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FF vibrations even with 'effects' off?

Discussion in 'Assetto Corsa' started by Mr Whippy, May 5, 2014.

  1. I've not driven AC in a while so fired it up tonight.

    This Ferrari 312T drives really nicely and feels great.

    But the FF vibrations are terrible. If I understeer a bit, brrrrrr... lock up the tyres, brrrrr... it feels very canned on my G25 wheel.

    All the effects are off, FF damping and filtering are at 50% from 0% and the vibrations still persist.

    It's really sad to say but it ruins the entire experience, and I can't imagine these forces are real or come from some real tyre behaviour. OK I've only ever driven road car tyres on road cars in anger, but when I lock up it's always been super smooth and light, not a high frequency vibration.

    The same with some understeer, or extreme slip angles... never noticed almost identical frequency vibrations here to when locking up as above. Yes I get vibration IRL, but it's not something I'd feel through my steering wheel so much... a subtle damped rubber type vibration, but not the clattery type I get.

    Is AC using some canned effects over it's primary FF channel still? Using DirectPlay/DirectX effects to do some primary forces? Or are some of the effects still active even when at 0%?

    Is there any way to log the actual Fy * scrub axis rack forces in AC so I can see where exactly these forces are coming from?

    All I can guess is the tyre CP is flapping at high frequency and causing an Mz oscillation, but it's weird why the frequency just feels so static and samey, and has no subtitles and dynamics.


    • Agree Agree x 1
  2. Perhaps lowering your OCD level and realising that a 200$ wheel thru a PC on USB with tiny motors can't reproduce the same effects as quickly as in a real car can help :p

    Get a servo wheel. It may cost up to 2000$ but hey might be worth it :)
  3. I run this and feels pretty good
    Logi Profiler
    87% ffb force
    Centering spring disabled
    Allow game to change settings

    In game
    85 ffb gain
    0% filter
    0% dampening

    20% kerbs
    10% road effects
    10% slip effect
  4. The forces you mention come from the tyres themselves, as their surface constantly changing from grip to slip over the tarmac when sliding.
    Actually this is the reason why you can hear the tyres screech in real life, as the constant changes in slip produce vibration that generates high pitched sound.

    This "effect" may not be the most realistic in AC, as the frequency of the rumbling may be a little bit lower than what could be observed on real tyres, but the general idea (and underlining physics equations) is.
    (Idk if side force - Fy for each tyre is possible to get, but its possible to see each tyre's "Self Aligning Torque" and it does "vibrate" when sliding, so it is an actual physics element.)

    Also not a lot of people seem to realize that the road/kerb/slip effect sliders are not some artificial "canned effects" but just multipliers for effects coming form FFB simulation. So even at 0% you can still feel the slip "rumble", road effects at 0% can still be felt on some cars like X-bow, (especially with stiff bump damping).
    And Kerbs need to be emulated either way since our hardware couldn't really simulate real kerbs.
    Setting them all to 0% will not mean we get "the most realistic experience (tm)" but rather, the most raw "logitech experiance" (assuming your G25). They are a useful tools for adjustment of our hardware and not some "arcade crap".

    That said it's very much possible that your G25 makes a mess out of whatever input the game provides. (My G27 has problems with high frequency osciallations, making the wheel rumble very loudly, to fix that i use lowered FFB frequency - to 125hz it may help you too.) (the setting is in the assetto_corsa.ini file in ...\SteamApps\common\assettocorsa\system\cfg\)
  5. He doesn't need to get anything else. The game is the one who has to improve the FFB.
    I feel weird force feedbacks despite any configuration or wheel i use.

    one of the biggest FFB fail is: if you try to increase wheel weight to match reality, you are stuck with insane damping forces. just as if you were fighting someone inside the car an he is turning the wheel abrutly the opposite way.
    Last edited: May 6, 2014
  6. Pedro!
    • Beer Beer x 1
  7. It's the truth...
  8. I'm just glad to see you're still compla...I mean talking about Assetto Corsa.
    Last edited: May 6, 2014
    • Winner Winner x 2
  9. Assetto corsa has to be designed with a compromise in FFB because there is no way modern PC's and wheels for 200$ can get anywhere near the feedback from a real car.

    You just have to acceppt it's not possible to get the FFB exactly as in RL with current technology. Perhaps wait 15-20 years? :whistling:

    That being said AC feels far ahead of anything so far.
  10. I know everything is a compromise.

    But I know for example (despite everyone who will say otherwise), that Gran Turismo 5 makes a really nice job of FF.

    In the end the only way I'll get real F1 car type FF loads is to have a £2500 wheel that will twist my desk over and smash my PC screens hehe... but this is where good programming and normalisation of forces comes in.

    Ie, we render in HDR, and tone map to LDR to display on 'crappy' screens that have very low dynamic range vs 'reality'
    We render our audio in HDR and compress it to LDR to play it through our 'crappy' speakers that have low dynamic range.
    We render our FF in HDR and compress it to our wheels range to make it feel about right.

    All I'm thinking is that the logic that I need a better wheel is kinda flawed. We all (99%+) have crappy wheels, so the job is for KS to just think about how to make crappy wheels feel ok, not just tell us our hardware is crap?

    Thanks for the in-depth post Stary Precel, very interesting! I'll take a look at the FF update speed in the AC config files... :D
    Shame that this variable isn't pre-set for the G25, or configurable through the UI, if it makes such a difference it shouldn't be hidden really?!


  11. Does anyone really want completely realistic forces? Realistic would break your fingers if got them caught in the wheel when hitting something solid.
  12. There are people that wear race helmets, race suits, race shoes, and race gloves when they sim race so realism has no boundries in the sim community.
    • Haha Haha x 1
  13. I have much more real experience with richard burns rally FFB... about 10 years old sim!!!!
    ...what do you say about that now???
  14. That Richard Burns Rally FFB is a masterclass and thus is a greater embarrassment on every other sim that has worse FFB then Assetto Corsa?
    • Agree Agree x 1
  15. Better than DIRT 2?
  16. I just want to underline that Assetto's FFB is not good enough yet.
  17. That FFB refresh rate change only fixes notoruis problem with G25/G27 that occurs on some wheels, when there is a some clearance between the motor gears, so that high frequency oscillation makes it rattle and wear like crazy. (it works similar to using very high filtering/damping, but without numbing the actual effects)

    Oh and after some thought i think the "rumbling" effect of slip has more to do with simulation of oscilation of the whole wheel, rather than just the vibration of tyre surface.

    AC is the fist sim i see it simulated. It works like this: when the car starts sliding, the high pitched vibrations from tyres create low pitched vibration in the wheels themselves (due to limited stiffnes of suspension elements and joints), so that they change their camber and toe angles several times per second (it's possible to see this in replays) creating that vibration rumble effect on the steering wheel.
    Since suspension doesn't have much ability to damp these vibration, when it occurs it doesn't stop until the tyre is returned below limit of grip.
    I saw this effect in real life wheels to some extent in my uni's laboratory, so its amazing to see this level of detail in a game.
    This should occur on real racecars but i had no luck in driving one so its all theory. :p
    • Like Like x 1