Assetto Corsa | News and General Discussion

[skazz]

I'm lucky if they stay around 70c, in most cars they're usually in the 55-65c range no matter how hard I drive. In some cars it doesn't seem to matter much but in others after the first lap it feels like driving on ice. I think there's only a couple cars I can keep the tires at or above 80c.

Different cars are running different versions of the tyre model. Most are on v5, some are on v6. I think it's safe to say two things:
1. We don't know if the plug-in is accurately monitoring tyre core and surface temps (I believe there is a dev tool you can activate for better info).
2. The tyre model is in a state of flux, and it's highly likely that patch 1.5 will normalize all cars on one tyre model.

 

[ALB123]

I've never understood why we see the core temp of tires instead of the surface temp of the tires. Isn't the surface temp much more important to know in real time?

 

[BrandonW77]

Different cars are running different versions of the tyre model. Most are on v5, some are on v6. I think it's safe to say two things:
1. We don't know if the plug-in is accurately monitoring tyre core and surface temps (I believe there is a dev tool you can activate for better info).
2. The tyre model is in a state of flux, and it's highly likely that patch 1.5 will normalize all cars on one tyre model.

Yes, but some v6 tires have the same issues with not keeping their heat so I don't think it has anything to do with a specific tire model.

I'm not sure how accurate either are but the mod tire temp app and DashMeterPro both show the same readings for tire heat (or lack of).

I'm hoping v1.5 will fix these issues.

 

[LeGeNd-1]

I'm hoping it will be fixed by the time of console release at least. After the fallout of PCARS we don't need another sim with basic features not working at release. I would understand if AC is still in Early Access, but this is a full priced game we're talking about. C'mon Kunos, ISI got it right 10+ years ago!

 

[Punknoodle]

I'm hoping it will be fixed by the time of console release at least. After the fallout of PCARS we don't need another sim with basic features not working at release. I would understand if AC is still in Early Access, but this is a full priced game we're talking about. C'mon Kunos, ISI got it right 10+ years ago!

To be fair, they are trying to do something a lot more sophisticated than what was achieved back then.

 

[LeGeNd-1]

To be fair, they are trying to do something a lot more sophisticated than what was achieved back then.

I appreciate that. If it doesn't work then all that sophistication is for nought though.

 

[BrandonW77]

I appreciate that. If it doesn't work then all that sophistication is for nought though.

Preach.

 

[skazz]

I'm hoping it will be fixed by the time of console release at least. After the fallout of PCARS we don't need another sim with basic features not working at release. I would understand if AC is still in Early Access, but this is a full priced game we're talking about. C'mon Kunos, ISI got it right 10+ years ago!

In the current PC version, AC is good to drive with every car. A few are perhaps 95% right now and will get a little better with some tweaks to their tyres, but we're certainly not talking "broken" or anything. We're talking nuance here. pCARS tyre changes were much more dramatic.

But the more relevant question: What are "basic features" to you?

[hint: AC has a relatively small "feature" set compared to many PC sims, and I'm curious what you regard as the minimum to be able to enjoy it]
[extra hint: There is a reason that you hear people say "AC is my favourite driving simulator": It gives an amazing driving feel, but the AI and multiplayer can be a little flaky. If you hate the idea of hotlapping the laser scanned Nordschleife in all those different licensed road and racecars then you might find AC content light. Those of us who loved hotlapping Nordschleife in Gran Turismo basically get a huge quality improvement in AC for doing the same thing]

 

[BrandonW77]

In the current PC version, AC is good to drive with every car. A few are perhaps 95% right now and will get a little better with some tweaks to their tyres, but we're certainly not talking "broken" or anything. We're talking nuance here. pCARS tyre changes were much more dramatic.

But the more relevant question: What are "basic features" to you?

[hint: AC has a relatively small "feature" set compared to many PC sims, and I'm curious what you regard as the minimum to be able to enjoy it]
[extra hint: There is a reason that you hear people say "AC is my favourite driving simulator": It gives an amazing driving feel, but the AI and multiplayer can be a little flaky. If you hate the idea of hotlapping the laser scanned Nordschleife in all those different licensed road and racecars then you might find AC content light. Those of us who loved hotlapping Nordschleife in Gran Turismo basically get a huge quality improvement in AC for doing the same thing]

I think by "basic features" he meant "tires working correctly" which is a pretty basic and necessary feature of any racing game/sim. I too hope they get this issue sorted before the console release because right a lot of the cars have tires that don't work properly.

 

[FS7]

It gives an amazing driving feel, but the AI and multiplayer can be a little flaky.

I like hotlapping but good AI & offline racing is important to me too.
Does AC have multiclass offline races? Multiclass race weekends is my way of doing road car track days in PCars.

 

[skazz]

I like hotlapping but good AI & offline racing is important to me too.
Does AC have multiclass offline races? Multiclass race weekends is my way of doing road car track days in PCars.

In the PC version you can select each specific car you want to race against, so you can race anything you like. I understood that the console UI might be more restrictive, but not sure how.

 

[Tired Tyres]

I like hotlapping but good AI & offline racing is important to me too.
Does AC have multiclass offline races? Multiclass race weekends is my way of doing road car track days in PCars.

Not multi class timing - but that is heavily requested if Lord Kuno's Multi this Multi that comment I read a while ago is anything to go by.

The PC version allows you to pick individual opponents but the console version won't. Somthing to do with car vs car balancing If I remember correctly. Same model or class only I think.

 

[ALB123]

That's one thing that stinks about the console version compared to PC version (no multiclass fields). One of my favorite things to do is trackday sessions, on a track like Bridgehampton (addon mod track). From Miata's to LaFerrari's on the track. It's a good time...

 

[LeGeNd-1]

In the current PC version, AC is good to drive with every car. A few are perhaps 95% right now and will get a little better with some tweaks to their tyres, but we're certainly not talking "broken" or anything. We're talking nuance here. pCARS tyre changes were much more dramatic.

But the more relevant question: What are "basic features" to you?

[hint: AC has a relatively small "feature" set compared to many PC sims, and I'm curious what you regard as the minimum to be able to enjoy it]
[extra hint: There is a reason that you hear people say "AC is my favourite driving simulator": It gives an amazing driving feel, but the AI and multiplayer can be a little flaky. If you hate the idea of hotlapping the laser scanned Nordschleife in all those different licensed road and racecars then you might find AC content light. Those of us who loved hotlapping Nordschleife in Gran Turismo basically get a huge quality improvement in AC for doing the same thing]

As Brandon said, the basic features I'm referring to are the physics simulation. I'm more of a hotlapper as well so the lack of career/multiplayer/AI doesn't bother me at all. I'm content if AC only has a Time Trial mode, but obviously for the console crowd all those "gamey" features need to be implemented.

And no, it's certainly not broken as bad as PCARS. I do find the driving aspect of AC 10x better than anything in Gran Turismo already. I'm just surprised that for all the praise of AC's physics engine, something as basic as tyre temperatures are not yet working properly. Certainly you can still enjoy the game without it, but it's a pretty crucial piece of the puzzle to be missing.

I remember when I first got rFactor I drove 100% for a few laps like I always did in GT. After 4-5 laps I noticed the car started handling weird. That's when I noticed the tyres overheated and I can't put down the power as effectively. That was such a shock coming from GT where you can overdrive the car all day, but it was awesome from a realism and challenge point of view. It was kinda disappointing to see this isn't yet possible in AC (on the other hand feeling a flatspot vibrating your wheel is pretty sweet ).

I dunno, it's just pretty annoying that all of the current sims seems to all be in a state of perpetual beta. iRacing, AC, PCARS, rFactor 2 all just keeps going back and forth with tyre physics changes every so often. The previous generation the game comes out and that was it. The ISImotor engine was used in 95% of games and it works pretty damn good without needing many tweaks. I understand that devs are always pushing for max realism, but at the end of the day a simulation is never going to match up 1:1 with real life. I'd rather take a simple system that works and replicates 95% of reality than a 99% complex system that doesn't always work.

Sorry for the overly philosophical post. I take driving feel and physics in sims very close to heart

 

[skazz]

The thing you need to understand is that in the past tyre models were purely lookup tables (Pacejka). This latest generation of sims is the first to start actually modeling some aspects of tyre behavior rather than using lookup tables, so the tyre models themselves are enormously more complex than anything which came before, but behavior characteristics which had to be faked in the past are coming out of the sim.

In the past, that tyre surface temperature was probably a simple combination of rolling speed and amount of slipping/sliding. Now it's a very complex thermodynamic mathematical model which includes the tyre wall, flex, core and surface temperature interaction, brake temperature interaction, etc...

I suggest you read up on the pCARS tyre model article they released last year, good reference.

Oh, and to be clear: iRacing, the PC sim which has without doubt the most financial backing and the best access to real data, has never had a stable tyre model. iRacing users are familiar with new releases of the sim bringing totally different feel to the tyres, as iRacing iterates their model further. This approach is clearly the only way forward as we model more complex tyre behavior, since pCARS and AC are following right along behind iRacing on this.

 

[Punknoodle]

The thing you need to understand is that in the past tyre models were purely lookup tables (Pacejka). This latest generation of sims is the first to start actually modeling some aspects of tyre behavior rather than using lookup tables, so the tyre models themselves are enormously more complex than anything which came before, but behavior characteristics which had to be faked in the past are coming out of the sim.

In the past, that tyre surface temperature was probably a simple combination of rolling speed and amount of slipping/sliding. Now it's a very complex thermodynamic mathematical model which includes the tyre wall, flex, core and surface temperature interaction, brake temperature interaction, etc...

I suggest you read up on the pCARS tyre model article they released last year, good reference.

Oh, and to be clear: iRacing, the PC sim which has without doubt the most financial backing and the best access to real data, has never had a stable tyre model. iRacing users are familiar with new releases of the sim bringing totally different feel to the tyres, as iRacing iterates their model further. This approach is clearly the only way forward as we model more complex tyre behavior, since pCARS and AC are following right along behind iRacing on this.

Exactly. And while it can be confusing as each build has a completely different tire feel - thats progress. And progress is good.

 

[LeGeNd-1]

The thing you need to understand is that in the past tyre models were purely lookup tables (Pacejka). This latest generation of sims is the first to start actually modeling some aspects of tyre behavior rather than using lookup tables, so the tyre models themselves are enormously more complex than anything which came before, but behavior characteristics which had to be faked in the past are coming out of the sim.

In the past, that tyre surface temperature was probably a simple combination of rolling speed and amount of slipping/sliding. Now it's a very complex thermodynamic mathematical model which includes the tyre wall, flex, core and surface temperature interaction, brake temperature interaction, etc...

I suggest you read up on the pCARS tyre model article they released last year, good reference.

Oh, and to be clear: iRacing, the PC sim which has without doubt the most financial backing and the best access to real data, has never had a stable tyre model. iRacing users are familiar with new releases of the sim bringing totally different feel to the tyres, as iRacing iterates their model further. This approach is clearly the only way forward as we model more complex tyre behavior, since pCARS and AC are following right along behind iRacing on this.

Thanks for that technical explanation. It's always good to understand more about what's going on under the hood 👍

I guess my thinking is that for a fully perfect tyre model, consumer grade computers aren't even going to cut it. Unless you have an F1 grade sim your best bet is just a close approximation. So it's better to use a consistent model. Otherwise when you adapt to one and it changes the next update it can be off putting. And when each build has a different feel, it's not so much progress as running around in circles You have 1 goal to replicate - real life - there should be one direction to go to. I've heard iRacing's tyre model is one step forwards, one step back with every update.

Anyway, it's clearly early days. I do hope the programmers one day manage to crack the code and simulate it perfectly. But for the moment, for a singular game like AC, I think it's best to have a consistent model (iRacing is excepted because of its unique service model).

 

[skazz]

If simulating a real life tire was easy, all models would be equal. The problem is not even so much about compute power but about our ability to understand what exactly is happening in a tire under load, due to too many variables interacting in a complex manner. Especially under extreme conditions there's still insufficient understanding of what causes a tire to do what it does, hence why so many simulators fail to capture the real behavior of tyres when they approach (or exceed) the limits of grip.

 

[BrandonW77]

The thing you need to understand is that in the past tyre models were purely lookup tables (Pacejka). This latest generation of sims is the first to start actually modeling some aspects of tyre behavior rather than using lookup tables, so the tyre models themselves are enormously more complex than anything which came before, but behavior characteristics which had to be faked in the past are coming out of the sim.

In the past, that tyre surface temperature was probably a simple combination of rolling speed and amount of slipping/sliding. Now it's a very complex thermodynamic mathematical model which includes the tyre wall, flex, core and surface temperature interaction, brake temperature interaction, etc...

That's all fine and good, but it's still puzzling that Kunos would release this tire model that can't keep temperatures up. Sure, it's probably a very complicated thing to make work correctly, but why release it when it clearly isn't working correctly? I'm sure it will be fixed, it just happened to come at a time when most of their resources are focused on the console release so they haven't been able to address it. I'm not slamming Kunos, we all make mistakes, but as others noted it is a bit frustrating when the content of most sims has some strange dichotomy of different tires models, physics models, and contact patch models, and due to the ever more complicated technology it appears that this is likely our new normal.

 

[Punknoodle]

Fair call, however I will say that when v5 came out I thought it felt amazing. Aside from the temperatures, they have done a spectacular job with the tire model in my opinion.

 

[super_gt]

Speaking about different tires models here's what's coming in LFS

Scawen
Developer

today, 14:05
Joined : 21 Jan 2003
Posts : 6409
Obviously it hasn't been proceeding a lot as I've been working full time on other things. There is only one of me.

What benefits they will bring? They will behave more realistically and feel better to drive. Nothing do do with changing a few numbers. It's an entirely rewritten tyre model.

For more info, drive a bit in LFS then go and drive a real car. What differences do you feel? Those differences should be reduced. That's the plan.
It will also allow us to simulate more different types of vehicles because the tyre model should scale correctly from small tyres to large tyres. There are so many possibilities from having a better tyre model, not only that it feels better and more fun to drive as you put the power on coming out of a bend and so on. A physics model based on real physical principles that produce the mathematical functions that produce the slip curves and the way of combining lateral and longitudinal forces (they aren't 'combined' as such, they just come out of the model naturally).

And no, I'm not going into details now. Right now I'm trying to get this quick update out of the way. And as I said then I'm working on functions for Eric and at last I'll be back on the tyre physics. If there's something interesting to say about it in a few months, then perhaps I will.

 

[BrandonW77]

Fair call, however I will say that when v5 came out I thought it felt amazing. Aside from the temperatures, they have done a spectacular job with the tire model in my opinion.

I guess I'm probably not one to be judging it since my system is perpetually screwed up and I never know if I'm actually feeling what I should be feeling.

 

[LeGeNd-1]

If simulating a real life tire was easy, all models would be equal. The problem is not even so much about compute power but about our ability to understand what exactly is happening in a tire under load, due to too many variables interacting in a complex manner. Especially under extreme conditions there's still insufficient understanding of what causes a tire to do what it does, hence why so many simulators fail to capture the real behavior of tyres when they approach (or exceed) the limits of grip.

Exactly because we still don't understand lots of things, that I think complicated tyre models should be in the domain of developers for now. Package the actual game for the masses with something tried and tested that works. Kunos can continue developing the perfect tyre model in the background. 5-10 years later when they have finished it and everything works, then it can get implemented in AC2/3 or whatever.

There's a really good pdf article posted by Niels Heusinkveld talking about tyres in sims vs reality (http://isiforums.net/f/showthread.php/3710-PDF-tires-in-race-simulations-some-thoughts). Give it a good read. He's the main physics guy behind rFactor's NSX mod and Game Stock Car Extreme, and also good friends with Aristotelis (AC's main physics guy I believe). Basically sim physics boils down to 2 models:

1) Top-down approach (ISImotor) - using lookup tables and preset curves, you input "fudged" numbers, and gives out game performance that matches real life as close as possible.

2) Bottoms-up approach (AC, PCARS, rF2, ?iRacing, ?GT) - using a complex physics generator, you input "real world" numbers (in quotes because as Niels said even real numbers are usually inaccurate), and it gives out performance that the physics engine thinks is right but might be a bit off from real life.

Some people like approach 1, some like approach 2. Ideally the physics generator in approach 2 = real life and you get the exact same performance, but we are not there yet. So personally, at the moment, I prefer the old approach 1 better. At the end of the day it's not the numbers, but the feeling through the wheel that matters.

My 2 cents

Speaking about different tires models here's what's coming in LFS

Scawen
Developer

today, 14:05
Joined : 21 Jan 2003
Posts : 6409
Obviously it hasn't been proceeding a lot as I've been working full time on other things. There is only one of me.

What benefits they will bring? They will behave more realistically and feel better to drive. Nothing do do with changing a few numbers. It's an entirely rewritten tyre model.

For more info, drive a bit in LFS then go and drive a real car. What differences do you feel? Those differences should be reduced. That's the plan.
It will also allow us to simulate more different types of vehicles because the tyre model should scale correctly from small tyres to large tyres. There are so many possibilities from having a better tyre model, not only that it feels better and more fun to drive as you put the power on coming out of a bend and so on. A physics model based on real physical principles that produce the mathematical functions that produce the slip curves and the way of combining lateral and longitudinal forces (they aren't 'combined' as such, they just come out of the model naturally).

And no, I'm not going into details now. Right now I'm trying to get this quick update out of the way. And as I said then I'm working on functions for Eric and at last I'll be back on the tyre physics. If there's something interesting to say about it in a few months, then perhaps I will.

I always seem to forget LFS in sim discussions for some reason. I think LFS in some situations (low speed and countersteering) still has the best physics out of anything right now. Also it's interesting how LFS and AC supposedly uses pure FFB with no canned effects, and yet they both handle very differently. AC feels a bit vague and mushy for me, but have excellent road feel (no doubt due to laser scanned tracks). LFS feels direct and I can feel that rubber-meets-asphalt sensation very clearly, but it lacks the subtler details. It's just such a shame all the cars and tracks are generic, updates are slow and it's not moddable, otherwise I think LFS would have been as big as rFactor...

 

[fatkrakr]

I read on the official forum that it is how AC is sending the tire info. Its using the core of the tire for temps and not the surface of the tire. The core shouldn't change much and can even drop in certain situations. In the same post it was also stated that it was a deliberate decision, weather or not its the right choice there looking in to, but it isn't broken its working as designed. Also that they may of got some bad tire info they needed to check. I cant find the post now, but was linked here a few weeks back. So what I took from it was the tires are in deed changing temps on the surface, you just have no way of seeing it as its not output by the game for whatever reason.

 

[Johnnypenso]

The core of the tire doesn't contact the road so why would we need core temps displayed in real time on the track other than as secondary information to accompany the more important surface temps? It still doesn't make any sense anyway because I'm running around in my Escort at a world class clip and my core temps are only 60-70C and remain there lap after lap which means my surface temps aren't much higher. And how do GT3 cars manage to run 100C core temps but still have surface temps that are usable? Running the F1 GTR for one hot lap at Mugello I had temps of 130C displaying in the final couple of corners. If those were core temps how come my tires didn't just melt right off the rim? Something is fishy in the state of Denmark!

 

[Kamuifanboy]

In real life, we don't check the surface temperatures. We usually stick a needle into the tire to measure the rubber a half inch or so inside of the surface. So, both ways are theoretically wrong.

 

[mister dog]

In real life, we don't check the surface temperatures. We usually stick a needle into the tire to measure the rubber a half inch or so inside of the surface. So, both ways are theoretically wrong.

So now we still don't have a clue
Best shot for a proper explanation is to grill Lord Kunos or Aristoteles about it on the AC forum.

 

[Punknoodle]

In real life, we don't check the surface temperatures. We usually stick a needle into the tire to measure the rubber a half inch or so inside of the surface. So, both ways are theoretically wrong.

What about race cars with ir sensors above each tire measuring the heat spread and temp across the tire? Surely if that info wasn't usable they wouldn't bother with that approach.

 

[Kamuifanboy]

What about race cars with ir sensors above each tire measuring the heat spread and temp across the tire? Surely if that info wasn't usable they wouldn't bother with that approach.

Generally speaking those thermal sensors are not accurate enough to what the engineers will want. They are just using it to see the change in temperature at different loads and with different geometry settings. It gives them an approximate idea as to how the tires change, rather than the exact temperature they are at.

 

[LeGeNd-1]

Crazily, I just put in some laps and tyre temps work now I tried a wide variety of cars (some tyre model V5, some V6), tried tyre blankets on/off, tried tyre wear on/off. They all work properly and heat up & cool down as it should (although it still cools down too easily). With some drifting I managed to reach 100 C in the McLaren P1. Also front wheels heat up much easier than rears, even in high powered RWDs. The temp displayed in pit garage works too, but only when tyre wear is on (if tyre wear is off it says N/A).

I don't know what happened, but I'm a happy bunny now

Moving on to another issue, has anyone experienced torque steer in AC? In GT and rFactor if you drive an FWD and take a tight hairpin, then mash the throttle on/off rapidly you can feel the wheel pulling side to side. In AC I tried the Abarth and did not get anything. Do you need to turn on canned effects (one of them is called slip effect I think) for this to happen? Normally I wouldn't have a problem turning on canned effects but in AC with its already weak FFB it covers up too much steering information.