Unreal Engine Issues

Chaos Cloth: NaNs can be introduced from bad AnimatedPositions/Normals

We've worked out at least a possible way this can occur from using uninitialized AnimatedNormals values when changing LODs. Ensuring all AnimatedNormals are initialized appears to fix the problem. ...

Native gameplay tags in plugins are cleared when reading config files

When references to Gameplay Tags are loaded, it checks to see if they are already registered. If they are not already registered, it will notice it is invalid and may print a warning depending on th ...

Chaos Cloth - Visualization materials cause async load flush and slows down starting a PIE session.

The loading of the cloth visualization materials disturbs async loads shortly after starting PIE which causes an async flush and several seconds stall. The solution would be to move these to a sing ...

Tracks that manipulate byte properties may have different (non-deterministic) results even for the same frame

This issue is relatively easy to reproduce, e.g., in the timing of switching between the two types of property operations within the same track. It seems to be easy to reproduce the above problem in ...

Sequencer- 'Dynamic Binding' SoftObjectPtr parameters fail to resolve after reloading editor

When reloading the editor and a level where a sequence has a dynamic binding with a soft object ptr parameter to an actor in the same level, the director blueprint will recompile on load of the leve ...

Render Graph pass merging issue with async compute transitions

A UDN user reported an edge case in RDG that triggers an assert. ...

Volumetric cloud shadow bug with two directional lights

Crash in FPBDJointUtilities::ConditionInverseMassAndInertia

We seem to be setting the InverseInertia to zero, even though the InverseMass is non-zero. FPBDJointUtilities::ConditionInverseMassAndInertia assumes that the inverse inertia is only zero if the in ...

Thin Translucent rendering output is different on UnrealEditor/PC and PS5 with Ray Tracing enabled

Reported from UDN With RT Translucency and Reflections enabled, Thin Translucent rendering is incorrect on PS5 in UE 5.3 ...

Motion Matching: Check failure when adding sequence into DB that references a niagara emitter

The serialization code for the motion matching database has a check that will fail if a property has the IgnoreForMemberInitializationTestName meta tag.  Niagara emitters contain a property that has ...