Cannot Add Actor Blueprints to Object Library When Base Class is Set to Actor

Tools - Jan 25, 2016

Setting the base class dropdown of an Object Library to Actor prevents you from being able to add any actors to the library. This occurs even when the Has Blueprint Classes bool is checked. Found ...

InterpToMovement Component Causes Crash During PIE

UE - Gameplay - Feb 23, 2016

When using an InterpToMovement component in a blueprint with the "Auto Update Tick Registration" and "Auto Register Updated Component" options unchecked, PIE will result in a crash. Found in 4.10. ...

uncaught exception: out of memory after launching project onto HTML5 (32-bit browsers)

UE - Platform - Mobile - Mar 20, 2017

First person template project is struggling to run on Firefox 32-bit Version 52.0.1 and eventually throws an "uncaught exception: out of memory" error. Occurs in both BP and C++ projects. May be a ...

[CrashReport] Tutorial crash UObject::execLetValueOnPersistentFrame()

UE - Gameplay - Blueprint - Jul 7, 2017

This is another Tutorial crash that shares a similar callstack with [Link Removed] and [Link Removed], but those specific repro steps have been fixed while this one is still occurring in 4.16.2. On ...

[CrashReport] Mac crash - FMetalRenderPipelineDesc::CreatePipelineStateForBoundShaderState

UE - Rendering Architecture - RHI - Aug 25, 2017

This is an infrequent Mac crash that has been affecting users since at least 4.15. Users have not provided any descriptions of their actions when the crash occurred. The callstack is similar to the ...

The vertex color becomes red when importing a static mesh without Color Set

Tools - Aug 28, 2018

It seemed to be white at 4.19, but it seems to be red at 4.20. I found out that there seems to be a cause for initialization of Mesh Attributes. As a result of fixing this, it is now displayed in wh ...

Niagara GPU particles will always have a lifetime of one second if they use a Collision Module

UE - Niagara - May 2, 2019

GPU Particles will always have a lifetime of one second when using a collision module. This is a result of an issue with how off screen timing is handled. GPU particles that are off screen should on ...

Niagara Crash : ExportParticleDataToBlueprint module causes buffer overrun

UE - Niagara - Aug 10, 2021

This buffer overrun is probably caused by the ExportParticleDataToBlueprint module does not respecting the GPUAllocation Fixed Size setting in the module. In fact, out-of-range export data is not c ...

Marketplace plugins "missing precompiled manifest" on Mac

UE - Platform - Apple - Oct 12, 2021

Summary This issue was reported by a licensee via UDN. It appears that all of the plugins generate a "missing precompiled manifest" error when packaging a project on Mac in UE4.26.2.Licensee Platfor ...

Atmosphere related scan line artifacts for Path Tracer with MGPU

UE - Graphics Features - Path Tracer - Feb 10, 2023

There are two UDNs related to this issue.  It makes the Path Tracer unusable with MGPU, with atmosphere enabled. I already have a one-line fix implemented and tested.  The atmosphere scan line arti ...