GT Sport physics thread

[TheCrazySwede]

The way in which I normally explain it (as I get exactly what you are saying) is that a large part of it is the speed at which everything is happening.

With a road car like an MX-5 the lower level of grip means that when the grip is exceeded not only is it happening at a lower speed, ut its also happening much more slowly. So its easier to predict and react to as a result.

With a race car the higher level of grip means that when the grip goes you are going much, much faster and the forces acting on the car are much higher as a result. So not only is it happening at a quicker speed, but its also happening a lot faster. As a result its far harder to react to and deal with.

That can be further compounded by having in some cases to deal with two different degrees of grip, aero and mechanical. So you have to deal with not one, but two points at which you have a loss of grip and a transition of balance.

Yes, you are absolutely right. One of my biggest gripes back when Forza 4 released was how slowly high performance cars and race cars lost grip. Lose traction in the BMW M3 GT3 ALMS car and you just start sliding like you're on ice, in contrast to being tossed off the tarmac like a fly caught in a strong wind. I spent some with the Turn 10 team (eventually working alongside them for Forza 5) talking about the driving physics and their answer was essentially "The Xbox (360) just can't handle the data." But even to this day, racing games insist on butchering your grip in order to 'mimic' not being able to handle the car. Most average drivers and gamers might not quite understand the distinction, but most know that 'something is wrong' when it comes to the driving bits.

Worst offender of this was the original pCars. I remember talking to Ben about it and he had just as much of a hard time cooping with it as I did - and I remember him giving similar feedback to the SMS team. In fact, he was so bad at playing the game that his continuous crashing resulted in one of the guys asking him whether's he's a racing driver or if he just crashes cars for a living. I'm not sure if the team got back to him with actual answers for why the cars had really obscure and inconsistent levels of grip, but I didn't get any. Instead, I got booted off my contract cause I spoke about the issues on their private forums and openly criticized the game. And now here we are with GT Sport - same situation all over again; cars have really odd and inconsistent levels of grip.

a 911 GT3 RS has fully adjustable seats

Can confirm; I drive one. I've also had plenty of seat time in the 918, which also had adjustable seats - both in positioning and tilt.

 

[ScottPuss20]

Perhaps your sentence is better worded like that.

A very easy example to use are LMP and Formula cars. Have you ever seen the Top Gear episode where Richard tries to drive a Formula One car?
Everyone would surely agree that an F1 car has an immense amount of grip, right? I mean, just look at how fast F1 drivers set lap times and the amount of G's they pull in the corners. Then how come the poor 'Hamster' kept spinning out? Surely he's not an inexperienced driver - he drives high performance cars for a living and has been doing it for decades. Then what is it? F1 cars require you to drive them to a certain point where their aero provides you with grip. At low speeds, you either understeer like a pig or you spin like a dog chasing its own tail. This is a case of a car that handles poorly, but has a ton of grip. Even at the point of high levels of grip, every wheel, throttle and braking input has to be surgically precise.

Race cars tend to lean far more towards grip than handling, mainly because they are intended to be driven at their limit by experienced drivers.
This is another reason why cars like the Mazda 'MX5' Miata are so wonderful. They handle beautifully well and with some relatively inexpensive modifications, you can increase the amount of grip they achieve and hit the track. But you eventually get to the point where you start to sacrifice handling for grip, and that turning point is something I've never seen done right in a racing game before.

I hope that explains things a bit better.

That's because the car doesn't handle well at low....
Oh, wait, I think I just answered my own question. Race cars have to be driven at high speed for the aerodynamics to work... Then again, what's with all the complex suspension systems? Are they useless or something? I don't think manufacturers intentionally make it handle like crap.

 

[7HO]

F1 cars require you to drive them to a certain point where their aero provides you with grip. At low speeds, you either understeer like a pig or you spin like a dog chasing its own tail. This is a case of a car that handles poorly, but has a ton of grip. Even at the point of high levels of grip, every wheel, throttle and braking input has to be surgically precise.

There is more to it then that though. Race tyres are designed to work within an operating range and these high downforce cars often also don't stay in the tyres operating range if they are not driven hard enough.

For me unfortunately this doesn't explain the grip issues with various tyres in this game. My two biggest issues with the physics in this game are the lack of longitudinal grip or tractive grip and the rate at which tyres overheat and the effect of overheating tyres. And it is almost like TC helps combat these issues. Personally I think small changes to these two things would make massive improvements to this game.

 

[qwbufp]

I don't know if I'm just not used to the physics model but The MR Gr.3 cars are pretty terrible to drive with a wheel (T300 RS) The worst offenders are the NSX Gr.3 and the Huracan GT3. Both cars just suddenly oversteer like hell. I've used them in PC2 and they feel pretty much stable. I'll have to try playing with the setups as they are way too loose with the default settings.

 

[Flaren89]

That's because the car doesn't handle well at low....
Oh, wait, I think I just answered my own question. Race cars have to be driven at high speed for the aerodynamics to work... Then again, what's with all the complex suspension systems? Are they useless or something? I don't think manufacturers intentionally make it handle like crap.

There's where the driver skill comes out. The suspension and mechanical tuning serves on the purpose to maximize the aerodynamic first, then to "fix" some of the problems when the aero doesn't work, like low speed. Driver skill is involved into that he/she has to keep the car safe and clean, eventually choking the power by gently pressing the throttle pedal untill the car gets either stability because of losing torque (check power/torque curves) and/or enough downforce to oppose the wheel spinning.

 

[Skygrasper550]

I don't know if I'm just not used to the physics model but The MR Gr.3 cars are pretty terrible to drive with a wheel (T300 RS) The worst offenders are the NSX Gr.3 and the Huracan GT3. Both cars just suddenly oversteer like hell. I've used them in PC2 and they feel pretty much stable. I'll have to try playing with the setups as they are way too loose with the default settings.

Have you tried the 650S GT3? I won that as a gift car and did a test run, and I was surprised at how stable it was compared to FR Gr.3 cars like the Corvette and FT-1.

 

[danardif1]

Have you tried the 650S GT3? I won that as a gift car and did a test run, and I was surprised at how stable it was compared to FR Gr.3 cars like the Corvette and FT-1.

The McLaren is fast, but not as stable as the 911 which I think is probably the most stable of the MR Gr.3 cars. At Maggione and now the Nurburgring GP track I've been happier driving the 911 over the longer runs, but faster in the McLaren, its just harder work keeping it going.

Gran Turismo has always been slightly more sensitive with how you treat cars with different layouts. MR cars tend not to like braking whilst turning, but in GT they're always even more sensitive to that (the Gr.4 Alfa being a big proponent of that), but they also tend to be faster if you drive them correctly.

 

[OdeFinn]

Is certainly not for everyone that's certain.

I can deal with it as the physics are the main draw for me (and the AI is actually rather good now), but that's a conversation for another thread.

Back to GTS and I'm afraid the tyre model appears (again) to have some issues with low speeds.



Annoying as the Copper Box build had seemed to resolve it from my time with it.

Is this TCS blinking identical on other cars too?

On Focus its just realistic, last four years (or bit more) volvo/ford has used their stability/traction control software way over limits, on normal turn even on 5kmh speed volvo/ford WILL USE software to brake inner rear wheel for better turn, there was some normal manouvers when it uses brakes on front too in low speeds.
Scaff as volvo owner can verify this on slippery surface (dust, grass, snow, etc) by turning car first with DSTC and then without, or just check service bills and wonder why rear brakes worn out so soon, verifying from service isn't big deal, this is common knowledge of volvo/ford scene.

Gonna get yalls two cents on this:

I don't get this? Where's flaw? Can you explain it to me?

 

[Scaff]

Is this TCS blinking identical on other cars too?

On Focus its just realistic, last four years (or bit more) volvo/ford has used their stability/traction control software way over limits, on normal turn even on 5kmh speed volvo/ford WILL USE software to brake inner rear wheel for better turn, there was some normal manouvers when it uses brakes on front too in low speeds.
Scaff as volvo owner can verify this on slippery surface (dust, grass, snow, etc) by turning car first with DSTC and then without, or just check service bills and wonder why rear brakes worn out so soon, verifying from service isn't big deal, this is common knowledge of volvo/ford scece

Every other car, and while the Volvo TC can be overactive, nothing close to that degree at all, certainly not in my V40.

 

[Imari]

That's because the car doesn't handle well at low....
Oh, wait, I think I just answered my own question. Race cars have to be driven at high speed for the aerodynamics to work... Then again, what's with all the complex suspension systems? Are they useless or something? I don't think manufacturers intentionally make it handle like crap.

They kind of do. They're willing to accept poorer handling (because driver skill can compensate for that) as a trade off for higher absolute grip (which driver skill can't do anything about).

You see it in some sims in the differences between beginners and alien setups. Alien setups can be staggeringly fast in the right hands, but if you give them to Joe Blow he simply doesn't have the skill required. He'll probably end up being slower if you give him a basic setup that's more progressive but with lower grip, for the simple reason that he won't be trying to get branches out of the windshield every other corner.

 

[Scaff]

That's because the car doesn't handle well at low....
Oh, wait, I think I just answered my own question. Race cars have to be driven at high speed for the aerodynamics to work... Then again, what's with all the complex suspension systems? Are they useless or something? I don't think manufacturers intentionally make it handle like crap.

Complex suspension that is designed and set-up for a car under a high aero load (and in some that's more than the actual cars weight), now unless you are using an active aero system (which is pretty much banned in all series) then the aero set-up is going to compromise the non-aero side of things.

A lot.

 

[danardif1]

Back at E3, during the rally racing at Sardegna, I had the feeling the cars were limited in their roll angle. Launching the car on an off-camber yump, it felt like the car couldn't roll to the side more than, say, 30 degrees. It actually reminded me of GT1.

I know we could flip cars in the beta, and that's probably still the case at Willow in the final game. But has anybody else noticed the resistance to roll over during rallying?

I think that's something that comes down to the tyres again. There's so little grip in the dirt tyre model that they basically skate over the surface and thus never really generate any significant pitch in the car itself.

 

[Scaff]

I don't get this? Where's flaw? Can you explain it to me?

Rotation should be around a single front tyre, left or right depending on the direction of rotation, and shouldn't see the car wandering around the track as much.

However a mobile recording off screen is not exactly clear what is going on.

 

[danardif1]

Rotation should be around a single front tyre, left or right depending on the direction of rotation, and shouldn't see the car wandering around the track as much.

However a mobile recording off screen is not exactly clear what is going on.

In your own video you mention that the tyre model doesn't really 'kick in' as such until about 20mph. I think in this video what we are seeing is that we are not seeing that rotation until the front tyres hit a certain speed, then they 'grip' properly and behave as they should...

 

[Imari]

However a mobile recording off screen is not exactly clear what is going on.

It always entertains me when people take phone videos of a screen playing a console with a share function. It's like screenception.

 

[7HO]

In your own video you mention that the tyre model doesn't really 'kick in' as such until about 20mph. I think in this video what we are seeing is that we are not seeing that rotation until the front tyres hit a certain speed, then they 'grip' properly and behave as they should...

Watch his video again but watch the tyre temps. 20 is when the tyres get too hot, coincidence, it's pretty easy to understand where the problem lies.

 

[super_gt]

Gonna get yalls two cents on this:

The video description:
''Sooo the wheel is turned right, but the car keeps spinning left. I don't know about you, but to me this seems to go against the laws of physics.''

 

[danardif1]

Watch his video again but watch the tyre temps. 20 is when the tyres get too hot, coincidence, it's pretty easy to understand where the problem lies.

Its not about the temperatures, and even if they are a part of it, they shouldn't be getting that hot that early, because the tyre should be providing some level of grip from standstill, not once a certain wheel speed has been reached. GT's tyres act like they do nothing until that certain wheel speed and then behave mostly as intended. This may be where the snap oversteer people are experiencing is stemming from as well, that the physics and tyre models are not dealing with the transition from low speed grip to acceleration out of a corner.

 

[7HO]

they shouldn't be getting that hot that early,

That's my point, that's one of the two major issues, the other is the lack of longitudinal grip. Just go and run a test, turn the TC off and abuse your tyres and pay attention to how they behave while monitoring the tyre icons. That should explain it all.

 

[qwbufp]

Have you tried the 650S GT3? I won that as a gift car and did a test run, and I was surprised at how stable it was compared to FR Gr.3 cars like the Corvette and FT-1.

Yes. I have no issues with the R8 LMS, the 650S and the 458. Well.. Not as much as the Huracan and the NSX. The 650S and the R8 are relatively glued to the track once you get used to them. I tried to put TCS at 5 with the NSX but I still have to be overly gentle on the throttle which makes me 2-3 seconds slower than with the R8 for example. I’ll have to play with the anti-roll bars I guess.

 

[Johnnypenso]

I don't get this? Where's flaw? Can you explain it to me?

I thought the flaw was the potato vertical cam

 

[OdeFinn]

Good news. Its 1:1 atleast with a wheel. No change in steering angle while accelerating.

This Post cost me 59€ and I'm enjoying it..
FFB is way better than on demo, I'm using ssens7, ffb8, ffbsens4 and feeling front tires well, also road surface and kerbs are coming thru.

Actually feeling lot more than expecting, even gear changes on FF car kicks on FFB.

 

[Skygrasper550]

Yes. I have no issues with the R8 LMS, the 650S and the 458. Well.. Not as much as the Huracan and the NSX. The 650S and the R8 are relatively glued to the track once you get used to them. I tried to put TCS at 5 with the NSX but I still have to be overly gentle on the throttle which makes me 2-3 seconds slower than with the R8 for example. I’ll have to play with the anti-roll bars I guess.

How about decreasing the LSD Accel setting or increasing Rear Toe-In? That usually works for me in reducing throttle-induced oversteer.

 

[Flaren89]

LSD Power (or accel if you prefer) set to 5 is key to drive quite comfortably with TCS 0, even on Gr.3.

 

[Skygrasper550]

LSD Power (or accel if you prefer) set to 5 is key to drive quite comfortably with TCS 0, even on Gr.3.

LSD Accel set to 5 is terrible. Inside wheels spin too much, hindering the car's ability to turn while on full throttle in high-speed corners. I usually set mine to 20-25, but around 10-15 in some cases.

 

[Flaren89]

LSD Accel set to 5 is terrible. Inside wheels spin too much, hindering the car's ability to turn while on full throttle in high-speed corners. I usually set mine to 20-25, but around 10-15 in some cases.

Depends on the car. 4C in both classes with LSD 10 starts to be too much tricky to keep on line for a safe pace.

 

[qwbufp]

How about decreasing the LSD Accel setting or increasing Rear Toe-In? That usually works for me in reducing throttle-induced oversteer.

Good advice thanks

 

[ScottPuss20]

They kind of do. They're willing to accept poorer handling (because driver skill can compensate for that) as a trade off for higher absolute grip (which driver skill can't do anything about).

You see it in some sims in the differences between beginners and alien setups. Alien setups can be staggeringly fast in the right hands, but if you give them to Joe Blow he simply doesn't have the skill required. He'll probably end up being slower if you give him a basic setup that's more progressive but with lower grip, for the simple reason that he won't be trying to get branches out of the windshield every other corner.

Complex suspension that is designed and set-up for a car under a high aero load (and in some that's more than the actual cars weight), now unless you are using an active aero system (which is pretty much banned in all series) then the aero set-up is going to compromise the non-aero side of things.

A lot.

This makes more sense to me now.

 

[praiano63]

I am not happy with the automatic clutch. You can even start in 3rd gear. I liked it more the way it was in GT6.
When you performed a standing start ,for a certain amount of torque and grip, you must have a small sweet spot where the car launch perfectly. A bit under the car stay stucked, above it spin the tires.

Also the lost of grip during accel out corner is too quick , almost immediate , This transition have to be more progressive.

EDIT:in my opinion this lost of grip that happen out corner under accel can be due to this auto clutch effect. Even low Differential value don t resolve the problem most of the time.

I did just a quick test 1.06 but it seems that they have fixed the clutch issue i was refering a month ago. I don t have time to do this now but apparently the lost of grip is not so sudden. LSD accel settings must be more easy to spot on. I will make a test in deep later this night.

 

[7HO]

What's the story with the auto clutch and why can't I decide if I want to use the clutch pedal? I could have sworn there were times earlier I could use my clutch pedal but now it does nothing and other people have told me their clutch pedal works for them. I can understand Gr3 cars having autoclutch because they do in real life but if I drive a manual production car that in real life has 3 pedals I would like to be able to drive that car in a realistic way using all 3 of my pedals. I mean I have a Thrustmaster T-GT which is the official GT Sport wheel and it has 3 pedals so why does only 2 of them work in the game for me?