FTransform(ENoInit) ensures in Debug on mobile platforms

UE - Foundation - Core - Sep 25, 2018

As of 4.20, ENABLE_NAN_DIAGNOSTIC is now enabled in all Debug configurations. However, this does not work well with the TransformNonVectorized that is used on platforms like android. If this combina ...

Movement Tolerance for Spawn Per Unit Does Not Function

UE - Niagara - Oct 19, 2018

Motion tolerance for Spawn Per Unit does not affect the particle system. Even if the vaules are set very high. Found in 4.18 CL# 3832480, 4.19 CL# 4033788, 4.20 CL# 4369336, 4.21 Preview 2 CL# 4472 ...

Navigation Mesh ignores Hierarchical Instanced Static Meshes using "Build Paths" or the "Build" Button

UE - AI - Feb 1, 2019

Hierarchical Instanced Static Meshes are partially ignored after building the navigation mesh. This is causing the navmesh to be generated within all or part the HISM instead of around it.  This ...

Massive FPS drops in editor when moving mouse over menu items on Linux

UE - Platform - Linux - Apr 22, 2019

Navigating various dropdown menus in the Editor causes the FPS to drop down to around 25 or 10 in the Viewport on an empty project. This does not reproduce on Windows with -vulkan This issues was ...

Cannot set auto success range to an invalid value in the AIPerception component

UE - AI - May 3, 2019

When modifying the value of "Auto Success Range from Last Seen Location" to a value that is not it's default, you can not set it back to its default -1 one value. This was reported and tested in 4 ...

DirectX Tesselation Crash

UE - Graphics Features - Dec 12, 2017

Per UDN Licensee: I have 2 crash repro when enabling DirectX12, both linked to tesselation and still present in 4.18 stock engine and easy to reproduce. Crash 1 -Start editor with DirectX12 -Cre ...

Ray traced shadow sample settings greater than 1 cause shadow artifacts

UE - Graphics Features - Lumen - Sep 23, 2020

Alternative you can follow these steps to reproduce 1. Create a new project with ray tracing enabled 2. Activate the groom plugins 3. Import a groom asset into the scene 4. Add any light type to the ...

Landscape Paint Layers will not scroll to the end when using mouse wheel

UE - LD & Modeling - Terrain - Landscape - Sep 28, 2020

In a normal detail panel, each element has its own SDetailSingleItemRow and are mostly uniformly sized with some exceptions of having a few bigger rows (i.e. asset pickers). However, these layers ar ...

HiResScreenshot has incorrect masking when screenshot resolution scale does not match the viewport.

UE - Rendering Architecture - RHI - Sep 6, 2021

After a bit of investigation, the way to fix this would be to modify MergeMaskIntoAlpha to pass in the actual resolution scale and the requested size, and only mask the overlapping pixels. Currently ...

Memory leak when using Blueprint Debugger while inspecting a return value

UE - Gameplay - Blueprint - Mar 11, 2022

Potential memory leak when using Blueprint Debugger to inspect a return value multiple times while playing. User also reported this would cause a crash, but I didn't try to max out ram usage to trig ...