Physics The Physics discussion thread

[William Levesque]

Yeah - isn't it amazing how being smooth and not over driving a well setup street car can still allow for 130mph+ on a short track and average 1.2g cornering with 2g peaks and still barely any tire squealing. Thanks for noticing that by the way - not everyone can appreciate a well setup car being driven smoothly at speed

Speed is relative, it's easy to claim you go fast with a lot of power and lots of meat under the car. Smooth is good, but smooth doesn't mean not driving at the limit. That's just being slow.

In the end, no idea how your car handles here because it's going too slow for what it apparently can do.

 

[RC45]

@RC45

You still haven't answered my question. When you input the parameters that you measured from your car, what exactly is lacking in the handling of the C5? You keep saying that you had to increase the camber beyond the factory envelope, yet you don't reveal the original issue when real-world parameters are used. All I'm suggesting is, it's a complex model, it will never be perfect, so maybe there's an inaccuracy with how you modeled one of the many, many other parameters that go into the model. Fudging the camber may just be offsetting an error in another part of the model .That error could be from you, or it could be from Kunos. Since you're not willing to share your data, we can't say for sure.

Regarding the camber adjustment; ok, an assumption was made by Kunos to simplify the model, so they didn't account for movement of the LCA location. It's not some monumental shortcoming, it's just an assumption that greatly simplifies the model; 99.99% of people won't be able to feel the difference. Imagine how complex the kinematics model would be if they included the camber adjustment strategy of every car in the game (inboard eccentrics, outboard rod ends, inboard shims, outboard shims, mac strut camber plates, mac strut eccentric bolts...). Now you would have to quantify (in addition to the location of each suspension point) how that asjustable point moves the rest of the suspension points in 3D space when the given mechanism is adjusted. So now the kinematics model is at least twice as complex as the simplified method (increasing their own workload and turning off many modders who don't have access to that level of data), but they've only made minuscule improvements to the accuracy of the model. The value they would be getting from that added complexity would never be worth it, so I say that simplification is totally valid.

In other words just fudge the numbers and move on - I get it. That's what I did - I guess I thought I was bringing out a revelation but it turns out everyone has been fudging the numbers since day 1, how was I to know - I thought it was a simulation and all.

So at the end of the day no harm no foul - I'll just keep going based on how each car feels at the end of the exercise and not get caught up in the real data

 

[Chris]

The language you used was not at all relevant nor was it appropriate. In addition, you directed personal insults to AccAkut, which I did not notice at first, but now have, which is totally uncalled for.

So, given that you've been warned, and clearly have no respect for the people trying to help you out, perhaps you need a week off. Cool down and come back when you can speak respectfully to those trying to actually help you.

See you then.

 

[Radu Oros]

In other words just fudge the numbers and move on - I get it. That's what I did - I guess I thought I was bringing out a revelation but it turns out everyone has been fudging the numbers since day 1, how was I to know - I thought it was a simulation and all.

So at the end of the day no harm no foul - I'll just keep going based on how each car feels at the end of the exercise and not get caught up in the real data

But why don't you build a tyre from the data you take from your car instead of trying to use tyres of another car in game.
You haven't yet said what are the problems you find when building with your real data instead of borrowing from other cars in game, the only problems you're finding is when trying to mix and patch things from here and there.

I know he's in Simberia now.. but his whole approach to modding a new car is laughable due to not trying to build everything with the data he has but instead just cutting and pasting from other cars.
He said he began modding the car in 2009 for rfactor...

 

[Stereo]

So if the sim engine was truly a modular sim engine then I should be able to use the same WING file on 2 different cars.

Therefore the sim engine should APPLY the wing data to the car and then compute the resulting wing/car combo

If it doesn't and the WING data needs to be tweaked for each car then again this is NOT a modular sim engine.

Just for the record, no realtime racing simulator will work the way you want. From a programming POV what you ask is entirely unreasonable. The people who do run this sort of simulation go at fractions of realtime (like, hours of CPU time to simulate 30 seconds of airflow and let it reach a steady state that lets them estimate the downforce) and even then they'll prefer wind tunnel numbers because ultimately what happens in the real world is what matters.

AC was never advertised as this because it's not; neither is RF2, or AMS, or anything else you can mod.

 

[Michael Hornbuckle]

Wait, you mean you can't build a car in AC as easily as you can add a Forza wing in FH3? I want a refund.

 

[AccAkut]

Mod Edit: Personal insults not needed.

Cheers

 

[norbs]

This.

Please understand you are playing a consumer product which retails for less than £25, designed to be able to model many different vehicles to a very respectable degree of accuracy. It it perfect? Nope, but its pretty great considering the price point.

This as well.

It isnt a professional simulation. It is a game.

 

[Jim Layee]

RC45 meets the ignore list

 

[AadHofman]

Disgusting how this place allows AC trolls to gang up against any sort of criticism. I guess RD just simulates a discussion forum, eh?

 

[mclarenf1papa]

Disgusting how this place allows AC trolls to gang up against any sort of criticism. I guess RD just simulates a discussion forum, eh?

When the criticism is completely invalid, then yes, we'll "gang up" against it...

 

[William Levesque]

Banning him was probably a bit much tho.

 

[Chris]

Not at all. He'd broken the rules multiple times, been warned both verbally and officially. I stand by the ban 100%

 

[AadHofman]

When the criticism is completely invalid, then yes, we'll "gang up" against it...

Well, it wasn't completely invalid. To claim so is just part of the trolling.

 

[ALB123]

This as well.

It isnt a professional simulation. It is a game.

It does surprise me when people expect their $40 game to be as precise as the Red Bull Formula 1 simulators. I don't get it.

Also, the guy who was doing all of the whining -- did he ever mention that this was going to be a mod he was going to try and sell? If not, why wouldn't he post specific numbers or even data files to backup his cause? I'm not saying that this is the case, but for all I know the guy might even be working on a car mod and just trying to get a rise out of people. I don't actually believe that, but it IS a possibility.

There are definitely some names that I recognize in this thread - people who know their way around car mods in AC pretty well. He wouldn't accept a single suggestion, so I'm glad he's gone. He had an agenda to just yell at the top of his lungs "AC sucks!! Hurr Durr Fan Boyssss!!" and call people names. Its unfortunate because I was hoping to learn a lot from this thread. Instead, I've only learned that he's loco.

 

[StefanoCasillo]

It does surprise me when people expect their $40 game to be as precise as the Red Bull Formula 1 simulators. I don't get it.

You genuinely think that F1 simulators have realtime CFD running? Oh dear. Why would they? Once you can get the data from a real wind tunnel why bother? And even if you had a perfect CFD solution (that obviously won't run in realtime) why bother trying to use it real time?

At the end the guy is a bit (ok.. a lot ) bitter but I understand where he is coming from. He's expecting AC to be this "modular physics engine" (whatever that might mean in his head lol.. I can only try to guess what he is trying to express) to allow hack together a couple of numbers from a real car and get the perfect a virtual representation.

This is a common and widespread misconception but it isn't really something to be surprised about. As humans we tend to vastly underestimate the complexity of tasks we don't understand very well; interestingly that is also the reason why programmers get time estimations always wrong and are taught to always "double whatever time you think a task might need".

He managed to argue for 5 pages without bringing on the table one single concern at a level that could have been a starting point of a serious analysis or brainstorming.. nothing at all, which really should say everything you need to know about this whole thread.

So combine genuine and innocent ignorance (we can't be all expert in everything right?), misunderstanding and wrong expectations about a software, macho ego (I got this, I got some numbers but the software isn't doing what I want ergo.. the software is obviously wrong cause I can't be) with an underlying bitterness towards us (the devs and whoever tried to explain stuff to him) and you end up like this. It's all quite predictable actually.

 

[William Levesque]

interestingly that is also the reason why programmers get time estimations always wrong and are taught to always "double whatever time you think a task might need".

So basically the same as when you work on cars IRL ?

 

[Eduard Mallorquí]

It does surprise me when people expect their $40 game to be as precise as the Red Bull Formula 1 simulators. I don't get it.

rF2 physics set the bar too high, so it's normal to get disappointed when they sell you a game with the simulator word on it.

 

[Borbor]

Ever thought of maybe using Pacejka's formula for tires?

that's the first post that made me laugh in this thread. And you can't be possibly serious to even think that the in game physics model can replicate something that's useful out of the post 02 pacejka models.

 

[Borbor]

So basically the same as when you work on cars IRL ?

Maybe for the hobbyist mechanics . But definitely not when there's a countdown timer to the next session staring at the mechanics in the face