Unreal Engine Issues

If a mesh contains more than 32 material slots, it can cause a hash collision when computing the Raytracing CachedMeshCommandHash

When exporting from a level sequence, the LOD for the bones is based on the camera distance, instead of using LOD0

When exporting a level sequence to an animation sequence, the bones used will be based on the LOD for the current camera location, instead of exporting LOD0. This is very noticable if you pull the ...

HZB Occlusion causes large stalls on the render thread

HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...

Vertex color does not work on Skeletal Mesh with Nanite enabled

Nanite enabled skeletal meshes don't work with materials containing a vertex color node. The vertex color material does work for non-Nanite skeletal meshes and Nanite-enabled static meshes. ...

Converting a mesh to Nanite merges mesh sections with the same material index, but with different material overrides

When a mesh with multiple sections which point to the same MaterialIndex but have different settings enabled (e.g. bCastShadow is enabled on only one section) is converted to Nanite, the material sl ...

Landscape Textures Patches issue when using "Texture Backed Render Target" as the Height Patch Source Mode where Landscape patches are not applying properly the first time a level is opened after restart

Context: Landscape patches are components that can be attached to meshes to affect the landscape as the mesh is repositioned. Problem: The problem is that when using "Texture Backed Render Target" ...

Recompiling an ABP that another ABP has a Property Access dependency on without recompiling/linking the other causes a crash

The crash comes from the pointers in FAnimSubsystem_PropertyAccess::Library::Indirections in the layer ABP from pointing to old/invalid functions and properties from the trash ABP_Manny, as they hav ...

FNiagaraScalabilityManager incorrectly reactivates a NiagaraComponent that was deactivated by runtime user code

Context: The Niagara System is the primary tool to do visual effects inside Unreal. Niagara systems can be culled due to distance. Problem: Once a deactivated Niagara System is culled due to distan ...

OnTextChanged not called for UEditableTextBox / UMultiLineEditableTextBox when text is set programmatically

When calling SetText() on a UEditableTextBox or UMultiLineEditableTextBox, the OnTextChanged delegate is not triggered. This regression was first reported in UE 5.3 and acknowledged previously in UD ...

Virtual texture fallback displays in incorrect color space on mobile platform (VT:OFF) Preview