SKP import - Mirrored groups will display with the default material in Keep Hierarchy imports

TM - Interoperability - Apr 10, 2025

Reported in SF [Link Removed] SketchUp models containing grouped elements that are mirrored will incorrectly display these elements with the default material when imported using the Keep Hierarchy ...

Animation - Imported fbx animation mesh appears distorted

TM - Tools - Apr 9, 2025

Reported by user in SF [Link Removed] An animated FBX file from Mixamo appears with a distorted mesh inside Twinmotion. Distortion appears regardless of settings used for import. ...

CitySample - Level MassCrowd - interactions with SmartObjects/ContextualAnimScene is broken in 5.5

UE - AI - Apr 9, 2025

The 5.5 version of the CitySample project, particularly the MassCrowd scene, was not properly maintained. The previously working functionality of NPCs being able to sit on a bench is now broken. CAS ...

Crash when changing window resolution with AMD GPU, D3D11 and renderoffscreen

UE - Rendering Architecture - RHI - Apr 9, 2025

Context A crash can be induced with running Unreal Engine with DirectX11, a AMD GPU and running -renderoffscreen flag, and the main window is resized. This issue was first observed with the PixelStre ...

Iris - large fast arrays serialize multiple elements when only one is dirtied

UE - Networking - Iris - Apr 8, 2025

This seems to be a result of how the changemask is handled for fast arrays. Because the changemask is a fixed set of bits (defined by IrisFastArrayChangeMaskBits), a single bit can represent multipl ...

Sampling textures with bias in the path of a custom data pin causes derivative operations when avoidable

UE - Rendering Architecture - Materials - Apr 8, 2025

Materials that make use of the analytical derivatives path to avoid hardware derivatives can still generate derivative operations on texture samples when the shading model has a custom data pin and ...

Incorrect volume bounds check in FTranslucentLightInjectionCollector::AddLightForInjection

UE - Graphics Features - Apr 8, 2025

The 'VolumeBounds' array in FTranslucentLightInjectionCollector::AddLightForInjection is accessed as a pointer instead of with 'VolumeCascadeIndex' and thus fails bounds checks for the outer volume. ...

Memory Leak When Raytracing Enabled with Specific Rendering Settings

UE - Graphics Features - Ray Tracing - Apr 8, 2025

When a shipping build is packaged using specific rendering settings a memory leak can be observed. The licensee has noted that this leak presents as a 10MB per hour increase in RAM usage. It has a ...