Unreal Engine Issues

Optimize FActorFolders when there's level streaming in PIE.

This will need more investigation, but at least in PIE (to check if we can do the same in editor), when a level is streamed-in, we should only add the new missing folders for this level and when str ...

World Partition Editor minimap build failed

The issue was reproduced when building a minimap for an open world level with no Actors with "Is Spatially Loaded" enabled. Placing additional Actors with "Is Spatially Loaded" enabled in the level ...

Compilation error in Mac editor builds when adding UWorld::IsStreamingLevelBeingConsidered function

This code passes the build when compiled using the windows editor (Visual Studio), but fails when compiled using the mac editor (XCode). Adding ENGINE_API to struct FStreamingLevelsToConsider and ex ...

[Ensure] LoadStreamingLevel and UnloadStreamingLevel are called at the same tick

There is no particular error. Developer can ignore it. ...

Mesh reduction modules selection aren't properly applied on engine restart

Recent changes in the MeshReductionManagerModule::StartupModule() have introduced issues where it won't respect what reduction modules have been set in the config file. This is a big issue for plugi ...

Validate whether the usage of FPIEFixupSerializer can be removed from UWorld::DuplicateWorldForPIE

Add support for referencing non-spatially loaded actors without clustering them together.

The engine doesn't allow cross-level references as it assumes a referenced object is immediately available which we guarantee by placing any reference clusters into the same cells. This means the be ...

If the DataLayerAsset name or asset path changes, Actors registered to it will ignore the DataLayer's settings

If you change the DataLayerAsset name or asset path, all Actors registered with that DataLayer will ignore that DataLayer's settings. Specifically, even if you set the DataLayer to the Unloaded stat ...

Newly placed actor unloads after playing in editor once

The actor placed in the level will be unloaded after play in editor.  Without save the level (repro step4), the actor is not unloaded and show in editor. ...

ISM GetInstanceOverlappingBox() ignores the scaling & rotation of instances

This functions only uses the instance location and does not rely on it's rotation and scale. It should ideally get the bounds of the mesh, and test intersection using an oriented bounding box built ...