I would be surprised if it hasn’t been discussed elsewhere yet but I can’t find anything about it in the older threads. If so, feel free to post a link here and close this thread.
Many scenery developers love to make parts of their scenery optional for performance reasons. Thinking about airports that either have lots of animations, thousands of parked cars in open air or other items, which could have a considerable impact on performance.
Problem now is that while it’s easy to make parts of a scenery optional (e.g. by renaming some BGL extensions to OFF), MSFS just doesn’t “see” them once they have been activated.
Initial load of the scenery reads Airport.BGL of course.
Then once the user decides activate the parked cars, either by an external tool or manually (due to the lack of a scenery density slider as we had in in the “old days” of FSX):
The second file is now there but MSFS won’t read it on next launch. It just completely ignores it and won’t load the content it contains.
It appears that after an initial “indexing” of the scenery, it is possible to rename BGLs from BGL to OFF do deactivate their content, but not the other way around?