Crash when Undo after deleting a Material Layer of a Material Instance.

UE - Rendering Architecture - Materials - Apr 2, 2025

In Unreal Engine version 5.5.4, the Editor crashes when performing Undo after deleting a Material Layer of a Material Instance ...

Branching Points in a Montage Affect the Rotation Outcome of Root Motion

UE - Anim - Runtime - Mar 28, 2025

When playing Montages with Root Motion, the sub stepper extracts root motion transform in small increments. If a Branching Point exists within the interval being extracted, the extraction range is s ...

In Packaged builds, Chaos Cache Manager can't animate Geometry Collections with Nanite Enabled if Cache Mode is set to Static Pose

UE - Simulation - Physics - Destruction - Feb 27, 2025

In Packaged builds, Chaos Cache Manager (CCM) can't animate Geometry Collections (GC) with Nanite Enabled if Cache Mode is set to Static Pose. The licensee tried to animate a CCM using Sequencer onl ...

Packed Level Actors will create ISMs with inverted normals when a portion of static meshes have negative scales. This is apparent with two-sided materials.

UE - World Creation - Worldbuilding Tools - Feb 17, 2025

Packed level actors will create ISM instances with inverted normals when the selection of meshes used to create the packed level actor contains a subset of meshes with negative scales. This is the ...

Bundled compute PSO compilation stalling tender thread

UE - Rendering Architecture - RHI - Feb 13, 2025

EA Motive has pointed out a potential bug they found related task graph synchronization and when compiling compute PSOs: [Link Removed]. From the screenshot they sent over, it seems that a task grap ...

Deleting transient actor marks level dirty

UE - World Creation - Worldbuilding Tools - Feb 6, 2025

The licensee has noticed that the deletion of a transient actor still marks the scene as dirty and asks it to be saved. Checking the source it was noted that the transient flag is not verified on de ...

ensure(false) being fired in FGenericParticlePairMidPhase::FindOrCreateConstraint from key collision

UE - Simulation - Physics - Jan 27, 2025

ensure(false) being fired in FGenericParticlePairMidPhase::FindOrCreateConstraint from key collision. The licensee reports one of their users reported this issue and they were able to reproduce a fe ...

A Skeletal Mesh simulating physics that hits a Geometry Collection Actor with OneWayInteraction true, OneWayInteractionLevel 1, and is using Damage Propagation (default) will be accelerated so fast it immediately disappears by hitting the world limits

UE - Simulation - Physics - Destruction - Jan 20, 2025

A Skeletal Mesh simulating physics that hits a Geometry Collection Actor with OneWayInteraction true, OneWayInteractionLevel 1, and is using Damage Propagation (default) will be accelerated so fast ...

Navigation: Exiting game while async nav building tasks are running can cause null pointer access of OctreeController.NavOctree from worker thread

UE - AI - Navigation - Jan 14, 2025

Context Projects can turn on the project setting bDoFullyAsyncNavDataGathering to execute navigation mesh building tasks on worker threads. Some of these tasks will access the NavOctree, whose life ...

Params in material instance disappear when grouping is changed in material with a material layer

UE - Rendering Architecture - Materials - Jan 11, 2025

If there is a texture parameter within a specific material attribute stream in the base material and also within the base material layer, they must have the same parameter group otherwise the parame ...