Physics discussion thread

Hence why I said first tests of these things always need to occur with no aids and especially TC=0. That way we can possibly get to a point to conclude that it is the design of the TC in the game causing some or all of the issue for people.

 

Here's something interesting:

I came across this topic through a simple question: Why does the TC in the GT3 class seem to have such a reduced effect, even when set to the maximum possible?

It's something that has always caught my attention in AMS2, regardless of any other feature. And, at least for me, it's 100% what gives me the feeling that the car is disconnected from the surface: excessive oversteering.

I've always thought that the TC in this game, and how it's implemented, is what fundamentally sets it apart from others.

Reading and understanding a little more about how things work in the setup, however, I understood that the biggest problem isn't so much the TC, but how the cars' differential settings have a significant impact on its performance.

In a car like the BMW GT3 with the default setup, I can rotate (and even easily spin) by being a just a little more aggressive on the throttle in third gear, even with the TC at maximum.

Now, if I adjust a few things in the differential, like preload and clutch ratio, I get a car that has a certain rotation on curves, but a much more effective TC. In fact, with these aforementioned setup tweaks and the elimination of excessive oversteer, I've come to consider the AMS 2 GT3s very, very good.

 

You can make these adjustments, and they will do what you want them too, but you will also be 2-3 tenths slower out of the corner and down the following straight.
There is always a trade off to making a car easier, there’s also the benefit of making less errors to mitigate those losses. So it comes down to individuals either adjusting to the car, or adjusting the car to themselves.

 

There is definitely argument that "floatyness" of cars is very subjective. So here is my subjective opinion.

AMS2 front feels too strong compared to other sims. And with that I mean, I very rarely make a mistake of applying throttle too early out of corner, you can always steer out of corner. For me it makes the feeling that rear is always in slip angle as it tries to keep up with front. Have to say that with every update since 1.6 the feeling has improved for the best, by having more grip in rear, and the angle at which you exit feels tighter. But MY(I point out MY because its personal opinion) issue with front grip still stands.

The way I would describe how it would feel good for me is like this. Currently I absolutely love how under heavy breaking it feels my rear "unloads weight from rear tires", front gets loaded , I can feel weight transferring, car squirming depending how hard you hit the break, its great. It does give floaty rear in corner entry(trailbraking), that I think is realistic and give depth to driving. But after I start applying throttle, I don't feel weight transferring back to rear and unloading front tires, which would give more understeery feeling. Addition to that it should lead to more rear grip and traction as rear tires get more weight on them. The current feeling is that weight transfer stops somewhere in middle and front tires never unload when on throttle, witch gives this feeling of very strong front grip in this game.

Currently adjusting setups is all about giving enough rear grip and its very very rare that I would need to adjust to give me stronger front. If AMS2 would have slightly more limited front grip by unloading it on corner exit, IMO would lead to more interesting setup changes which would lead to find compromises in front to rear grip balance, which would lead to more depth in driving, particularly corner exits.

Does this have to be ACC levels of understeer? Absolutely not. I think ACC is pretty much polar opposite of AMS2, where in ACC absolutely everything(driving and setups) is dictated by overcoming understeer. Just slight improvement in unloading front tires so it makes it crucial to be on throttle at the right time.

 

Sorry, you misunderstood - the cars felt floaty in AC, not AMS2.

 

I'm gonna steal that post and post it to the beta physics discussion thread; it's absolutely bang on the money.

 

Anyway, you know my stance on Ams2 and GT3. But I don't think it'll do any good. It will stay the way it is. And it will continue, with many people complaining about it, others not. Personally, I don't try to race GT3, so that's it for me.

 

I think you described this very well. Even with major setup tweaks, it's hard to get the car to unlead a lot of the front load when you get on throttle and it doesn't happen that fast (though this I think you can impact with setup changes more, the fronts just keep having enough grip on slow to medium speed corners, but you also get grip faster to the rear).

I'm going to add couple of past comments from Renato related to this subject (added when 1.6 was released)



(read the whole thing, that's just small part: Automobilista 2 V1.6, IMSA Track Pack, Endurance Pt2 & Lamborghini DLCs RELEASED (V1.6.3.6 Live Now) + read the following comment from Dicra too)

and this:

(Automobilista 2 V1.6, IMSA Track Pack, Endurance Pt2 & Lamborghini DLCs RELEASED (V1.6.3.6 Live Now))


So there is plenty of things for me to agree with Renato as well with the critique. Nobody has this perfect and there is always some room for improvement .

As a overal package, I find current AMS2 is most enjoyable to drive overal, I even like driving the GT stuff over the other sims I have played, even with some apparent flaws (I take rather have less front limitation thant more, it's just boring and tedious to me to drive chronically understeery car). I also think it's improved since that 1.6 release (but honestly I don't find the changes to these cars that dramatic since that).

 

What you are describing is how a relatively heavy, front-engined car (like a BMW or MB GT3) should behave. Maybe it is exaggerated in AMS 2, who knows? But my question is whether you have this same experience when driving a FWD car (like the JCW Mini) or the new Alpine or cars with mid-to-rear engine placements? I agree mostly with your description for the front-heavy cars, but when I hop in a different configuration, including some of the other GT3's, I can more easily induce understeer. So, my question is do you believe what you described is a universal "feature/flaw" of AMS 2? Is it just the GT3s? Is it just some of the GT3s?

 

I'm not a GT3 authority, I just like to see them on track when I drive LMP1 or LMDh cars . But still...
I don’t think GT3s are flawed in AMS2.

I recently had to drive a Porsche GT3 in RaceRoom. It felt good. Then I tried the McLaren GT3, and it didn’t feel as good - I had to increase the steering lock to make it feel less numb. Same sim, same class, completely different default experience/pleasure. Perhaps it's just a matter of liking a car more than the other and not about "a car is well done in sim, the other isn't".
Also tested LMU Porsche GT3 - RaceRoom felt better.

Back in AMS2, the Porsche GT3 also requires increased steering lock. It’s easy to see the pattern: I simply prefer a more direct steering feel. I get a more precise control that way.
If I change the setup to have a more neutral car - less grippy front and less aggressive rear rotation (engine braking, fewer clutch plates, etc.) - the car feels better, more balanced for me. Perhaps not as fast on track, but I haven’t explored that deeply.

Personally, in AMS2 I prefer the feeling of the higher-performance cars (GT1, Group C, LMDh). But that may be simply because I like those types of cars more, not because the others are bad or worst.

My camera settings are newer (not legacy) camera movements, everything at "0".
The most annoying camera, floaty inducing aspect of AMS2 is the slow roll recover time (feels like a boat on high sea).
I cannot praise iRacing, never drove it, but it is the sim I like the most on footage. If only AMS2 could make a new camera setting with those parameters... (Legacy/Normal/Not Floaty )

 

Here's a super-simple experiment for those following and who might want to contribute to this floatiness discussion:

Since we have the videos of the Lambo Evo GT3 above, hop in that car at your favourite track (I used Oulton Island because it has lots of tight corners and it's a beautiful RealWeather day there today Use the default set-up with TC=0 and any generic aids off. I am pretty sure all of us will experience something close to what @Hanzo_Voss describes above in terms of the significant front bite (no understeer) and possible difficulty keeping the rear under control. But please, reply with your own opinion.

Then, make one and only one change to the default set-up--increase the diff preload to 200 Nm. Now what do you experience?

 

I can't resist butting in despite promising myself (and weary forum members) to swear off the subject...

When running baseline comparisons to see if there is a "floaty" feel or not to AMS2, can everyone make sure they have calibrated their wheels correctly? I ask this because people are still getting tripped up by this fundamental setting, nearly five years after the confusing calibration instructions were first written and never revised. When everyone is singing from the same hymn sheet, progress will be easier.

And if anyone is unaware of the confusion caused by the instructions - that's my point. Particularly when the subjects under discussion are physics, driving feel, car rotation and steering lock.

 

I actually didn't want to say anything more about this, as, as I said, I'm less interested in GT3 cars. But it seems to me that the yaw moment of these GT3 cars isn't right. In other words: The yaw moment is too strong, or becomes too strong in certain situations, causing the rear end to suddenly "skid." This uncontrolled behavior can occur suddenly and without warning and is particularly noticeable when cornering at high speed. This instability of the yaw moment is, in turn, caused by the lateral forces of the tires and the car's center of gravity. So it would be a combined problem with tire physics and car physics. This strong yaw moment also affects the car's stability, and perhaps that's why these cars feel "floating" or "boat-like." Just my theory; I could be completely wrong. But what I definitely feel on my steering axis is this "boating" sensation.

 

Fascinating how everyone is obsessed with GT3 in a game with so much depth as AMS2, but hey ho. One thing that sits on my mind reading through these discussions is that every real car that I have either driven or been driven in close to the limit has felt 'floaty'. I found that to be the greatest surprise when I first experienced it, something that you think of as planted and on rails all of a sudden starts to feel like it's floating on the surface. AMS2 models that really well. I've even heard F1 drivers describing F1 cars in this way.
I also don't quite get the obsession with comparing AMS2 to other sims (most of which to me feel slightly dead in comparison).
Anyway, to me AMS2 feels the most 'alive' of any sim/game I've played, I can feel the balance of the car shifting second by second as the weight moves and the tyres squirm. I can feel when I've gone too far and I get what I deserve. So I like it the way it is, and if I want different behaviour from my pretend racing cars I've got plenty of other choices, I'm glad they aren't all the same.

 

I've just driven the Lambo GT3 at Spa to test your theory - especially the sudden oversteer when cornering at high speed. To counteract the yaw moment described by you I stiffened suspension at the front and had everything else at default settings (even brake pressure at 90%):
Spring rate 7 (default: 6)
Slow Bump 17 (10)
Slow Rebound 21(10)
ARB 13 (11)

Finding:
Lap times after two preparation laps each where almost identical - default setup 2:17.306 and stiffer front 2:17.220.
Even with default settings I didn't suffer that sudden oversteer moment at Double Gauche which occasionally occurs when I brake too hard (with 100% brake pressure).
With the stiffer setup I didn't even feel to come close to that point where the front grips particularly well while the rear is stepping out.
Maybe it's worth a try for you.
It was just a qucik test but with these stiffer settings you may tackle the sudden oversteer effect and the floaty feeling for you.

I have to test with brake pressure at 100% but for me the stiffer settings are too ... well ... stiff. Lap time isn't drastically worse but I like how the Lambo "feels" with the default suspension settings - even it can be tricky at times at Double Gauche.

Edit: What I am trying to say is that the floatiness and the sudden oversteer effect are no flaws in physics but just setup related.

 

Guys this can sound weird… But have you tried driving some laps with the chase cam? I agree with @Joaquim Pereira that there is something weird with the visuals… And I notice some differences between external cameras and cockpit camera… External ones feel more aligned with what I feel on the wheel with Default FFB setting. I use the same camera settings as Joaquim BTW.

And I also agree that iRacing cameras are impressive and are truly aligned with what is happening with the car.

 

Definitely disagree. The car's settings are only a small part of the improvement. The other, bigger problem lies in physics. We'll probably never know, but I'm fine with that

 

BTW, Damping at 50 is quite a lot, have you tried lower settings?

 

I just ran some hot laps around Laguna Seca in the Porsche GT3 Gen 1 , this was the first time driving this combo and at first I was spinning mid corner and locking the rear axle at times with over aggressive inputs and trying to hard to brake late and hard and then quickly transition to coast before accelerating as smoothly as I could .

it wasn’t working out well , the car was loose and struggling with the rear .
you could say the car was “ sliding “

so still using the reportedly underivable default set up , I focused on not braking too late , not allowing free coast mid corner by way of throttle management, getting the car pointed more towards the straight exit, and it was starting to push on acceleration a little as the tyres got good temp , but there was little moments that the rear became nervous on entry as I was just on the edge , but I could feel that and make small corrections, and also some understeer in final sector on big sweepers which needed some slight lifting on throttle to keep in line .

All this controlled safe smooth inputs and caution is fine and well …the car wasn’t sliding , only a little balanced drift.
but it isn’t competitive right ? I must be slow surely…?

Well no… 4th fasted GT3 on TT in this combo, and just 2 tenths of WR .
( I am not alien level , not even the fastest among my peers )

adjusting your driving before you adjust the car . Listen to what it’s telling you , Not what you think it should be doing ..drive to the front axle , don’t expect the rear to save you when come in too hot or miss the apex and suddenly lift off .

by the way :
Legacy head movement with all on zero apart from head movement on 5 for natural neck damping. Is what I recommend.

 

Will be nice at least for reiza to make a better default setup.