Unreal Engine Issues
Unreal Engine Issues
When creating a new NiagaraSystem using existing system, the DefaultEffectType set in ProjectSettings is not reflected.
UE - Rendering - Architecture - Niagara - Jul 24, 2023When creating a new NiagaraSystem, the DefaultEffectType set in ProjectSettings should be reflected. If another EffectType is already set, it should be respected. The problem here is that when creat ...
GPU-ARM Mali 400 series phones will render an Opaque Unlit Material as black
UE - Platform - Mobile - Feb 12, 2016ARM Mali 400 Series GPUs are rendering Opaque Unlit Materials as Black instead of the designated color. This is a *regression* from 4.10.2.Devices where Issue OccursDevice NameBrandBug Description ...
Misaligned sampling in UI Material with with CustomStencil
UE - AI Workflows - UI Systems - May 19, 2025The output of the CustomStencil node in a User Interface material does not align with the viewport dimensions. Toggling fullscreen/windowed mode (F11) causes the offset to reappear, so scaling the n ...
Regression - Nav mesh is not generated on BSP brushes after loading a map
UE - Runtime - Character - Dec 18, 2024In UE 5.5, when loading a map and selecting "Build – Build Paths", the nav mesh is not generated on any BSP brushes (although it is correctly generated in static meshes). This did not happen in earl ...
Regression - Nav mesh is not generated on BSP brushes after loading a map
UE - Runtime - Character - Jan 14, 2025In UE 5.5, when loading a map and selecting "Build – Build Paths", the nav mesh is not generated on any BSP brushes (although it is correctly generated in static meshes). This did not happen in earl ...
FAnimationRuntime::BlendPosesPerBoneFilter() causes an assertive crash when Skeletal Mesh LOD is changed
UE - Runtime - Animation - Nov 1, 2023The crash occurs from "check(BoneBlendWeights.Num() == NumBones);" This crash occurs when the following conditions are met;The skeletal mesh LOD is changed.The number of bones is difference between ...
Crash when Live Coding is triggered after engine source edits Blueprints using ChildActorComponent
UE - Framework - Blueprint - Nov 28, 2025After editing engine source files and triggering Live Coding, derived Blueprints that inherit from a Blueprint containing a ChildActorComponent cause UChildActorComponent::Serialize to run on a Live ...
Content is Missing from Cook and indeterminism: StaticMeshComponents in Blueprints that copy data into themselves from StaticMesh have indeterminism due to StaticMesh not yet finished loading, postloading, or building
UE - Core - Systems - Nov 12, 2025Content is Missing from Cook warnings are warnings reported at the end of cook phase of a project's data build. They report that data used by a cooked package will not be available at runtime. This ...
GPU Scene reserved resources can break Niagara mesh preview rendering
UE - Rendering - Architecture - Niagara - Sep 28, 2026When a Niagara emitter has multiple Mesh Renderers and each renderer draws a different subset of particles (via Renderer Visibility), all renderers are drawn using the color of particle index 0 in t ...
Light Function and World Position in 5.4
UE - Rendering - Features - Nov 4, 2024When rendering a Light Function into the Translucency Lighting Volume, the World Position Material Expression returns the position relative to the Camera (unrotated), not the World. This can be mor ...