Fix the skeletal mesh merge tool material assignment, change the API to avoid confusion

OLD - Anim - Jul 25, 2018

UDN user ask us to change the API for the material to remove confusion with the material ID. Also apparently there is an issue with the skeletal mesh merge tool, the user did not give any repro ste ...

Level Bounds Incorrectly Calculated If Particle System Does Not Have "Use Fixed Relative Bounding Box" Enabled

UE - Niagara - Jul 26, 2018

If "Use Relative Fixed Bounding Box" is disabled, level bounds will be incorrectly calculated. This seems to be similar to [Link Removed]. Found in 4.19 CL# 4033788, 4.20 CL# 4212847, 4.21 CL# 4233 ...

Fix up IOS errors calling UI API from non-UI threads

UE - Platform - Apple - Jul 27, 2020

4.16 Mobile Compat Pass - QA-Decals - UI glitch when playing on a 9.3.5 iOS Device

UE - Platform - Mobile - Apr 21, 2017

While testing in QA-Decals on iOS device, after loading into the project the UI will be glitched ~50% of the time. After further testing, it seems this bug only occurs on iPads running the iOS vers ...

The Editor freezes during PIE when loading a .sav file from 4.7 in a 4.8 or 4.9 project

UE - Gameplay - Jun 24, 2015

The Editor freezes during PIE when loading a .sav file from 4.7 in a 4.8 or 4.9 project. The user reporting this reports a memory leak and crash, but I have not been able to reproduce that in partic ...

Backout attempted fix for - AutoSize triggers ensure on shortened Skel Anim Section moved past anim length

UE - Anim - Sequencer - May 29, 2026

In Sequencer, calling "Edit > Auto Size" on a UMovieSceneSkeletalAnimationSection triggers the LowerBound > UpperBound ensure in UMovieSceneSection::SetRange (MovieSceneSection.h:333) when the secti ...

Bug in StringTemplate.cpp related to modulo operator in MaterialTemplate.ush (code fix provided)

UE - Rendering - Architecture - Materials - Jun 25, 2024

Shader Template files like MaterialTemplate.ush do not submit previous chunks when encountering a `%` character, unless that `%` character is `%s` or `% {...} `. Because the error is happening ...

Fix PrimitiveComponent overlap indirection

UE - Simulation - Physics - Sep 27, 2016

When doing overlap tests in PrimitiveComponent, UWorld->ComponentOverlapMulti is used. The callstack for that ends up looking like this (callstack is inverted, highest level on top): UWorld::Compo ...