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Physic discussion thread

Discussion in 'Automobilista 2 - General Discussion' started by Avoletta1977, Jan 3, 2021.

  1. Raceracerace

    Raceracerace Active Member

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    How have other sims gone about addressing this problem or situation?
     
  2. Avoletta1977

    Avoletta1977 Well-Known Member AMS2 Club Member

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    Yes, I tested also with zero preload and modifying clutches and ramps.
    The Ginetta responds quite well.
     
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  3. CrimsonEminence

    CrimsonEminence Administrator Staff Member AMS2 Club Member

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    -pCars2 suffers from the diff issue too, to an extend, until today.
    -AMS1 might be even a bit too good with coast diff/preload behaviour, maybe even opening too much/odd(according to Niels Heusinkveld i remember some commentary on that in one of his videos and i tend to agree for some "modern" cars, but this seems more on the "nah, just marginal" side of things)
    -R3E seems fine
    -rF2 seems fine
    -ACC might be also a bit lenient with diff coast/preload behaviour, but just personal criminal assumptions and it's also no gamebreaker there
    -AC seems to differentiate fine and reacts okay to changes. (maybe also the same like ACC, but like mentioned, no prove)
    -LFS seems fine

    I actually don't know any other sim, besides pCars2 and AMS2, that should tackle this issue in this kind of manner. (Or where i notice crazy oddities)
     
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  4. Raceracerace

    Raceracerace Active Member

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    Preload zero is my new fave thing to do on some cars where I'm bombing it.

    Well then because diff attaches to wheels via Axel's ect I guess now with a new tire model they'll do something about this.

    New cars are great to drive then there's always p1s and roco don't exhibit this behaviour, mc2000. But some definitely egregious diff issues. No longer Ultima I would say, never ginetta, f3s seem great and open wheels usually.

    What do people think the biggest problem cars to have a play with
     
  5. oez

    oez Mayor of Long Beach AMS2 Club Member

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    I tried 0 preload with 85 coast and 50 power ramp. McLaren F1 GT1 at Interlagos. This is T4 (or whatever that left turn number is after the long straight). Just a massive snap, rear turns into a shopping cart and I have a code brown. Big correction follows. Just impossible to race like this, cause I have 0 condidence in the rear. The default setup is better in that it doesn't slip that much once it decides to open at all.

    This is just before the diff opens. I'm turning left and trail braking. As you can see the rear tire speeds are practically identical at this point. But that's not the biggest problem. It's how much difference there is just a few tenths later. Peak difference there at the bottom is 9 rad/s.

    diff_snap.jpg

    Another thing I will say about the driving experience now vs previous versions: it was somewhat easier when you knew the rear was stiff and did not loosen up in a blink. You had to throttle oversteer your way through tight corners. This was of course unorthodox driving technique, but car control nevertheless. Now on some cars you have limited ability to throttle oversteer, because there's so much inside tire slip on acceleration (it stabilises the car somewhat). And then you have this sudden code brown in slower corners. Or worse mid corner when you've applied a lot of steering input to hit the apex with the stiff rear in mind.
     
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  6. CrimsonEminence

    CrimsonEminence Administrator Staff Member AMS2 Club Member

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    You might hit engine braking here. Do you blip, downshifting the GT1?

    But yes, the GT1 cars are actually a bad exhibitor, they turn pretty okay-ish. But we see still very hesistant differentiation, probably also contributing to the snap, but this is the mentioned grey area, that has to be eliminated by fixing the diff, so other oddities can be wiped.

    I can recommend taking F-Retro for a drive, there things are really interesting, because they behaved way better, when it was possible to change their clutch LSD to a geared LSD/torsen diff.
     
  7. Raceracerace

    Raceracerace Active Member

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    So the vague rear problem is still there but reduced in prevalence but issue remains all the same?

    The diff has a lot to answer for. Most cars improved out of sight for vagueness. Not Camaro road but many others.

    Now upon pushing cars and isolating issue as much as able they have a hole.

    To get around this one must drive slow I know the turn well. That defeats the purpose of racing or to accept slide or chopping the corner.

    If the rear is more tight and present surely the feel will improve.

    Can they not impose hard limits on a per car basis
     
    Last edited: Jan 3, 2021
  8. oez

    oez Mayor of Long Beach AMS2 Club Member

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    Nope, 2nd gear there for a while. I think it hits a bump or something and that triggers the differential to open.
     
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  9. CrimsonEminence

    CrimsonEminence Administrator Staff Member AMS2 Club Member

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    Renato answered in the beta forum right now, regarding the diff talk. I'm so free to say, it definetly seems related to values in the whole drivetrain model (matches with the "better results at Ginetta, than 620R" discovery) as a whole. So they're still on it and my hope is regained...for now...:whistle:
     
  10. Raceracerace

    Raceracerace Active Member

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    But no diff ever operates in a vacuum. Gears slip, diffs clunk and jut now and then.

    There needs to be an invisible downward counter weight on cars thrusting them forward. Edit: Or..ok... A wider look at components.

    If tires slip in a limited fashion then they need to be alleviated or otherwise buffed. They just don't do everything exactly at the right moment for the contact patch to affect things maybe
     
  11. CrimsonEminence

    CrimsonEminence Administrator Staff Member AMS2 Club Member

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    Yes, like mentioned. It's the whole rats tail. Drivetrain+influenced parts.

    That's what Renato Simioni actually confirmed right now.
     
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  12. Raceracerace

    Raceracerace Active Member

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    Cool! What about gear ratios and the like in the diff
     
  13. CrimsonEminence

    CrimsonEminence Administrator Staff Member AMS2 Club Member

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    Of course it will also have influence. What exactly is going on with the system can only be solved by the guys, working on it directly.
    The drivetrain model of the Madness Engine is pretty advanced, as far as i know and so it will be complex af to get into the details of what exactly contributes to the found issue, especially when adding the tyre, the car, weight transfer, everything etc...
     
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  14. SlowPoke80

    SlowPoke80 Active Member

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    Maybe some problems that I thought were in the tire model were actually in the differential.

    Specifically, a general lack of on-power oversteer exiting all but hairpins, but the hairpins having too much oversteer.

    Is this the cause of the problem wherein even very high horsepower cars won't spin around in medium and high speed corners when the throttle is heavily abused?

    This thread should definitely be kept alive.
     
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  15. psone

    psone Guest

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    @SlowPoke80 its a physics thread in a racing sim. Have no fear, it will live forever. :D

    very glad its here though, am learning things already.
     
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  16. CrimsonEminence

    CrimsonEminence Administrator Staff Member AMS2 Club Member

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    Yes. The tyre model is actually pretty nice, as soon, as cars are dialed in (and don't suffer from the golden outlap syndrome). Also the way, tyres develop over a stint in temperature window alone etc. is WAY MORE interesting in AMS2, than 1 (and also in pCars2) IMO.

    This is something, that can be caused by a fully locked diff, when traction breaks, yes. (The reason why V8 Supercars need such a careful, but slightly pre-apex driven style, because of the spool, for example)

    Also the "pivoting", many people talk about and lack of lift-off-oversteer can be caused by very high differential lock.
    Just to mention it: The SuperV8 in AMS2 actually turns pretty nice, despite actually being 100% locked(by design), because the concept of such a car (front suspension geometry etc.) is dedicated to it.^^ (Likely the reason, why V8 Supercars are also good in pCars2, that also suffers from the diff issues, but a spool like on the Aussie Machine means=no diff..so...)
     
    Last edited: Jan 3, 2021
  17. oez

    oez Mayor of Long Beach AMS2 Club Member

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    I thought the Super V8s are nice to drive as well. I mean the concept is tricky, but it's like that 24/7 so you can rely on the rear.

    I think many LSD cars used to behave like spools before thanks to some drivetrain bug which locked the diff completely. It would never open. And while the car control required relative to their real counterparts was incorrect, they were easy to control after a while and felt correct for spools. Well as easy as spools are ever. If you could drive the Super V8, you could drive a lot of the other cars.

    This is important to me, because consistency is key within a sim. It doesn't matter if the car matches the real counterpart on paper if a lot of feeling is missing and it behaves randomly.

    Now with the clutch LSD doing whatever it wants it's hard to push some cars in my opinion. It'll just wait for the perfect moment to ruin your day with a violent snap.

    I believe the tire model never contributed to these issues as much as the unreliable differential. And who knows if the current tire situation is a temporary measure to make the cars drive correctly. With the known issues of course. It's actually a bit surprising how well the Group A cars turn seeing as their diff is also very much locked 98% of the time.

    Yep. The inside tire likes to spin which stabilises the car rather than making it oversteer. And when you lift, rather than turning more (what people are used to with GT3 for example), it'll just want to go straight. I would set up the differential like this if I wanted to maximise confidence for whatever reason.
     
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  18. Big_Mama

    Big_Mama Ben Suttor AMS2 Club Member

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    Crimson, did you have a look at Project Cars 1, and compared it to Project Cars 2 / AMS 2? I came across a video a few days ago from someone that seems to prefer the way that cars in pc1 drive (compared to pc2). Maybe this could be diff related, who knows?
     
  19. CrimsonEminence

    CrimsonEminence Administrator Staff Member AMS2 Club Member

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    Who knows, no clue, but yes...many oddities aren't down to a "faulty" engine, like many people think, but down to not enough time and polish for the content itself, IMO. Some cars in pCars1 and 2 are amazing, while others are abysmal.

    I have played pCars1 the last time one year or so ago. Was frequently playing it with a good friend on his PC, when this game was pretty much new, with an Xbox360 controller actually. (was also able to test it with a wheel, though) I don't own it myself, because at the time, pCars1 was a thing, i had a potato-PC, running GTR2 the most time...and then AMS1 came...
    But i might visit him in the next weeks and i could make some tests.^^

    pCars1 had one specific oddity for me: Drifting is forbidden...you just can't really do it. (and playing it with a wheel was no difference. The FFB also had this weird fast centering. You stand still, apply some high wheel angle and accelerate a few Km/h and the wheel was bungeecording to the center with high speed, even if just using a lower powered G27)

    The drivetrain model in pCars1 was also a bit more simple, if i'm not wrong here, i also remember the setup options to be less extensive.

    But i actually have to say, pCars1 was IMO not nearly as bad, as people were talking it into, when driving racing cars with "reasonable" setups...AI was......phew....though.
    I also like pCars2 with the right cars, though. I actually had some pretty stunning experiences with this sim and i don't drive it that much.

    The pCars2 iteration of the Madness Engine has pretty complex ingredients and has to be understood well, to benefit from it, if i understood the comments of the big boss Reiza-Dev correctly. (Which sounds reasonable, when thinking about all the things, it features)
    So it's more about the understanding to make it work together with all the surrounding components.
     
  20. Avoletta1977

    Avoletta1977 Well-Known Member AMS2 Club Member

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    Tested the Porsche GT1 at Ortona track...
    It's more agile than a fVee :D

    I think this kind of tracks tell you a lot about vehicle dynamics and their implementation in game...
     
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