Unreal Engine Issues
Unreal Engine Issues
FBX Export - StaticMesh export to FBX crashes if UVElements has more channels than VertexInstanceUVs
UE - Editor - Content Pipeline - FBX - Jan 22, 2026As indicated in the repro steps, we have a StaticMesh asset that, for some reason, has a mismatch in their serialized bulk data where:MeshDescription->GetNumUVElementChannels() == 2FStaticMeshConstA ...
Server doesn't process anim notifies with montage tick type set to queued when bad network conditions occur
UE - Anim - Gameplay - May 3, 2023After some testing this issue looks to only occur with queued notifies and not with branching point notifies. UDN: https://udn.unrealengine.com/s/question/0D54z00009643x4CAA/server-doesnt-process-a ...
Mass is not calculated if an object's Collision Enabled field is set to No Physics Collision even when Simulating Physics
UE - Foundation - Core - May 22, 2015If an actor has 'Simulate physics' enabled and the Collision Enabled field is set to anything other than Collision Enabled (i.e. OverlapAll sets this to No Physics Collision) then mass is reset to 1 ...
RenderTarget Texture Alpha rendered incorrectly when SceneCapture2D AA set to true
UE - Graphics Features - Jan 8, 2016The Alpha Channel of the Render Target Texture is rendered as a value of 1 (solid white) when the SceneCapture2D actor is set to LDR with PP and Anti-Aliasing is set to true in the General Show Flag ...
CharacterMovement doesn't clear velocity
UE - Simulation - Core - Oct 11, 2024Velocities are not being cleared when physics simulation set to false. ...
A LevelSequence will lose the binding to objects contained in a level instanced inside another level
UE - World Creation - Worldbuilding Tools - Level Instances - Sep 15, 2025A LevelSequence will lose the binding to objects contained in a level instanced inside another level on 5.6 and up. Refer to the reproduction steps or the shared repro project provided by the licens ...
Modulated shadows do not render in the correct area on older devices / versions of Android OS
UE - Platform - Mobile - Apr 5, 2016This issue was reported by a user who was having issues with their modulated shadows showing up in random spots on their mobile devices. Their devices were a Samsung Galaxy Note 2 and a ASUS Zenfon ...
NavMesh debug material color is changed by lighting with high lux values.
UE - AI - Debugging - May 23, 2024There is a clear difference in color saturation for the nav mesh debug material between when lit by a light with low lux values (6) and when lit with high lux values (1000) and eye adaption is enabl ...
Crash trying to convert skeletal mesh to Nanite
UE - Rendering - Graphics Features - Nanite - Mar 6, 2025In SkeletalRenderNanite.cpp / FDynamicSkelMeshObjectDataNanite::UpdateBonesRemovedByLOD, bone indices are of type FBoneIndexType (defined as uint16 from BoneIndices.h), instead of int32. On line 18 ...
Insufficient precision of Decode71 function
UE - Rendering - Architecture - Shaders - Jun 5, 2025Encode71 and Decode71 in DeferredShadingCommon.ush are functions that convert 8-bit values to 7-bit values and mask values, and licensees have reported that the accuracy is insufficient when usi ...