After upgrading to 4.14 and doing a lighting build that split the map into two parts we were able to save. However saving the map now is incredibly unstable and will often fail. Also the file size has quadrupled (from 600MB to 2.5 GB) over the course of trying to save the file and re-do light builds. Not sure what “reproducible issue” I could provide, but just wanted to bring attention to the fact that there might still some kinks to work out with the map file split. But in general I appreciate the change.
I remember getting the failing to save during the 4.14 previews a couple of times, but I’ve not had it since the 4.14.0 release. If you happen to have any repro steps that make this more reproducible feel free to let me know.
I also don’t see the issue with map sizes quadrupling or even doubling.
As an example, I used the default map with the chairs and table. I copied these around with the floor mesh so that I had a few hundred. I set the Lightmap Resolution for these to be 256 just so they had some weight in size. In 4.13 when I built the lighting the map size came out to 113.37mb. In 4.14 I rebuilt the lighting so that it would break out the lighting for the _BuildData file. When checking the size on this it was 113.6mb and the Map file was now at 1.547mb. I rebuilt lighting a few times and restarted and did this but didn’t see any change in the size of the build data.
Are you using any particular setup for your levels, like sub-levels with stored assets and if so how many? How many meshes, approximately, are you using in your level? I’d be curious if you see this same behavior in a blank level vs your current level, since I’m not seeing it in my test.
Haven’t run into the issue since I deleted the BuiltData file and tried building again. It probably had more to do with upgrading existing maps from 4.13->14 than anything. Our other maps seem to be behaving correctly also, which is why I mentioned it being hard to show a “reproducible issue”. Thanks for the response.