Unreal Engine Issues
Unreal Engine Issues
Invalid GUIDs on new material instance parameters cause overrides to break on base param rename
UE - Rendering Architecture - Materials - Sep 3, 2025When 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, 2016When 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 ...
Crash on play if a BP uses a ClearInstances node followed by an AddInstance node
UE - Graphics Features - Jul 21, 2017Crash on play if a BP manipulates a InstancedStaticMeshComponent by using a ClearInstances node followed by an AddInstance node. This is a blocker for the licensee. This is a regression: Working ...
Crash in FUniformExpressionSet::FillUniformBuffer trying access deleted UTextureCollection
UE - Rendering Architecture - May 30, 2025Crash 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, 2019When 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 ...
Updating Material does not update platform stats in derived Instance
UE - Rendering Architecture - Materials - Nov 26, 2024It 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 ...
UMG widget callbacks do not set PIE context in editor
UE - Editor - UI Systems - May 21, 2018This is from a UDN post. Several gameplay functions, such as level streaming and SoftObjectPtr resolution, depend on the GPlayInEditorID being set when that code is executed in PIE in the editor. T ...
The light in the Blueprint Editor's Preview Scene does not respond to any lighting channel but 0.
UE - Framework - Blueprint Editor - Jun 28, 2024In 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 ...
Landscape Splines in Partially Loaded World Partition Levels Can Cause Nanite Landscape Invalidation
UE - Graphics Tools - Terrain - Nov 7, 2025Certain placements of landscape splines in world partition levels can cause Nanite landscape proxies to invalidate, and switch back to their non-nanite version. This happens when specific regions of ...
Exported Particle Emitter Tries to Reference Graphs of Original System
UE - Niagara - Dec 7, 2017User reports that the bug was initially discovered in 4.18 and then reproduced in 4.16 project (attached). Per User: For some reason when exporting this emitter to any other system bugs out. When ...