Brushes stay in place in transformed level instances

I made a pull request with a fix for the precomputed light volumes: https://github.com/EpicGames/UnrealEngine/pull/3627

I haven't got started on the problem with brushes. I also found out lightmap directionality breaks when level instances are rotated, which is something for another fix.

Hi manoelneto,

It's not that the lightmass volume isn't being transformed, it's that lightmass relies on precomputed lighting. This is explained in more detail in this post. During play in your level, I'm sure you noticed all of the warnings to build lighting even though lighting was built in the tile room.

I tested several other volumes (trigger, navmesh, camera blocking, etc) and all transformed and worked correctly in your project. Even the lightmass volumes are showing they are in the correct place if you look in the details panel and click through them while ejected.

Cheers,

TJ

I need to study the character indirect lighting source to see if its possible to displace the pre-computed light probes at all. But did you test geometric volumes? Solid brushes don't get transformed with the instances. Place a brush box in the tile level and play the "dynamic level", and this is what happens:

The coordinates of the objects in the details panel is transformed, but their actual geometry isn't:

I was going through the source to see what could be done in regards to the lighting. My findings:

• Each level has a FPrecomputedLightVolume object, which is used to sample pre-computed lighting. This class has a method called "ApplyWorldOffset", which is used for world origin rebasing. The FPrecomputedLightVolume internal world offset is then subtracted to light sample query coordinates, so the data itself doesn't need to be actually moved around. It doesn't support rotation, so that would require modifications to the FPrecomputedLightVolume class.

• Streaming levels are transformed using FLevelUtils::ApplyLevelTransform() in LevelUtils.cpp after they are loaded or made visible. All it does is loop through all Actors in the level and adjust their transforms accordingly.

• Levels have a multicast delegate called OnApplyLevelTransform which is broadcast after FLevelUtils::ApplyLevelTransform(), which can be used so other parts of code can react to level transformations without the need to modify LevelUtils.cpp.

Since all that stuff is marked as ENGINE_API, I did a quick test which doesn't involve modifying the engine (because I didn't download the source for 4.16 yet). I created an actor class with a SceneComponent root and added this to its BeginPlay:

 GetLevel()->PrecomputedLightVolume->ApplyWorldOffset(GetActorLocation());

Then I placed one of those at the origin of the Tile level. The result:

I'll download the 4.16 source code and make a proper fix this weekend.