Can't set "r.Shaders.Optimize" to false in UE5.4

UE - Rendering Architecture - Shaders - Jun 7, 2024

The CVar "r.Shaders.Optimize" cannot be set to false from DefaultEngine.ini in the section "[ShaderCompiler]" as its help text describes. Also tested on UE5-Main, CL: 34200103 ...

When a Niagara System has SimTarget set to GPUCompute Sim, CameraQuery is only returning data from the Player0 camera, ignoring the PlayerControllerIndex.

UE - Niagara - Nov 8, 2024

When a Niagara System has SimTarget set to GPUCompute Sim, CameraQuery is only returning data from the Player0 camera, regardless of PlayerControllerIndex. The expected behavior would be to have the ...

CPU Lightmass generates different lighting results on a landscape if executed via a commandlet vs through the editor

UE - Graphics Features - Jul 3, 2025

Building lighting via commandlet and via editor are giving different results. To prevent one method from polluting the other via Swarm cache, the cache needs to be cleared in between tests. ...

The collision of objects moving at high speeds seems to move in front of the object

UE - Simulation - Physics - Mar 9, 2015

The collision of objects moving at high speeds seems to move in front of the object. The faster the object is moving, the further the collision will be from the mesh. AnswerHub report: https://an ...

Static Meshes in Precomputed Visibility Cells are not occluded by landscape

UE - LD & Modeling - Terrain - Landscape - May 5, 2016

When using precomputed visibility on device for occlusion culling the landscape does not take the cameras view into account for culling objects when out of view of the camera and inside a visibility ...

Physics Constraint no longer constrains components that are set to Query Only

UE - Gameplay - May 5, 2016

Physics Constraint no longer constrains conponents that are set to Query Only Regression from 4.11.2 User Description: Testing a 4.12 copy of my 4.11 project and when I tested in editor, all my ...

Image widget does not scale the inner borders correctly

UE - Editor - UI Systems - Oct 24, 2014

When Scaling in and out in the UMG blueprints with an image applied to an image widget that is set to border as it's "Draw as" selection the image does not scale correctly. EDIT: The UI should prev ...

Default Data Wire Thickness in the Editor Preferences only affects Single Value data wires. Containers (Array, Set, Map) line thickness are wrongly tied to Default Execution Wire Thickness.

UE - Gameplay - Blueprint Editor - Aug 19, 2024

Changing the "Editor Preferences > Content Editors > Graph Editors > Tracing > Default Data Wire Thickness" value in the "Editor Preferences" only affects single value data wires. Containers (Array, ...

Lack of multi-bounce when using software traced lumen radiosity

UE - Graphics Features - Lumen - Apr 4, 2025

Certain Lumen Hardware Ray Tracing CVars, when disabled in isolation, will not fall back to tracing the Global Distance Field, because the Global Distance Field is still disabled. The function "Lum ...

Assigning a static mesh to a Mutable Clip Mesh With Mesh Node can crash the editor

UE - Anim - Mutable - Jul 4, 2025

Context: The Mutable plugin has a modifier node called Clip Mesh With Mesh that allows Static Mesh modifiers to be assigned as the clip mesh. Under certain circumstances, an assert can be triggered ...