Gran Turismo 7 Physics

Do you want more detailed and realistic physics on the next GT


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    203
  • Poll closed .
I think it's more a ffb issue than a physics one with the game. Its a bit hard to find the right throttle input but for the rest i would suggest for people with a t300 to set the string force to 0% and try again. Let me know how it feels... For me its much better now. Very precise and easy to feel the weight balance
 
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Rather that what they are doing, it's basic vehicle dynamics, pretty much all that section of apex is.

It basically a collection of different bits of fundamental vehicle dynamics collected into a well presented package. I know this because I taught most of it in one form or another in the industry before GT came out (as in the first one).

Some of it GT 7 does well, so of it doesn't, but they've used the traction circle since the very first GT title. Back when we used to get half inch thick game manual.

Jebus, I'm sounding old.

I’ve read and practiced a lot of this in the real world too either racing, with training with class 1 car and bike riders and out on the road applying it.

Advanced stuff is beyond the theory of the mechanics, it’s about things like limit points (vanishing point management), being slow to go fast, trusting the tyres more leaning on ABS deliberately etc etc

I mean just literally opening your vision up and reading the road better will shave days from a lap time, watching other cars attitudes entry or exit give you an idea of the corner etc etc.

But where the rubber meets the road, I’m coming round to the way GT7 wants you to play. As with all of the sims they all have a unique way they interpret driving and physics. And all and I mean all of them are trying to factor in substitutes for actually feeling it in your arse and inner ear. All while using blunt instruments like controllers and wheels.

The on limit stuff in the physics is confusing because the drift boys clearly show handling a car beyond its limits looks absolutely piss easy.

Conversely even the mildest of slip or understeer seems massively punished. I know mastery takes time but it does feel like things like aquaplaning don’t work the way they should and oversteer and understeer recovery should be less of a lottery.
 
I think it's more a ffb issue than a physics one with the game. Its a bit hard to find the right throttle input but for the rest i would suggest for people with a t300 to set the string force to 0% and try again. Let me know how it feels... For me its much better now. Very precise and easy to feel the weight balance
What does one mean by string force? And where does one set it?
 
What does one mean by string force? And where does one set it?
You connect you wheel to a pc install the drivers etc and in the wheel control panel you will see string force and 2-3 other settings (yes those settings impact ffb in your console)
 
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I must admit te BMW M3 challenge in the wet is hard... but fun. The RBR one is harder despite starting dry because the AI is faster. Caught him last corner. I was on SM. Maybe SH has more wet grip?

Following the AI helps as it gives you an idea of cornering speeds. And they are slow. Really really slow.

At nurburg GP it is wetter and sometimes you suddenly spear off the track in a straight line, from the racing line, no puddles. 1 lap ok. Another, same speed, same gear, same line... Weeee! I don't mind tricky and/Uber realistic but as it's a game and even 0.2s of warning will make online races less of a pointless lottery. I can't see many leagues using wet races.

Why do the tyres squeal under hard braking in the wet? The ABS does nothing. Surely it should be kicking in much sooner, not failing to completely?
 
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Rather that what they are doing, it's basic vehicle dynamics, pretty much all that section of apex is.

It basically a collection of different bits of fundamental vehicle dynamics collected into a well presented package. I know this because I taught most of it in one form or another in the industry before GT came out (as in the first one).

Some of it GT 7 does well, so of it doesn't, but they've used the traction circle since the very first GT title. Back when we used to get half inch thick game manual.

Jebus, I'm sounding old.
Nice to know, yeah at least that section right now it def feels a lot more closer than its ever been in ways.
 
But conversely if you are under steering and release the brakes the tyres should start to rotate and progressively come back to 100% grip, but largely they don’t or if they do at extremely unrealistic distances.
So releasing the brakes still causes the car to have an acceleration (a negative one here as it will slow down), so the vector they show in the chart on the friction circle will not be zero if you step completely off the gas but the car is still in motion. I think it is important to first separate acceleration and speed. Despite intuition, if your car is going at exactly constant speed and in a perfect straight line, net acceleration is 0, even if the throttle is floored. Centripetal acceleration is proportional to the square of the speed so the decrease in speed from letting the gas go should still help as the speed keeps decreasing but it might not be as immediate as one might think.

Tires also behave a little weirdly when it comes to friction. As the load on them increases, their coefficient goes down but total friction still is linearly proportional to that load (F = mu (N)*N). So, your outer wheels will have this at play and while you need the curve for the tire to get real numbers, iirc in most cases this does not cancel out and you will be losing grip on the outer wheels so the effective circle will become smaller.
 
So releasing the brakes still causes the car to have an acceleration (a negative one here as it will slow down), so the vector they show in the chart on the friction circle will not be zero if you step completely off the gas but the car is still in motion. I think it is important to first separate acceleration and speed. Despite intuition, if your car is going at exactly constant speed and in a perfect straight line, net acceleration is 0, even if the throttle is floored. Centripetal acceleration is proportional to the square of the speed so the decrease in speed from letting the gas go should still help as the speed keeps decreasing but it might not be as immediate as one might think.

Tires also behave a little weirdly when it comes to friction. As the load on them increases, their coefficient goes down but total friction still is linearly proportional to that load (F = mu (N)*N). So, your outer wheels will have this at play and while you need the curve for the tire to get real numbers, iirc in most cases this does not cancel out and you will be losing grip on the outer wheels so the effective circle will become smaller.

I understand the actual frictional physics.

What I struggle with is both in my road cars and race stuff I’ve driven, the implementation doesn’t represent the reality to a degree. I’ll admit on my motorbike I avoid any sort or provoked understeer.

But in my cars both rwd and ff understeer for example whilst proportional to the forward speed there is zero difference in grip after loss of traction whether the wheels are straight or full lock, there is some inertia that prevails the force relative to the speed, but at full lock the deceleration increases as the grip starts to come in which can have two real world effects, pitch the front tighter when grip is regained about 101% or the rear moves laterally following the force of the inertia/momentum depending on how you want to define the force for this exercise.

I get the carry on loss of adhesion, my problem is that it’s a very small window especially on things like hairpins. The line seems artificially small or punishing, and that combined with brake fidelity for some reason causes much more dive than you’d expect that exacerbates the understeer.

The oversteer stuff typically is undulation related or my ambition out weighs my talent or I get greedy.

But overall we are talking a broad theory of physics applied to everything from Gr C to the fiat 500 in changeable conditions…
 
You connect you wheel to a pc install the drivers etc and in the wheel control panel you will see string force and 2-3 other settings (yes those settings impact ffb in your console)
Are you sure about that?
If I remember correctly the changes you make only apply if you play on PC.( T300 )
 
After playing it some more, I don't even want to bother with the game with how ganked the tires are right now, and rather I just shelve the game until a new update comes out to fix these issues.
On DualSense, there's nothing to tell you of a possible oversteer. No rumble, no sound. It's literally all on intuition. I have set the wing on my Ford GT to max and I am still suffering massive snap oversteer if I even venture slightly beyond the load my tires can carry.

Using DS4windows. Even without rumble, old sims like NR2003 and even GPL have better feel when it comes to their tire physics. I can tell when I'm getting close to the edge of my grip based on the sounds and behavior of the car. If I suffer snap oversteer, it's a diagnosable issue.

GT7 makes me wanna hit my head against the wall.
 
If they have the data from Pirelli i don't know why almost every car it is so slidy on that game,even GT3 cars slide like their on ice. Ffb is also complete **** and that is related with the tire model...But that's OT,let's not turn this on a GT vs Forza thread

I use P Zeros on my road cars and they definitely don’t feel like this…
 
Are you sure about that?
If I remember correctly the changes you make only apply if you play on PC.( T300 )
Yes from experience in the past day 100% sure. Maybe it doesn't impact every game but in gt7 its very noticeable set the string strength to 100% and then 0 to test
 
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I finally got the game downloaded and I've got to say, the physics feel downright broken at times. I think the main problem is how the game simulates grip when torque is applied to the rear wheels while turning in any car, not just RWD cars (though, the RWD cars suffer the most). It feels like whenever torque is applied to the rear axle in a corner, grip is progressively reduced with application of the throttle. It doesn't matter how much weight is being transferred to that axle or how the suspension is supposed to react when throttle is applied, More throttle = less grip, it's as simple as that and it's absolutely infuriating because I know from experience that is NOT the case IRL. This wouldn't be so bad if the transition to oversteer was smooth and obvious but it's not, most of the time cars snap instantly to oversteer with little to no warning. I tried tuning all this out of the RX-8 in the game since it's the most similar dynamically to my own IRL MX-5, no dice. Though definitely an improvement over stock, it's still a snappy, oversteery mess and it does not resemble an IRL RX-8 or NC MX-5 dynamically at all.

I'm really bummed out, I was hoping for better from Polyphony after so long. I have several problems with this game aside from the poor driving physics and I'm losing faith in Polyphony because of it. I hope they solve my problems with updates but until then, I'm going back to Assetto.
 
I finally got the game downloaded and I've got to say, the physics feel downright broken at times. I think the main problem is how the game simulates grip when torque is applied to the rear wheels while turning in any car, not just RWD cars (though, the RWD cars suffer the most). It feels like whenever torque is applied to the rear axle in a corner, grip is progressively reduced with application of the throttle. It doesn't matter how much weight is being transferred to that axle or how the suspension is supposed to react when throttle is applied, More throttle = less grip, it's as simple as that and it's absolutely infuriating because I know from experience that is NOT the case IRL. This wouldn't be so bad if the transition to oversteer was smooth and obvious but it's not, most of the time cars snap instantly to oversteer with little to no warning. I tried tuning all this out of the RX-8 in the game since it's the most similar dynamically to my own IRL MX-5, no dice. Though definitely an improvement over stock, it's still a snappy, oversteery mess and it does not resemble an IRL RX-8 or NC MX-5 dynamically at all.

I'm really bummed out, I was hoping for better from Polyphony after so long. I have several problems with this game aside from the poor driving physics and I'm losing faith in Polyphony because of it. I hope they solve my problems with updates but until then, I'm going back to Assetto.
Felt this exactly when driving the GT3. once the rear went slightly, going into full throttle with opposite lock only caused the car to gain more angle, which is quite different from how a rear engined car would react. As soon as grip is lost it feels as if the surface switched to a substantially more slippery one and the only way out is oppo fast enough and no acceleration.
 
Felt this exactly when driving the GT3. once the rear went slightly, going into full throttle with opposite lock only caused the car to gain more angle, which is quite different from how a rear engined car would react. As soon as grip is lost it feels as if the surface switched to a substantially more slippery one and the only way out is oppo fast enough and no acceleration.

Which is how you catch a slide? You either power through it and trust the LSD or you gently ride in to it with corrective oppo? With the mass of a flat six over the rear axle in real life I’ve always lifted to to let the rear catch and see where I’m pointing to be fair.
 
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I finally got the game downloaded and I've got to say, the physics feel downright broken at times. I think the main problem is how the game simulates grip when torque is applied to the rear wheels while turning in any car, not just RWD cars (though, the RWD cars suffer the most). It feels like whenever torque is applied to the rear axle in a corner, grip is progressively reduced with application of the throttle. It doesn't matter how much weight is being transferred to that axle or how the suspension is supposed to react when throttle is applied, More throttle = less grip, it's as simple as that and it's absolutely infuriating because I know from experience that is NOT the case IRL. This wouldn't be so bad if the transition to oversteer was smooth and obvious but it's not, most of the time cars snap instantly to oversteer with little to no warning. I tried tuning all this out of the RX-8 in the game since it's the most similar dynamically to my own IRL MX-5, no dice. Though definitely an improvement over stock, it's still a snappy, oversteery mess and it does not resemble an IRL RX-8 or NC MX-5 dynamically at all.

I'm really bummed out, I was hoping for better from Polyphony after so long. I have several problems with this game aside from the poor driving physics and I'm losing faith in Polyphony because of it. I hope they solve my problems with updates but until then, I'm going back to Assetto.
Like that explanation. It's like the loss of grip is cumulative rather than peak. So that if you keep the angle and speed the same there is a value that keeps adding up, instead of staying the same. I.e. a quantitative error in the code.
 
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I finally got the game downloaded and I've got to say, the physics feel downright broken at times. I think the main problem is how the game simulates grip when torque is applied to the rear wheels while turning in any car, not just RWD cars (though, the RWD cars suffer the most). It feels like whenever torque is applied to the rear axle in a corner, grip is progressively reduced with application of the throttle. It doesn't matter how much weight is being transferred to that axle or how the suspension is supposed to react when throttle is applied, More throttle = less grip, it's as simple as that and it's absolutely infuriating because I know from experience that is NOT the case IRL. This wouldn't be so bad if the transition to oversteer was smooth and obvious but it's not, most of the time cars snap instantly to oversteer with little to no warning. I tried tuning all this out of the RX-8 in the game since it's the most similar dynamically to my own IRL MX-5, no dice. Though definitely an improvement over stock, it's still a snappy, oversteery mess and it does not resemble an IRL RX-8 or NC MX-5 dynamically at all.

I'm really bummed out, I was hoping for better from Polyphony after so long. I have several problems with this game aside from the poor driving physics and I'm losing faith in Polyphony because of it. I hope they solve my problems with updates but until then, I'm going back to Assetto.

The physics model is very simplified. It's likely attached to how much throttle is applied and the position of the steering wheel plus speed.

Thats simplified arcadey mode set to insane difficulty.

It's quite amazing how folks are denying this.
 
Getting everyone in this thread together for a real track day would be the most hilarious thing ever.
You're on. Do you want a Subaru Forester or a Yamaha V-Max? They both suck in different ways. 🤣

Makes me miss the little Ninja 250. That thing was a corner ripper.
 
Over in the tuning forum... A welcome surprise,
Praiano and Praiano Racing Tunes is back in full swing, for GT7 seems he's making a lot of Sports tyres 550-600PP tunes, so best some of you try them out see if they fix any of the issues with snap oversteer!

He's even done the classic camaro on sports soft tires here, Check it out!

 
The on limit stuff in the physics is confusing because the drift boys clearly show handling a car beyond its limits looks absolutely piss easy.

Conversely even the mildest of slip or understeer seems massively punished. I know mastery takes time but it does feel like things like aquaplaning don’t work the way they should and oversteer and understeer recovery should be less of a lottery.
Thing about drifting is if you drift on the lowest grip tires for consistency, say Comfort Hard, with a proper tune, and most importantly a proper driver, the G forces you take around a corner wouldn't be as high as taking it on a race/grip tune typically. The front tires typically aren't as stressed out compared to race tuning. There's also a lot less braking overall for the front tires for a given corner, it's mostly handbrake work for the rear to hold out the angle before corner entry. Add to this about the comfort hard tires, is it was the standard drift tyre for GT Sport, everyone was forced to use it because drift lobbies often demanded it. I'm not surprised the drifters can do what they do in GT7. It's awesome that they also have steering angle kits and other drift-specific parts available, a first for a GT title.
 
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The physics model is very simplified. It's likely attached to how much throttle is applied and the position of the steering wheel plus speed.

Thats simplified arcadey mode set to insane difficulty.

It's quite amazing how folks are denying this.
Yup, that's pretty much what it feels like to me. It's like someone tried to make a sim racer out of NFS Physics, lol. That's being a bit harsh but still.
 
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Like that explanation. It's like the loss of grip is cumulative rather than peak. So that if you keep the angle and speed the same there is a value that keeps adding up, instead of staying the same. I.e. a quantitative error in the code.
I would really like a video of this happening, my guess is that you are not keeping the speed the same but the throttle and those are not the same. Keeping the steering and throttle consistent through a corner can still increase your speed and that is indeed a cumulative value as you put it here as the centripetal acceleration the tires need to handle is going up with the speed. At one point it is expected that your tires cannot keep up with the grip needed to make that turn at that speed.
 
Are you sure about that?
If I remember correctly the changes you make only apply if you play on PC.( T300 )
Yes from experience in the past day 100% sure. Maybe it doesn't impact every game but in gt7 its very noticeable set the string strength to 100% and then 0 to test
As far as I know they do work for games like ACC that don't adjust the wheel rotation settings on a per car basis, but this has changed for ACC PS 5 version so I don't know if it still holds true. However, also as far as I know, it doesn't work for any any of the past GT games or any other game that sets the parameters in-game.

I've been unable to test any of this with GT7 or ACC (PS 5 version) at the moment because TM's janky website won't let me update my wheel base :irked:

Edit: @xtro01 It's spring not string ;)
 
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Love driving different cars feeling each car's limits.. the sensation you get coming outta a turn when the wheel dampen a tad bit letting you know you have the traction it’s truly amazing!
 
Felt this exactly when driving the GT3. once the rear went slightly, going into full throttle with opposite lock only caused the car to gain more angle, which is quite different from how a rear engined car would react. As soon as grip is lost it feels as if the surface switched to a substantially more slippery one and the only way out is oppo fast enough and no acceleration.
Which is in direct contradiction to PD’s own guide for GT7:

“It's important to remember that tyre grip is strongest when there is a bit of slip between the tyre and the road surface.”

Source

And if it worked like that in GT7, we wouldn’t experience this snap overesteer behavior whenever tyres lose traction. It would be a much more progressive experience, much like that in real life.
 
You connect you wheel to a pc install the drivers etc and in the wheel control panel you will see string force and 2-3 other settings (yes those settings impact ffb in your console)
Ah ok. I think you mean spring force no? I don't see string. Surprised it effects the console considering you have to switch modes and on PS4 mode the PC doesn't recognise it (unless you're running it on PS3 mode in the PS4??) scratch that, pretty sure pedals don't work when in the PC/PS3 mode.
 
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I just started driving on GT Sport again to compare and honestly, I wish we had these physics in 7. Don't get me wrong, they aren't the best sim physics in the world but they beat out GT7 easily for me. I know I just made some people mad by saying that but I really believe Sport has a better physics model than 7.
 
The physics model is very simplified. It's likely attached to how much throttle is applied and the position of the steering wheel plus speed.

Thats simplified arcadey mode set to insane difficulty.

It's quite amazing how folks are denying this.
Do you think your favourite game uses a Starfleet issued replicator to somehow get the cars and tracks into that glowy box in your living room? It's math. Add some formulae for calculating track surface and tire grip and such and, yeah, you're right. I would assume every video game ever works like this.
 
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