Though I'm a long time simmer, I'm somehow puzzled how scenery (bgl files) works in FS2004:I have my sceneries incrementally numbered in scenery.cfg (I use the valuable scedit for scenery file handling purposes).Let's assume that my "addon scenery" folder has layer number 035.Let's also assume that I have a new scenery to install and do this in layer 040.And finally, let's also say that I have a folder "My AFCADs" in layer 060 where I put files which AFCAD produces in.As far as I understand is: higher layer number = more importance in FS2004.Now let's assume I'm unhappy with my new scenery (layer 040, see above) and open AFCAD to add for instance a tower viewpoint or some more precise parking positions. I for myself store the file AFCAD produces in the "My AFCADs" (layer 060, see above).At last, let's assume that I have an AI traffic package which stores reworked AFCAD files in the "addon scenery" folder (layer 035 in this example, see above).So here's the important question:As you can see, it can happen that an airport scenery file exists in multiple different layers; in my example, I can have the stock airport of FS9 (lowest layer number), then my AI traffic package has a reworked file for it in a higher level layer, then I installed a scenery for the same airport in another, even higher layer, and then I put my own rework in AFCAD into the highest level layer I have available in my scenery.cfg file.Does only this highest level layer count for FS9 or are all layers with lower layer numbers kind of ORed together?I ask this because I exactly did what I described in this example; and in the end, I had massive AI traffic even parking within buildings!After renaming the lower layers, the situation was better, in my opinion.Maybe this was just imagination, but I'd like to see the whole thing clearer.Maybe some of the experts can answer this?Andreas

Personally, I wouldn't mess around with the default scenery layering. I would leave everything up to the end of the default scenery.cfg, which is Area 38, the Addon Scenery folder.You are correct that as you add areas in the Scenery Library, they go the top of the priority heap. You are also correct to assume that scenery with a higher priority will exclude scenery at a lower priority.As an example, AFCAD deletes the entire airport from the default scenery file and replaces the airport in the AFCAD file, except for Approaches. Approaches are still read from the default scenery file for that airport. So it can be a total exclusion or a partial exclusion of the default scenery.Another example you presented was to add a higher priority AFCAD scenery folder above the default Scenery, Addon Scenery, and other Addon Scenery folders. If you have an AFCAD file in Addon Scenery and one in your new higher priority AFCAD scenery folder, the one in your new folder will exclude the scenery files below it in priority.W. Sieffert