This post is going to be a bit of a brain dump: I will explain where the various new types of data go for the new airports and ATC system.
First: everything lives in scenery packs. Since X-Plane 9, every bit of scenery X-Plane has (including the default airports, global scenery, and art assets for taxiways) all live in scenery packs. Those scenery packs live in Custom Scenery (if installed by user) or Resources/default scenery (if installed with the sim). The global scenery packs have their own folder in the main X-Plane folder so you can find them easily – at 78 GB it’s likely you might need to delete some, then reinstall later.
A scenery pack in version 9 can contain the following “stuff”:
- DSFs – that is, scenery tiles for 1×1 degree areas of the world. Those DSFs can contain a base mesh or just overlay 3-d on top of another base mesh.
- Art assets (.obj, .fac, .png, etc.) in any sub folders desired.
- apt.dat – an apt.dat file can provide replacement airport layouts on a per-airport basis. You can replace one or all of the airports.
- library.txt – a scenery pack can publish its art assets to the library for use by other scenery packs.
In X-Plane 9 we ship a scenery pack with most of our airport art assets (published to the library) and we ship another scenery pack containing Robin’s latest data – we try to update this scenery pack in each patch to match Robin’s latest.
In X-Plane 10, scenery packs are still the way you get your data into the sim. In fact, all ATC data sits inside a scenery pack too. We figure that you might want to make a custom airport with custom ATC, custom airport layout, and custom buildings. So rather than reinvent the wheel, ATC data is part of scenery data. The ATC data shows up in a few places:
- Airport ground operations data actually live in the apt.dat file. This includes “flow” information (e.g. which runways are in use, what’s the pattern runway) for various operations as well as the ground taxiway layout. The ground taxiway layout specifies a connected line graph of where airplanes can taxi. (Note that there is only one taxi layout even if there are multiple flows. This is because even if the runway in use changes, the concrete doesn’t move.)
- Airport controller and airspace specifications (including tower controllers) live in a new atc.dat file – you can put one in each scenery pack, not unlike the apt.dat file.
- Voice packs are created using a .voc file and a pile of sound files. Like OBJs, they can be put into the library – voice packs are the “art assets” of ATC.
Why is it that the ground layout is in the apt.dat file but the controllers are not? Robin collects the apt.dat file, and we wanted to make sure that if someone moves the pavement, that person moves the taxi layout too. Having them in separate files would be a recipe for a loss of synchronization.
Note that there is no mention of airport buildings in any of this. Airport building locations will ship as DSF overlays – they’re a scenery pack just like we have in version 9. The default art assets made by Tom will also live in a scenery pack and be exported to the library for anyone to use.
Since everything is implemented via scenery packs, you can create anything we can create, and you can publish your work directly via a custom scenery pack. You don’t have to share your data with any of the central collection-and-databasing efforts to use this new technology.
There will be two types of scenery packs that ship with X-Plane (and are updated via free patches during the lifetime of the sim).
First, we have default art assets that we provide to make the sim work and to help you create scenery.
- Default airport elements, including the airport building lego brick library.
- Default ATC voice packs.
Then we have scenery packs that come from collected data. We ship the latest updates.
- Default airport file from Robin, containing airport pavement layouts, gate positions, and (in v10) taxiway diagrams and runway flow information.
- Default airport building placements (in DSF form). We will start this file off but then it will become something that everyone can contribute to and use.
- Default ATC controller file, containing airspace information and controllers/frequencies. We will seed this file with center controllers to cover a big chunk of the world, but I am hoping that we can accept user-submitted corrections and contributions.
(If you squint at this list, you’ll see the divide: we are trying to involve the entire community in data-gathering activities, but we are having our internal art team make the default art assets.)
Finally, there is one more piece to the puzzle: autogen. Autogen is a horribly ambiguous world in flight simulation because it means 85 different things. So let’s be more specific: automatic in-sim generation of data. When the sim is missing data, what data will X-Plane “make up” on the fly? There are two cases of automatic data generation in the sim while you fly in version 10:
- If there is no controller specified in any scenery pack for a given airport, but there is a tower/ground/delivery frequency for the airport, Chris’s ATC engine will automatically create a controller based on the frequency. This means you get tower/ground/delivery ATC on the right frequencies for all of the towered airports, even if we don’t put those controllers in the default controller file.
- If there is no airport layout for a towered airport, we will generate a taxi layout and default flows by picking runways and analyzing the taxiway structure. This allows you to have AI ATC at any towered airport. (The layouts that X-Plane generates are not going to be as good as what you can build in WED.)
We almost always prefer pre-generation of data to in-sim generation – it lets us use a higher quality algorithm without hurting fps. (One of the limits of the ATC layout generation algoirthm is that it can’t use too much memory since it is running inside X-Plane.) But in the case of airport controllers and layouts, a custom scenery pack can contain an airport that we’ve never seen before – so we have to be able to generate the matched ATC data on the fly.