Unreal Engine Issues
Unreal Engine Issues
Wrong density calculation in UBodySetup::CalculateMass
UE - Runtime - Simulation - Sep 29, 2025Wrong density calculation in UBodySetup::CalculateMass. The licensee has provided the following analysis and suggested fix: In UBodySetup::CalculateMass, the following code is present: // physical ...
Non-Nanite meshes not being correctly cleared from all levels of VSMs on actor destruction when r.Shadow.Virtual.NonNanite.IncludeInCoarsePages=0
UE - Rendering - Graphics Features - Shadows - Jun 15, 2026When using the r.Shadow.Virtual.NonNanite.IncludeInCoarsePages=0 to optimize VSM performance there are errors in how the VSM is invalidated when actors are destroyed with non-Nanite meshes. The curr ...
Custom Primitive Data is not affected in the skeletal mesh on BP instances in the editor
UE - Rendering - Architecture - Jan 22, 2026Editing Custom Primitive Data values in the details panel of a placed BP actor with a Skeletal Mesh component does not reflect in the Editor viewport. ...
SkyLight Leaking does not affect reflections when the SkyLight is static but static lighting is disallowed
UE - Rendering - Graphics Features - Sep 10, 2025Reflections do not receive SkyLight leakage contribution from a static SkyLight when static lighting is disallowed. This is caused by the function UpdateSkyIrradianceGpuBuffer checking if the SkyLig ...
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 ...
Replicated subobjects list crashes with unreachable yet valid objects when UE_NET_SUBOBJECTLIST_WEAKPTR=0
UE - Networking - May 8, 2023This seems to occur when the subobject is considered unreachable but is not yet pending kill/marked as garbage. In this case, IsValid returns true while FWeakObjectPtr::Get returns nullptr for the o ...
ChaosWheeledVehicleMovementComponent is breaking the const CDO contract and changes to the instances are being applied to the CDO
UE - Runtime - Character - Apr 28, 2025As described by the licensee, the const CDO contract is being broken on ChaosWheeledVehicleMovementComponent. The issue the licensee is facing is that by spawning cars with different configurations, ...
WPO is incorrectly generated on materials using Material Attributes as input to Landscape Layer Blend node
UE - Rendering - Architecture - Materials - Jan 31, 2024This comes from this UDN : [Link Removed] It occurs with this setup : [Image Removed] , where Set Material Attributes expressions act as inputs to the Landscape Layer Blend material expression. ...
Missing Triangles on scaled MetaHuman assets with Nanite enabled
UE - Rendering - Graphics Features - Nanite - Feb 19, 2025Additional information: only happens when all three conditions are true: the camera is very close to the character, the MH is Nanite, and a scaled mocap animation is appliedmaterial is opaque, shows ...
Chaos: geometry collection with One Way Interaction never breaks from its own collisions
UE - Runtime - Simulation - Aug 21, 2026A geometry collection with One Way Interaction Level set to 0 never breaks from its own collisions. It falls, lands, and stays intact no matter what it hits. Set the level to -1 (feature off) and ch ...