Unreal Engine Issues
Unreal Engine Issues
Null Material Layers in Material Instances cause Opacity Mask and WPO to break on Nanite Meshes
UE - Rendering - Architecture - Materials - Oct 31, 2024When 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 ...
Nanite Landscape Visibility Layer Crash
UE - Graphics Tools - Terrain - Landscape - Jun 10, 2026Upon saving the level after creating the landscape and painting visibility, the editor crashes. When you restart the editor and load the level, you are greeted with a warning in the upper right corn ...
No Dynamic Shadows From Stationary Lights in Forward Shading Without Building Lighting
UE - Graphics Features - Apr 24, 2018I've observed this issue in 4.18.3 and 4.19.1. Per Licensee: So we've spotted an issue that I wanted to put on your radar with dynamic shadowed stationary lights + r.ForwardShading=1 What we're s ...
Tabbing out of exclusive fullscreen leaves the window & backbuffer in an incorrect state
UE - Editor - UI Systems - Apr 24, 2020With windows 10 there has come some new swap chains, which unfortunately messes some things with regards to fullscreen up. We've fixed a bunch in the renderer (which would downright cause crashes), ...
Editor Crash when trying to get Color data from Vertex buffer
UE - Graphics Features - Nov 6, 2019When attempting to get the vertex color of an instance of of a static mesh that is painted after placing it in the World Viewport. The Editor crashes returning an "Unhandled Exception". The cause o ...
Failure to sign when packaging for iOS Distribution when using Remote Compile from a code project on Windows
UE - Platform - Mobile - Feb 20, 2019Packaging for iOS Distribution from Windows using Remote Compile results in a failure during the signing portion. This seems to be caused by a hardcoded "false" for a property that is used to determ ...
Preview Rendering Levels Do Not Display Supported Optimization Viewmodes in Viewport Dropdown
UE - Platform - Mobile - Apr 2, 2019When attempting to set an optimization viewmode while using a Preview Rendering Level other than Shader Model 5, the Optimization Viewmodes dropdown is missing all of its options and instead display ...
PCG sampling of RVT does only works when sampling the first texture layer
UE - World Creation - Procedural Tools - PCG Component - Dec 11, 2025The logic for selecting a page table texture in FVirtualTexturePageTable::Initialize() uses the indexing for texture layers (index 0-7) to fetch from the page table textures (index 0-1). All RVT for ...
Crash when adding Actor Array Element to a Sequencer Event Struct
UE - Anim - Sequencer - May 25, 2017Crash when adding Actor Array Element to a Sequencer Event Struct Error message: Assertion failed: 0 [Link Removed] [Line: 56] Source Context: 42 N = FName(*StringName); 43 ...
Crash when changing r.MaterialQualityLevel when FastGeo plugin enabled in cooked build
UE - World Creation - Worldbuilding Tools - Sep 5, 2025The engine crashes when the r.MaterialQualityLevel is changed in a cooked game that uses the FastGeo Streaming Plugin. The crash doesn't repro with the same steps in Editor, just in a cooked build. ...