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FSX Fuel Truck Behaviour Around Parked AI Aircraft

After a sugar rush I looked for patterns of behaviors. Somewhere in my deepest darkest mind (somewhere up the faraway tree with the pixies) I remember someone (might have been the scruffy duck crew) saying the fuel truck is programmed act AI (ish). Its supposed be called (shift.f) then the closest truck tries to get the the plane. OK so far. However, from its vehicle park spot if takes on the purple line to the next node (dot). Then, if it cannot find a node it does a "if , then" IF I can't find a purple node THEN take the closest taxi way node and continue. Looking at your ADE image and then your last real route in fsx image there is a pattern - the truck starts bottom right of image, moves to the first node, it commenced up the first track and suddenly its checking for next node. The closest isn't at the top behind the ac, its actually to the trucks right, in front of the ac coming from your building. The truck swings right to hit the node and then attempts to drive to the ac but oh dear, no more nodes! It does the creeping action which I think is the decision making engine looking to see best route. When it looked around it sees the only close node is the ac node itself. It goes there. The next node is the next node is the one to the ac's 11 o'clock and off it jogs !!
As stated, if you look at the Ade image then you last one then there appears to be a logical pattern .

This is interesting. There must a logic process required for the vehicle path that we,re missing , and I hate to say it but I suspect we are starring right at it. This is one of those puzzles you cant put down! I'll also look about to see if there is any info source to crack this unless one of the guys jumped in here......
 
I think you're right about the node search. He seems to panic when he hasn't seen a node for a while, particularly if he's within striking distance of a parking spot. Rather like when you can see your hotel from the motorway but there's no exit. Though I don't think I'd be tempted to head off cross-country like he does !

Adding one or two additional nodes to the vehicle track changes the behaviour significantly - see below (truck track in red). Note that in the first example, the truck parks up in front of the a/c in the 1 o/c position, which may be desirable in some instances . I'm guessing (though I haven't tested) that by judicious manipulation of the vehicle track and nodes it may be possible to have the truck stop at any desired position around the a/c. Easier when you can make the tracks invisible, as on grass or concrete, where it's not so obvious the truck is taking an odd route.

Errant Truck B.jpg Errant Truck C.jpg
 
GREAT !!! Me thinks we're getting there.

In addition I took time this morning to test MS FSX owb stock Ap (KBOS - Boston). I think I have more to add here .

Heres how it played out - Using my 737 I spawned on the parking area A. Called the truck as normal and the black dots indicate the route - Note its not exactly to the nodes and does cut across when getting to the Craft - Therefore - stock Airports have the same issue and no reason to think its us.

I then dropped it again but on B. Again it followed the same route as A but crossed over the taxiway to the vehicle nodes - Note there is no vehicle track only taxiway on the that bend where blue and purple drawn line are. So that means the truck is looking all the time for a fastest route.

I move the Craft over to C - This is where the wheels came off the proverbial bus! If you follow the orange broken line you will see it stop at a corner - There should be no reason for it to stop but that is exactly what it did and the craft was never refueled at all - The truck just stayed there. Yest there is clearly a path there to be followed - I did that same test this time zeroing my fuel and making sure break on etc. Still came to a stop exactly the same place - I checked ADE and can see that the lines are constant, no breaks, arrows all in same direction etc . So Im assuming this is a bug in FSX coding and not necessarily us not getting it right.

Now look at the drawn in purple line - I have my graphics on 100% across everything - An AI fuel truck appeared during test A on the apron when I spawned plus the one on the set up vehicle parking spot (A) - The AI truck took off when I was being refueled at B. followed the route passed where the one I called stopped at X, therefore proving there was track and went off to end of the purple line where I lost it as I was in F12 mode watching it live in fsx - It didnt return. So that was purley eye candy.

The node are the key in play with the Aircraft parking spots diameter. The arrows on the vehicle track are an indicator in the first instance here the Artificial Intel truck will go plus any other like bagge and sewage that the Artificial Intel Engine generate subject to how high you have your graphics set up in the setting screen.


This has been a really nice learning mode - The assumption we all make is that the vehicles will go where we set them to go when in fact, we only offer a guide for it to go and allow it to work with the AI engine in making decisions after - Having seen it in work at an FSX default busy airport its clear(ish) what you can / cannot do and what you have 100% control over as well.

It might be useful to open a small USA AP and look at that for refuelling options and how they deal with User called trucks and AI Traffic using the vehicles track - I dont think it will allow precise positioning when the truck arrives and having looked back at some of the posts in 2010 / 14 I can see that the parking spot sizes were offered up as a reason that the truck was miles from the tail etc
 

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I'd also read the historic posts about called fuel trucks stopping before reaching the aircraft. I only dabbled with calling a fuel truck once, and sure enough it stopped several hundred yards from my a/c. Not something that particular interests me right now, so I didn't pursue it.

I also saw some oddities during my testing this morning. Exploring the errant truck problem, I removed lots of stuff from the test parking spot, including the taxiway. I guessed that would stop the truck even turning up. But no - he trundled up the vehicle track, did his stuff and then returned. After which the aircraft promptly disappeared. Waste of fuel if you ask me.

I also had a truck turn up at a spot via the vehicle track, and then immediately turn on its tail and drive back down the taxiway and off to another spot. While I was puzzling this, a second truck turned up from somewhere and fuelled the original a/c.

On the subject of trucks finding the fastest route - one thing I noticed (and I have updated one of my posts above) is that if you run the vehicle network along the same route as the taxiways, and don't want the trucks to move from one to the other, you must make the vehicle tracks zero width, or certainly very narrow. It's not enough to ensure they don't intersect in ADE. If you give them a width, and they run close enough to each other, the trucks will move between them.

My next task is to figure out how trucks are dispatched to service parking spots. Yesterday I set up six trucks to service 6 parking spots at the same time. Three of the six were dispatched. I then reduced the number of trucks to three, and only one was dispatched. Maybe it doesn't like to send out more than half the trucks at the same time ?
 
"My next task is to figure out how trucks are dispatched to service parking spots. Yesterday I set up six trucks to service 6 parking spots at the same time. Three of the six were dispatched. I then reduced the number of trucks to three, and only one was dispatched. Maybe it doesn't like to send out more than half the trucks at the same time ?"

having watched the MS FSX programmed default airports AI truck (whose visibility is dependant on the traffic settings being turned up in settings) "do its own thing" then see one that FSX had set on a designated vehicle spot not follow the route to the end just jam up Im beginning to wonder how it all happens myself. Might be worth asking the lads in ADE (Scruffyduck) if they have anything more in depth - the amount of data on what the vehicles do , how they perform and their decision making seems sparse across the internet
 
I do recall some discussion about allocation/dispatch of fuel trucks quite a while back, although I can't find it right now. And I'm not sure it came to any firm conclusion anyway.

But I've now got things working reasonably well for my specific purposes, even if I don't fully understand how or why. And I've learnt a lot in the process. On to the next challenge !

Thanks for all your help. I may be back !
 
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