Flaws of the tyre model simulation

sabamber
I owned a TVR T350c and M3 CSL recently and can confirm its definitely harder to drive a quick car properly in real life than GT.
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i love TVR. only seen one in real life, am 80's model iirc. Not many made it to the USA.
 
SlipZtrEm
If the 911 GT3 RS was as unruly in the real world as it is in GT Sport, I probably would've been a dead man back in October.

GT's had an issue with acceleration times — especially those of front-drive cars — since around GT3. Low-speed physics seem to be tough to nail for most of the sims out there. I'd guess it's less of a concern to devs since most players won't be exploring that part of the speedometer as much as the others, but it's important nonetheless.
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In the past I would have agreed, however over the last few years a growing number have gotten around those issues.


Voodoovaj
Not to be a fly in the ointment, but the grip modifier within a tire model affects the items listed, not the tire model itself.

For a tire model you can think of this like the carcass of the tire without rubber on it. The tire model would be how the tire behaves under load: Lateral load, gravitational load, weigh transfer, does the tire diameter grow with speed, how does the tire react to compression and rebound from bumps in the road, how does the tire flex differently when these load occur in a not rotating versus rotational condition. Stuff like that. That's a tire model. Imagine a tire in the general sense and think of all the things it does and that is what you are modelling.

What you listed are elements of grip, or IRL terms, the rubber compound.
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Modern tyre models most certainly do include the rubber.
 
A couple of weeks ago I tried rFactor 2 (E30 M3 around Nordschleife) and one of the first things I noticed was how I could feel the car connected to the tarmac.

Also, when going into the grass, the car didn't behave as it was touching ice. You could even bring it back to the track (as IRL). In GT, you touch the grass, aka ice, and you're gone 99% of the times.
 
Scaff
Modern tyre models most certainly do include the rubber.
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They "include" the rubber because that's an element of the model being used.

When you use the term tire model, it refers to the type of tire that the game tires are modeled after. Such as, the tires on a Ford Model T, or a radial tire, or a bias ply tire, or maybe even the tires on those mining trucks, or a tractor. Those are different types of tire that can be used as a model for the developer to work from. That's a "tire model". If a tire slips more or less, that's not the tire model, it's a parameter of the tire.
 
GordonS
I've tested launching LaFerrari vs. Veyron TCS on with RS tyres and the drag times are quite life like that way.
The footage is here:

But yes, more normal tyres should be more grippy in launch situations.
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Just out of curiousity, what are the accleration times for the Veyron and Ferrari on soft racing tires in real life?
 
Voodoovaj
They "include" the rubber because that's an element of the model being used.

When you use the term tire model, it refers to the type of tire that the game tires are modeled after. Such as, the tires on a Ford Model T, or a radial tire, or a bias ply tire, or maybe even the tires on those mining trucks, or a tractor. Those are different types of tire that can be used as a model for the developer to work from. That's a "tire model". If a tire slips more or less, that's not the tire model, it's a parameter of the tire.
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No when I use the term tyre model, I am quite specifically talking about the software tyre model in the title I am discussing.

Such as the SETA tyre model from Project Cars:
http://www.wmdportal.com/projectnews/inside-project-cars-seta-tire-model/

Or the Live for Speed Tyre model:
https://www.lfs.net/report-dec2009

Or Assetto Corsa's tyre model:
http://www.assettocorsa.net/forum/index.php?threads/tyre-model-v10-specs.36686/

The term "tyre model" when discussing tyre physics in sims is used almost universally to describe the software physics model of the tyres, and every element of the tyre.
 
zzz_pt
A couple of weeks ago I tried rFactor 2 (E30 M3 around Nordschleife) and one of the first things I noticed was how I could feel the car connected to the tarmac.

Also, when going into the grass, the car didn't behave as it was touching ice. You could even bring it back to the track (as IRL). In GT, you touch the grass, aka ice, and you're gone 99% of the times.
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This is one of the most frustrating things about this game. Hitting ice is not even an exaggeration, it is literally as if they modeled the grass in this game to effect your car the same as driving over an ice patch would. It doesn't even matter if your other 3 tires are still on tarmac. Those green patches of run off area at Suzuka do the same thing too.
 
Scaff
No when I use the term tyre model, I am quite specifically talking about the software tyre model in the title I am discussing.

Such as the SETA tyre model from Project Cars:
http://www.wmdportal.com/projectnews/inside-project-cars-seta-tire-model/

Or the Live for Speed Tyre model:
https://www.lfs.net/report-dec2009

Or Assetto Corsa's tyre model:
http://www.assettocorsa.net/forum/index.php?threads/tyre-model-v10-specs.36686/

The term "tyre model" when discussing tyre physics in sims is used almost universally to describe the software physics model of the tyres, and every element of the tyre.
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Correct, those are all tire models in the proper sense of the term, but when I read the original post, it seemed to only discuss the grip. That element, is not the tire model. That's all I am saying.

I was hoping for insight into what they all do differently compared to what GTS is doing.

Saying the charger is 2 seconds slower to 60 doesn't give me any insight.

On a side note, I hadn't read the PCars tire model info. That's some pretty good stuff there.
 
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Voodoovaj
Correct, those are all tire models in the proper sense of the term, but when I read the original post, it seemed to only discuss the grip. That element, is not the tire model. That's all I am saying.

I was hoping for insight into what they all do differently compared to what GTS is doing.

Saying the charger is 2 seconds slower to 60 doesn't give me any insight.
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The OP also used a number of my videos to support his post, as such it using evidence about the entire tyre model.
 
Scaff
In the past I would have agreed, however over the last few years a growing number have gotten around those issues.
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Do you know of any links that specifically explain what happens to physic engines at slow speed directly? I'm not interested in which game does what but I am interested in finding out exactly what is being coded and why. I hope that makes sense as this has been the achilles heel of the sport and I've not seen it properly addressed or given the importance it deserves.

I'm glad it's been brought up and I'd rather not see it glossed over if you know what I mean, iirc at the time I was looking into it there were two distinct trains of thought and two ways of programming for it.
 
LennyB
Do you know of any links that specifically explain what happens to physic engines at slow speed directly? I'm not interested in which game does what but I am interested in finding out exactly what is being coded and why. I hope that makes sense as this has been the achilles heel of the sport and I've not seen it properly addressed or given the importance it deserves.

I'm glad it's been brought up and I'd rather not see it glossed over if you know what I mean, iirc at the time I was looking into it there were two distinct trains of thought and two ways of programming for it.
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In all honesty its not really the same problem it was in the past.

Most older tyre models were based almost exclusively around the Paceja magic formula.....

https://en.wikipedia.org/wiki/Hans_B._Pacejka#The_Pacejka_"Magic_Formula"_tire_models

....which was never specifically designed for sims. However it was easy to use, lightweight in terms of system demands and saved devs the problem of building a specific model themselves. It does however fall apart as the curves begin to converge around pit lane speed.

Most sims now have moved away from using it as a basis for tyre models as they have had more system overhead to work with, more experience of working around the issues with Pacejka models.

Its easy enough to see, as below pit lane speeds (10 to 15 mph and below) tyre exhibit far less grip than they should, and at the worse end of things will slide when stationary on sloping ground.
 
Scaff
Most sims now have moved away from using it as a basis for tyre models as they have had more system overhead to work with, more experience of working around the issues with Pacejka models.
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The information I was looking into at the time was talking about not working around but using something completely different, which probably meant working around things at other speeds.

Thank's for the name of it, that will get me started. I'm not satisfied with what we are seeing now even from the games that do it really well, something is off, it is way better though. To me it's like squeezing that last bit of juice out of it before moving onto another fruit.

Again, I'm glad to see some take notice of slow speed physics. 👍
 
Scaff
In all honesty its not really the same problem it was in the past.

Most older tyre models were based almost exclusively around the Paceja magic formula.....

https://en.wikipedia.org/wiki/Hans_B._Pacejka#The_Pacejka_"Magic_Formula"_tire_models

....which was never specifically designed for sims. However it was easy to use, lightweight in terms of system demands and saved devs the problem of building a specific model themselves. It does however fall apart as the curves begin to converge around pit lane speed.

Most sims now have moved away from using it as a basis for tyre models as they have had more system overhead to work with, more experience of working around the issues with Pacejka models.

Its easy enough to see, as below pit lane speeds (10 to 15 mph and below) tyre exhibit far less grip than they should, and at the worse end of things will slide when stationary on sloping ground.
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That is truly interesting. I'm sincerely hoping we could push PD to do something about this.
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Okay, so based on what I’ve read here we have some insight into the game’s current tyre simulation model.

Rather than ask the question of if it can be “fixed” I want to point the discussion in another direction:

  • Given the knowledge that we have, how can we use this information to drive faster in-game?

Are there certain driving habits and Assist settings that, taking this tyre simulation model into account, will make a driver go faster? Sport Mode races typically use SH or RH as standard, so let’s see what we can exploit with those.

Let’s ignore reality for a moment and treat this like a game, a game which most likely has an “optimal way of playing”.
 
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PJTierney
Okay, so based on what I’ve read here we have some insight into the game’s current tyre simulation model.

Rather than ask the question of if it can be “fixed” I want to point the discussion in another direction:

  • Given the knowledge that we have, how can we use this information to drive faster in-game?

Are there certain driving habits and Assist settings that, taking this tyre simulation model into account, will make a driver go faster?

Let’s ignore reality for a moment and treat this like a game, a game which most likely has an “optimal way of playing”.
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I find using Racing Intermediate tyres on supercars way more realistic than Sport tyres. 0-100kph times are still unrealistically slow but it's definitely better.

With that said, I don't recommend using them with slower cars like Toyota GT86 as they provide too much grip for a car like that. Simply like putting hypercar tyres to it irl.
 
GordonS
I don't know.
In the "Racing Soft" test I noticed the times are close to the documented real life times.
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The only way the acceleration times could be lifelike is if you compare them to RS tires in real life. Given that you needed RS tires in the game to get them to behave similarly in the test, that would mean they aren't lifelike at all wouldn't it?
 
MidFieldMaven
N1000 is complete. The king of N-category cars is officially the LaFerrari.

N1000
0:53.770 - Ferrari LaFerrari
0:54.708 - Bugatti Veyron 16.4

53 seconds is wild. To avoid oversteer, I found 5th gear to be ideal for almost the entire track, with 6th necessary on the straightaway. Using 1st-4th gears is not advised.
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This is a quote from the Suzuka East car times thread. Well of course using 1st to 4th gears is not advised, because the tyre model is a total joke. Using only 5th gear in those slow corners in Suzuka? Rubbish simulation.

Take a look at this video for example:



The guy drives the car pretty quickly and he can use all gears according to the speed just fine. No crazy rev bouncing around the rev limiter. Yes, he probably uses a traction control but still. The car in GTS on the other hand is completely out of control at ANY speed. Even with TCS.
 
Lord Protector
a 900+hp Supra, wheels won't stop spinning even at 300kph
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Well I will not exactly call it impossible but the amount of wheelspin may be a bit too much for a 903 HP supra.

But to be honest I really like that it goes pretty wild like that even wheelspinning in 3rd gear.

Here is a video of what I believe a 1099 HP supra: in the videos description "lots of wheelspins". Surely not as much as the GTS supra but you can clearly see the steering wheel rotating in order to keep the car "stable"


Shame PD only simulated stock sounding road cars with no added parts otherwise the rev should be higher!

But I get it the way it is translated in the game seems like there must be some kind of miscalculation in the friction or some sort (too much wheelspins).
 
PJTierney
Are there certain driving habits and Assist settings that, taking this tyre simulation model into account, will make a driver go faster? Sport Mode races typically use SH or RH as standard, so let’s see what we can exploit with those.
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CSA on strong and ABS on weak, no other aids on. Brake late and short shift on exit.
 
Johnnypenso
The only way the acceleration times could be lifelike is if you compare them to RS tires in real life. Given that you needed RS tires in the game to get them to behave similarly in the test, that would mean they aren't lifelike at all wouldn't it?
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I really don't have time for this kind of arguing Johnny.
 
Johnnypenso
The only way the acceleration times could be lifelike is if you compare them to RS tires in real life. Given that you needed RS tires in the game to get them to behave similarly in the test, that would mean they aren't lifelike at all wouldn't it?
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Besides that, stating the times can be matched or are similar in no way means the model is accurate. There is a serious problem and it's been that what like fo eva.
 
LennyB
Besides that, stating the times can be matched or are similar in no way means the model is accurate. There is a serious problem and it's been that what like fo eva.
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I have tested several cars with racing soft tyres, hell even super soft and the cars still failed to reach 100kph as fast as they can irl. Even if they did, cornering that way is very unrealistic - too good. So it's unrealistic either way.
 
Scaff
In all honesty its not really the same problem it was in the past.

Most older tyre models were based almost exclusively around the Paceja magic formula.....

https://en.wikipedia.org/wiki/Hans_B._Pacejka#The_Pacejka_"Magic_Formula"_tire_models

....which was never specifically designed for sims. However it was easy to use, lightweight in terms of system demands and saved devs the problem of building a specific model themselves. It does however fall apart as the curves begin to converge around pit lane speed.

Most sims now have moved away from using it as a basis for tyre models as they have had more system overhead to work with, more experience of working around the issues with Pacejka models.

Its easy enough to see, as below pit lane speeds (10 to 15 mph and below) tyre exhibit far less grip than they should, and at the worse end of things will slide when stationary on sloping ground.
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Wasn't it Project Cars where the cars used to slide sideways on a slope when stationary?
 
phil_75
Wasn't it Project Cars where the cars used to slide sideways on a slope when stationary?
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Can't say I've noticed but then again, I wasn't looking for it. I can tell you that they do start rolling down an incline or decline in a realistic seeming way and you can bump start your cars that way if you don't have auto-start on and you have a clutch and manual transmission. Haven't tested it with the paddles.
 

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