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Guest jshyluk

AI traffic control in FSX

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One of the most disappointing aspects of FSX is the fact that ACES didn't bother to fix AI control. How difficult can it be to include a simple routine that keeps AI planes a few miles or minutes apart, and land in sequence! I have however noticed some changes FSX (e.g. not all aircraft rush to take-off immediately), but I am not sure what I am seeing. In FS9, with full AI, it would take 20 minutes after game start for traffic to resemble anything normal, for the go arounds to stop, etc. Now in FSX I am observing different behaviour at different airports. At some airports there are no go-arounds at all. The other day at SFO I had 10 planes coming in well-spaced with no problems, right after game start, something that would have never happened in FS9. Yet last night at KMEM it was back to total chaos - 3-7 planes approaching on top of each other. I do observe a slight improvement over FS9, but I don't know what it is exactly. Can anyone enlighten me? Was there a change, or are the good days in FSX just pure coincidence? I do wish SP1 would address this but I don't think there's hope, do you?

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One of the most disappointing aspects of FSX is the fact that ACES didn't bother to fix AI control. How difficult can it be to include a simple routine that keeps AI planes a few miles or minutes apart, and land in sequence! There is a fix - consistent flight dynamics where classes of AI aircraft fly takeoffs and approaches at the same speeds.FS2004 and FSX are very, very good at establishing AI aircraft separation on approach. Our AI flight dynamics are the reason the carefully setup scheme falls apart.Unfortunately the quest for realism has resulted in AI aircraft which are tweaked to the point where A320 and B737 aircraft cannot fly approaches without overruns.Implementing speed control with new intensive programming and CPU usage would be a major rewrite of how the user and AI aircraft work in the FS world.I've even seen proposals to reduce the number of cycles used to control AI aircraft now, not increse the work load for that process.Like almost all AI issues, the separation is a self-inflicted problem.We overload airports with more traffic than the program is designed to handle on clearing runways.We overload airports with more aircraft than there is parking.We insisit that AI aircraft fly differently on takeoff and rollout, and then complain when they fly differently on approach.I will tell you from my experience that using a common set of flight dynamics really helps making almost realistic levels of traffic possible without approach issues.

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Hi Reggie. Do you have any sense if there is a group that may jump to the forefront in terms of FSX AI advancement? (Like real world FSX compliant flight plans and AFCADS, AI aircraft FD conventions, etc.) I like the way FSX performs, and visually I like it better than FS9, but I'm really hankering for realistic AI traffic.

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I honestly don't think its as complicated as all that. You are saying that had the AI models correct flight dynamics, we wouldn't see (separation) problems? I find that hard to believe. >>Like almost all AI issues, the separation is a self-inflicted problem. The sim seeds planes in the same place - unrealistic and the source of many problems. Sometimes planes come riding virtually (virtually virtually :) ) on top of each other - what would flight dynamics have to do with that??? >> We overload airports with more aircraft than there is parking.Why not implement a routine that limits #of planes to # of slots in 100 m radius. Why not have the option to assign "min. distance of Ai aircraft" and "max. # of planes displayed in # radius". These options would reduce workload rather than increase it. aismooth did a very good job with a very simple concept. Most users would eagerly sacrifice #of planes and level of realism if the AI aircraft would stop crashing into each other, flying on top of each other, and going around more often than they land.

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AI aircraft generation - where the aircraft are created and when is a function of how the positions for the grids are written into the traffic .bgl files.Once aircraft are generated atop each other - which is something that only occurs 30-100 nm from the user aircraft - the program separates them quite well in about 5 to 10 minutes before the ever come close to the user viewpoint.AI aircraft are spaced out on approach very well in FS2004 with up to five aircraft/ waypoints for each runway. FSX appears to spread the 5 nm separation of FS2004 to seven miles at busy airports. But a lot more testing is needed to be sure.After this separation is created is where the 'realistic flight dynamics' destroys the carefully created system of AI landings.FlightSim is designed to maintain AI aircraft separation upon approach by having AI aircraft fly at very close to identical speeds for each phase of the approach and landing.The mechanism to control these speeds is the AI aircraft.cfg file and .AIR file.When we create multiple AI aircraft configurations and speeds, we abandon the system MS setup for Flight Simulator - because it 'not realistic'.Now even with perfect aircraft separation upon approach, any runway has a capacity to land and clear only X number of aircraft per hour.Much of this has to do with runway and taxiway configuration. SBEG will never handle as many aircraft as SABE. When we added parallel taxiways to LSZH Rwy 14/32 - we almost never see go arounds with good flight dynamics in an X-Rwy configuration.Just as the real world airlines once had 96 flights scheduled to arrive at KDFW in a one hour period - when the runways can only handle about 78 - we in FS do the same thing - and get the same delays. However, the real world controllers are better at putting delays enroute rather than on approach.As far as the overloading and scaling, there are some indications that FSX has some capacity for that to occur.We have seen some flights at very heavy FSX airports never appear, yet the same flights appear when we reduce the workload to only the one airline. We have seen the same flights at 100% traffic levels in FS2004, but not in FSX.We have seen very few Cessna aircraft being overflowed into very large parking spots.We have seen commercial GATE coded aircraft will not park in empty MIL_CARGO spots.We are just scratching the surface at what the AI really does in FSX.The tool for scaling is Microsoft's TrafficDatabaseBuilder which creates traffic files. The AI community has abandoned TDB because they do not like having restrictions on airport capacity imposed upon their flight plans and traffic files.Lee Swordy's Traffic Tools has a primary focus to create traffic files which violate the basic rules of AI traffic operation in FS.When we create traffic files whose main design goal is to NOT play by the Flight Simulator rules, what right do we have to complain? We are carrying a lot of baggage about how we think AI should work with very little understanding of how it actually works. The vast majority of our ideas and concepts from FS2002 and FS2004 except in the past 18 months to one year are simply wrong.

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Good post! I have only a simple knowledge of how the AI handles its aircraft, and I seldom have time to pay much attention to them when I do sim. So, my contributions to this discussion are going to be on the very simplest level:1) I have turned down my AI aircraft considerably in FSX versus FS9. I find I just don't need all of the extra AI vehicles, just a few are neccesary to keep the sky and the airports looking busy. Of course, in terms of realism, i.e. virtual airspotting, this is less than ideal, so that until FSX runs faster and smarter, we do have to make choices as to what we want MSFS to really do -- it can't be all things to all people right now. 2) Another user mentioned the excellent AiSmooth freeware utility in the past tense. There is a version available for FSX, and I use it a lot. If you've never heard about it, AiSmooth basically shuffles around the airplanes that you can't see so that you avoid conflicts at choke points like airports. You can download it from Avsim for free.Jeff ShylukAvsim Product Reviewer

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