Dear Epic Team,
I wonder, why the PlayAreaHeight setting is in Engine > BaseLightmass.ini instead of some section in Project Settings. I believe, this is a project specific setting and the value should be stored there.
The problem with this: Editing this for one project makes that change for all other projects using that engine version as well. So if I rebuild on another project at some later point in time and forget to adjust the value again, or even forget, which value I had chosen for this project months ago, this calls for trouble.
I found the answer: It simply can be overridden per project by manually creating a DefaultLightmass.ini file in the Project Config directory. Fill with for example
It actually is described in the ini file comments itself. But I believe, it would be better, if this was described in the docs here as well, which only mention to edit the Engine wide ini file (which I did without reading all comments)
I did come on this idea when playing with Device Profiles: BaseDeviceProfiles.ini is in the Engine folder, DefaultDeviceProfiles.ini in the Project can override settings.
So it looks, like creating a DefaultNNN.ini in Project directory for the BaseNNN.ini in Engine directory to get project specific settings seems to be the general way to get project specific changes.
BTW: see also my post here on the topic of project specific ini files - there seems to be some documentation bug for the device profiles.