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959 Dakar Testing

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  • bantel_catbantel_cat Member Posts: 842 ✭✭✭✭✭
    edited August 2018
    Sherby90 said:
    969 hummer, 1957 kg
    Cool, thanks.
    So I just wanged a Wildtrack up the hill.
    Fairly comparable at 969, 2002KG/7.3/81
    As we know Handling shouldn't have an impact here in a straight line.

    The time is 37:70
    So on this one inconclusive test, it would appear Offroad is conveying a good traction advantage as you would expect against All Surface.
    Obviously, there will be other aspects such as Torque/Power Curves etc.
  • hillclimberhillclimber Member Posts: 2,141 ✭✭✭✭✭
    edited August 2018
    I don't have the Hummer  :'(  but...
                                                                                                        Sand / Dirt wet
    Ford Raptor RQ24 / 969 / 2452kg / 5.2s / 4WD / OFF / 14.26 / 30.93
    Ford Raptor RQ24 / 639 / 2539kg / 5.6s / 4WD / OFF / 14.86 / 32.70

    so the sand times are not to far off but I have no clue why the Dakar gets a DNF on the wet dirt hill climb. All the other cars with a DNF had either low ground clearance or RWD. 
    Post edited by hillclimber on
  • hillclimberhillclimber Member Posts: 2,141 ✭✭✭✭✭
    BoxtaS said:
    I had to check the hill climb DNF myself and it’s really true.


    I seriously cannot believe Hutch has sold the Dakar in a tri series event of that size and £value without testing it first. That is just shockingly poor. The Vauxhall Frontera makes it up wet dirt hill climb in class e! With about 1/4 of the BHP!!


    I really hope they are serious about fixing it properly and urgently too. Offering a P2W prize car that is bugged is just shameful. 
    boy! if YOU r talking like that than things have to be really bad.
  • BoxtaSBoxtaS Member Posts: 1,487 ✭✭✭✭✭
    The mass = better traction theory is rubbish too as the jimny makes it at under 1000kg


    And the standard tyred e class ranger too


  • David_FookDavid_Fook Member Posts: 2,372 ✭✭✭✭✭
    BoxtaS said:
    The mass = better traction theory is rubbish too as the jimny makes it at under 1000kg


    And the standard tyred e class ranger too


    This should be fixed with the footprint issue right? If you really wanna get hutch’s attention find a similar weight coupe that makes it up...
  • BoxtaSBoxtaS Member Posts: 1,487 ✭✭✭✭✭
    BoxtaS said:
    I had to check the hill climb DNF myself and it’s really true.


    I seriously cannot believe Hutch has sold the Dakar in a tri series event of that size and £value without testing it first. That is just shockingly poor. The Vauxhall Frontera makes it up wet dirt hill climb in class e! With about 1/4 of the BHP!!


    I really hope they are serious about fixing it properly and urgently too. Offering a P2W prize car that is bugged is just shameful. 
    boy! if YOU r talking like that than things have to be really bad.
    I’m just in a bad mood today that’s all 😁
  • BoxtaSBoxtaS Member Posts: 1,487 ✭✭✭✭✭

    TD01055 said:
    BoxtaS said:
    The mass = better traction theory is rubbish too as the jimny makes it at under 1000kg


    And the standard tyred e class ranger too


    This should be fixed with the footprint issue right? If you really wanna get hutch’s attention find a similar weight coupe that makes it up...
    I’ll see what I can do... 👍
  • hillclimberhillclimber Member Posts: 2,141 ✭✭✭✭✭
    edited August 2018
                              
  • HeissRodHeissRod Member Posts: 4,878 ✭✭✭✭✭
    It's amazing how bad the upper level A & S class SUVs do on the wet dirt hill climb, compared to lower class ones.
  • bantel_catbantel_cat Member Posts: 842 ✭✭✭✭✭
    HeissRod said:
    It's amazing how bad the upper level A & S class SUVs do on the wet dirt hill climb, compared to lower class ones.
    Yep, quite how a Range Rover SVR can be 6.5 seconds slower than its largely comparable 5.0 V8 sibling up the Wet Dirt Hill I just don't know.
  • ATSR_997ATSR_997 Member Posts: 583 ✭✭✭✭✭
    HeissRod said:
    It's amazing how bad the upper level A & S class SUVs do on the wet dirt hill climb, compared to lower class ones.
    I think this is all related to the hill climb bug that's been there for something like 8 months
  • DeserTDeserT Member Posts: 502 ✭✭✭✭
    I don't have the Hummer  :'(  but...
                                                                                                        Sand / Dirt wet
    Ford Raptor RQ24 / 969 / 2452kg / 5.2s / 4WD / OFF / 14.26 / 30.93
    Ford Raptor RQ24 / 639 / 2539kg / 5.6s / 4WD / OFF / 14.86 / 32.70

    so the sand times are not to far off but I have no clue why the Dakar gets a DNF on the wet dirt hill climb. All the other cars with a DNF had either low ground clearance or RWD. 
    Sand hills in the game are not exactly like the other hills. Many 4WD medium height cars do great times and it is very much dependent on speed. Dakar should trash all other cars in the game with the off road tires and it’s speed.
  • MSteeLMSteeL Member Posts: 905 ✭✭✭✭
    edited August 2018
    So: any news about it hutch?

    Edit: saw there will be bug fixing update soon, will wait to see what it brings.
  • Hutch_TimHutch_Tim Administrator, Hutch Staff Posts: 615 admin
    edited August 2018
    So I've been going over how this works in some detail, I also see a few misunderstandings in the posts above so let me lay out where we're at.

    1) Better weight can give better traction for launch on low-traction surfaces
    2) How that applies in Top Drives
    2) In-game, off-road tires probably don't give enough advantage vs Cars with 4WD and Performance tires

    Let's break those down!

    1) Better weight can give better traction for launch on low-traction surfaces
    Based on the comments, it looks like I wasn't clear enough on this. Yes, having more weight is almost always a bad thing, that's why the upgrade removes weight! If you're trying to brake, or turn a corner, or get up a hill, having more weight makes that job harder. The added traction force due to extra weight is exactly countered by the added power needed to turn, accelerate, or decelerate, and more than countered when going up a hill.

    The one exception is at very low speeds (especially launch from a standing start) on low-traction surfaces on flat ground. So why would that situation be different?

    Here's some acceleration curves for cars, as deduced in an amazing post from back in the day by Bazzi:

    The line is steepest at the lowest speeds, which means acceleration is highest there, which means the tractive force being applied is the highest there too (as Force = mass * acceleration).

    Fundamentally, why can't a car that does 0-60 in 3.1s on asphalt do the same on a rough surface? The answer is traction. Imagine a fridge sat on a road - you can apply a light force and it won't move, but if you apply enough force it will scrape along. Put the same fridge on ice and you need less force to break the traction between the fridge and the ground and so get it moving. In the same way, the interface between the wheels of a car and the ground has a certain amount of friction - a certain size of force - after which the wheels will no longer grip and you'll enter wheelspin. On ice in particular that force is a lot lower.

    In the above chart we saw that acceleration and therefore force is biggest at the lowest speeds. So, that's when you're most in danger of losing traction and just spinning your wheels.

    @hillclimber is correct that on the Top Drives show, I said the AI tries to drive perfectly (almost always, Slaloms are tricky). In this case that means it applies the perfect amount of throttle to accelerate as fast as possible, without ever exceeding the force that will cause it to lose traction.

    All that given, how can weight help? The tractive force is proportional to weight: if you add more weight you get more traction (going back to the fridges, if you fill a fridge full of sand it will take more force to push it, don't do that). But as we know for braking or cornering, the added weight is going to make it harder to accelerate - right? So why doesn't that just cancel out the traction benefit like it does in those other situations?

    The crucial point is that to avoid wheelspin, the car is not applying the full force it is capable of - the AI reduces the throttle to the maximum amount it can while maintaining traction. If you add a little bit of weight, you have a bit more traction, so you can throttle a little more and accelerate a little faster without losing grip on the surface - and (this is the important bit) the car has the power to spare (as you're at reduced throttle), so even with the added weight it can take off faster. [Edit 9th August 2018 - uh no, because the maximum traction force has only increased by the amount of weight added, you still can't exceed that force, and the added mass means applying that force results in the same acceleration - more investigation needed, see posts below]

    If you keep adding weight, you'll reach the point where the car could drive full throttle without losing traction... but it then has so much weight to move that it can't get going as fast as it could without the weight. So it's not that any amount of weight is better - only enough weight that the car can accelerate faster without losing traction.

    2) How that applies in Top Drives
    This is what is modelled in-game:
    - There's a maximum traction you can apply without slipping, derived from the track surface and the car (tires, drive type, traction control)
    - There's an 'ideal' amount of traction a car could apply if it was able to go full throttle
    - If the ideal traction exceeds the maximum traction on the track (i.e. you would start spinning the wheels if you tried to go that fast), the AI will throttle down just enough to exactly match that maximum traction

    (Incidentally, on a standing start hill climb this same effect will apply at launch, but then as the car starts to go up the hill any extra weight becomes more of a burden. I think that's part of why hill climb results can often be odd - depending on how fast the car is, the trade-off between weight helping at the start vs. hindering on the hill will be in a different place. I think this is also why hill climb times can vary quite a lot too - if a car slows down too much on the hill it reaches the point where it can't apply maximum traction without wheelspinning, so it has to slow down even more.)


    3) In-game, off-road tires probably don't give enough advantage vs Cars with 4WD and Performance tires
    Reviewing the exact calculations used in game to determine the maximum traction force that can be applied without slipping, it does look like cars with performance tires and 4WD aren't being penalised as much as they should be. This is something we can review, although obviously we'd need to be very careful about changing anything like this as it would alter the outcome of every off-road race in the game, as well as altering what everyone has gotten used to (which is that you can currently get away with quite poor tires on a drag race as long as you have 4WD).
    Post edited by Hutch_Tim on
  • MSteeLMSteeL Member Posts: 905 ✭✭✭✭
    2.: so how does this apply to the "raw power of the audi", which has performance tires and a great amount of weight? As we seen from screenshot it does very well on hillclimb.
  • Hutch_TimHutch_Tim Administrator, Hutch Staff Posts: 615 admin
    I should stress, the game runs on the physics equations (like a = F / m), and not my understanding of them (fortunately)! So it's certainly possible that my understanding of them is wrong. I'm going to see if I can get actual values for these various forces from the start of an off-road drag race, and that way I can confirm what's happening rather than just try to interpret equations.

    Regarding the Audis on hill climbs, I'd need to check the physics on power/weight ratios, but as per point (3) above, I now think the 4WD/Perf combination is probably being allowed too much traction. If and when we come to review that, Audis on hill climbs will definitely be something to test.
  • David_FookDavid_Fook Member Posts: 2,372 ✭✭✭✭✭
    So as I understand it the hill climb bug will be fixed - is there any chance you could share the new time for the Dakar on wet hillclimb?

    but the drag issue will not be fixed untill such time that if/when you visit the performance tyre grip levels? To me It still doesn’t explain the carrera 4 loss, or the Metro loss on ice. As you know the metro is lighter and slower to 60.
  • MSteeLMSteeL Member Posts: 905 ✭✭✭✭
    If Dakar isnt better than metro on drags, then its inferior to it on every track(exept motocross and hillclimb after bug fix). I mainly wanted to get him cause I thought it had quite good drag performance...
  • Hutch_TimHutch_Tim Administrator, Hutch Staff Posts: 615 admin
    Hill climb for Dakar will be fixed, I'll see if I can find out what it will do.

    The 'off road tires aren't good enough on drag' issue won't be fixed until/unless we revisit that 4WD Performance tire traction thing, which is a big change to make.

    Going back over the 'more weight for better launch traction' thing, the only thing that matters in my huge post above is that "car has power to spare" argument - but checking again, @Elias_Huber is totally right, I'm totally wrong; in particular it doesn't matter about power to spare because the maximum possible traction force only increases by the amount the mass increases, which is exactly counterbalanced by the slower acceleration due to more weight. So I'll definitely need to check the in-game moment-to-moment calculations to see why heavier cars are taking off that much faster.
  • 43MK443MK4 Member Posts: 1,800 ✭✭✭✭✭
    MSteeL said:
    If Dakar isnt better than metro on drags, then its inferior to it on every track(exept motocross and hillclimb after bug fix). I mainly wanted to get him cause I thought it had quite good drag performance...
    That will be really disappointing is it stays that way. 959 has an rq that is 4 levels higher!
  • bobdylanbobdylan Member Posts: 3,443 ✭✭✭✭✭
    Now I avoided winning the dakkar because I knew it would suffer these problems but in the light of potential bug fixs can I trade my Porsche rally car in for the dakar  ? Shall I msg support 
  • Elias_HuberElias_Huber Member Posts: 203 ✭✭✭
    it's me again  :#

    there are some parts of your statement I don't agree:
    ...
    The one exception is at very low speeds (especially launch from a standing start) on low-traction surfaces on flat ground. So why would that situation be different?

    Here's some acceleration curves for cars, as deduced in an amazing post from back in the day by Bazzi:

    The line is steepest at the lowest speeds, which means acceleration is highest there, which means the tractive force being applied is the highest there too (as Force = mass * acceleration).
    the maximum applied force in this case is always limited either by the friction between tires and surface or by the torque delivered to the wheels. The true reason why the acceleration curve decreases is because the air resistance exponentially increases. Imagine there would be a road to the moon. In empty space your car would always accelerate with the same speed. (assuming there would be gravity and your top speed wouldn't be limited by the gearbox)

    This is not 100% right @hillclimber
    Even without air resistance the acceleration decreases with improving speed.
    Pay attention to P = F x v
    So to mantain a certain acceleration in higher speeds you need more power ( linear increase )
    Or just imagin you are driving in one gear and accelerating up.
    Without air resistence (and rolling resistance) the required torque for a certain accelleration stays the same, but the rpm increases while geting faster.
    and since P = T x n x 2(Pi)   the needed power increases proportionally with the speed ;)

    but i get what you are trying to say, and in the example above the air resistence ist the big limiting factor.
  • hillclimberhillclimber Member Posts: 2,141 ✭✭✭✭✭
    it's me again  :#

    there are some parts of your statement I don't agree:
    ...
    The one exception is at very low speeds (especially launch from a standing start) on low-traction surfaces on flat ground. So why would that situation be different?

    Here's some acceleration curves for cars, as deduced in an amazing post from back in the day by Bazzi:

    The line is steepest at the lowest speeds, which means acceleration is highest there, which means the tractive force being applied is the highest there too (as Force = mass * acceleration).
    the maximum applied force in this case is always limited either by the friction between tires and surface or by the torque delivered to the wheels. The true reason why the acceleration curve decreases is because the air resistance exponentially increases. Imagine there would be a road to the moon. In empty space your car would always accelerate with the same speed. (assuming there would be gravity and your top speed wouldn't be limited by the gearbox)

    This is not 100% right @hillclimber
    Even without air resistance the acceleration decreases with improving speed.
    Pay attention to P = F x v
    So to mantain a certain acceleration in higher speeds you need more power ( linear increase )
    Or just imagin you are driving in one gear and accelerating up.
    Without air resistence (and rolling resistance) the required torque for a certain accelleration stays the same, but the rpm increases while geting faster.
    and since P = T x n x 2(Pi)   the needed power increases proportionally with the speed ;)

    but i get what you are trying to say, and in the example above the air resistence ist the big limiting factor.
    are you referring with that to what finally ends in the barrier of light? I was think of that but thought this doesn't really help us here so it can be neglected.                                 
  • Hutch_TimHutch_Tim Administrator, Hutch Staff Posts: 615 admin
    Right, so we're generally getting to agreement - in particular @hillclimber I agree on the 'which fridge slips first' argument on the slope. Sorry my correction on launch traction came so late.

    (For the record, we model for rolling resistance and air resistance as well. We obviously don't have great air-resistance profile data for every single car so we have to make an approximation there.)

    In terms of 'penalising' all 4WD cars, just compare a 4WD with All Surface tires vs a 4WD with Performance tires on an ice drag race for two similar (including similar weight) cars - I do think the Performance tires currently do too well in-game, although I'd be interested to know what you guys think.

    In terms of having the Dakar perform as it "should", that looks like it will come down to this weight effect that I'm still investigating...
  • Elias_HuberElias_Huber Member Posts: 203 ✭✭✭
    are you referring with that to what finally ends in the barrier of light? I was think of that but thought this doesn't really help us here so it can be neglected.                                 
    No, just saying the acceleration decreases with increasing speed, even without air resistance ;)
  • hillclimberhillclimber Member Posts: 2,141 ✭✭✭✭✭
    Hutch_Tim said:
    Right, so we're generally getting to agreement - in particular @hillclimber I agree on the 'which fridge slips first' argument on the slope. Sorry my correction on launch traction came so late.

    (For the record, we model for rolling resistance and air resistance as well. We obviously don't have great air-resistance profile data for every single car so we have to make an approximation there.)

    In terms of 'penalising' all 4WD cars, just compare a 4WD with All Surface tires vs a 4WD with Performance tires on an ice drag race for two similar (including similar weight) cars - I do think the Performance tires currently do too well in-game, although I'd be interested to know what you guys think.

    In terms of having the Dakar perform as it "should", that looks like it will come down to this weight effect that I'm still investigating...
    once more I would like to express my gratitude to be able to talk to one of the developers of this game directly. Thank you Tim! 

    If you are looking for those air resistance values this here might help http://rc.opelgt.org/indexcw.php
  • HeissRodHeissRod Member Posts: 4,878 ✭✭✭✭✭
    edited August 2018
    Its a good thing hutch doesn't introduce airplanes and treadmills into the game.  The forum would melt down.
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