“ 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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    I don't how it sounds/means i'm not a native english speaker. So that bit is still unclear

    i will try to comment on following ->

    So here is how i understand this bit->>
    are you basically saying that quali laps have excessive sliding for both i.e understeer and oversteer (which myself and many other agree on )
    Of course sliding is much less visible outside, it is pretty obvious that onboard cams where you will see more yaw , more steering angle basically more action than outside cam.
    Also if you are one of the fast guys yourself then you will notice more sliding feedback in FFB than what you would expect from given car , this is especially bad if it a car that has good downforce.

    P.S ->> Although personally i can see excessive YAW on outside cams as well, if you see IRL footages and compare it to in-game car motion then you would see. Bit harder to spot but definitely observable.
     
    Last edited: Jan 2, 2021
  2. billyblaze

    billyblaze Registered

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    Hmmmmm....food for thought there, goes well with a nice bottle of wine and a good book...

    [​IMG]

    [​IMG]
     
  3. John R Denman

    John R Denman Registered

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    "Excessive sliding"
    First off thats an anecdotal answer; it needs to be quantified. Second none of the drivers who have actually driven the real cars have mentioned that, in fact most have said almost the opposite, including the teams I've worked with. Indeed faster lap times under qualy conditions tend to have just enough sliding to keep tire temps within a narrow window and avoid flat spotting, but certainly not always, in fact there are a number of tracks where sliding into tight turns, or drifting up the banking is way faster.

    Under passing conditions tires need a lot of reserve, other wise cars get knocked off the track or its merely a parade finishing as they qualify. Take away the reserves and one might was well just be running time trials.

    If you want to developers to make changes, the first thing is to describe explicitly what needs to change. To do that will require understanding the inner workings of the physics component at hand, which in this case are tire physics. Have you examined the TGM file structure and the worksheet? That's the level of detail required to begin requesting any changes, and frankly, thats where the physics changes would actually be made. Other than encrypted files, one can create tires that suit them the best, but those updated files won't pass the online filters.

    As for DLC with encrypted files its pretty doubtful any changes will be made, particularly with GT cars.
     
  4. mantasisg

    mantasisg Registered

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    1:30


    Great talk and drive video btw
     
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  5. hitm4k3r

    hitm4k3r Registered

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    I've watched that talk and drive video, but I still don't get why he comes to his conclusion based on how alien drivers get their optimum laptimes. There were similar experiments with AMS vs. F1 2019 were drivers could get completely out of this world laptimes in AMS compared to the F1 game. Does this make the F1 game more realsitic or AMS a bad sim in general?

    I can't drive like the alien drivers and I wouldn't be able to run a handful of consistent laps with their setups. The Porsche 911 GT3R setup is a prime example. I am allmost 100 % sure that the default setup was provided by an alien yet I find it undrivable especialy over longer stints. It actually makes me slow. And it's that fine line that makes this threat a bit of a mess. Some people give their expertise on what seems to be broken yet noone even makes the effort to boot up the game and provide some motec data and scientific clues on what should be improved. And to even claim based on a single car/class that is driven wierdly to get fast laptimes that the whole physics engine is broken is quite wierd. As Lazza allready pointed out, unless you start quantifying what is actually broken it's hard to fix it. I too have the feeling that rF2 GT cars allow for too much slip angle without penalizing the driver or getting enough tire wear especialy with with softer compounds. But I can't point my finger at what's actually causing this and how much of too much slip angle we are talking about. Is it 1 or 2 degrees? I don't know. Or maybe we are at a point where track and ambient temps should finaly affect the rubber?
     
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  6. TJones

    TJones Registered

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    About that "excessive sliding": I think as long as you drive the car within it's normal threshold of the tires, and don't overdrive the car those GT cars doesn't feel bad at all. Maybe, only maybe a tad to wide threshold.
    But if you overdrive the car, you're able to slide through fast corners at about, lets say 180km/h and a slip angle of 20deg and that sometimes through the whole corner. I would expect that the tire would simply give up at some point, and rear end swing around.

    Also changes of camber doesn't seems to have much of effect of quite some range, until you reach some very low or very high degrees.

    About tire temperature readings, at very low pressure 140kp (cold) you still get higher temps at the middle measure point compared to outer/inner or even at best, while i would expect a bit higher "inner" and "outer" temps here.

    Completely closed brake ducts, even at high ambient temperatures doesn't seems to make any difference, so fading for example.

    Just remember another little issue.
    Setup of these days GT- cars with theire quite efficient undertray aero, are often so, that you let the front axle "sit" on bump-stops especially for mid and fast corners. So with only a few mm of space until the suspension touch the bump-stop. So basically the increase of downforce you get with this very stiff and stable front, and theirwith pretty constant ground clearence of your splitter, is high enough that it overwieght the loss of mechanical grip here.

    So I tried this technique recently with the new C8r (beautiful car btw) at Zandvoort. It doesn't worked out very well, seems like the bump-stops are way to stiff here to really be useful in the way I tried. Maybe S397 could spend the car softer bump-stops, or even better implement the possibillity to change bump-stop stiffnes in the setup. Like it's done in ACC for example.
     
    Last edited: Jan 2, 2021
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  7. mantasisg

    mantasisg Registered

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    @hitm4k3r It is not about laptimes, but about how they are achieved. And although there isn't quantified absolute golden proofs that would be impossible to deny. Some people just has enough understanding to observe that some stuff is just out of the ballpark and by quite a bit. And there is room for observations, guesswork, logic and common sense.

    Some people thinks everything is awesome. Some people thinks it is so awesome, it is too awesome, and thus not that awesome. I think that way about most cars that are carying the flag of rF2.

    Is it because something about aero not sensitive enough ? Is it about high temperatures being too forgiving ? Is it about temperatures not rising enough ? Is it simply about coeficients of friction not being in correct ranges ? Sliding friction not sensitive enough to velocity of sliding ? Tires construction is wrong ? Too weak bristle springs and dampers ? Rubber load sensitivity ? Some combination of all those ? Or is it none of them, and everything is fine ?

    Some people might assume that these rF2 front runners cars are perfectly configured. Maybe they are ? But then those people who still has an opinion that they doesn't perform in entirely correct way would have a basis to say that rF2 underlying physics are wrong. While there also is a possibility that there really is something wrong about few aspects, no one has slapped super proof on the table, so it just remains suspicious.

    I am wondering about few specific areas. Personally I think a tire with vacuum inside should drive rather badly and slowly. To my exprerience it didn't in one mod. But I have not tried to build a tire with ttool that wouldn't display such capability. Next, rolling resistance seems not to have that much change per rather significant differences of tire pressure, but I have not examined it that much, and then again didn't put serious effort to try to build a tire that would have lots of rolling resistance with very low tire pressures. So basically can't claim anything about rF2 physics fundamentals.
     
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  8. Remco Majoor

    Remco Majoor Registered

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    Just for fun I looked back at my GTE competition system race in motec. My quickest lap was lap 8. In that lap I had one spike of ω being -0.94 with usual spikes being -0.8 ish. Maybe the people here with big brains and know how to use this can compare it to IRL cars? How much more rotation do cars have than IRL, so we know how far off it is?
     
  9. Stefan_L_01

    Stefan_L_01 Registered

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    If I may pick up that point: Even if you cannot model a 3D aero fluid model around a body in full detail, you would expect that at least the limited model that can be build up is the same for every car, ok? But this isnt the case. Take the 488Gt3, it has a way more sensitive underbody aero than any other car. If the nose is too high is has no grip at all, if it is pressed down it has a suction that makes you spin out. You can not reproduce that suction even with cars like the Porsche who can be set up also very very soft on the front.
    So it is not only about a physical model, say weight distribution or spring stiffness, the cars own a unique physic (which is a NOGO) obviously by some parameters which influence aero and other param, say underfloor aero in dependency of ride height or other. And this is BS. This kind of physic param, coefficients of ride height dependencies or whatever, should be the very same for all cars but they aren´t for sure. There is no common line in the GT3 series. Every modeller can do what he wants. At the end everyhting is put into a BoP by weight or other, not recognizing modelling faults like wrong bumpstop hit travel and so on, and the car is somewhat in the pace. Good enough to deliver.
     
  10. Ermz

    Ermz Registered

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    Really glad that somebody brought this up. Context is often lost in these situations. Painting this in terms of a wide-eyed fan gradually becoming progressively jaded by allowing themselves to follow a trail of cold logic to its inevitable conclusion, arriving at a 'Santa doesn't exist' moment would be fairly accurate in this case.

    The prime objective of the video was to reignite this discussion, to which end I'm very glad to see this thread exist.

    One of the prime movers of content creation is the understanding that human beings are negatively geared. Negative experiences stick out to us far more viscerally than positive ones. This is corroborated to us statistically every day. To that end, you do what you can to trigger that impulse in viewers to make the content visible, and then ideally turn it around to derive something more meaningful through the content itself.

    Irrespective of what people think of the content of the video, the fact is that the state of many, if not all of the recent s397 cars leaves them highly susceptible to suspect setups and driving styles to operate at a top level. This is virtually indisputable. It's been corroborated by the 'aliens' themselves, real GT drivers (some of whom I've both interviewed and spoken to privately about this), race engineers, various articles during the Sim racing boom and not least of which: the developers themselves. The driving physics of the latest cars in rF2 are in need of an overhaul - that's the important discussion to have. Whether or not you feel my methodology was incorrect, my manner insufferable or whatever else is beside the point.

    Further, it's not the players' responsibility to tell the devs exactly what to fix. The players identify problems - the managers and coders isolate what it is and how it's best addressed. When customers come to my company, saying that our products aren't working with a given OS or host app, I don't expect them to tell us why that is. I only expect them to tell us that it's happening.

    The channel has sold many, many copies of rfactor 2, mostly under the hope that, as Marcel said, we were investing in 'the most realistic simulator on the consumer market'. I would love to see rf2 able to take that mantle.

    With the public roll out of the competition system and UI, it may be high time for the focus to shift back to physics. They are, after all, rf2's point of distinction in the industry. Without superiority here, there is very little to set it apart from the competition. Its audio-visual flare and ease of use certainly won't. Its small slice of the market share already speaks to the validity of this.

    I'm witnessing an exodus. Very skilled drivers, some of whom have tutored me, are now leaving rfactor 2 because they're tired of how they have to drive the cars. Real GT drivers across the board are swearing by ACC as the closest thing to reality. Yet 2 years ago in early access that title was barely drivable. How is this possible? Through a concerted effort and constant small adjustments to the physics engine over years, just as Reiza are now continually doing in each AMS 2 update. You can only coast on your laurels for so long.

    Ultimately, what I want are more reasons to be able to recommend rfactor 2 - not less. I can't recommend it on the grounds of its graphics, its sounds, nor its level of accessibility. Having an online ecosystem where cars have to be driven and set up as mentioned to be competitive does not help.
     
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  11. Slip_Angel

    Slip_Angel Registered

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    Very good discussion going on now.

    Just my opinion->>
    2 things will make RF2 more realistic IMO
    1.Tire temperature sensitivity
    Currently i feel like tires are too forgiving and have quite good amount of grip even when they are overheating on tier HUD.

    2.The drop off after going over the peak is very very smooth, sometimes i don't even know if either i'm at maximum slip angel or am i sliding a touch too much.

    Making this 2 things more punishing will make car behaviour much more realistic.
     
  12. Joaquim Pereira

    Joaquim Pereira Registered

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    I didn't read all oppinions, but do you guys have "Exaggerate yaw" at default value? (I set it to 0, where it should be ;))

    A side note: some videos from YT (and real race driver) Driver61 show the exploids used by top world drivers. I think reality is also broken, because they cannot do that and get away with better lap times and world championships...
     
  13. Slip_Angel

    Slip_Angel Registered

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    Perfectly sums up my feelings, thanks for video. People here asking us customers to give scientific data and whatnot...lol we are just customers we have no idea how the physics engine works. Neither we have access to code nor the data of car. Even in telemetry most of the important channels are blocked due to NDA and stuff.
    All we can do is compare real to sim and after watching thousands of hours of real car driving,listening to PRO driver we get good ideas about car characteristics.
    Simply comparing real life to some alien laps is extremely good evidence in itself, sadly some people are still not convinced.
     
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  14. Slip_Angel

    Slip_Angel Registered

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    This is serious discussion going on here, if you are not going to contribute then your silly and sarcastic comments are not needed.
    Refrain from talking useless things.
     
  15. mantasisg

    mantasisg Registered

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    Last edited: Jan 3, 2021
  16. John R Denman

    John R Denman Registered

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    So far all tire physics changes mentioned are defined in the TGM file. Granted DLC content is encrypted and that blocks MoTec from reading certain data. MAS files are encrypted for 2 simple reasons; it keeps others from copying and redistributing and its virtually impossible to bypass any cheat filters for online use. Therefore if the mod has encrypted MAS files you're simple at the mercy of the developers and its highly unlikely to get any changes that will have a larger negative impact on the customer base.

    Personally, I buy the GT cars only to support S397. It's not like I'm a fast driver, they just aren't very challenging. Why eat a day old hot dog when their are cases of Prime Filet Mignon waiting?

    If anyone wants tire physics that are perfect for them, Tire physics development begins here:
    https://docs.studio-397.com/develop...nt/car-physics/tgm-spreadsheets/tgm-generator

    The user defines geometry, construction, test conditions & boundaries, compound, temperature-grip coefficients, contact properties, load sensitivity and a few other key parameters. No other "sim" has this level of detail in tire structure, not even close. The only reason rF2 can offer this level of detail is due to the heart of the engine, the tire algorithm thats based on a bristle concept. Every other tire algorithm, rF1 included, uses a very high overhead approach that swallows CPU cycles. It doesn't get any better than rF2 in terms of tire algorithm efficiency.

    Once you go through the first iteration, and that will take several hours, test drive and note what it needs to feel better. Than go back to the TGM Generator spreadsheet and make changes, generate files and re-test. Repeat until you have what you want.

    It would be nice if S397 engineers worked for free and had spare hours building cars to the liking of any individual. Not something I would plan on.
     
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  17. John R Denman

    John R Denman Registered

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    Paid endorsements.
     
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  18. romaFC

    romaFC Registered

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    I have some bad news for you.

    rf2 does not have Michelin tam data.

    now this may shock you even more iRacing and ACC don't either (in ACC case Pirelli data)

    Also tgm generator requires some inputs that hasn't been tested/don't exist in real world.

    One of the most annoying thing about rf2 or any 'sim' game.

    Its always my sim is choice is better than another sim. If pro driver say ACC is good game, oh wait of minute he must be paid driver.


    Also I posted earlier.

    That compared to real motec data that I have around Road America.

    GT3 do match rf2.

    Because they all get real data now ( iRacing and ACC included)

    The only differentiator between iRacing/rf2 and ACC is the tyre model.

    Which is up to anyone guess which one is realistic.
     
    Last edited: Jan 3, 2021
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  19. John R Denman

    John R Denman Registered

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    Nor do the simulators used by F1 teams or OEM's.
    Even the TGM simulator is only a sample based system with limits.
    Maybe when CPU's are running in the terrahertz range we can add more detail to get realtime response. Until then we get to choose between one that runs 100x more efficient than the rest (which are based on 20+ year old Rigs Of Rods algorithms) or one of the inferior games.

    The first thing every pro driver learns is no public endorsement is ever free.
     
  20. Remco Majoor

    Remco Majoor Registered

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    I did a shower and kept thinking. I have driven many cars in rF2 and many in other sims as well. I am going to keep this rF2 for now though, since that's the sim I have raced competitively for the last few years. The cars are so different to each other. For example compared to the GT cars you have the tatuus for example, which you can't do the removing rear arb thing due to excessive understeer and you slide a bit more, but also less, since sliding loses you time. Slide too often and your tires start wearing quickly and overheat as well. Renault Megane trophy (which is way older) makes this even more interesting. That car, although you can still drive it very much on the limit, has that thing that if you go over the limit, you overheat the tires and it takes a bit to cool down (maybe a bit too long) before you can push again. Both in the megane and the tatuus I have spun quite a bit going over the limit (megane more than the tatuus). With the GT cars, I simply can't. You can lose control, but you still with counter steering completely won't go backwards. It's a fun thing to test out, the difference from the megane to the GT cars. It just feels like the tyres heat up quickly at too high of an angle. It should heat up at a lower angle. This is why you see qualy laps of people throwing their car into the corners with insane drift angles, but in long races you don't see them doing that.

    I still believe though that it's good that they focus on the UI and the competition system ATM. Sim racing not only simulates the driving aspect of things, but also as the name suggests, the racing. rF2 for the longest time had complaints about pick up racing not really existing. Everything was leagues, which not all people want/can to commit to. So this system is needed so badly. The physics are still very good, even with these exploits. More than good enough to have a lot of fun racing with it. You can push the cars to the limit and have tons of fun racing.

    After this system I think there are still things that are more important than the physics. For both the single player and multiplayer crowd I honestly believe that a good damage model will change the way they have to race others in a very positive way. And on this subject of racing others, for the single player crowd wants good AI, which is not in the best state atm. Even though other sims are rapidly catching up and starting to get better physics wise, these things atm are more important than updating physics. And I think for good reason.

    Of course it would be great that you get punished a bit more by getting too high angles, or using a soft suspension/detach rear arb, but to the racing part of the simulator physics like the compounds actually working like they should, tire temp being affected by track temps, wind being a thing, puddles/aquaplaning and those things that actually affect the racing are far more important atm.
     

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