Unreal Engine Issues
Unreal Engine Issues
Clearcoat material behaves differently between 5.5 and 5.7
UE - Graphics Features - Jan 16, 2026Starting with Unreal Engine 5.7, specular reflections on clearcoat Materials are less pronounced. Unreal Engine 5.5 tests performed on //UE5/Release-5.5/, CL: 41545209 ...
HISM flickering when any character is visible
UE - Graphics Features - Jan 12, 2026On an NVIDIA GPU, Instanced Static Meshes can flicker when a Groom card or mesh LOD is visible. This appears related to an issue rendering the ISM into the Scene Depth. At the end of the Prepass, t ...
Lumen Global Distance Field Trace Leaking due to Surface Cache Sampling
UE - Graphics Features - Jan 12, 2026At specific distances from a thin wall, surfaces inside of a sealed chamber can receive indirect lighting from outside, leaking light into the chamber. This appears to be due to how SWRT handles sa ...
Temporal blur artifacts on Geometry Cache Components in Blueprint actor
UE - Graphics Features - Jan 9, 2026When a Geometry Collection is in a Blueprint, attached to other components, it can render incorrect motion vectors at some angles. In the test project, any angle that is not a multiple of 45 will re ...
Velocity Scene Texture Data Integrity Issues
UE - Graphics Features - Jan 8, 2026When a Post-Process Material uses the Scene Texture Material Expression, the following code is generated: ``` MaterialFloat2 Local0 = Parameters.TexCoords[0].xy; MaterialFloat2 Local1 = ClampSceneT ...
Out-of-Bounds Access During Partial Updates of ISMC Per-Instance Custom Data
UE - Graphics Features - Jan 6, 2026When using instance custom data values, removing an instance and changing the number of custom data floats in sequence can cause an array-out-of-bounds crash. The underlying arrays are not resized ...
When r.SSR.Stencil is enabled, there is wrong logic observed.
UE - Graphics Features - Dec 19, 2025When r.SSR.Stencil is enabled, the areas with high roughnesss are not discarded and Unlit materials are incorrectly handled. See the linked EPS case (Additional Info URL) for a full explanation of ...
WorldToClip/ClipToWorld transform in materials not behaving as expected
UE - Graphics Features - Dec 19, 2025In 5.3, the specified code will return all 0 or very small as expected. However in 5.4.4 and onwards (also checked in 5.6.1 & 5.7.1), it returns very large numbers. ...
Viewport stuttering during orbit/zoom navigation
UE - Graphics Features - Dec 17, 2025Received a report of persistent stutters in the editor when trying to navigate in the viewport, including asset editor viewports like the Skeletal mesh editor and control rig editor. Hardware used ...
UInstancedStaticMeshComponent::AddInstances does not appear to be adding per-instance previous transforms when enabled
UE - Graphics Features - Dec 3, 2025Instanced static mesh component does not add instances transforms to PerInstancePrevTransform array when using UInstancedStaticMeshComponent::AddInstances. Additionally Updating the transforms of th ...