Physics/FFB rates upgrade?

Discussion in 'General Discussion' started by Stan, Mar 8, 2017.

  1. Stan

    Stan Registered

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    Hi all,
    I was looking for a statement regarding an eventual physics/ffb rates upgrade, like Reiza did?
    Could we dream of it? Does Studio-397 contract with ISI allow/include this kind of upgrade, I don't remember?
    And again thanks in advance for your lights!
     
  2. peterchen

    peterchen Registered

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    I think this isn´t necessary as rF2 ran on pretty high refresh-rates since the beginning, what Reiza-game didn´t.
    Sorry no numbers here, but they float around in this forum somewhere.
     
  3. Flaux

    Flaux Registered

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    From here: https://forum.studio-397.com/index....-lock-max-frames-to-or-multiples-of-60.33123/
     
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  4. Stan

    Stan Registered

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    Thank you both for your answers and thanks Flaux for the nice read!
    AMS run 500hz for the ffb/input refresh rate, not that much more, but still 25% faster... and 720hz for the physics (almost twice rf2); if the gap was bigger in the upgrade of AMS, I still think that an upgraded rf2 would lead nothing but good things... don't you?
     
  5. stonec

    stonec Member

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    I doubt 400 or 500 Hz would make a difference, for example with monitors I would say most people cannot tell a difference between 120 Hz and 144 Hz, and that's three times lower numbers. Also I think iRacing is still using 60 Hz for their FFB. In worst case, the only notable effect would be an increase in CPU usage, and rF2 is already quite CPU hungry with certain old AMD's.
     
  6. Korva7

    Korva7 Registered

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    In automobilista the wheel position is read with 500 hz frequency, but the ffb update rate is selectable from 720, 360, 240, 180...Hz. I haven't found yet a way to use 720 hz update rate though, so i'm limited to 360 hz which is less that the rf2 update rate.
     
  7. Lazza

    Lazza Registered

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    How much can you move a wheel or pedal in 1/400th of a second?

    As for physics, press Ctrl-C when you're alone on track and have a look at the CPU physics (purple) usage graph. AMS doubled the rate of the rF1 physics, with a mostly unchanged rF1 physics model, and modern PCs could run it a lot faster than that too. It's not better than rF2 just because it's running at a faster rate. Otherwise ISI would have just done that instead of developing an entire new tyre model, and improving the chassis physics.
     
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  8. Stan

    Stan Registered

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    Thank you guys, but I did not said it was mandatory, I was just thinking that the faster... the smoother. The cpm, flex and all the wonderfull physics developpement done by ISI are of course far more revelant, but what's next in term of physics upgrade?
     
    Last edited: Mar 9, 2017
  9. Emery

    Emery Registered

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    AFAIK, the main advantage of faster physics calculation is the enhanced resolution of shock/spring responses which would allow denser road meshes. The tradeoff is that we're already kind of on the edge for what is reasonable when it comes to graphics display of higher meshes and then you end up going down the road of AC's separate physics mesh.

    Hmm... the shock/spring response of the tires would also benefit from an enhanced update frequency, but the lookup tables would grow as a square of the increase, as would the time to calculate them (which modders would hate since that time is already in the 1-day range). Probably not so good from a CPU/memory perspective for single-player large fields.

    From the driving perspective, as others have noted, the ffb probably wouldn't feel significantly different (e.g. there's a bigger difference between a G29 which can't handle the update rate, a Thrustmaster which can, and a direct drive wheel which can with significantly higher force) and it's still divorced from the video lag.
     
  10. RaceNut

    RaceNut Registered

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    When AMS received the upgrade, there was a noticeable improvement in FFB feel using DD wheels.
     
  11. Stan

    Stan Registered

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    @Emery:
    Thank you, good and fair answers! However I did not know that multiplayer cars physics was re-calculated, I thought they were just "drawn"...
     
  12. Comante

    Comante Registered

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    In multiplayer, opponent's cars receive some love because the software do some magic to overcome the effect of ping and lag, I think this love is not server side but client side, so you can see the car ahead of you behave in a plausible manner even if the other driver is pinging high and has some lag/packet loss.
     
  13. stonec

    stonec Member

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    They are not calculated, multiplayer cars cause minimum CPU overhead, only their positions are updated and a prediction algorithm determines the position in between the updates.
     
  14. Emery

    Emery Registered

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    I said "single-player".
     
  15. Stan

    Stan Registered

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    @Emery:
    Sorry, I don't know where I get this from... my mistake... strange!
    And thanks again for your answers

    @stonec:
    Yes that's what I thought, thank you
     
  16. Euskotracks

    Euskotracks Registered

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    In the physics side i don't think the difference would be much appreciated. However, it might be interesting for the FFB if it can actually be updgraded in frequency without increasing physics one.

    The reason I say is because considering that the same amount of FFB filtering would reduce the delay of FFB. Physics are not filtered that I know.
     
  17. Stan

    Stan Registered

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    Very good and judicious point!
     
  18. Marek Lesniak

    Marek Lesniak Car Team Staff Member

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    Our physics has a base frequency of 400Hz and that applies to most of stuff, but some parts of the code run at a higher rate - TGM tyre model runs at 2400Hz.
     
    Last edited: Mar 13, 2017
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  19. Stan

    Stan Registered

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    Thanks Marek, I didn't know that some physics rates were higher than the base...
    So you don't see a valuable reason to upgrade that base from 400hz to, let say 500hz?
    The CPU impact would be higher than the benefit?
    Anyway, thanks again for sharing your knowledge.
     
    Last edited: Mar 14, 2017
  20. Ozzy

    Ozzy Registered

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    2400Hz! That should be used for marketing. ;)
    Now I understand why you are at the limit on older systems. Is the UltraChassis updated at the base rate or higher?
     
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