AMS2 vs AMS1 Physics

Since I have some inside info in this topic I thought I´d add some relevant info to the discussion

The aero / chassis / suspension / engine physics models are 90% the same as what they were in AMS1 - they were afterall branched out of the same original codebase. Brakes is likewise very similar since our more recent latest developments, leaving only tyre and driveline models in Madness as significantly different (or a complete departure) from the models in AMS1.

So far, the most significant improvements in AMS2 physics development have come from either fixing errors in the "translation" of one physics engine to another where these differences are, or from actually getting a better handle on the features of these new models. How far along we are in that process is hard to say, and how well the resulting experience stack up against the old one is obviously a topic that is open for debate and highly subjective to taste - I´m personally very happy with the new engine but I´m also aware we´re still learning how to get the best of it, and that whatever we are doing now may seem rough looking back one year or even six months from now,

Handling-wise the main difference is the tyre model - AMS1 had the advantage of having a highly parametrized Pacejka model, which was simpler but allowed a lot of room for "crafting" the handling by finetuning those parameters; the STM we have in AMS2 is a more intrinsic model and while there are many parameters to adjust the tyre construction, they´re intertwined in a way that demands a better understanding of why a given tyre may not be producing enough longitudinal slip (or whatever it is that may need adjusting) to get that result without breaking anything else on the tyre.

The other side of the coin is that AMS2 tyres are ultimately more advanced and since more of its dynamics are hardcoded within the model they´re ultimately more consistent, whereas the extra freedom for crafting "bespoke" tyres in AMS1 often allowed for flaws or inconsistencies in other parts of the physics to go by unnoticed - this ultimately has led to the aero, suspension, chassis physics as well as the tyres themselves being a bit more refined in AMS2.

At this stage I personally find the results similar for many cars present in both games so I´ve found a bit surprising how some people have found the transition so jarring - there´s most likely an FFB component to that (with current AMS2 profile being a lot less saturated than AMS1), and an element of taste with some being bery sensitive to and prefering AMS1 peakier tyres relative to slightly more forgiving counterparts in AMS2, even though on the balance they could very well be equidistant from what "real" is

Wherever you currently land in that argument, the important thing is that as with everything else in the game, AMS2 physics will still continue to evolve through it´s shelf life just like it did with AMS1 - the physics are what they are at the moment because that´s where we are landing with them in an ongoing development process that won´t end any time soon

 

Great read! Love it. While AMS 1 have its moments. AMS 2 also have its moments. I love some of the stuff in AMS 1. Specially some of the FFB-effects. Like the wobble. But AMS 2 is under the hood a better package. Only need refinement and proper love till the end. It's like a baby and it need to reach adulthood.

By the way if you guys ever going to do a Rally Sim. 2025 or so. Don't forget to hire Workerbee. He solely transformed RBR into a masterpiece. I am so curious how AMS 2 will feel when it's 'completed'. And wonder if you ever do a rally sim. Richard Burns Rally needs a worthy successor.

Sorry for offtopic.

 

It really is?
Don't take this as an attack on your product, i'm overall pretty happy with AMS2, but here some things, that crack me up personally, when it comes to the surprise of compared behaviour in driving feel of both sims. (FFB is taken out of the equasion completely, i mostly drive with audio-visual hints, FFB is just an immersion extension for me)

So here we go, the examples, that i have so far, why AMS2 can feel very uncomfortable/incomprehensible sometimes, compared to AMS1, driving wise (most things, that i would find to be different, are diff and tyre related):

F-Retro: The BT44, which is obviously the design, the AMS1 car was aiming for, drives fundamentally different in both sims.
The AMS1 Retro turns in a lot more agile, while the AMS2 one feels sluggish and restricting to front bite. especially in slow corners with LSD. It somewhat forces you to add more and more steering angle, because trailbraking makes it even worse. Then you apply throttle and the car becomes nervous. It feels, like the diff is broken and you should come into the pits immediately to call it a day.
Also over crests, dips and bumps, the AMS1 F-Retro is controlable totally fine, while the AMS2 one still wants to take away all of the steering authority, when/until regaining grip.

Example F-Vintage: Tyres are heating up and have a hard time, to get rid of temperature. Brakes are heating up the tyres by quite a large bit, no matter, what countermeasures are taken into consideration and pressures are climbing a lot, these cars becomes pretty un-enjoyable to drive, then.
Also, they communitcate a lot less of depth in driving behaviour, i'm not talking in FFB terms here, i'm talking in "car want's to understeer or get lose terms". It feels less "dynamic" than AMS1. I have once described it on an example at Tamburello Imola 70s Historic. The AMS1 car basically communicates all its needs (still no FFB talk), while the AMS2 car is delivering a less "refined" sensation of what the car does.

Another thing, that isn't an AMS1/2 comparison by car, but by feel of approaching the limit: The Ginetta G55 Cup car slides suspiciously much in slower sections and is often faster (like the F-Retro) when driven with scrubbing off speed while sliding into corners instead of driving it clean with slight brake application. Weight transfer and braking, to load up the fronts often is more unsatisfying, than just "yeet" it into corners and give'em hell. Trying this with the Boxer Cup in AMS1 (totally different car, i know, but still), for example would punish you big time, because overdriving (which, in my opinion, makes sense).

It can also work the opposite way, like the Stock Car Brasil 2020, which i think, is just brilliant and feels loved. This class just wants you to use proper driving abilities and makes sense.
Also SC2019 feels pretty similar to the AMS1 2017 version, but with more slow cornering rotation, which can be strange sometimes.

Also the new Formula V10 gen 1 is feeling, as if it has more "depth" in behaviour and agility, than the gen 2, for example.

This has all to be taken with a grain of salt, of course, but AMS1 is my most played sim, next to GTR2, i could recall driving behaviour and approaches of being on decent pace with many vehicles of these sims, if somebody would tear me from sleep in the middle of the night. I can't help but compare it to AMS2 and i find some things, that leave me scratching my head sometimes, especially when it comes to tyres and differential.^^

But still: Thanks for your work, i'm convinced you deliver the best, you possibly can archieve!

 

While I agree in parts and disagree in others, I don´t think any of that fundamentally contradicts what I said As a fast driver you´re more sensitive to certain handling nuances coming from the tyres, while I tend to look it from an overall perspective, and the overall is not very different (with a few notable exceptions).

One thing that´s worth distinguishing is what´s being communicated, vs what is actually happening - here both the FFB saturation and the tyre´s relative sharpness from AMS1 will be a factor in "communicating" what the tyre is doing through the FFB, particularly for those on a G2X wheel or similar.

Ultimately a lot of what you describe comes down to tyres and the fact they´re still under development - I´d agree the F-Retro tyres as a whole is a bit more understeery and edgier than it should be and thus more likely to snap than the AMS1 equivalent, but you may notice that has been gradually improving since the first beta release as I figure out what can be reasonably adjusted in it. I could easily add 5mm of front tire tread and kill that understeer, and in AMS1 we´d probably just do the equivalent which would be just adding more lat CoF to the front tyres (within the thresholds of reason) - but in AMS2 that´s a hack that would probably have ill side effects elsewhere, so I need to understand where in the construction the understeer is coming from.. Mind you despiste the fundamental engine differences in PMotor´s relative tweakable tyre model, it was not a very different story with the original F-Retro development process - that car was first released in GSC2013 and that was not the car that you drive in AMS1 now, even though the fundamentals have remained mostly the same.

Similar story with the G55 - it was a lot more slidish in initial release than it is in the current beta. Should it be a big tighter still? Possibly, but I need to work on the whole GT4 tyre construction which shares components with other similar tyres in a way that will keep them consistent relative to each other.

Fun fact: the GT4 tyre on the G55 which seems slidish shares a lot of its construction with the Stock 2020 tyre that you find just right - devil is in the details

One thing I can assure is that there is no car that receives more love than the other - the physics like most of other fronts in the game is developed in a holistic manner, rather than focused on the latest release. If something is found to be off or worth a revision, then all tyres from all cars get revised, and that is a process that we´ve gone through several times since the Beta release. That may slow down things a bit but means the whole physics evolve in a consistent manner, even if there are still cars that may seem more "right" than others.

 

Thanks for this detailed reply!
Yes, the F-Retro class has improved a lot, not gonna lie and i'm also aware of the process, you guys have with understanding the new tyre model better. I mentioned it, just to give a perspective, why some people have a totally different experience with both sims in comparison, i'm glad to read, that it's not just seen as voodoo at this point.

I have the impression (it's just this), that something in the way, the tyres load up and generate grip is not "responsive" enough. (The "over crests, dips, bumps and high load understeer" topic, when the tyres receive a lot of strain)

Regarding the SC2020 and G55 comparison, both cars are actually pretty slidey, but in a "different manner". The G55 benefitted more of "yeeting" it into the corner, lowering the wing a lot, even restricting turn-in with more coast diff lock, when i was driving it last time, while the SC2020 needs some serious car control by the driver, making a clean turn and you can't just "eyeball" it in and also setup tweaks aren't making thaaaat much of a difference.
Yes, the devil is in the details, i absolutely agree!

In the case of noticeable differences, some cars in AMS2 give quite a good chunk of different experiences, when comparing them to AMS1. (Especially old Formula cars.)

I'm convinced, you guys have a reasonable approach to improve on a totally new physical tyre system, also making progress at a whole, including all dependencies, don't get me wrong.

 

I kind of know, what you describe, but it's mostly not related to consistent cornering, but changes on the actual platform, provided by driving style. If you keep a bit too much maintenance throttle, than required, you actually accelerate already a tiny bit (also inducing a tad too much wheelspin) and unload your fronts, even move your car a tiny bit too much already in whole, which makes the behaviour more pronounced, especially, if you drive a pretty open on power diff configuration. It will eat up your friction circle quite a lot.

Add some track elevation and loss of mechanical grip into the equasion and it can feel very "broken" but it hasn't to be.

You can also generate something similar, if you drive the Silvia Turbo Group 5 car on Bilsterberg with cold tyres in R3E, for example. The car will heavily punish you after rotation into a washing out understeery-oversteery kind of thing, where the car wanders to the outside. You have found your (at least) personal limits at this point. The way around it is probably to be more patient, trying to induce more rotation on the brakes and applying less maitenance throttle. This will widen up your tyres window to handle combined situations of forces torturing them one by one.

I was describing the behaviour into corners, when you put load on your tyres, which then leads to a fairly long phase of occuring understeer, that takes away much steering authority. It will also influence the exit, though.

Btw.: Does the car somewhat behave like this?: