Traction Levels Between Sims

Discussion in 'General Discussion' started by vegaguy5555, Mar 21, 2017.

  1. Andregee

    Andregee Registered

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    The cars in AC has to much inertia values i think. Thats the way Mr. Vasilakos of Kunos used to recreate the physics of the Power & Glory Mod compared to the original GT Legends simulation and he keeps his way of creating an easy driveability in Assetto Corsa. The Mini feels like a light little car in GT Legends. Driving the Mini of the Power & Glory Mod, it feels like a fishing cutter. The Cobra in AC feels like it has e weight of 2 tons. It compensates hectic reactions while oversteering and provides an easier control because all reactions are slower and damped.
    This in combination with a very big slip angle of the tyres, which feels like they gut pulled like a bubble gum instead of sliding over the road, makes it easy to drift and countersteer, but it feels wrong and boring.
     
    Last edited: Apr 20, 2017
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  2. Euskotracks

    Euskotracks Registered

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    I just want to have the reaction at the wheel for the physics model that I am driving and that I need to control. I don't know how realistic is that model but it is the model that I am driving.

    I am tired of listening about g forces. How do G forces help to perceive the difference between driving in wet or dry conditions? The achievable turning speed and accelerations are very different. The way to perceive how close to the limit or that you have surpassed it, comes mainly from FFB. If you guys want to obtain something different to what corresponds please do not call it FFB or at least remove the word realistic from it.
     
  3. RaceNut

    RaceNut Registered

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    Geforces are an integral part of our ability to detect the edge, limit, or threshold of grip and control in reality. The way that we utilize FFB with today's Sim-hardware works to replace some of what is lost compared to RL driving. RL driving engages most of our senses - not just what we feel through the wheel; many cars steering feedback feels quite dull and lifeless in reality. Fortunately we have the ability to choose how it feels in Simulation - even morso with better hardware.

    Sure, the proportion of senses used to drive in certain conditions changes as we adapt to the environment but, we also slow down (Adapt) to allow that to happen. FFB in Simulation is just another way that we adapt to the virtual environment.

    Subjectivity of FFB wouldn't be much of an issue if all controller hardware and game FFB were designed to one comprehensive standard accepted as being most comparable to reality but, of course, that's not the case.
     
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  4. vegaguy5555

    vegaguy5555 Registered

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    I just started driving highway tractor, pulling super B's (two trailers known as trains here) this week. I don't notice much for feed back put somehow I know exactly how far my pup is leaning in a corner. I instantly know I am a gear to high in a corner as well. So I guess there is more feed back then I thought?

    Even though I'm having problems with AC at the moment I encourage as many people as possible to invest in all these sims.

    Trying to understand it all is a lot of fun.:)
     
  5. RaceNut

    RaceNut Registered

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    The depths of Simulation go far beyond what we realize when we first dip our toes into the pool; learning Race-craft and putting it into practice in Sim's takes things to a whole new level. My wife says I'm obsessed but, there's so much more I want to explore and learn . . . sometimes I feel like a 55 year kid! ;):D
     
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  6. Emery

    Emery Registered

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    "There's always modding" says the 54-year old kid. ;)
     
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  7. 2ndLastJedi

    2ndLastJedi Registered

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    When i drive my car i cant feel all the bumps and dips through my wheel nearly as much as i feel it through my whole body . This is what we try to achieve through our FFB wheels . We have lots of different settings and strength sliders trying to get what we feel through our whole bodies into a $200-$2000 toy .
    If it was as objective as just give me what the car is doing through my wheel and be done , whats the point of all the adjusting and (have a look around at all the different people settings) sliders .
    Some people i know set the FB 100 for all adjustments but have damping 100 with no smoothing others run no FFB at all . Tell me thats objective ?
    I asked Niels just because he seems to know the inner workings of his Sim and i just thought that i could learn to like his settings (adjusted to my wheel) . Physics guy he might be but he wasnt a sharer :(
     
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  8. RaceNut

    RaceNut Registered

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    Niels uses a Bodnar wheel so I don't think his settings would be of much use and really, there isn't much to adjust with DD-wheels with AMS / rF2; they really do work with little - if any tweaking.
     
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  9. Euskotracks

    Euskotracks Registered

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    I disagree on bumps not being felt in the wheel in a real car. If they are big enough they even pull the wheel to a side.

    The massive effect of a flatspot is the clearest sign of it. Trying to obtain something different to the real output is IMO an error.

    FFB gives the biggest information about front wheels contact patch. There is a big relationship between pneumatic trail and aligning torque. It is true that for the rear tires doesn't help that fast since the effect will be felt a bit later due to changes in front loads after losing the rear.

    However, as said, trying to provide more info by distorting the calculated FFB with dampings, sensitivities or any other postprocessing is not very clever.
     
    Last edited: Apr 21, 2017
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  10. TechAde

    TechAde Registered

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    I have!

     
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  11. QUF

    QUF Registered

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    Green track in AC offers nowadays quite low traction compared to a long time ago. It used to be that optimum track was too grippy and green was good to start with
    But since the first and second update on the tyre model 10, Fast and Optimum surfaces give better starting traction but at the same time it isn't over grippy. So is fine to always use one of these two when hotlapping or racing.

    About the 427 cobra, in Assetto Corsa is a semi-competition car and in rfactor2 is a road with more power, speed, and I think torque as well. The cobra in AC was updated in its tyre model and inertia values, and is quite a loose car compared to older times. So if you take it on a Green surface it will quickly get out of control because it doesn't grip that well. Try the 427 cobra with optimum track and then with fast track. You can also see what are the starting tyre pressures between AC and rf2 for this car, because default setup in AC is not the same as in rf2.

    Vegaguy, one of these days you should give a go at a GT race car in Assetto Corsa, if you want more grippy cars. Although mind that in the first laps tyres will be cold, so keep an eye on the Tyre app to monitor the temperatures and pressures and adjust in the setup if it stays too hot or too cold.
     
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  12. hitm4k3r

    hitm4k3r Registered

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    Not entirely true. Both cars have the same or atleast similar amount of horsepower and both cars are available in semi-competition setup. Only the default version in rF2 is the road version. In the tuning menu you can select the S/C upgrade wich will make it edgier. :)
     
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  13. QUF

    QUF Registered

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    The 427 does have less traction at the front compared to the back because when you accelerate the weight goes behind and the front is lifted. With that front lift there is less contact patch touching the ground so the front end gets light and prone to throttle oversteer. You know this because you actually see the hood lift and the steering wheel gets lighter. Every time you push the throttle you get a lot of torque but that sudden weight doesn't go to the front.

    But you should definitely use Fast or Optimum surface and not Green in Assetto Corsa because that grip level is more appropriate for grip driving while with Green you're going to experience more sliding moments and not so effective braking.
    The Cobra in AC also has brake temperatures (the classic ones have but the modern cars don't), so in the first corners it won't be so effective until the brakes get warmer. Go with Optimum surface level and you'll have a different experience.

    The starting pressures for this car in AC are 35 psi on Vintage compound (there's only this compound). The starting front camber is -0.6º while it can go above -3º. That is also a factor for less traction but the main cause could very well be your driving style and low grip surface selected in main menu; try higher.
     
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  14. green serpent

    green serpent Registered

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    I am tending to agree with what Euskotracks is saying in this thread. I think in RL, you definitely get info from the g-forces acting on your body, but you get HEAPS of very important information through the wheel. I think the more you drive, the more important steering feel becomes, as you learn to interpret what the steering is telling you.

    A somewhat random example - I've been doing a lot of driving on a particular country road lately with lots of windy bends with a speed limit of 100km/h. My goal through the bends is to be as smooth as possible with the weight transfer of the car from corner to corner and during mid corner (i.e imagining there is an egg in a bowl on the bonnet, and avoiding any sudden weight transfer that might send the egg flying). Obviously this kind of smooth driving is going mostly by feeling the gforces. However, occasionally, mid corner, I will apply a little more steering lock than necessary, and I will feel the front tires scrub ever so slightly. There is no change in the speed or trajectory of the car whatsoever, and there is no tire squeal, the information is coming almost 100% through the steering. (I guess you could argue that the LACK of a change in gforces while applying more lock is telling you that you are at/approaching the tires limits.)

    Regarding ffb, and correct me if I'm wrong, but I think what Euskotracks is saying is that although we might PERCEIVE ffb in a subjective way (i.e what feels real for someone might feel fake for someone else and so on), the way the sim OUTPUTS ffb should be completely OBJECTIVE. As an example, hypothetically, if there was a slider in rf2 to control self aligning torque, and we were all having arguments about what was the best setting, Euskotracks would see that as absurd for a so called sim, because the self aligning torque of a particular car is 100% objective - there is no subjective element to it. The sim should output as close to the real life SAT as possible. It shouldn't be something that the end user can make a decision about because there is no decision to be made.

    Another example could be dampening or any other type of effect - if an historic f1 car's steering geometry results is a vague steering feel, that's how the sim should output it to the best of it's ability - the physics engine dictates the steering feel, it is mathematically objective, and it shouldn't be up to us to alter it with our subjective ideas of how we think it should feel or how we want it to feel.

    The counter argument would be that a lower end wheel cannot output what the physics engine is trying to tell it anyway, so we need all these various adjustments to exists so we can get our crappy wheels feeling somewhat more realistic. But I believe the point still stands that the steering forces of a car are NOT subjective, and a sim should try and replicate that as purely as it can, therefore the ffb in a sim should be dictated 100% by the physics and therefore be objective.
     
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  15. RaceNut

    RaceNut Registered

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    Simulations as we use them are simplified approximations of real complex physics; tire models are something of a black art; there is no standard to provide a basis for "real Sim Physics" or the FFB coming from them. The very models used in simulation are largely based on translation of data that is either incomplete, inaccurate or has to be fudged to get the results close to that of the real-world counterpart. Physics calculations can only go so far and the results will always be affected by the weakest link in the chain - certainly accurate tire data is just one such factor. Sim-Physics output already has an element of subjectivity long before reaching FFB output, not to mention a FFB API that is less than ideal. One can measure sim-physics output data all day long, it still won't make FFB feel real to any two people in the same way - and certainly not when using different FFB systems.

    Reality is right; everything else simulated is just different levels of not-reality. :confused::p:D
     
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  16. Euskotracks

    Euskotracks Registered

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    IMO you are failing to understand the big point. In simulation you drive a simplified model of a vehicle. It probably is not accurate with respect to the real model it represents. However, you drive a physics model. When you drive that model you need to know how that model is interacting with the track. The reactions are accurate for that model and so it is the torque at the wheel. Your black art statement does not apply in here.

    Just imagine that instead of a driving simulator you had a simulator that calculated the reaction of the wheel attached to a torsion spring. The torque should be proportional to the steered angle regardless inertial forces.

    The same could be applied with a rotation inertial mass, in this case with torque proportional to angular acceleration. What would I expect from FFB? Simply to obtain the same reaction that I would get in real life if I performed those tests.

    For sure the dynamic range will not be the same for every FFB controller. In order to compensate it several techniques could be applied: scaling and using a nonlinear correlation (sensitivity). However, we could compare different wheels in performance quite objectively.
     
  17. vegaguy5555

    vegaguy5555 Registered

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    I really think AC is not working the same in my rig as most others. Since tweaking my FFB and getting use to really driving all out in rF2 AC doesn't work at all. The videos I made are very kind. I love sim driving and probably always will support AC but I am really struggling with it right now.

    Latency. Feels like the wheel is hooked to a rubber column. I am always chasing the wheel instead of driving the car.

    I don't notice tire temp difference at all in AC.

    Weight sits at the back and stays there. Front tires just lock up with little braking, you can hear in all my videos. Over all I would say rF2 has less traction in general but with weight transfer braking is many times greater.

    Weightless drift snap. This is when I turn off AC and drive rF2. I would guess from weight not transferring in AC.

    Everything I tried with AC has not worked while in Pcars has done wonders. I had just wrote it off in the past as a pretty video game but all the advice I got in rF2 for FFB theory has really turned Pcars around for me. I set out to fix AC and fix Pcars instead. I can't explain it.

    I have not lost hope for AC. I will continue supporting AC for the love of sim driving. They are doing something different I just can't rap around right now.

    Please continue giving advice. I have learned a lot here. Thanks guys!!:)

    What a great hobby!!:):)
     
  18. RaceNut

    RaceNut Registered

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    I find the the tire-temps in AC to be quite effective - both in terms of front grip-loss detection and overall steering resistance through the FFB but, also clearly demonstrated in consistently improving lap-times. Lately, I'm using the Miata Cup car on short-tracks to refine my tire-pressure tweaks and monitor temps; one thing that stands out is how hard I have to push the car to build heat in the tires to get those faster lap-times but, stability through use of tire-pressure adjustments helps a lot too.

    Watching Aris' videos got me started down this path and it's really helping me focus on some fundamental things I can do to make good progress.
     
  19. peterchen

    peterchen Registered

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    Tyre-temp buildup in AC is a bad joke! Nothing more.
    Watch the tyre app and laugh....
    There you can see how "detailed" the tyre model of AC is - seems more simple than in rF1.
     
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  20. MarcG

    MarcG Member

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    After watching Aris' videos I took the BMW M2 round Silverstone and challenged myself, I could feel the tires coming to life once they got warmer. Slight adjustments to the pressures (as per the first video) and I was away breaking Personal Best after Personal Best. It was a great experience and showed just how good AC is, the V10 Tire Model really has come on a long way from the early AC beginnings, I absolutely love it now.
     
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