Unreal Engine Issues
Unreal Engine Issues
Duplicating a blueprint that implements an interface and then removing that interface will cause compile errors that don't occur if the interface was removed from the original BP
UE - Gameplay - Blueprint Editor - Aug 1, 2020See steps to reproduce. Looks like the fixup when saying Yes to "Would you like to transfer the interface functions to be part of your blueprint" doesn't work correctly on the duplicated BP. Inter ...
[MetaSounds][Stereo Mixer] - When changing the gain on the Right channel dynamically, the output has clicks and pops
UE - Audio - MetaSounds - Mar 31, 2022When changing the right channel gain of the stereo mixer at runtime, it generates clicks and pops in the output. ...
Masked TwoSided material causing lumen direct lighting to leak through walls
UE - Graphics Features - Lumen - Apr 23, 2024It appears that LumenScene's Hardware Ray Tracing is causing light leaking into a sealed room (which should be perfectly black). This bug does not appear to happen on AMD GPUs. ...
Custom node not working with material attributes
UE - Rendering Architecture - Materials - Jul 15, 2024Using Material Attributes as an input to a Custom Expression causes the HLSL Translator to create multiple CustomExpression# functions, for each used member of the Material Attributes, rather than u ...
High Virtual Texture Sample/Lookup Cost when using a Virtual Texture in a Material Layer Blend
UE - Rendering Architecture - Materials - Mar 14, 2025Some Material Attribute blends in Material Layer Blends can cause Virtual Texture samples to be duplicated in HLSL. This can be avoided by sampling the Virtual Texture in the Parent Material, and pa ...
Packed level actors and Level instances are sometimes not included in HLOD build on a World Partition Level
UE - World Creation - Worldbuilding Tools - HLOD - Mar 14, 2025Context World Partition - Hierarchical Level of Detail (HLOD) system uses custom HLOD Layers to organize large amounts of Static Mesh Actors and generate a single proxy mesh and Material. Problem T ...
Building Lighting will Generate Additional Lightmaps after Rotating Lightsource
UE - Graphics Features - Jul 7, 2015Lightmap sizes seem inconsistent after rotating a light source and rebuilding the lighting. This causes concern about file sizes when packaging the project that is using baked static lighting. The ...
Creating an exposed variable does not always update correctly to the bp's Details panel
UE - Gameplay - Blueprint - Feb 20, 2015Creating an exposed variable does not always update correctly to the bp's Details panel. They will show as having multiple values until the bp is clicked off and back onto. ...
The Add node does not update in the Construction Script
UE - Gameplay - Blueprint - Feb 28, 2015The Add node does not update in the Construction Script. Reproduced in 4.7.1 binary and Main (//depot/UE4/Promotable-CL-2455917) ...
PhysX generates extra "sleep" event when moving Kinematic actors away from Simulated actors with Teleport option.
UE - Simulation - Physics - Aug 4, 2016Issue seems to be related to NpRigidDynamic::setKinematicTarget. When called by itself (like in the case of Kinematic bodies moved without teleportation), the simulated actor is woken and is put ba ...