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Thread: A quasi-objective way to judge physics of sim cars

  1. #21
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    Quote Originally Posted by monsterZERO View Post
    You know, this forum is getting pretty damn toxic. It's a HUGE turn off to people new to rF2.
    +1

    Golanv, I would say this isn't the most scientific look at the physics, that's all...it is a public forum though, so say what you want eh...just don't mind when people want to judge you as a "mouth breather"

  2. #22
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    Honestly this isn't a good way of checking accuracy. The number of variables you can't account for is enormous, you've selected only one aspect of one small facet of performance with no particularly strong rationale and you've got no meaningful margin of error. The only real way we have is numbers and that takes an intense amount of research, working with ideal conditions and approaching compromises objectively based on the end goals of the product; basically what a sim developer does. People rattle on and on about 'looks right' and 'feels right' but these notions are catastrophically misleading.

    I've literally seen people give huge praises so called 'improvements' in car dynamics that weren't even implemented and praise dynamics en-masse that in all numerical senses were laughably off-base because they 'looked right' or 'felt right'. It's a strange and frankly unhelpful aspect of the sim community that people take 'this feels or looks like my (at best) partially informed guess seems like it should' as accuracy. If you've ever seen experienced, skilled racing drivers trying new cars and cars from different eras the first thing they'll talk about is how different it is and the ways it surprised them.

  3. #23
    @Minibull
    Interesting thought. You may have a point on this. this quick change on slip angle (in stage 2 and 3) as Chris Harris did on real car might not be well being modeled in sim or such "discontinunity" transition may not be well thought/learned indexed into the lookup table(??) who knows...?

    @Guineapiggy
    Your notion is well taken. However, the assumption here as stated in the beginning of post is that there is no field data (real data) for sliding so objective study may not be possible. Such assumption is not baseless though. If you watch the interview video from Co-Founder and Lead Developer Stefano Casillo at Kunos Simulazioni, Assetto Corsa. He said there is no theory to be published on how and where to slide. The sliding state is "black art", there is no data he can compare to.
    In the Chris Harris video (how to slide on the BMW), he said too that there is no theory to be written about how to do that (sliding).

  4. #24
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    Quote Originally Posted by Minibull View Post
    I personally think that the inherent lag in our sims are what make it tricky to drift well.
    I remember seeing a shot of kimi coming back on track, he cuts a big slide in his f1 car, but absolutely immediately you see his hands whip to correct, and as soon as it comes back out of it, his hands whip back to stop the overcorrection.

    When I've looked at slides that made me go "wtf", I always see my actual reactions are just ever so slightly behind the cars movements.
    The computer has to process the state, send it to the gpu and out to the monitor, which them has to display it there, and only then when I see it amd process it, can I respond, which has to go back in to the computer and be processed, etc.
    As far as I can see IRL, kimi would have had his whole body sensing the slide with just his uber quick reaction times as a delay.

    Not saying this is the answer, it's just something I always notice when something goes wrong for me.
    This delay you're experiencing i think is largely due to your hardware or your hardware/FFB settings. This is the sort of reaction that i kept noticing when i first tried rF2 and it's what made me want to try and find a solution. For me it was a delay in the response, but not because of some type of lag in the system, but because of the way the feedback was being sent to the wheel. I had a T500, which is obviously different than your G25, but i'm pretty sure it's the same fundamental issue.

    Lowering the STS helps deal with this issue on both the T500 and the AF, so i'm starting to think that it's an issue with basically every wheel based on the way people describe sliding and drifting cars in rF2 to be so difficult. It might not make sense if you don't completely understand how the STS changes the feeling, but adjusting the STS actually gives the impression that you're getting a more direct response and it's because of some balance in the forces that, in my mind 'line-up' and you can find a point where the forces will act neutrally in terms of pointing the front wheels in the direction of travel. For the AF and T500 you have to lower the STS to find this balancing point. So far i've tested the responsive mode AF to be close to this point with the STS at 0.181. With the T500 it felt more neutral at 0.275/6, but that could have been due to the T500 having more internal friction than the AF, and not any particular difference in the way these two wheels work.

    That said, there can be a limitation in the hardware itself, where if you don't have enough speed and power, then it really won't matter what you do with your settings, it'll simply be inadequate regardless. The AF doesn't have such limitations, or if it does, then they're completely negligible. If you can't react to quick losses in traction, or have a hard time controlling the cars during a slide in general, it's not because of rF2, or because of some inherent latency in these systems. It's either because of the driver's skill, hardware limitations, or some combination of those.

    Here's a collection of slides and mistake-management during a qualifying session i did with the FR3.5:



    I have a very good sense of what the car is doing at all times, so it's relatively easy to push the car like this. I know that even if i make a mistake that i can usually catch it and minimize it. I only spun once during that session, never crashed, and i was doing 3 or 4 qualifying style laps back-to-back in each outing, i was getting into the low 1:16's lap after lap. I'm editing this entire session for a full video where you can see everything, but that won't be for awhile. It'll hopefully show the difference that decent FFB can make in terms of the way a person will perceive the 'realism' of a sim.
    Realistic FFB settings with Accuforce (responsive mode): Accuforce settings

  5. #25
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    ^cool post Paul, good reading eh
    I'll have to delve deeper into my setup, but then again, why bother, until I get something decent XD

    Make no mistake, I can drive the cars fine and catch my slides and twitches. Just that there have been more than a few times where I don't catch it and think "eh?", put the replay on and slow motion, where I see the "delay".

    Just something that might play a part sometimes, especially when trying to balance the sliding car

  6. #26
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    The problem, IMO, is that sim cars (with the exception of LFS) don't recover from a drifts/big slides in a natural way. It's got nothing to do with sensory information or hardware/software delays IMO, because even when real drivers react and correct far too late, the car still moves differently even compared to when we anticipate in the sim.

    In real life, when the drift ends and the car starts to snap straight, the rear swings like a pendulum about the front. Even when the countersteer is held on too long (see some of the Youtube "drift fails"), it's only once the 'pendulum' has swung some distance back that the front of the car starts steering off in the counter-steered direction. Whereas, in the sims, the moment the rear starts to return, the front of the car starts turning in the same direction of rotation. The result is that the car rotates about a central axis and looks like both ends are sliding rather than the front initially planted and tail wagging. No wonder it's hard trying to keep up with it if you wait for the FFB message. But as I say, even if you anticipate it (as you have to) the recovery phase of the drift looks all wrong; you still see the front trying to dart off immediately the rear has hooked up.

    I've just fired up LFS for the first time in a year to confirm my opinion and it's definitely a different looking dynamics, although it's not nearly as violent as real life, and too easy to drift.

    Word of caution: if you've a Logitech wheel, they can go off centre if you jerk them around (bits come loose), so don't bugger it up trying to convince yourself I'm wrong about this...unless you really have to.

  7. #27
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    Quote Originally Posted by Old Hat View Post
    The problem, IMO, is that sim cars (with the exception of LFS) don't recover from a drifts/big slides in a natural way. It's got nothing to do with sensory information or hardware/software delays IMO, because even when real drivers react and correct far too late, the car still moves differently even compared to when we anticipate in the sim.

    In real life, when the drift ends and the car starts to snap straight, the rear swings like a pendulum about the front. Even when the countersteer is held on too long (see some of the Youtube "drift fails"), it's only once the 'pendulum' has swung some distance back that the front of the car starts steering off in the counter-steered direction. Whereas, in the sims, the moment the rear starts to return, the front of the car starts turning in the same direction of rotation. The result is that the car rotates about a central axis and looks like both ends are sliding rather than the front initially planted and tail wagging. No wonder it's hard trying to keep up with it if you wait for the FFB message. But as I say, even if you anticipate it (as you have to) the recovery phase of the drift looks all wrong; you still see the front trying to dart off immediately the rear has hooked up.

    I've just fired up LFS for the first time in a year to confirm my opinion and it's definitely a different looking dynamics, although it's not nearly as violent as real life, and too easy to drift.

    Word of caution: if you've a Logitech wheel, they can go off centre if you jerk them around (bits come loose), so don't bugger it up trying to convince yourself I'm wrong about this...unless you really have to.
    Sounds like tire model issues, i think there's too much lateral grip, or the range of lateral grip loss isn't large enough which might cause the issue you're talking about. That said, i'm pretty sure that with the Panoz i can continue a drift after a corner on a straight for a short period and have the rear pull back in instead of the front sliding out, provided that the tires are a bit worn out, because it's possible to do both in a real car and i have done both, both by accident. It all depends on exactly how you're driving and if the car is up for it. I prefer having the entire car neutral at corner exit, i point the car at the exit, open the throttle, and try to line the car up with the direction i want to be traveling in at the end of the corner. What results is called a 4-wheel drift, but you aren't forced to do that in rF2.

    I prefer to do that myself since it's a good training exercise because it requires you to balance the car perfectly through the entire corner in order for it to be pointing in the direction you want by the end of the corner, and it's almost an exaggerated version of the way i would normally drive some types of cars while racing. It takes more precision to be able to do this and make it look seamless, than it does to keep the tail of the car hanging out or to regain traction too soon. So even if what you're feeling or seeing is a result of the tire models, it's probably not as big of a difference as you think. The fact that LFS is simply easier to drive probably is the reason why you feel it's somehow different in it's dynamics, when in reality, it's probably just easier to drive it in a certain way compared to rF2, not that rF2 can't be driven in a similar way. I think LFS is easier because things are a bit exaggerated, meaning that you will see the car do relatively extreme things and you'll feel it's easy to do.

    EDIT: Another possibility for what you're describing could actually be the STS. If you have a high STS it has a tendency to pull toward the sliding direction much more, meaning that you'll regain traction and the car will stop sliding before your wheel actually starts to straighten out. Which could result in the front sliding out instead of the rear continuing. You can try lowering the STS and try the same thing, if you rely heavily on the steering feedback, you'll probably notice that you can continue sliding much longer.

    Quote Originally Posted by Minibull View Post
    ^cool post Paul, good reading eh
    I'll have to delve deeper into my setup, but then again, why bother, until I get something decent XD

    Make no mistake, I can drive the cars fine and catch my slides and twitches. Just that there have been more than a few times where I don't catch it and think "eh?", put the replay on and slow motion, where I see the "delay".

    Just something that might play a part sometimes, especially when trying to balance the sliding car
    Well there should be some sort of delay considering your wheel. The only way it could be instant is if the wheel is powerful enough to overcome your grip and the weight of your hands/arms on the wheel. Which even in real life won't happen most of the time, you'd only ever have that much torque through the wheel if you're already too far gone, obviously not accounting for bumps and things.

    The problem with trying to look at this sort of thing as some type of delay is simply that you can't know for certain if it's actually a delay in the system or in your own reflexes. Based on what i found after adjusting the FFB settings, i went from thinking it was just problems with the sim or hardware, to suddenly not being able to perceive any sort of lag or latency at all. Whatever amount of latency there is in my system is something i can't feel, and i have pretty fast reflexes out in the real world.
    Realistic FFB settings with Accuforce (responsive mode): Accuforce settings

  8. #28
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    Quote Originally Posted by Paul Loatman View Post
    Sounds like tire model issues, i think there's too much lateral grip, or the range of lateral grip loss isn't large enough which might cause the issue you're talking about. That said, i'm pretty sure that with the Panoz i can continue a drift after a corner on a straight for a short period and have the rear pull back in instead of the front sliding out, provided that the tires are a bit worn out, because it's possible to do both in a real car and i have done both, both by accident. It all depends on exactly how you're driving and if the car is up for it. I prefer having the entire car neutral at corner exit, i point the car at the exit, open the throttle, and try to line the car up with the direction i want to be traveling in at the end of the corner. What results is called a 4-wheel drift, but you aren't forced to do that in rF2.

    I prefer to do that myself since it's a good training exercise because it requires you to balance the car perfectly through the entire corner in order for it to be pointing in the direction you want by the end of the corner, and it's almost an exaggerated version of the way i would normally drive some types of cars while racing. It takes more precision to be able to do this and make it look seamless, than it does to keep the tail of the car hanging out or to regain traction too soon. So even if what you're feeling or seeing is a result of the tire models, it's probably not as big of a difference as you think. The fact that LFS is simply easier to drive probably is the reason why you feel it's somehow different in it's dynamics, when in reality, it's probably just easier to drive it in a certain way compared to rF2, not that rF2 can't be driven in a similar way. I think LFS is easier because things are a bit exaggerated, meaning that you will see the car do relatively extreme things and you'll feel it's easy to do.

    EDIT: Another possibility for what you're describing could actually be the STS. If you have a high STS it has a tendency to pull toward the sliding direction much more, meaning that you'll regain traction and the car will stop sliding before your wheel actually starts to straighten out. Which could result in the front sliding out instead of the rear continuing. You can try lowering the STS and try the same thing, if you rely heavily on the steering feedback, you'll probably notice that you can continue sliding much longer.
    Nope, you're missing the point. If the sim driver completely fails to straighten the steering during the recovery stage (maintains full counter-steer), then in LFS you see essentially the same behaviour as you see in real life when the driver is too late. And that's completely different to what an ISImotor sim will do. It's got nothing to do with hard/easy, skilled or unskilled. I have never, ever seen the correct behaviour in another sim. Over 10 years of sim racing however, I have seen lots of videos where people think it's happening correctly when it isn't (IMO).

    And I don't need a lesson thanks - I know what a 4-wheel drift is. LOL.

  9. #29
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    Quote Originally Posted by Old Hat View Post
    Nope, you're missing the point. If the sim driver completely fails to straighten the steering during the recovery stage (maintains full counter-steer), then in LFS you see essentially the same behaviour as you see in real life when the driver is too late. And that's completely different to what an ISImotor sim will do. It's got nothing to do with hard/easy, skilled or unskilled. I have never, ever seen the correct behaviour in another sim. Over 10 years of sim racing however, I have seen lots of videos where people think it's happening correctly when it isn't (IMO).

    And I don't need a lesson thanks - I know what a 4-wheel drift is. LOL.
    What videos of this behavior in real life are you talking about? This would make things a lot easier to know what you're saying. Since it sounded like you were only distinguishing between a drift where the car straightens out by having the front sliding back out vs the rear sliding back in, and if you're saying it's neither of those, then it's a 4-wheel drift.
    Realistic FFB settings with Accuforce (responsive mode): Accuforce settings

  10. #30
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    @Joe,

    https://drive.google.com/file/d/0B9w...ew?usp=sharing

    Here's a replay file of me drifting the Panoz, tire wear is turned on so you can see the car gradually losing more traction. I was going to make a video, but it would take forever for me to upload the whole thing, plus you can view it however way you want as a direct replay file.
    Realistic FFB settings with Accuforce (responsive mode): Accuforce settings

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