Tire deformation exaggerated?

Discussion in 'General Discussion' started by avenger82, Jan 25, 2018.

  1. avenger82

    avenger82 Registered

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    Like the title says - isn't tire deformation/flex (at least visually) exaggerated compared to RL? It looks like tires have very low pressure, especially when going over kerbs or hitting ground after a big bump. I can upload some videos showing ridiculous deformation in extreme situations.
     
  2. LokiD

    LokiD Registered

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  3. MarcG

    MarcG Registered

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    In a word, No. Search YouTube for V8Supercars tire/wheel cam and you'll see the similarities.

    Edit: I'll save you the bother, check this out!
     
    Last edited: Jan 25, 2018
  4. caravan_driver

    caravan_driver Registered

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    The tyres are so cool to watch in RF2.
    Can only imagine the next RFactor with a new tyre model and bodywork visual flex. It is going to be NSFW.
    Like the crazy tyres in Spa last year.
     
  5. avenger82

    avenger82 Registered

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    Thanks,

    OK so it looks in general visual deformation in rF2 is pretty close to reality. Especially after 17th second of the F1 video when tire is at high load. However, I'll try to upload a replay with some really extreme case in rF2.
     
  6. dadaboomda

    dadaboomda Registered

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    High guys.

    Is RF2 is the only one simulation to have tyre deformation and chassis flex ?

    And thank's for the movies guys.
     
  7. caravan_driver

    caravan_driver Registered

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    Something like this?
    [​IMG]
    [​IMG]

    From the marketing material I remember Live For Speed, Forza series and Project Cars have this kind of tyre deformation.
     
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  8. LokiD

    LokiD Registered

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    Raceroom actually has it too. Not sure of its entirely simulating tyre physics but its there visually anyway.
     
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  9. Filip

    Filip Registered

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    AC has tire deformation in physics but not visually
     
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  10. caravan_driver

    caravan_driver Registered

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    Are you guys sure? Cause Automobilista have tyre flex too. But it is very different from this crazy deformation.

    In the games [blog] there is a link to an article from the Automobilista physics guy explaining the difference. Basically some games like RF2 use a physical representation of the tyre that is what we see in the replays. Others use curve fitting using tyre tests results. They model flex but it is very different as far as I know.

    At least when you open the car files from the games with notepad you dont see a physical description of the tyres in those games. Or I couldnt find where that is.
    Open the AC and RF1 car files in the steam folder.
     
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  11. Lazza

    Lazza Registered

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    rF2 has always looked too extreme in this regard, even more so in early builds. But graphics and physics don't necessarily have any correlation, in any game (only the devs really know, and any engine can do weird things in certain situations), so I wouldn't worry about it as far as handling goes.
     
  12. LokiD

    LokiD Registered

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    i apologise RR doesn't have it.. blast i thought i saw it once.
     
  13. avenger82

    avenger82 Registered

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    As promised, here is a video showing "ridiculous" tire deformation in rF2(starting at 8th second):
     
  14. Lazza

    Lazza Registered

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    @avenger82 The forces involved in that landing are outside the parameters used when testing (calculating) tyres. The deformation is therefore extrapolated and leads to those 'ridiculous' results. I think that's a pretty rare case and shouldn't be seen as a weakness as it's not indicative of normal use (which is where people care about tyre behaviour; no one cares whether a landing like that is realistically modeled at the tyres).

    Now, if you're talking about overly-deformed and compressed tyres under normal load, I agree. The modern Formula cars in rF2 have always shown too much tyrewall compression under normal loads, visible from external cameras, which don't match reality in similar situations. But again, graphics <> physics, so it's probably not a huge deal. (**I haven't looked at this in recent builds/versions, so maybe it's changed)
     
  15. avenger82

    avenger82 Registered

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    @Lazza
    Ok thanks, that explains it for extreme cases and I fully agree.
    However, regarding visual deformations <> physics - I’m not so sure about that. I think I even saw a comment that the visuals are directly tied to tire model calculations in rF2 ( which was also my understanding).
     
    Last edited: Jan 26, 2018
  16. Lazza

    Lazza Registered

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    I don't know if we've seen exact details of this. I'm pretty sure most graphical tyres are simpler than the physical model (something like 70 sections & 15 nodes, vs 200 sections and 60 nodes for the physics), I don't know whether the tyres are then graphically altered at the same resolution as the physical model or the physical deformations are applied to the graphical mesh only. The results of the latter might not be optimal.

    Might also be some wishful thinking on my part. I should check recent versions of the FISI cars to see if-mid corner tyre deflection looks more realistic. In the past I assumed physics and graphics weren't directly linked based on the exaggerated deflection (and a couple of comments in the tyre files).
     
  17. SPASKIS

    SPASKIS Registered

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    If I am not wrong there is a tyre deflection channel in motec where you should get the internally calculated tire deformation.

    Should be easy to check if it matches visuals. BTW providing realistic deformation of the tires shouldn't be black art at all.

    If a tire model doesn't provide realistic deformation the results will be certainly wrong.
     
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  18. Lazza

    Lazza Registered

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    I forgot, there's another side to this. You're rarely watching your own tyres under load while driving, which is the only time really the game could update the graphics with the true physics calculations in real time. Any time you're looking at a replay (of yourself or others), or watching someone else driving remotely, or watching AI drive with their simplified physics, the game doesn't have all the data it would need to show all the nuances of the tyre model. Vertical deflection might fare better though, at least in periods when it's fairly consistent.
     
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  19. Lazza

    Lazza Registered

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    Just did a little testing and measuring (hey! Stop giggling in the back there! ...), plus reviewing some footage from real F1, and I'd say the vertical deflection shown seems to match that in the telemetry (around half to 2/3 the total amount, measured at the sidewall), and I'd also say it seems a reasonable amount overall.

    Visually though, and I haven't gone too scientific in this, in the game the vertical deflection of the sidewall is more apparent than in similar situations in real life. I don't know if it's partly because the real life sidewall branding is taller than in the game, but although it 'flattens' a little it still largely retains a circular shape, while in the game there's a definite flattening off of the sidewall above the contact patch. Overall deflection seems very similar though. As I said this could be a trick of the eyes due to different branding width, or something about the way the textures are mapped on the tyres and get distorted, or perhaps it indicates the way the tyre compresses isn't quite right.

    Hitting harsh bumps under load shows quite a balloon-like bulging of the sidewalls which has always seemed a bit off, but from race footage it's hard to be sure that doesn't happen. I don't recall seeing anything quite like it though. (the V8 footage above doesn't have the same ballooning when hitting bumps in a straight line)

    Finally, it's been quite a while since I really looked at the FISI tyres like that, and I suspect the bulging and deflecting isn't as extreme as it once was. The side-to-side flexing I think is about the same and matches real life footage well, apart from very extreme situations as discussed above (and they're easy to achieve while driving on weird camera angles watching the tyres :D).
     
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  20. Amanda Santini

    Amanda Santini Registered

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    Tire deformation is correct under most circumstances (the ones that actually matter), there are numerous videos of real world tires showcasing that already in this thread.

    About your video: That scenario is not only unlikely and unnecessary to calculate and get real-world data from, it's also unnecessary to have even a semi-accurate representation of it in-game since nobody is going to purposely do that in a race while trying to get a slow-mo of it.
    In addition, nobody is going to even notice the "more liquid" effect in such case since it'll happen too quickly.
    And in addition to that, your race would probably be ruined too.

    I didn't think I would find a video showcasing a car being dropped from +2m where the weight being transferred to one tire is definitely more than 4 tons, but I found an interesting clip.
    Look at this video from 2:25 to 2:30. The car went up the air way less than the car in your video, I'd say less than a foot, with no lateral load, and still the tire deformation was as I've seen many times in rF2 in similar situations.
    Then the car landed on the left tires, and again the deformation was exactly as I've seen in rF2.

    Then here from 2:42 to 2:47, also exactly as showcased in rF2.

    Then here from 3:50 to 3:56.

    Then here from 1:08 to 1:12.

    Then here from 0:53 to 0:57.

    Then this video.

    And numerous other ones.

    If anything, I'd say rF2's deflection is pretty much on point.
     

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