Ghost not in the same thermal

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witor
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Ghost not in the same thermal

Post by witor » Fri Apr 09, 2021 12:33 am

I tried to fly with one of my ghosts and I was surprised to see that the ghost was thermalling next to the cloud not in the actual thermal. Flight plan was used from the ghost ftr file but the time of the task start was changed in order to avoid a long wait before task start.

Does that mean that for the ghost to be in perfect sync with the weather the start time must not be changed? If yes is there a way to avoid a long pre-start wait if you just want to race with your ghost having all helpers on?

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wickid
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Re: Ghost not in the same thermal

Post by wickid » Fri Apr 09, 2021 12:34 am

If you change the time the weather will be different. No way around this.
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Pit_R
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Re: Ghost not in the same thermal

Post by Pit_R » Fri Apr 09, 2021 10:24 pm

But if you change time, ghosts are also in different place... Where they should be at given time. It is like with time machine journey - what happened will be happen again and again and you can watch this. And - as weather changes are literally always the same - ghosts should be in proper place, but aren't. So there is time dilation :) But why?
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wickid
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Re: Ghost not in the same thermal

Post by wickid » Sat Apr 10, 2021 12:11 am

The weather seed is different. That is the number that it used to generate where the thermals will be.
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Pit_R
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Re: Ghost not in the same thermal

Post by Pit_R » Sat Apr 10, 2021 10:37 pm

The weather initial seed is exactly the same, why should be different for same task? Weather is changing same way from initial seed. And initial seed is known - just time is later.
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Sprunga
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Re: Ghost not in the same thermal

Post by Sprunga » Sun Apr 11, 2021 5:20 am

I could be wrong but is the "Randomize weather on each flight" box ticked (see pic)? I'm not sure time should make a difference to the weather?
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witor
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Re: Ghost not in the same thermal

Post by witor » Sun Apr 11, 2021 5:29 pm

No weather was not randomised.

My logic was that if I change the time everything will go forward. let's say original flight started at 12:00 but ghost started the task at 12:30. I thought that if I start my flight at 12:25 using the flight plan from ghost's ftr the ghost will be exactly where it was at 12:25 in the original flight (just 5 minutes before start) and that the weather will develop to be exactly as it was at 12:25 in the original flight so at 12:25 everything (glider's position and thermals position) should match, but they don't, which is a pity. It looks like the whole ghost idea is a bit useless as I don't want to just wait for 30 minutes just to start a task in sync with my ghost and weather.

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Pit_R
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Re: Ghost not in the same thermal

Post by Pit_R » Mon Apr 12, 2021 12:18 pm

witor wrote:
Sun Apr 11, 2021 5:29 pm

My logic was that if I change the time everything will go forward. let's say original flight started at 12:00 but ghost started the task at 12:30. I thought that if I start my flight at 12:25 using the flight plan from ghost's ftr the ghost will be exactly where it was at 12:25 in the original flight (just 5 minutes before start) and that the weather will develop to be exactly as it was at 12:25 in the original flight so at 12:25 everything (glider's position and thermals position) should match, but they don't, which is a pity.

It is (or should be) exactly as you described. Just - for unknown reasons - there is little shift/displacement. Time dilation. ;)
BTW I think it worked properly in C1.
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wickid
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Re: Ghost not in the same thermal

Post by wickid » Mon Apr 12, 2021 12:45 pm

I will try to explain:

If you change something in the fpl the weather seed will be different. If it wasn't you'd always get the thermals in the same place with the same weather settings. That is undesirable as the weather would become predictable. Only if you use the exact flightplan of the ghost with the weather seed saved with it the weather will match. As soon as you alter anything (like the time) a new seed is generated and the thermals will be in different places.

This is also the purpose of the randomise weather each fight option. It will regenerate the seed every time the fpl is loaded so the weather will be slightly different (same strenght thermals but in different spots)
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Pit_R
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Re: Ghost not in the same thermal

Post by Pit_R » Mon Apr 12, 2021 2:25 pm

If you change something in the fpl the weather seed will be different. If it wasn't you'd always get the thermals in the same place with the same weather settings.

That's obvious - but you don't change fpl or whether there...

Only if you use the exact flightplan of the ghost with the weather seed saved with it the weather will match.

That's what we are talking about there...

As soon as you alter anything (like the time) a new seed is generated and the thermals will be in different places.

Why that? Isn't this the bug?! Thermals should be in their place (in fact are not-yet-generated but virtually existing - in very first initial seed, as weather there is deterministic). Notice - for ghosts, thermals are very close to what they used during non time shifted race, not in random positions and same strength, what could be, if you're right. From same initial seed, weather will be always the same during whole task. From ghost's initial seed weather should be exactly the same for given time for whole task - no matter if you re-fly in RT or you just change clock.

IMHO: Changing time is not change initial seed to random (for what?, again). (Finally you don't write down new fpl to re-fly it with ghosts with randomize weather preset). ;) I guess C2 is trying to recalculate weather/seed for chosen time - but with not enough precise - so this make little shift/displacement we can observe. Hope it can be fixed some day. Personally I could wait even 5 minutes to proper time/seed calculation and bit perfect flying ghosts. ;)

BTW: Possible small experiment - make several fpls with 1 min shift time (always change time from same 1st loaded fpl) and than run same initial 1st task with every minute screenshot. :) On-air start, no move, just recording clouds changes... :) Will try to check this if will have free time.

Let's wait for comment from Uros about this very interesting aspect of C2. Flying with ghosts is really good C2 feature.
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JShieck
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Re: Ghost not in the same thermal

Post by JShieck » Mon Apr 12, 2021 5:28 pm

Getting an other weather seed makes Condor realistic, because in RL you would never have the exactly same weather a second time.

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dgtfer
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Re: Ghost not in the same thermal

Post by dgtfer » Mon Apr 12, 2021 8:00 pm

wickid wrote:
Mon Apr 12, 2021 12:45 pm
As soon as you alter anything (like the time) a new seed is generated and the thermals will be in different places.
Actually no, shifting only the time setting does not change the weather. We get exactly the same thermals at the same time.
And some other weather settings, like strength, also do not affect the random seed. So the thermals will be in the same position, but their strength will be affected.
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Crakob
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Re: Ghost not in the same thermal

Post by Crakob » Wed Apr 28, 2021 10:19 am

i'm flying with a ghost quite often.
I check, at what time the ghost starts. And than wait until that time to start myself. (i always select airstart )

That way i have the same weather conditions as the ghost. At least it seams to me that i have the "same" thermal as the ghost.
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witor
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Re: Ghost not in the same thermal

Post by witor » Wed May 19, 2021 2:29 pm

Yes, but the problem is that if the ghost started the race an hour after start is open you will have to fly for an hour to wait for the ghost to start. I would like to start my flight later to save some time. Flying with ghosts with randomized weather makes no sense what so ever. Condor should just calculate where the thermals from ghost's ftr (seed) should be at a given time, that's all we need.

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Kekelekou
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Re: Ghost not in the same thermal

Post by Kekelekou » Wed Jan 11, 2023 3:04 pm

Bumping this "old" thread because I faced yesterday the very same issue after mass-downloading FTR files thanks to ryanwoodie's nifty tool.

An idea to improve things here.
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