if (!Ar.IsCooking()) // ...

Popping Ribbon UVs

UE - Niagara - Mar 10, 2025

Please see the Additional Link for related UDN information. The UV popping described can be subtle, depending on settings; it's affected by spawn rate and GPU vs CPU. The popping shown in the gif t ...

Display Blueprint Added Components on subobjects with meta = (ShowInnerProperties)

UE - Gameplay - Blueprint Editor - Sep 28, 2021

Right now only native subobjects are displayed in the details panel with meta = (ShowInnerProperties) is set. Child Actor Components are an example of this, where if the child actor you have added h ...

Engine crashes when building GPU Lightmass in large scenes

UE - Graphics Features - May 12, 2022

Engine crashes when building GPU lightmass in larger scenes. This does not occur on smaller maps like the Unreal Engine Templates. I was able to reproduce this issue in CitySamples SmallCity map. T ...

Datasmith .WIRE Import - Shader name inserted into Material Element Slot

UE - Editor - Content Pipeline - CAD - Apr 2, 2025

Can we please implement a feature whereby the shader name applied to surfaces / objects is used for the Material Element Slot? When using Dataprep and replacing the materials using a table, it give ...

Input consumed by a widget's action binding can be skipped if using key modifiers

UE - Gameplay - Input - Oct 29, 2021

The following code in UPlayerInput::GetChordsForKeyMapping is at fault for this:  !(KeyMapping.bAlt || KeyMapping.bCtrl || KeyMapping.bShift || KeyMapping.bCmd || ActionBinding.KeyEvent == EInputEv ...

NumNonClothingSections logic is bad

UE - Editor - Content Pipeline - Datasmith - Jul 26, 2019

We use the NumNonClothing section number to iterate in the sections, this is an error if the cloth sections are not at the end of the sections array. See the following picture of a search on NumNonC ...