Invalid GUIDs on new material instance parameters cause overrides to break on base param rename

UE - Rendering Architecture - Materials - Sep 3, 2025

When a parameter value is assigned on a newly created material instance (constant or dynamic) using Set***ParameterValueInternal, the parameter’s ExpressionGUID is left invalid (0,0,0,0). Parameter ...

[VR] Camera attached to non-root scene component in BP will sink into floor after Reset to Floor Origin

UE - Platform - XR - Aug 12, 2016

When a project is first created following the Setting up UE4 to work with SteamVR docs, the Vive camera works correctly and will display at the correct height. However, if at any point during develo ...

Adding Text Widget BP as "Widget Class" in Actor Class BP and compiling multiple times, changes Text visibility in Viewport

UE - Editor - UI Systems - Sep 15, 2017

Adding a new Text Widget Blueprint as a Widget Class to a new Actor Class Blueprint changes the visibility of the Text in the Viewport when compiling the Widget Blueprint multiple times. Regressio ...

Crash in FUniformExpressionSet::FillUniformBuffer trying access deleted UTextureCollection

UE - Rendering Architecture - May 30, 2025

Crash in FUniformExpressionSet::FillUniformBuffer trying access deleted UTextureCollection (Experimental in 5.6). The licensee describes their crash, their analysis, and a proposed fix: This crash ...

Initializing custom Component on Actor in constructor causes odd hierarchy and details panel issues

UE - Gameplay - Blueprint - Feb 19, 2019

When testing with a simple setup, as follows: MySceneComponent has a UProperty(VisibleAnywhere, BlueprintReadOnly) of a USphereComponent pointer, initiated in the Constructor AMyActor has a UProper ...

Focus mode in the Editor does not handle Actors without PrimitiveComponent correctly, treating them as if they were at the origin (0,0,0), skewing the camera placement.

UE - World Creation - Worldbuilding Tools - Nov 18, 2024

Focus mode in the Editor does not handle Actors without PrimitiveComponent correctly, treating them as if they were at the origin (0,0,0), skewing the camera placement. Some Actors like the WorldDat ...

Updating Material does not update platform stats in derived Instance

UE - Rendering Architecture - Materials - Nov 26, 2024

It would seem that updating a material does not update the associated platform stats in a material instance editor, only the parameters. Can workaround by manually invoking shader compile in the ma ...

The light in the Blueprint Editor's Preview Scene does not respond to any lighting channel but 0.

UE - Framework - Blueprint Editor - Jun 28, 2024

In the Blueprint Editor, Primitive Components can be configured to respond to Lighting Channels 0, 1, and/or 2. However, if channel 0 is disabled (even with another one enabled), the Preview Actor's ...

[CrashReport] UE4Editor_CoreUObject!UObjectPropertyBase::CheckValidObject() [propertybaseobject.cpp:510]

UE - Gameplay - Blueprint - Sep 28, 2017

This is a trending crash after the 4.17.2 hotfix, but has occurred since 4.17.0. Users have not provided any description of their actions when the crash occurred. The callstack shares similarities ...

Tabbing out of exclusive fullscreen leaves the window & backbuffer in an incorrect state

UE - Editor - UI Systems - Apr 24, 2020

With 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), ...