Physic discussion thread

I found that related to how the "look towards the apex" setting was. I ended up zeroing it up

 

for me, having played RF2(lot in recent weeks) and RRE(bit since the All free content popped up last week), what I am struggling with in AMS2 is a better sense of car weight.
overall it feels still too much light and floaty compared to the above mentioned Sims where vehicles feel really planted on the track and also transmit better this sense of weight transfer through the FFB

 

Well, I just adjusted "SPEED SENSITIVITY" to 50 (was 0) and some lack of precision is long gone (I must have set it to zero to have, well... no speed effect! - perhaps values should be more self explanatory or well documented like car setup settings). Generally, I guess, for certain sliders "50" means "0" and less imposes an exponential curve and more imposes a logarithm one.

Yesterday I spent all day tuning my own custom FFB based on "rFuktor 5.0.X.X - By Karsten with Shadak & Panos" version and got it next to what I want - which is something like rF2/RRE. Those are a reference but AMS2 has the potential to adjust to everyone's taste!!
I'm using Thrustmaster TS-PC with ACELITH formula wheel.

Those changes made screen oscillations be felt on the wheel and hence less floaty/light feeling. The Default+ is good but needs a lot more road/suspension oscillations passed on to the wheel.

 

Another thing about light/floaty feeling - I believe (and it just that) some came from the "display damping internal settings" - these competition cars oscillate a lot more that my road car, which is not what we expect, right? The car should shake under vertical road forces, but should land hard and dry, not bouncing around. RRE and rF2 do this better and AMS2 will also do, I have faith in Reiza .
Even if AMS2's physics are correct, our eyes have a stablization subsystem governed by our internal ear and body "sensors" - we do not experience car oscillations like that.
Try read a phone in someone's else hand with and without touching his/her hand - our eyes/body immediatly compensates for the hand motion and reading becames much easier.

Reiza should add that feeling, considering some found the current model to be good.

 

Thanks Joaquim for sharing your views.

As we have the same wheel base (TSPC Racer owner here), do you mind posting your Custom FFB file and also both TM control panel and INGAME settings?

What cars&tracks combo you are using for your testing would also help if you can share this.

thanks a lot

 

Warning: It's just a work in progress, not something I want people to download as a good product.

I also changed steering speed sensitivity to 65-75 (instead of default 50, "linear") because it seems to reduce some more sloppiness around the center (imposes a logarithm curve or just turns it into a real "linear" curve, I believe).
Been testing only with 911 GT3 at Hockenheim (because I wanted a back to back comparision with RRE, a very good reference).

All my TM driver settings are at 100%, but the max force - I have it at 70% since I feel more details using less overall forces (or perhaps avoiding clipping?)
My in-game settings are GAIN:70, LFB:15, FX: 50, DAMPING: 30

Search "#JP" lines to find the ones I've been changing and their original value.
Today I reverted back a lot those values with little overall significance.
This is really a matter of what's important to you. Mess with the values.

If someone can help, here's what I'm looking for: a more gradual sense of front wheels load under turning - it's almost like it depends more on steering angle and less on effective wheel loads.
Example: try to turn at variable speeds and it seems the force is constant and not speed/g-forces dependent until the car stops and we feel a sudden force drop - in a real car, that force should be coupled with speed.

 

thanks, I appreciate you sharing. Custom FFB is for experimenting anyway so I am not going to blame you if I dont like it
Actually I want to like AMS2 more because the base package is good, I am not giving up on it right now because of these car physics lacking, for me that is

 

Niels Heusinkveld isn't on AMS2 because he disagrees with the new tire model. I do wonder why that sim physics genius disagrees with a supposedly more "realistic" tire model especially when AMS1 felt more realistic?

This is beginning to feel like a marketing business model to make money rather than make an accurate simulator in fact i felt this way when rfactor 2 came out as a new game (selling for almost 60 bucks!!) rather than just a graphics patch for rfactor 1....

With a patch you can't justify such massive prices but with a "new" game you can and thus profit and make shareholders happy and realistic representation of real world cars comes second.

 

Niels may be smart but even he knows his limitations. He also admitted in the past that his approach to physics building weren't taking into account aerodynamic models, to which (at the time) he also gave credit that Renato was the better person in that approach I am sure he has learned a lot since. Niels is also still credited in AMS2 so while not an active employee, he has probably been consulted enough times to warrant being credited.

Niels simply prefers an empirical approach, which, while simpler to implement, still carries its limitations in what regards a very dynamic engine and approach to physics. A physical tyre model is not a scam, but it is a very complex thing to work on and the reason the tyres keep getting overhauled is because the team's knowledge over such a model keeps getting deeper and as such, they are able to extract more out of said model.

If this is grounds for you to consider it a marketing scam... so be it xD
I'll just keep enjoying the improvements.

Oh and AMS2 is an independent studio made of passionate people seeking to produce the best game they can so they are free to evolve the game as they see fit. No shareholders to please here (except for us users) but money still needs to be brought in to put food on the table and to pay for licenses.

 

I think Niels just says that maybe adding more complexity isn't the way to go, rather the opposite. That's why he prefers the empirical model. There's some beauty in simplicity, if you can find a simpler code without having to compromise the fundamental physics aspects, that could also work quite well.

Sometimes less is more and maybe SETA is a bit too complex. ACC e.g. took tyre pressures to a whole new level, but do you really want to deal with things like .1 or .2 psi difference decide over 'grip' or 'no grip' in the next corner? That's not even what happens IRL.

Didn't Einstein say 'make everything as simple as possible but not simpler'?

To be clear: I think Renato and the team are doing a fantastic job, but maybe they could find a way to simplify things and still have realistic tyre behaviour and vehicle dynamics.

 

....

 

Simplification was never the way forward in Simulations.

 

...

 

When you have no arguments to reply back with;
When you spit out RD's "Top Minds" talking points;
When you don't want to concede that your so called opinions are easily shattered,
Hit them back with

"..."

That'll show them.

 

I can only agree with you. Sometimes less really is more. I changed a lot in ffb and sometimes removed things because I felt something was wrong. The shouting was always big and dismissive, but in the end they suddenly found it better. Reiza is doing great work and making progress with the physics of the cars too. But in my opinion there is a lot to do because of the ffb. You should deal with it more intensively, especially with the standard ffb. What good is this excellent physics of the cars if the standard ffb is so bad. I hope Reiza will take care of it in the future

 

Agreed. If people want to play with the same rFactor 1 tyre models for another decade, AMS1 will always be there. I'd rather the tyre models move forward even if progress sometimes comes with some hick-ups.

 

Personally I play the standard FFB (no default + and no custom) and I prefer it over Rfuktor etc. FFB is very subjective and largely depends on your expectations and experience driving sports and race cars if any.
I don't get why people consider their own personal choice as a universal rule especially on such a subjective matter. Even different real world cars have different feeling at the wheel.

 

Simplification doesn't necessarily mean you're making steps backwards, the opposite is the case. Of course you need a minimum of complexity in a simulation game as you're trying to do nothing less than coding real life physics into a piece of software. A 5 point contact model is better than a 1 point contact model. Just to be clear. I'm not saying 'throw everything out of the window and make Trackmania type of tyre physics'.

I think the argument is that you don't need to re-build every aspect of reality in the game. As an example you can look at how people started flying without doing it exactly as the birds do. It is much easier to just have some kind of propulsion and use lift.

If you can get a similar or even better result of realistic tyre physics with a simpler method without compromising the physics itself, then that is probably what Einstein was meaning. Overall simulation games will get more complex as the tech will get better as well, but maybe you can optimise certain parts by using a simpler method. Optimisation through simplification if you will.

Anyway, I don't want to talk down what Reiza's doing, AMS2 is amazing and I love it!

 

Not aiming at arguing or attack anyone, I just think some light needs to be shed on what a physical model brings to the table vs the empirical models IMHO.

From what I can gather from my previous involvement with automotive engineering, the conversation over rendering tires behaviors is basically on two levels.
1. Rendering tire performance in terms of pure grip from a global standpoint (where the meaning of global is basically disregarding what happens "inside" the tire) : in simple word which forces is the tire exchanging with the ground in different conditions, whether it's tire type or track temperatures and rubbering conditions and so on
2. How these forces are are transformed into torque on the steering wheel, which bottom line is what we call FFB (although some additional effects are also overlayed later on in simracing).

When it comes to empirical models the conceptual idea is to have a certain amount of data that could be effectively collected through telemetry and adjust the empirical equations parameters to fit the data the best way possible. The conceptual downside of this approach is that the data available, no matter how comprehensive the database, will always be limited to the conditions those data were collected in. So, to make an example that everyone understands: let's take the last Monaco GP, F1 teams will be able to collect data for the race at full car weight under wet conditions and later damp and green conditions for dry tires. There won't be available data for that track (i.e. aero, suspensions etc. settings) in a fully rubbered hot and full tank conditions.
Therefore conceptually, the data you can empirically measure will always be limited to the conditions you encountered and the car settings you were running.
Everything else has to be extrapolated by use of corrective equations with again more parameters that the user/developer must populate either by experience or literature.
Generally, the empirical equations or corrective equations user defined parameters also won't have any immediately identifiable physical meaning, e.g. you have for instance an exponential function whose exponent is a parameter that is determined to match empirical data, but if data are not available you have to set it by experience or literature and in both cases there won't be any guarantee that the result is in fact close to what the real life would have been.
So bottom line, when you go empirical the correspondence between real life and the model is theoretically only guaranteed for the exact conditions in which data were collected and everything else (which is the vast majority of conditions) is likely to be quite off and anyway pretty much based on engineering judgement at best or personal feeling at worst if you are talking about people with less experience like a modder could be.

In this scenario, what a physical model brings to the table is to base the properties and behavior of tires on equations with physical meaning and much more on actual "architecture" of the tire in its sections and components.
Generally the parameters that the designer/developer uses have a physical meaning and could potentially even be measured (although they are not always measured).
Going this route, means the complexity necessary to achieve a good match with global data of the tire grip and forces is far bigger as the amount of variables is generally far bigger and at times the sensitivity of the models to slightly incorrect data can be significant. It generally requires a deeper understanding of the tire mechanics as some of this variables can have unexpected impacts down the line.
However the advantage is that by using a physical model, once your basic parameters are about right, your model will be able to "swallow" much bigger excursions of its variables (whether it's tire/track temps or pressures, or suspensions angles etc.) keeping results much closer to real life than empirical models would do, especially if excursions are big.
Also, you could imagine the advantage in using physical models for very old tires for which there is little to no empirical data available.

Finally, when you move from point 1 (determining the tire forces) to point 2 above (determining the FFB or the "feeling" of the tire at the steering wheel), the accuracy of the forces, the pneumatic trail, the tire elasticity required to pass on a correct feeling to the driver is the highest. Very few percentage mistake on those or the suspensions/steering arms geometry can ultimately affect a lot the feeling and the user will recognize it immediately.
This is really where a physical model can potentially shine: having a far more accurate representation of what happens "inside" the tire, with its structure and elasticity (vertical and lateral) because those translate into recognizably different steering wheel feelings.

The reasons above is why a physical model has higher potential than an empirical model IMHO, and despite RD has a few "invested" guys who keep saying the opposite, empirical models will never be capable to match a physical model accuracy over a wide range of conditions, because they are far more "actual data" dependent to depict any conditions and those data are simply not available.
Yes, the physical models require a very tough learning curve, yes they require a lot of tuning to figure out the best parameters and yes there will always be some of those parameters that developers have to guess by themselves as they are not public knowledge, but what happens beyond that is engineering equations not "artist impression" of a certain matter as is far more the case of extensive portions of the empirical models.