Volumetric lightmaps (and legacy sparse lighting samples) not compatible with level instances

The new Volumetric Lightmaps, and the old Sparse Lighting Sample system, do not seem to work when you load a level through a ‘load level instance’ node, if the level is translated or rotated from its initial position.

This video explains the issue - - YouTube

Steps to reproduce -

  • create a simple level with some static lighting, and bake the map
  • in another level, create a blueprint with the ‘load level instance’ node to load the first map at different location and rotation, and during play, spawn that level
  • the character (or any moveable components) are not receiving the correct volumetric lighting from the leve instance

it clearly says on the page that it does not support level streaming :

Thanks for the reply. You’ll note that in the title and in the description of the issue, I mentioned that the same issue applies when using legacy sparse lighting, which is the lefthand column, which does support level streaming.

Hi bud, found something that might worth a try, and it makes sense if you think about it.
volume light samples (both methods) are more than likely to be location based, and hence if you move the level they break. The lightmap errors that come up will most probably result from the reflection captures freaking out about the same thing.

[QUOTE=“Arnage;n714020”]When you use lightmass with streaming levels you should bake the lighting with all sub-levels visible. During gameplay you can then safely show and hide them without worrying about the lighting.
[/QUOTE]

yeah I agree with what you’re saying. The lightmap errors appear to be due to the instanced level having a rotation different to the rotation it was baked at. I discovered that as long as the rotation doesn’t change, the lightmap isn’t corrupted even if the level is translated to another location.

The reason we’re not using standard level streaming, and instead using instanced levels is that many of our rooms are repeated in various locations and rotations, so we only need a single baked map, that can be used in various locations. If we used standard distance streaming, we’d need a duplicate of the map in each location, to baked individually.

I did do some more looking into this, and it appears to be the same fault referenced here - Brushes stay in place in transformed level instances - Programming & Scripting - Unreal Engine Forums