Anti-Pushback Node Technique in ADEX?

The Tutorials forum section is the place where you can learn the various techniques that go into the creation of AI traffic packages.
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ejwells409
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Anti-Pushback Node Technique in ADEX?

Post by ejwells409 »

Quite by accident I came across a post by John Young concerning his "anti-pushback" technique for getting aircraft to taxi straight out rather than the unrealistic pushback for Military Jets. I tried it in ADE (his post referenced the old Lee Swordy AFCAD program I believe) and found that a few aspects he spoke about didn't directly show in ADE. I tried it and initially found that it worked on a few AI I used as a test, however when I did the remaining parking spots (about 18 in all) they reverted back to the old pushback and I haven't been able to get it working again since.

Below are a few shots of the entire layout and a closeup of the Jets ramp (F-100's) and how I have the taxiways laid out. I know there will be a lot of questions so ask away and I'll explain how I got to this point.

ImageADEX images-2022-oct-16-003 by Ed Wells, on Flickr

ImageADEX images-2022-oct-16-001 by Ed Wells, on Flickr
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John Young
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Re: Anti-Pushback Node Technique in ADEX?

Post by John Young »

You need to disconnect the rear (green) parking links. You can still draw them, but make sure they are not connected to the centre spots.

John
ejwells409
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Re: Anti-Pushback Node Technique in ADEX?

Post by ejwells409 »

Thanks John, however if I redraw them they automatically snap to the center spot and if I leave them out how do the AI Jets locate the parking spots?
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TimC340
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Re: Anti-Pushback Node Technique in ADEX?

Post by TimC340 »

Draw your link outside the spot, then drag it to where you want it.

The AI engine will not reliably respect the red 'closed' links. If they make a shorter route than the blue or green paths, then the AI engine will say 'you made it, I'll use it'. So the only way to ensure they aren't used is to make sure they don't make a connection.

To Illustrate:

Image

In this picture, the bottom two parking spots have been connected. AI parked on them will pushback - whichever direction they are parked. However, they will only spawn facing the way the parking spot is oriented. The top spot has been drawn with the link not connected. The node (the blue spot) can now be dragged to where you want it...

Image

Note that in this layout, the AI will never use the link to the rear of the parking spots as it will always mean a longer route to or from any runway, so the links are redundant apart from the purpose of drawing a centreline. They can thus be drawn as 'closed' links if you want to make it clear that they won't be used. In P3D, they can be drawn with no visible surface, just like the green 'paths', if that helps.

Image

The 'anti-pushback' node is a kind of cheat, as the pushback length is determined by the length of the segment to the first node after the parking spot, and so making that segment as short as possible does the same for the pushback - you may still notice a slight movement, however.
ejwells409
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Re: Anti-Pushback Node Technique in ADEX?

Post by ejwells409 »

Thanks for the explanation John, and a "cheat" is fine with me rather than doing "outgoing and incoming plumbing". I found a 9 page tutorial on that subject and read about 3 pages before my head started to hurt. . .so thank you!
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TimC340
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Re: Anti-Pushback Node Technique in ADEX?

Post by TimC340 »

Ah, Don Grovestine’s treatise on plumbing! Yes, it’s a stiff read, but it’s a very good guide. If you’re interested in the theory of the MS AI engine, seek out Jim Vile’s contributions on FSDeveloper. Jim and Don have both left us now, but their legacies are a library of great info (and apps, in Don’s case).
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