“ are rfactor2 physics broken” video

Discussion in 'General Discussion' started by GTClub_wajdi, Dec 29, 2020.

  1. Slip_Angel

    Slip_Angel Registered

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    yep tires in this game are very real
    check out this amazing behaviour of latest tire model dlc car (just look at 0:51 ) ->>
     
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  2. Jihemme

    Jihemme Registered

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    This was already stated actually, it is bad driving and it is ruining tires but real cars can do the same (well, he is surely very low on ffb to be able to move that fast) but :

    1) it is very hard to do wirhout losing the car, of course
    2) you are losing time since you basically slow down the car
    3) you are ruining your tires so you'll have incredible vibrations, of course since his ffb lvl is far from realistic, he doesn't suffer those vibrations

    I remind you Fernando Alonso was F1 World Champion TWICE using this kind of technique, I don't think you can actually say this is impossible nor efficient, what is above F1 in terms of difficulty on track racing?
     
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  3. mantasisg

    mantasisg Registered

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    I think it is very tricky subject, thats why it requires very in depth discussions, and we having all this pleasantly hard time having those discussions :D

    You have some good points. I have no doubt racing tires will be harder to drive, because they will be more peaky, more peaky and thus dropping away faster, and returning faster. Other factor is aerodynamics, aerodynamics will loose efficiency with angles, so it adds up to the challenge. Other things like improved suspension, brakes, less mass, less power might of course help to have car handle better. I would say that more power could be useful sometimes, for example in case of oversteer to maintain rear wheelspin for extra moment and in that way cause the car to return from oversteer more smoothly, because if rear wheels grips too hard and too soon it can destabilise the car, or even send into a tankslapper.

    Also good example of that Audi spinning out and really biting quite quickly into the tarmac once it overrotated a bit. It is indeed demonstrating high friction in there. Also beutiful to watch these cars overall, how much grip they have and how they run firmly planted, yet they loose control like that and run off the track. I'd like to present some suggestions/assumptions on how this might not be a sign of a car being too much simple to handle.
    • First, it ran off the track and spun :D
    • I am not sure, but it could have been still running on tires that were too cold, and by sliding temperatures might not have had risen too far which may have helped to keep sliding friction high enough
    • Driver was able to get car slow enough, and it helped not to exceed dangerous sliding velocity
    • Good point for dirty tires, have no explanation, apparently it wasn't big issue for that audi tires.
    • The way how strongly the car gripped when it stopped sliding shows how strong the static friction is. It is good for performance, but won't necessary make it more simple to handle the car. Imagine same effect, but at speed and recovering from slight oversteer (something that apparently sent that audi off the track in the fist place), imagine oversteer happens and the rear tires snaps back in that much strongly before driver returns the steering wheel... well no need to imagine, thats how that audi went off.
    it was very interesting to try to explain how this whole audi moment worked, I could ofcourse be wrong, feel free to point out what you disagree

    By the way other accident, which displays tires gripping up hard before driver returns the steering, this time at very high speed. These things happens because peaky tires/aero and fast drop off/fast return.


    And another of just spinning with no return, lost aero, sliding velocity too high:


    Basically, IMO it is very important to go technical in this subject. As easy can turn out to actually being hard in particular circumstances and vice versa. As displayed how great grip can cause accidents, more precisely great grip fluctuations in short time.
     
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  4. Stefan_L_01

    Stefan_L_01 Registered

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    If you have a steering wheel, you can turn your front tires any time to any angle.

    What would you have expected that happens with that steering??

    He gets a bit understeer, he could have made the corner also with normal steering angle, I just tested it.
    Just a hint, the cup steering rotation for the wheel is max only 15°, the cos(15°) is still 0.966.
     
  5. Slip_Angel

    Slip_Angel Registered

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    and there is your problem. after such harsh input one would expect sever understeer ,even oversteer.

    Also since u tested this corner with normal technique , did u reach same cornering speed ? or was it higher or lower ?
     
    Last edited: Jan 17, 2021
  6. Slip_Angel

    Slip_Angel Registered

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    1) it is not hard to lose car doing this in RF2
    2) not losing as much time as one would expect reaslistically
    3)hotlaps IRL are not done ruining the tires like this.
     
  7. Rastas

    Rastas Registered

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    Drifting in rFactor2 is awesome :D
     
  8. Jihemme

    Jihemme Registered

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    You actually won't lose that much time, especially since the braking wasn't ideal so the car was a bit too fast, which is possible to handle in a simulation because you can set the ffb very low. In a real car it would be much harder to handle because forces involved are huge. Tey to do it with harder ffb, you'll see why it is not that unrealistic within the game but it becomes with hardware setup.

    I did it only 2 corners and with me ffb settings, vibrations were so important that I couldn't keep on driving those tires.

    The main problem I can see here is the ffb being too gentle when he is abusing but I don't think car behavior is unrealistic.


    Now I've seen the famous streamer Jardier in ACC using the same kind of steering technique and he is pretty damn fast. Check his videos, he is often inducing willingly understeer on some corners to be faster. So basically, this is not a rF2 only thing.
     
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  9. Slip_Angel

    Slip_Angel Registered

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    ACC is nowhere near this forgiving at such input. i have played ACC too, i tested it on many cars.
    Such extreme is only forgiving in RF2
     
  10. Nieubermesch

    Nieubermesch Registered

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    What's up with people and their never ending posts?! :D:D:eek:

    Kidding here, but I was in a hurry reading this. Was going to reply yzangard about sliding and the difficulty of gt3 cars, but I think you've already done it well.

    Anyway, great insights into the whole industry too.

    Very very nicely said. This subject goes more then just one can make car slide and not lose it and how difficult they should be, as if some of us just want the cars to spin out once you get a slide... :rolleyes:
     
    Last edited: Jan 17, 2021
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  11. Bruno Gil

    Bruno Gil Registered

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    Welp I'm leaving this thread...

    EDIT: should've read this last page before posting this. Keep the good discussion going, ima be lurking. At least until someone shows up to derail the convo again...
     
    Last edited: Jan 17, 2021
  12. mantasisg

    mantasisg Registered

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    @Nieubermesch haha, thats a bit of failure on my side, I wrote that first line yesterday, and then didn't post it, because I decided it sounds grumpy, which I didn't mean. Apparently I forgot that line and it was saved automatically, and got it posted today.

    Ironically, I wasn't too efficient myself, and surely did too long post, I would be more proud if I would have stayed more by the text to edit it, shrink it, so it would be at least twice shorter, but still transfer all thoughts. I also think I did messed up and quoted post from entirelly different thread, although that thread is pretty much about same broad topic.

    It is hard to say a lot and be elaborative by saying little.

    But I am glad you read it, and found some thoughts useful. I think the Audi example turned out rather well, I'll be looking for counter arguments. The knowledge body that I have seems to be gaining shape, however can never be fully certain about anything.
     
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  13. Nieubermesch

    Nieubermesch Registered

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    Well, that last sentence is applying to myself very well too. I am very careful about bold statements even if I am pretty sure about something :confused:.

    I have to limit my participation on the discussions as I am on epoch of exams and next one is thermodynamics and I am not that great a student, but I have the passion at least :D:D.

    Long posts are nice, I just was in a hurry and was wondering when that would stop :rolleyes:;).
     
  14. Bruno Gil

    Bruno Gil Registered

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    Even in real life. If you check driver61s videos, a RL coach, specifically the "How to find the limit" one, he mentions one good way to find the limit safe and fast is to willingly induce understeer at corner entry (so, lift brakes too abruptly for example) so you can get the car sliding in a controlled and safe manner, and get used to the feeling
     
  15. Stefan_L_01

    Stefan_L_01 Registered

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    Why do you expect oversteer? If you expect oversteer, that would mean that you expect in reality that the front tires generate more grip turning the wheel like this. But this is what you claim as physic fault all time. You contradict yourself. If it would create more grip in reality, it would be used, no? You don´t know what you say. Think first then talk.
    If it creates less grip, what is the theory, it is a understeer effect as result, and tire expensive. I dont know why he uses that technic but he is not forced to do so imo.
    I would not drive that way in reality in a race car, maybe if I have 200m asphalt next to the track for some test. However with my front wheel driven car in reality, I can assure you you can oversteer the front wheels without problems, I did this multiple times going up some mountain roads in the past for example - no race car for sure, not really comparable, but its not unsafe, in opposite. Once you slow down you get into the area of max grip
     
    Last edited: Jan 17, 2021
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  16. Slip_Angel

    Slip_Angel Registered

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    The videos i posted are hotlap....this has nothing to do with "how to find limits"
    Not to mention no car can be driven like that IRL without consequences.

    It is interesting that the exploit video i posted got some dislikes...looks like people don't like being shown the problem in their favourite simulator.
    Another very disappointing thing about good chunk of this community is lack of observation skills
    The things that are possible in RF2 driving wise are never seen IRL videos without big consequences.
    The setup that is being used don't even need a degree to prove how unrealistic they are....ever heard a SINGLE racing team detaching ARB and running low wing leman setup on sebring ? lmao.

    No observation skills, full of excuses and comparisons that makes no logical sense.

    RF2 physics needs improvement deal with it.
     
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  17. Slip_Angel

    Slip_Angel Registered

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    Oversteer is one of the possibilities in that situation... i don't think you will be understanding the explanation. Because you are focused on wrong things instead of finding what's wrong with RF2.
     
  18. ATQ

    ATQ Registered

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    Well, personally I don't like the behavior of normal road cars. Because they are less responsive they also have a tendency to make you a passenger when things go wrong. It's sort of like how cars handle in Assetto Corsa, when you lose the car and you can go make yourself a cup of tea while the car is sliding in a long arc that goes on forever. Racecars are much sharper and twitchier, requiring fast reactions, but obviously a hell of a lot more responsive.
    Anyhow, peaky slicks makes the car sharper and twitchier but it doesn't mean you can't slide around without losing control. Racing slicks can be used in drifting and some actual like them. I would assume it takes a lot of skill, but nonetheless... In this regards rFactor behaves as I would expect. The cars are twitchy and sharp, you can slide them a bit but it's hard to maintain a controlled slide.
    As for aerodynamics, it's difficult to predict how it should work. I mean, sure, we can say that the car should lose downforce and ge increased drag as the yaw angle increases when sliding. To what extent though? What other effects do we have? The increased yaw angle should also create more lateral force pushing the car in - how much does that compensate for the reduced downforce?
     
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  19. mantasisg

    mantasisg Registered

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    Yeah, especially if the car is with big fins. There will be an aerodynamic component resisting car to overrotate. But it could not be anywhere near enough to compensate friction loss due to loss of downforce and just simply friction loss due to increasing sliding portion of tire contact patch if it happens to go much above peak slip angle. High grip, stiffness, downforce, other aerodynamics... all that stuff that makes these cars so grippy and responsive might not help to return car smoothly back from the slide, if steering angle won't be properly aligned with desired vehicle direction, car can "think" it is about to do a turn off the track or into a tankslapper. Assuming the car did not get sent into spin with no return in the first place, which also is result of drop in friction amount per particular amount of time.

    It boils down to our perception of how we perceived real cars racing. I can not tell you are wrong. But in my personal opinion the drivers just simply has to react faster, the faster the cars happen to react. Those particular modern race cars are stiff and high grip, that makes them to work in a lot higher natural frequency than normal cars. Everything just simply happens fast in them, they grips good quickly, forces gets transmitted through chassis quickly. For a driver to react very quickly to all that is a must. I have read a book about tires by Paul Haney, great book, he published his conversation with Bridgestone engineer there, asked about grooves on the tires of F1 (2002 maybe?), also asked about having lower profile tires... afaik groves were to reduce grip of these tires, because they would have been too fast for the drivers to handle, same goes for low profile tires - too fast to handle, as they would be even more reactive. I don't remember exact details, but IIRIC road cars are designed to work at about 1Hz frequency, F1 works at about 5Hz, and it could be made to be even higher ! This means drivers must have to be able to react to everything happening faster than in 200ms all the time, imagine you would be getting into and then out of the big oversteer in 400ms without expecting it ? That would be undrivable, you'd just begin to steer into a slide, and you'd already be thrown out into a tankslapper. Like Vettel here:


    And they are planning to use higher profile tires, how will Ferrari handle them, I don't know.

    Anyway, my observations could be wrong, and it is easier than it looks to me, maybe I overrate pro drivers by some amount.

    By the way... I just wanted encourage anyone to drive ISI Megane or Camaro GT3, to me those are pretty much the real deal, IDK what others think.
     
    Last edited: Jan 17, 2021
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  20. Slip_Angel

    Slip_Angel Registered

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    I agree with you view.
     

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