SP1 Tip of the Week:AI at 80% max

AI at high is a big cost, at least as much because some of the default aircraft have high Draw call counts.   We fixed this for the 3 AI aircraft ( MD-80, Dash8, Cherokee ) and they are 25% of the world wide traffic DB, but default aircraft like the 747 and A320 get used a lot as well. 

This adds up. Quickly. High AI is one of the quickest ways to cancel out the benefits of the Draw and SetTexure call reductions we did in Autogen buildings and vegetation.

Having fiddled around with 100% AI a bit, I think you are wiser off sticking at 80% max anyways.

And here is why:

1) Above 80% and the landing pattern gets thrown off, and the AI system injects a plane between 2 that are spaced at 5+ mi, and you get a lot of "wave offs or flybys" by that middle plane; which can be disconcerting because you would never see that at a commercial airport. You still see this at 90%. I haven’t tried 85% or any 1% increments between 80 and 90, but I didn’t notice the flybys at 80%

2) If you are flying the heavy iron, with more than 80% traffic its hard to get a gate, which means no jet way animations, no refueling.

So stick at 80% max.

Fun Factor Alert:

I will say that it’s worth parking on the grass at a busy airport somewhere that you can see both the landing and the takeoff pattern, switching to night time, and switching to 4x time factor. Extra bonus if you can view the terminal at the same time. It’s a hypnotic display at a busy airport and is great as a "screensaver". If you haven’t done this yet, take a couple of minutes and check it out!

Comments (11)
  1. fatboysim says:


    Thanks for your comments concerning AI traffic.  My favourite scenario (at least as far as FS9 was concerned) was a busy airport at sunset, and just watching the traffic come and go as you describe.  And that’s just great at LAX, watching the planes coming in over the fantastic FSX water.

    I fly with 3rd party addons for AI traffic, which increase the density much above the levels compared with FSX “out of the box” (and not to mention real world airlines, schedules) etc.  To make airports busy, I  do without autogen and for the most part jetways and ground traffic.  When you are flying commercial, you are soon so high that the objects have little impact on your view.

    While many things have improved with FSX and SP1, it’s a challenge to get the kind of traffic levels enjoyed in FS9.  You are right about the slider settings.  You can resolve approach contention with the AISmooth package, but with very high slider settings you can get insane runway queues building up.

    Do you have any plans for building on the infrastructure that renders AI traffic (particularly for 3rd party add-ons) for better FPS?  In SP1 there were some fixes to default AI aircraft, but nothing I understand like the work autogen received to improve performance.    It would be great if there was something under the DX10 packaging you could do, even if it is not an actual DX10 exploitation.  Anything you can do to render AI in a separate thread, or batch calls together ala autogen?


  2. Phil Taylor says:


    unfortunately the main perf issue with high AI is the model draws, and to fix that we would have to re-export all the aircraft.

    DX10 is all about code and not content, so its unlikely we will get to touch the aircraft.

  3. tyguy says:

    Hi Phil,

    Thanks for all of your work on this blog. Its been extremely helpful. I am running FSX on a Dell with an ATI X1400 card and 1GB RAM. I was having major issues until I applied the tweaks you recommended.

    Now I have a dumb question. How do I get AGS to work in FSX? The gate push back feature works fine, but is there a way to get the jetway to move and connect with the plan at the gate? I’ve also downloaded planes that include AGS and I can’t get them to work (nothing in read me), so I take off with the AGS stuck to my plane (hahaha). Help!


  4. Aberforth says:

    This may be a little off-topic, but i read somewhere that DX 10 update is going to cost 30 bucks and that it includes Xpack as well. Is it true??? I thought DX10 update was free…it’s not that I won’t buy it but i’m bit confused.

  5. Phil Taylor says:


    I dont know, thats problably one for a developer forum.

  6. Phil Taylor says:


    you heard wrong. XPack will cost $30 and contain DX10. DX10 will also be available as a free download, as I committed to months ago. Anything else you hear is FUD.

  7. SilentGenie says:

    hi Phil, how long do you think DX10 is gonna take ? not rushing or anything its just ive read on forums that DX10 on Vista and FSX is gonna be marvelousm, do you have any goodies to tell about yet ?

    thanks 🙂

  8. Phil Taylor says:


    we are on track for this fall.

    soon I will have more to say. end of the month-ish.

  9. SvenGroot says:

    Hi Phil, I hope you’re still seeing (and replying to) comments on this post.

    You say AI at max 80%, but how does this translate to the sliders in the game? There’s two of them: general aviation and commercial. I set them both at 80%, but it’s problematic; frequently I get asked to land behind a slower aircraft. Now I realize slow flight isn’t one of my strong points but if I’m in a 737 and am asked to follow a Cessna on final, there’s just no way it’s going to be clear of the runway before I touch down so I’ll have to go around.

    The reverse also happens. In fact, just now I was making an ILS approach in a Mooney. Suddenly I get “Crash: Object Collission”. What had happened? The MD-80 that was supposed to follow me just crashed into me.

    What’s the best way to fix this? What slider settings do you recommend for both GA and commercial traffic?

    Thanks in advance.

  10. Phil Taylor says:


    good question. that recommendation was for the commercial traffic slider. you’d have to iterate thru the settings for GA traffic to see what merges well. I usually keep mine at 20-30% and dont see many issues.

  11. SvenGroot says:

    Phil, thanks, I will try that.

    I suppose it might be best to set the commercial slider high and GA low if I’m flying in a jet, and vice versa if I’m flying in a slower aircraft. That should keep the odds that whoever’s in front or behind me is about the same speed in my favour.

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