“ are rfactor2 physics broken” video

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

  1. Lazza

    Lazza Registered

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    If you use 'vehicle set' for steering wheel rotation this setting has no effect on steering ratio.
     
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  2. AMillward

    AMillward Registered

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    Few of the pros said exactly the same thing.

    Don’t know if it makes any difference but the tyre wear in rf2 as far as I know is done through thermal degradation rather than slidey slidey on tarmac.
     
  3. Nieubermesch

    Nieubermesch Registered

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    Well, I think it should and I believe there is some simulation moddelling on the slidey slidey, since Flat Spots are present.

    How much do you guys think soft tyres should last on a GTE car? I am curious.
     
  4. Lazza

    Lazza Registered

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    Re understeer vs slip angle vs rotation...

    Here's a couple of quick tests in the AM GT3, showing peak rotation ('corrected yaw rate', which is rotation divided by car speed) at around 4 degrees steered angle, which then drops out to around 10 degrees steered angle.

    Note that speed is dropping a bit, I later tried to keep the speed up but the rears let go (default set).

    AM GT3 1.PNG

    AM GT3 2.PNG


    Here's some of the skip barber TGM. Read the comments.

    Code:
    AbrasionVolumePerUnitEnergy=(7.02e-10,6.90e-10,6.66e-10,6.36e-10,5.95e-10,5.40e-10,4.25e-10,3.16e-10,2.29e-10,1.55e-10,1.20e-10,9.49e-11,7.64e-11,6.55e-11,6.00e-11,6.27e-11,6.82e-11,7.75e-11,9.71e-11,1.23e-10,1.64e-10,2.35e-10,3.22e-10,3.82e-10,4.31e-10,4.53e-10,4.64e-10,4.73e-10,4.80e-10,4.85e-10,4.88e-10,4.89e-10) // m^3/J volume of rubber sheared per Joule energy, max 32 values
    DegradationPerWearFraction=(0.993,1,0.9992,0.998,0.9972,0.9966,0.9961,0.9956,0.9951,0.9946,0.9941,0.9937,0.9933,0.9929,0.9925,0.9921,0.9917,0.9913,0.9909,0.9905,0.9901,0.9897,0.9893,0.9889,0.9885,0.9881,0.9877,0.9873,0.9869,0.986,0.98,0.88) // Degradation based on wear fraction, max 32 values
    DegradationCurveParameters=(344.15,6000) // (<activation_temperature_K>,<heat_history_step_Ks>) heat history is a linear progression of temperature over activation point multiplied by time
    DegradationPerUnitHistory=(1,0.9925,0.9862,0.9809,0.9765,0.9729,0.97,0.9677,0.9659,0.9643,0.9628,0.9614,0.96,0.9586,0.9572,0.9558,0.9544,0.953,0.9516,0.9502,0.9488,0.9474,0.946,0.9446,0.9432,0.9418,0.9403,0.9386,0.9367,0.9345,0.9322,0.93) // Degradation per heat history step, up to 32 values
    
     
  5. Nieubermesch

    Nieubermesch Registered

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    I have another recommendation for you. Do you usually race with softs, mediuns or hard tyres? Have you been testing on Soft maybe? I was just testing with medium and getting the inical pressures up to 175 Kpa on the BMW GTE M8. I have to report it felt much better. Try to run some pressures with that and report back. After all, we could have pressures above, that actually correspond to real life to lower values. The same for the soft tyre compound. It could happen that only softer tyre compounds are really more exploitative, not sure. Since I've never seen before the soft tyre getting down on percentage more than 98 on 5 laps, pushing hard, I am thinking that maybe uppin tyre wear rate would help.
     
  6. avenger82

    avenger82 Registered

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    It’s unrealistic to expect that for many cars, but if detailed performance measurements of one GT car on one track compared to RL counterpart would reasonably match and the pro driver would say it handles similarly to RL then it would bring more users who are into (physics) simulation aspect. Of course it should include comparison of detailed tire measurements from Michelin (probably obtained from tire testing machine separately, because some live data is can’t be measured on track). That would also shut up most of the critics. But it ain’t gonna happen because physics have low priority for S397.
     
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  7. Lazza

    Lazza Registered

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    I don't understand how that has anything to do with what I said.
     
  8. ATQ

    ATQ Registered

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    Biggest difference I see is that the steering input in rFactor is much smoother. There are none of those transient movements you see in the real life footage. I believe this is because the steering wheel animation is somehow filtered, because the wheel itself certainly makes the car feel lively.
    I've noticed this more after getting a VR headset, where I no longer see my actual steering wheel. My hands are certainly doing more work than the in car wheel shows.

    Maybe that's also a reason why, when comparing footage, rFactor looks to have more leeway?
     
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  9. avenger82

    avenger82 Registered

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    I believe it wasn’t addressed. IIRC Marcel said in in the interview with Ermin that they don’t plan to fix it right now, because real tire data from manufacturers is unreliable. While it’s true to some extent, it looked to me it was more of an excuse. I think things like tire wear (which is what Michelin said is incorrect) are relatively easy to measure objectively. There are some variations due to setup, driving style etc. of course.
     
    Last edited: Jan 16, 2021
  10. avenger82

    avenger82 Registered

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    I think it wasn’t about tire forgiveness, but about wear ratio , wich for GT cars is too fast in rF2 (according to Michelin)
     
    Last edited: Jan 16, 2021
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  11. Nieubermesch

    Nieubermesch Registered

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    I disable steering wheel on sims for a long time now. It feels weird to have that on, I can't quite put my finger on it, but it isn't just the fact that it shouldn't be there if you are already using one...

    Replays also aren't a good way to tell, because they mute a lot of car movements and that video looked to me like it came from a replay with low/medium quality. Altough in the end I still think Rfactor 2 is a bit too forgiving correcting some slides, not sure though.

    Also, FOV!! FOV plays a big part. Even watching real life onboards if cameras have a low vs high fov you can feel more the mass of the car and rotating doesn't feel so high. Most serious sim racers have their fovs low, so it can help feeling the car is over rotating, scrubbing more tyre than it actually is and sound also can help creating that feeling.
     
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  12. Nieubermesch

    Nieubermesch Registered

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    Well, I thought they didn't fall fast enough. I am not michellin, so I will not say anything more about wear as I don't want to sound dumb.
     
  13. avenger82

    avenger82 Registered

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    Grip fall off being too slow is another thing people talk about, but I think Michelin didn’t talk about it. But they were willing to work with S397 to make the GT Michelin tires more realistic in rF2.
     
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  14. Lazza

    Lazza Registered

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    Michelin said the tyres dropped off (grip) much more than in real life. How you would address that (I think we're expecting this to be addressed soon, aren't we?) will depend on what you think made them degrade too quickly - you could simply (and I mean simply) change the degradation curves so they stand up better to overheating and physical abrasion, or you could discourage driving that made them wear more than they should (if that was the case).
     
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  15. Nieubermesch

    Nieubermesch Registered

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    Well, that could be happening, the inicial grip drop off being closer to a road car tyre but in the end this makes Rfactor2 GT and other cars tyres feel too forgiving when they lose grip, opposed to a more abrupt feeling that a "slick" should offer. Am I getting that impression right?

    Some people are not understanding that more grip on a slick leads to a loss of grip that feels more snappy than one where grip drop off comes sooner and feels like it has less grip, but it's easier to drive.
     
    Last edited: Jan 16, 2021
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  16. Lazza

    Lazza Registered

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    I'm talking about grip dropoff over time, not during a slide. They said the tyres lost something like 2 seconds per lap over a 10 lap stint, and it should have only been a few tenths.
     
    Last edited: Jan 16, 2021
  17. avenger82

    avenger82 Registered

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    I think you’re confusing tire forgiveness (what I called grip fall off is too small with high slip angles), with grip loss due to too fast tire degradation in rF2. IIRC Michelin talked only about the latter.

    Sorry if I didn’t make myself clear.
     
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  18. Nieubermesch

    Nieubermesch Registered

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    Sure sure, my bad, they are interchangeable after all and I am mostly on about that aspect. No problem.
     
  19. Lazza

    Lazza Registered

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    Just talking generally about some of the rF2 videos posted here, the more extreme ones (so ignore the F-E one that looked pretty good) have an amount of rear sliding that makes me cringe based on my driving in rF1 and rF2. I wouldn't expect to be able to swing the back end around like that for more than 2 or 3 corners before needing to drive very conservatively to bring temperatures back under control and regain some grip. If people are able to drive like that and set competitive laptimes I think that points more to a lack of grip dropoff with temperature (live, not historical) or the temperatures not running hot enough in general. (or the working range being too high... it's all relative)

    This would also allow aggressive steering mid corner, and might even encourage it (if temps are generally too low), because the grip won't fall away as quickly as it could.

    I'll add here I spent some years driving in rF2, and doing a FISI-modified F1 mod for a small group driving 20 races a year, and none of those cars allowed such behaviour.
     
  20. Nieubermesch

    Nieubermesch Registered

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    Well, it seems to me you are well respected around Rfactor 2 communities, so I take that as a great step in the right direction. Not sure if any of the examples you refer as mine.

    I certainly like the theory that the tyres are the culprit. And no, this doesn't mean RFactor 2 tyre sucks... Rfactor 2 physics always feel to me like the most advanced, generally, but you need to get the parameters right, people...
     
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