Forza 4 VS GT5 (read the first post before you contribute)

[imported_xxDingerxx]

On your basis you may as well simulate no values what so ever. The simple fact is that if theres a setting for say stiffness of springs then there should be one for tyre pressures. If not then why bother having any values as its all just smoke and mirrors anyway and theres no real track surface or weather or heat etc etc etc.....

PD were just as most of GT5 proves....lax, and living off their inflated egos that they are the 'real driving simulator'....lol..yeah ok....

Without simulating variable conditions, not really. Every tire has an optimal temperature and with static conditions, the only real variable is how hard you drive and the friction you generate. Changing pressure and the way it changes handling can always be done better in the suspension. Thats a reason some cars are harder on its tires than others.

Oh, I like that you don't really have anything to add to this discussion but you just had to take a pot shot at PD and GT5 didn't you. A bit cheap if you ask me..

 

[Wolfe]

There are different track temperatures in Forza, though...I never play with tire pressure anyway, but has anyone noticed an appreciable difference between, say, Laguna Seca and Top Gear overcast?

I agree that tire pressure is kind of a gimmick in this game, but it may still make a little difference between tracks.

 

[imported_xxDingerxx]

There are different track temperatures in Forza, though...I never play with tire pressure anyway, but has anyone noticed an appreciable difference between, say, Laguna Seca and Top Gear overcast?

I agree that tire pressure is kind of a gimmick in this game, but it may still make a little difference between tracks.

Between tracks is a possibility. Can't really tell if it has anything to do with temperature or not but the most likely is the tracks themselves and the difference needed in suspension settings.

 

[Scaff]

Oh, I like that you don't really have anything to add to this discussion but you just had to take a pot shot at PD and GT5 didn't you. A bit cheap if you ask me..

Its an opinion and one that, as it doesn't break the AUP, if acceptable.

You don't have to agree with it, you can say you don't agree with it, and just as you are entitled to do that, he's entitled to say it.

Threads of this type will always involve comments that members don't agree on, however as long as they don't break the AUP and don't involve an attack on another member, then they are acceptable.


Scaff

 

[imported_xxDingerxx]

Its an opinion and one that, as it doesn't break the AUP, if acceptable.

You don't have to agree with it, you can say you don't agree with it, and just as you are entitled to do that, he's entitled to say it.

Threads of this type will always involve comments that members don't agree on, however as long as they don't break the AUP and don't involve an attack on another member, then they are acceptable.


Scaff

O.K but it wasn't like I was asking for the guy to be banned or anything.

I was really just saying how it didn't really have anything to do with this particular discussion and was just a cheap shot for the sake of taking a cheap shot.

 

[Scaff]

O.K but it wasn't like I was asking for the guy to be banned or anything.

I was really just saying how it didn't really have anything to do with this particular discussion and was just a cheap shot for the sake of taking a cheap shot.

Then please address the point he made with a reasoned rebuttal rather than implying he is cheap for making it.

One of those courses of action is acceptable, the other is not.


Scaff

 

[Killer46]

Thats to do with the tires optimal temperature (which they already know). The differences between sessions is caused by differences in track temperature and thats why start to fiddle with pressure settings, which highlights my point of simulating variable track conditions. A static model, which Forza and GT simulate, there would be no change in the pressure as optimal temperature would be constant.

In F1 during practice sessions, there is a reason the main focas is on suspension. They switch to tire pressures as a main focas after the teams are prohibited from changing anything else on the car when the cars enter Parc fermé and then the track conditions change.

Forza simulates track temperatures.

Also, the difference driving style makes to tyre temperatures and grips is huge in Forza.

Yes, optimal pressure on a certain track will remain constant. Fact is in Forza you aren't always on that optimal pressure.

 

[imported_xxDingerxx]

Forza simulates track temperatures.

Also, the difference driving style makes to tyre temperatures and grips is huge in Forza.

Yes, optimal pressure on a certain track will remain constant. Fact is in Forza you aren't always on that optimal pressure.

Thats why i'm talking about variable conditions. Anything you can do to handling by raising or lowering tire pressure can be done much more effectively by working on your suspension. If anything, adjusting pressure is a very fine tune option or used as a quick fix by people who don't know enough about suspension or just can't be bothered.

The downside to adjusting pressure instead of working on the suspension can inrease the wear rate. That though is a pretty pointless thing in both games, as the majority of races are nothing more than quick sprints.

As for driving style, in both games it makes a huge difference. If I wanted too I could shred tires quickly in both games while changing styles preserve them

 

[Killer46]

Thats why i'm talking about variable conditions. Anything you can do to handling by raising or lowering tire pressure can be done much more effectively by working on your suspension. If anything, adjusting pressure is a very fine tune option or used as a quick fix by people who don't know enough about suspension or just can't be bothered.

No, just no.

Tyres are not a different form of suspension.

You cannot get effects from suspension that you get from tyre pressures and vice versa.

 

[imported_xxDingerxx]

No, just no.

Tyres are not a different form of suspension.

You cannot get effects from suspension that you get from tyre pressures and vice versa.

Sorry but when did I say they were a different form of suspension?

Also, yes you can. Any kind of benefits you get from changing the pressure can be done by changing a combination of settings in the suspension to increase contact etc. Its alot harder to get right than going the cheap option of adjusting tire pressure but the pro's outway the con's.

Like I said though, both games let this option a little bit down as the biggest benefit is the increase of wear rate. Pretty pointless with quick sprint races.

 

[Scaff]

Sorry but when did I say they were a different form of suspension?

Also, yes you can. Any kind of benefits you get from changing the pressure can be done by changing a combination of settings in the suspension to increase contact etc. Its alot harder to get right than going the cheap option of adjusting tire pressure but the pro's outway the con's.

Like I said though, both games let this option a little bit down as the biggest benefit is the increase of wear rate. Pretty pointless with quick sprint races.

While you are right that tyres are effectively another spring and damper combo and as such pressure can be used to fine tune the suspension, and I would agree that they are not a substitute for correct suspension tuning. I would however have to seriously disagree that its a cheap option, were it that cheap it would not for a good number of years been used as the main reason why F1 teams effectively ran solid suspension and used tyre type and pressures to tune the 'suspension'.

It also seriously glosses over the effect pressure can have on a tyres deformation, and the result that has on the contact patch. Tyre dynamics and reactions are one of the most complex and important areas within motorsport, and as such all 'sims' should be aiming to model then as accurately as possible.

Neither GT nor FM have got it 'right' yet, but one is a hell of a lot further along that the other.


Scaff

 

[Imari]

Also, yes you can. Any kind of benefits you get from changing the pressure can be done by changing a combination of settings in the suspension to increase contact etc. Its alot harder to get right than going the cheap option of adjusting tire pressure but the pro's outway the con's.

Nope.

Imagine you have an entirely solid tyre, providing no "suspension" effects at all. Do you still want camber? You probably do, the car body will still roll under normal suspension in the corners so you'll want to match your camber to maximise grip there.

So now when going straight you'll be running on the inside shoulder of your extremely hard tyre. Your contact patch in a straight line will be tiny. Can you adjust your suspension to compensate for that? Not unless you get into some ridiculous dynamic suspension system that alters camber based on load or something.

Tyre pressures do things that suspension cannot.

And if you don't think that it's a big effect, change the pressures on your road car from stock values, which are probably in the low 20psi range, to track day pressures in the low 30s. The car feels a lot different.

I'm not sure why you doubt this. If variable tire pressure is not modelled, then by default the tires will behave as if they are set to a permanent pressure value.

Even the most horribly inept game developers can't model a tire with "nonexistent" pressure. I don't even know what that would entail. It may not have a specified value, but the pressure "exists." And if it can't be changed and doesn't change during a race due to temperature, etc., then it's permanent and static.

Let us define tyre model. A tyre model is a specific set of code designed to process data in a manner consistent with a real tyre. Given how complex tyres are, no tyre model is going to be perfect, but it's more of the intention that counts.

Now let us turn to examples. Wipeout can safely be said to have no tyre model; it has no tyres. Ridge Racer likely has no tyre model either, it's simply a sliding box simulation with a box that happens to be shaped like a car. iRacing and Forza definitely have tyre models, they make a big point of advertising this to their audiences.

GT5 could go either way. We have strong evidence to suggest that some values that might be expected to be used in a tyre model are either non-existent or fixed. I would suggest that a "tyre model" with fixed values is little more than a sliding box simulator with 4 boxes linked together. It's not modelling anything, it's simply a collection of values which coincidentally happen to produce the desired output.

You might argue that anything that produces correct output is acceptable, but I believe that a true tyre model should be aiming to be able to replicate any reasonable tyre state, not one single tyre state that the developer has found to work.

If you have a set of equations that predicts the weather with high accuracy only as long at the weather is fine, there is no wind, and the temperature is exactly 25 degrees C is that really a weather model? That's what I feel GT5 has, and I don't consider that to be a tyre model. Maybe you do.

Forza, on the other hand, definitely has a tyre model. And it will serve them in good stead in the future, as it can be expanded and developed.

 

[imported_xxDingerxx]

it would not for a good number of years been used as the main reason why F1 teams effectively ran solid suspension and used tyre type and pressures to tune the 'suspension

They have had to have near solid suspensions to maintain their constant ride height. With them cars its more about camber, toe and their pushrods. With F1 its the very smallest of changes that can win or lose a race. The teams that used tire pressure the most were the ones that had the higher tire degredation due to the increase of forces from mechanical to chemical grip

1It also seriously glosses over the effect pressure can have on a tyres deformation, and the result that has on the contact patch.

Deformation is an important factor. However, each tire brand/type has different amounts built into their casing dependant mainly on car type. It also has to have correct tire pressure to work. So unless you have a tire model for each car, its never going to be even close to accurate

 

[artboy76]

fact is forza has tyre pressure fine tune, you can't seriously be arguing that if you change tyre pressures in forza it has no effect??! I can't believe someone can defend a "real driving simulator" not have tyre pressure tuning.... the most fundamental of tunning options.
It's an option in real life, so I'd expect the self proclaimed "real driving simulator" to have it, simple really.

 

[imported_xxDingerxx]

Imari, I am really not sure exactly what you are getting at?

Of course tire pressures matter but the example that you are going on kind of implies that both tire manufacturer and tire maker has no idea what the best pressure or operating temperature is best for their tire.

Now, that might be a point if some numpty takes their suspension settings to the extremes and tries to balance it of with the tire pressure. However, if that is properly simulated you would expect the tire to give way as it certainly wouldn't last very long.

You just have to look at what happened this year in F1. RBR went just a fraction outside what the tire manufacturer recommended for camber settings and what happened....The tire gave way two corners into a race

 

[Scaff]

They have had to have near solid suspensions to maintain their constant ride height. With them cars its more about camber, toe and their pushrods. With F1 its the very smallest of changes that can win or lose a race. The teams that used tire pressure the most were the ones that had the higher tire degredation due to the increase of forces from mechanical to chemical grip

Yes I know, which makes the correct tyre pressure a little more than the 'cheap' option.

Deformation is an important factor. However, each tire brand/type has different amounts built into their casing dependant mainly on car type. It also has to have correct tire pressure to work. So unless you have a tire model for each car, its never going to be even close to accurate

A tyre model is not required per car at all to get close to accurate, far from it.

Deformation will vary from car to car, but not because each tyre has "different amounts built into their casing dependant mainly on car type", but because deformation will vary depending on load, suspension geometry (actively modelled), lateral acceleration, yaw rate vs steering rate, mU co-eff between the tyre and the road, etc.

Now these will vary depending on the car, but as long as the physics models being used are robust (load transfer, suspension model and tyre model by tyre type) then you are going to get good deformation modelling without the need to model per car.


Scaff

 

[imported_xxDingerxx]

fact is forza has tyre pressure fine tune, you can't seriously be arguing that if you change tyre pressures in forza it has no effect??! I can't believe someone can defend a "real driving simulator" not have tyre pressure tuning.... the most fundamental of tunning options.

Thats the thing, its not even close to being the most fundamental tuning option on a race circuit unless you have variable conditions and you are not taking that into consideration.

On the road, in real life, yes its vital. Thats only because of the amount of idiots who don't check their tire pressures very often, which causes higher fuel consumption or even an accident.

However, if you have a car, take a look at its handbook. There is a very good reason why it recommends a certain value. The only reason I see for changing from recommended values is if you are driving on something like snow which we all know, Forza doesn't have

 

[artboy76]

Thats the thing, its not even close to being the most fundamental tuning option on a race circuit unless you have variable conditions and you are not taking that into consideration.

On the road, in real life, yes its vital. Thats only because of the amount of idiots who don't check their tire pressures very often, which causes higher fuel consumption or even an accident.

However, if you have a car, take a look at its handbook. There is a very good reason why it recommends a certain value. The only reason I see for changing from recommended values is if you are driving on something like snow which we all know, Forza doesn't have

So your saying that's the reason PD left it out of GT5??
The whole thing is a game , smoke and mirrors. Its like saying that there should be no aero on the cars as there's no actual air in the game to create it. It's a crazy argument!! of course tuning of tyre pressure should be in the game, even if it's effects are nominal, it should be there cause its a driving game! hell it's all fake at the end of the day but it's about emersion, once you can't do a simple task like tyre pressure then you start to wonder.
Hell PD put in an option to clean your car and change its oil for performance yet not allow adjusting PSi!!!!!! lol

 

[Imari]

Imari, I am really not sure exactly what you are getting at?

My point is that tyre pressure is not suspension by another name. It is entirely different, and it is absolutely a fundamental tuning parameter. It's the first thing people tune when they take their cars to track days.

 

[Scaff]

However, if you have a car, take a look at its handbook. There is a very good reason why it recommends a certain value. The only reason I see for changing from recommended values is if you are driving on something like snow which we all know, Forza doesn't have

The handbooks I've seen (and in twenty years in the motor industry that's quite a few) have all given different pressures based on speed and load as a bare minimum.

Professional driving instruction for the road will also always discuss different pressures dependent on the temperature and weather conditions.

Simply because the majority of drivers can only deal with the concept of a single tyre pressure (and even then often ignore it) does not mean change is bad, if you know what you are doing.


Scaff

 

[RedSuinit]

If you want GT5 sound vs FM4 sound vs Real life sound for the 787b here you go, there are probably going to be some of the best examples you will find.

http://www.youtube.com/watch?v=81zhOQ5PvaE

http://www.youtube.com/watch?v=rNILs5iPiPg

[Nevermind, can't find a direct feed recording of the FM4 787b, will update]

Must say GT5 is really, REALLY close to the real deal.

 

[imported_xxDingerxx]

Sorry scaff, I was a little simplifying things. A high performance car will have a much stiffer composition in its low profile tires. However luxury cars however will have a rating at the complete opposite end of the spectrum. The rest, depending on the car itself will be somewhere between the two extremes.

Sorry but to think that one tire model can fit all, is off the mark. You can tell the difference quite easily in real life if you change tire types between brands. The difference after I switched from Dunlop to Bridgestones on my Audi was quite amazing, the majority of which was down to the more stiffer composition which suited my suspension type better.

Better performance, hell yes. My other half though hates it, as its not exactly made for comfort anymore (in fairness, Audi's have always had suspension on hard side)

 

[Scaff]

Sorry scaff, I was a little simplifying things. A high performance car will have a much stiffer composition in its low profile tires. However luxury cars however will have a rating at the complete opposite end of the spectrum. The rest, depending on the car itself will be somewhere between the two extremes.

Sorry but to think that one tire model can fit all, is off the mark. You can tell the difference quite easily in real life if you change tire types between brands. The difference after I switched from Dunlop to Bridgestones on my Audi was quite amazing, the majority of which was down to the more stiffer composition which suited my suspension type better.

Better performance, hell yes. My other half though hates it, as its not exactly made for comfort anymore (in fairness, Audi's have always had suspension on hard side)

That's not a different tyre model, that different data within the tyre model with factors such as width, profile, block size and height, sipes, carcass make-up etc.

As long as the physical calculations within the tyre model are correct, then you can add as much data in as you want and the end results will be robust. I know this to be correct because I've worked with tyre manufacturers and its exactly how they model and test data.

That tyre model (and its differing data) then interacts with the load and suspension models (which again would contain differing values depending on the car and the forces its currently undergoing.

I've worked with vehicle dynamics modelling on a number of different levels and have never run more than one model for a single process, rather you run differing data sets through a single model.


Scaff

 

[imported_xxDingerxx]

The handbooks I've seen (and in twenty years in the motor industry that's quite a few) have all given different pressures based on speed and load as a bare minimum.

Professional driving instruction for the road will also always discuss different pressures dependent on the temperature and weather conditions.

Simply because the majority of drivers can only deal with the concept of a single tyre pressure (and even then often ignore it) does not mean change is bad, if you know what you are doing.


Scaff

Yeah, if you know what you know are doing, you would change pressure depending on what you were doing. Example would be different pressure from Summer road conditions to winter or if you were taking the car out on a track day.

Then again, if you knew what you were doing and you had the money to do it, to get the best performance you would just switch the tire to different type which better suited the how you was going to drive.

 

[Scaff]

Yeah, if you know what you know are doing, you would change pressure depending on what you were doing. Example would be different pressure from Summer road conditions to winter or if you were taking the car out on a track day.

Then again, if you knew what you were doing and you had the money to do it, to get the best performance you would just switch the tire to different type which better suited the how you was going to drive.

You would, but that still would not remove the benefit of ensuring the pressure was correct for the tyre, conditions and use.

You can't get away from the fact that tyre pressure is important, its not more (or less) important that any other variable on a car, but it is a significant factor in the only part of the car that contacts the road.

Certainly in the time I've spent on track and proving grounds, tyre temp and pressure were the two most commonly checked things.


Scaff

 

[Killer46]

If you want GT5 sound vs FM4 sound vs Real life sound for the 787b here you go, there are probably going to be some of the best examples you will find.

http://www.youtube.com/watch?v=81zhOQ5PvaE

http://www.youtube.com/watch?v=rNILs5iPiPg

[Nevermind, can't find a direct feed recording of the FM4 787b, will update]

Must say GT5 is really, REALLY close to the real deal.

Yea, no.

It doesn't sound accurate in GT5 because it sounds to be generated by a computer and nothing else. It doesn't sound like an engine let alone the car it's modelled after.

Compare it to this video.



You can't just make a car sound high pitched and automatically make it sound like a high pitched car in real life.

The only reason I see for changing from recommended values is if you are driving on something like snow which we all know, Forza doesn't have

Forza's recommended pressure is 2.1 bar.

I rarely ever use that pressure on any of my tuned cars.

High powered rear drive car? The rear will be working harder and getting hotter thus stabilising at a higher pressure so I set the cold pressure lower.

FWD? Same but backwards.

Very slow car? Higher pressures because not a lot of heat will be generated.

Very fast strait line car? Lower pressures all around because high road speeds generate a lot of heat and temperature.

Likewise a high downforce car.

If you just want to do a couple laps, yea, "recommended" is fine. Want to be fast and get the most out of your car in a racing game tyre pressure is very very important.

 

[Killer46]

Oops, double post.

 

[RedSuinit]

Yea, no.

It doesn't sound accurate in GT5 because it sounds to be generated by a computer and nothing else. It doesn't sound like an engine let alone the car it's modelled after.

Compare it to this video.



You can't just make a car sound high pitched and automatically make it sound like a high pitched car in real life.

Yeah, no. It still sounds almost exactly the same, even compared to the video YOU posted. Take out the rose colored earplugs and listen again.

It does sound very similar. You must not have ears, if you can honestly say that the pitch and tone are not similar. Also it DOES sound like an engine.

 

[Wolfe]

GT5 could go either way. We have strong evidence to suggest that some values that might be expected to be used in a tyre model are either non-existent or fixed. I would suggest that a "tyre model" with fixed values is little more than a sliding box simulator with 4 boxes linked together. It's not modelling anything, it's simply a collection of values which coincidentally happen to produce the desired output.

You might argue that anything that produces correct output is acceptable, but I believe that a true tyre model should be aiming to be able to replicate any reasonable tyre state, not one single tyre state that the developer has found to work.

Well, anything that produces the correct output would have to be correct in the first place. I don't think any sliding-box-based simulator will ever produce a truly natural-feeling driving experience. You have to start from the ground up, literally -- suspending your "box" by the four contact points where the tire meets the road. Steering that turns the front wheels, not the car. Drivewheels that exert force independently, their behavior determined by differential type, traction, etc.

Forza definitely has GT5 beat on this; Scaff's Cobra test proves it, at least the last part (independent forces). It's funny that you bring up the sliding box metaphor, because that's exactly the vibe I get from GT5. But to be honest, I get the same feeling from FM4, just on a more sophisticated level.

At the very least, Forza's suspension modelling needs work. Every car is hunkered-down and oscillations are muted. Rollovers (and two-wheel close calls) feel more like a triggered event than a consequence of physics. If it wasn't for the motions of the cockpit view, the game would feel totally numb to me, like previous Forza games always did.

There are other suspicious behaviors -- I swear countersteer exerts a magic pull from the front wheels (on RWD cars), making oversteer recovery easy -- but it's still close enough to be gratifying. The excellent tire model masks any underlying simplicities.

If you have a set of equations that predicts the weather with high accuracy only as long at the weather is fine, there is no wind, and the temperature is exactly 25 degrees C is that really a weather model? That's what I feel GT5 has, and I don't consider that to be a tyre model. Maybe you do.

GT5 has some sort of tire model. It calculates tire wear and the traction/speed of each wheel; see open-diff burnouts and brake lock.

In my opinion, a model doesn't have to be correct to be a model. There's such a thing as bad models. I wouldn't even call GT5's tire model "bad." More like "average." There are many worse ones out there.

 

[artboy76]

Yea, no.

It doesn't sound accurate in GT5 because it sounds to be generated by a computer and nothing else. It doesn't sound like an engine let alone the car it's modelled after.

Compare it to this video.



You can't just make a car sound high pitched and automatically make it sound like a high pitched car in real life.



Forza's recommended pressure is 2.1 bar.

I rarely ever use that pressure on any of my tuned cars.

High powered rear drive car? The rear will be working harder and getting hotter thus stabilising at a higher pressure so I set the cold pressure lower.

FWD? Same but backwards.

Very slow car? Higher pressures because not a lot of heat will be generated.

Very fast strait line car? Lower pressures all around because high road speeds generate a lot of heat and temperature.

Likewise a high downforce car.

If you just want to do a couple laps, yea, "recommended" is fine. Want to be fast and get the most out of your car in a racing game tyre pressure is very very important.

Spot on, who says PSi should be the same at front and rear? real life dosen't, oh but wait GT5 dose and that game has a ready available band of men who see that as the piniacale, so much so to the point whwere by i constantly see them claiming arguing that real is wrong and actually GT5's physics/tyre model is right??