The online racing simulator
Does the tire temperture heat up and cool down too slow in LFS?
(56 posts, started )
Well there are actually some "wired things" with tyres.

I forgot to make a screenshot, but after a race I stopped and had -center core temp- of 540°C und -outside core temp- of around 380°C.

I wonder which rubber can stand that.

Ok I accelerated again and while breaking into the next turn it burst, but... *lol* ^_^°
Yes, that's an error or rather a not-yet-done part of tyre heating. Tyres only pop due to overheating when the average temperature over the whole circumference of the tyre gets > 200°C. Right now you can easily have one section at 999°C as long as the average is still below 200.
Quote from Shotglass :im guessing here but judging by the way lfs drives the underlying model seems to be simple rigid body dynamics with everything else working around it... which is the main reason that makes lfs feel so much better than any other sim out there

I don't think there's been a sim in many years that works any other way. Even most of the ones that people call arcade use rigid body dynamics.

Quote from gezmoor :I'd still like to see a comprehensive list of exactly how they've modelled the physics and the dependencies between the various models. Purely out of curiosity, (having had a scientific education - specifically physics), i'd be interested to know how it's all been put together. I can't see how it could be commercially sensitive either as it should all be pretty obvious science/engineering principles, unless they're doing stuff that's not known/understood in the world of vehicle dynamics/physics, (highly unlikely). One can't claim intellectual property rights over the way the world works. Anyway, I'm not asking for formulae.

I'd like to see it too, but good luck. Not many sim developers discuss those types of details publically.
Quote from jtw62074 :Even most of the ones that people call arcade use rigid body dynamics.

Agreed. Plug in a simplifed tyre model and give everything lots of inertia, and you've got a dynamics package that can be customised between near pure arcade and semi-sim easy enough. Adding clever imaginary forces can keep a car stable, force it to always drift but without spinning, fake bike leaning, or whatever you want really.

Once you've got something at a near-sim level, it's very easy to turn things off where appropriate to tailor the handling to the needs of the game.

(At work) I'm currently working on both an arcade and a semi-sim driving game, and tbh there's not all that much different between the two. I think the step to a hardcore sim would only require a reworking of the tyre and suspension models (from the vehicle dynamics perspective), plus a little more attention to detail in some other places.
Quote from jtw62074 :I don't think there's been a sim in many years that works any other way. Even most of the ones that people call arcade use rigid body dynamics.

im sure they do and yet none of them other than lfs manages to convince me that the cars body has any weight to it
ive got no idea what makes it different but both from the inside and the outside lfs has by far the most convincing rigid body dynamics code in any sim
Quote from AndroidXP :Just for your info, press Ctrl + Shift while the F9 menu is open to show the tyre surface temperature. The default F9 view only shows the average temperature over the whole rubber/tread thickness.

i learn something new about the game from the forum everyday

Quote from james_bskt :lol same. there should be a detailed summarized updated list of controls like ctrl + shift, i had one ages ago wen i first joined and printed it but it's long gone now, I'm pretty sure ctrl + shift wasn't on there i used to have it next to my p.c. wen i played demo

(sorry im off topic)

haha +1 they totally should
Quote from Bob Smith :Agreed. Plug in a simplifed tyre model and give everything lots of inertia, and you've got a dynamics package that can be customised between near pure arcade and semi-sim easy enough. Adding clever imaginary forces can keep a car stable, force it to always drift but without spinning, fake bike leaning, or whatever you want really.

Once you've got something at a near-sim level, it's very easy to turn things off where appropriate to tailor the handling to the needs of the game.

(At work) I'm currently working on both an arcade and a semi-sim driving game, and tbh there's not all that much different between the two. I think the step to a hardcore sim would only require a reworking of the tyre and suspension models (from the vehicle dynamics perspective), plus a little more attention to detail in some other places.

All of which is rather concerning with regard to believing that any sim doesn't just use "made up" physics. Which I don't really understand to be honest. I mean things like the behaviour of suspensions is all basic mechanics, even the way the spring works in a damped system is well understood in engineering and scientific terms. Tyres are a little more complicated but I don't see the issue with just simply using the emprical data from tyre manufacturer tests. If it describes the behaviour of a tyre, (coefficients of friction/slip/temp/pressures etc), then its just a matter of using the results as a kind of "black box". Input the variables in one side and get the figures out the other, which you then plug back in to the code to determine the resulting behaviour of the vehicle. Even the interface between the surface and the tyre can be modelled, as long as you know the position/velocity on the track, (allow for any weather variables at any given time), you can use the tyre data to work out the grip levels available etc.

It's all just a matter of processing power as I see it, (not saying that coding all of this wouldn't be very time consuming of course - I'm no programmer so I wouldn't know).

Where it really does start to get complicated is when you want to start modelling airflow for aerodynamics and to do finite element analysis on the car chasis and all of the components, (such as suspension struts etc), to be able you to stop assuming it all acts like a rigid body.

I actually know of a guy on another forum that claims to be associated with the Honda team in F1, in some kind of technical capacity but I'm not sure which. I haven't posted there for a few years but I'd happily let scawen know where and who in case he'd be interested in trying to talk to the guy and see what "secrets" he could be able to access/give away (legally of course).
Quote from gezmoor :Tyres are a little more complicated

Understatement of the year...
Quote from gezmoor :but I don't see the issue with just simply using the emprical data from tyre manufacturer tests.

Things would be a lot easier if the data manufacturers gave out was ever anywhere near complete. Knowing what a specific tyre does under very specific conditions, under a few different loads, and tested across a small range of either slip angle or ratio, does not begin to describe how a tyre reacts over all the conditions seen when racing.

Quote from gezmoor :Where it really does start to get complicated is when you want to start modelling airflow for aerodynamics

I'd imagine that's far less important for racing sims than it is for flight sims. Particularly if the sim concentrates on slower forms of motorsport (e.g. autocross, drifting or production car racing).

Quote from gezmoor :and to do finite element analysis on the car chasis and all of the components, (such as suspension struts etc), to be able you to stop assuming it all acts like a rigid body.

I think rigs of rods does what you are talking about here, but current CPU power is not really suffient to do it realistically (especially if you want some cycles left for visual bling).
Quote from Bob Smith :Understatement of the year...

Things would be a lot easier if the data manufacturers gave out was ever anywhere near complete. Knowing what a specific tyre does under very specific conditions, under a few different loads, and tested across a small range of either slip angle or ratio, does not begin to describe how a tyre reacts over all the conditions seen when racing.

But, I don't doubt however that they must have comprehensive test results for each of their tyre models otherwise they wouldn't be able to keep improving tyres like they have done for the last 20+ years.
However, I accept that getting hold of this data is probably going to problematic due to it's commercial significance. But to be fair for LFS at least most models are based on tyres which are 20years old. Surely it must be possible to get hold of such data for such old models of tyres. After all there isn't actually a need to model an exact tyre product just have reliable data so that you can model a make believe one, (that presumably could actualy be a real tyre should someone decide to make it).

Quote :
I'd imagine that's far less important for racing sims than it is for flight sims. Particularly if the sim concentrates on slower forms of motorsport (e.g. autocross, drifting or production car racing).

True, however even road car manufacturers go to some length to shape their cars to ensure they have relatively low coeficients of drag. This aspect is going to be very important once dynamic wind is included in LFS, especially for the lighter single seaters. The current F1 cars for example appear to be particularly sensitive to cross winds, (apparently).


Quote :
I think rigs of rods does what you are talking about here, but current CPU power is not really suffient to do it realistically (especially if you want some cycles left for visual bling).

To be honest I'm not familiar with what you're refering to there.
#36 - w126
Quote from gezmoor :I don't doubt that all of the above is probably true. But how do you know this to be the case?? Has any of it ever been stated by the developers or is it just assumption because of the way the cars in LFS appear to handle?

LFS is able to generate some output data (RAF and CAR_info.bin files) that we can try to process and analyse. Regarding the tyre normal load, it is possible for example to see how it affects the lateral grip of tyres: http://www.lfsforum.net/attach ... tid=4791&d=1136410311 (this is from on older LFS version).
Quote from gezmoor :True, however even road car manufacturers go to some length to shape their cars to ensure they have relatively low coeficients of drag. This aspect is going to be very important once dynamic wind is included in LFS, especially for the lighter single seaters. The current F1 cars for example appear to be particularly sensitive to cross winds, (apparently).

F1 teams have supercomputers a thousand times more powerful then a typical gaming PC (http://www.tgdaily.com/content/view/36905/135/) and they are still very far from doing aerodynamics simulations in real time. Did I understand it correctly, do you want it in real time in a computer game? It's around 40 years away it seems, if we are lucky.
Quote from w126 :LFS is able to generate some output data (RAF and CAR_info.bin files) that we can try to process and analyse. Regarding the tyre normal load, it is possible for example to see how it affects the lateral grip of tyres: http://www.lfsforum.net/attach ... tid=4791&d=1136410311 (this is from on older LFS version).

Interesting. I wasn't aware of that. What other info about the vehicle dynamics can be output in this way? Anything?

Quote :
F1 teams have supercomputers a thousand times more powerful then a typical gaming PC (http://www.tgdaily.com/content/view/36905/135/) and they are still very far from doing aerodynamics simulations in real time. Did I understand it correctly, do you want it in real time in a computer game? It's around 40 years away it seems, if we are lucky.

No, no. I know that real time analysis of aerodynamics is a long way off in a sim. At least to the extent required to design an F1 car. But I don't think anywhere near that level of modelling is required anyway. Lets be honest, LFS is never going to be an accurate enough model to be used for development of F1 car aerodynamics. But it could be accurate enough to model the affects of dynamicly changing head/tail and cross winds, surely?

Quote from Bob Smith :http://www.rigsofrods.com/

Interesting stuff, thanks.
#38 - w126
Quote from gezmoor :Interesting. I wasn't aware of that. What other info about the vehicle dynamics can be output in this way? Anything?

Just looking at the specification of CAR_info.bin files suggests a simple physical model which could use all the car properties listed in it. However, it is not complete. For example, aerodynamic components are provided with their lift and drag coefficients (using wing angles specified in a given setup) but this is not enough to know exactly the aerodynamic forces when the car moves at an angle or with cross winds.
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(Jacque1010) DELETED by Bob Smith : byeeee!!!
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(lfs-drift staff) DELETED by Bob Smith : byeeee!!!
I think the tires heat up fine.... The core temperatures are fine.. but I do think the tire surfaces should cool down quicker...


Most treads are designed to tread water.. With it catching air from the wheel spining the other way that should cool the tread a lot more. The open wheelers do this a lot better of course.. but I think the other passenger vehicles should have a fraction of this type of tire cooling so the tire surfaces don't get soo hot without the overall core being up there (from normal racing/hotlaping).


The slicks seem good open or closed.
Hello all,

I don' t see much complaints anymore about the tyres. I have been driving the FO8 and bf1 since patch Z. I am very dissapointed the tyres-overheating problem is still there. There is not one track where R2 tyres can be used on the bf1, irl on some tracks very very soft tyres were used in 2006

Same for FO8, it really feels like the FO8 and BF1 are using the same quality/spec tyres as the fox, which is not realistic.

What is most noticable, the tyres don' t cool down on straights. So on tight tracks with a realistic setup (R3, not much camber and not max pressure but "real life" pressure) tyres tent to heat up slowly lap after lap.. and get overheated after about 5 laps. Whatever you try to get it fixed... irl it takes a lot of rolling resistance to get this effect, i really think real tyres are better then the ones in lfs.


Please don' t reply about telling tyres heat up at high speeds, at monza f1 often also use soft compound! So that effect is not that bad irl and i am aware of that effect espacially if tyre-pressure is too low.
#41 - JJ72
you cannot objectively measure how soft the "really really soft tires irl" is compare with those in the games. soft and hard is relative, the softest tire in F1 now is considered hard compare with the qualifying tires in early 90s.

I don't see a problem unless there are combos which none of the tires can handle.
#42 - Dac
should your tyres heat up evenly or is that a result of inccorect camber? cause the insides of mine heat up the most. i obviously know why that is the case but i would have thought an even amount of heat over the entire lap would represent optimum camber?
Quote from Dac :i would have thought an even amount of heat over the entire lap would represent optimum camber?

Optimum camber for tyre wear, yes. Not for cornering performance, which is far more important for your lap times.
I like how the guy that started this argument isn't posting anymore XD
he just stopped playing LFS i fink...
#46 - Juls
Quote from w126 :
F1 teams have supercomputers a thousand times more powerful then a typical gaming PC (http://www.tgdaily.com/content/view/36905/135/) and they are still very far from doing aerodynamics simulations in real time. Did I understand it correctly, do you want it in real time in a computer game? It's around 40 years away it seems, if we are lucky.

You need supercomputer to obtain very refined aerodynamics calcuations. F1 teams need to reach a very high level of precision because they need to compare aerodynamics of different shapes and chose the best one. And difference can be very small.

But racing sims do not need such level of precision. Somewhere in my engineering books there is a table with aerodynamics. It contains the aerodynamics coefficients for many different rectangular shapes and their angle to wind direction. It has been used during more than one century to estimate wind effect on complicated steel structures like bridges, towers....etc. It requires almost no calculation at all and gives a very reasonable result. This table was filled by a guy called Gustave Eiffel.
yes, I feel same.
我的E文不好,给你凑一贴吧
#48 - w126
#49 - Juls
In that case it is resonance...engineer's nightmare...bridge is strong enough to stand the wind force, but starts oscillating more and more because his natural oscillating frequency is similar to wind change frequency.

I like the very calm guy crossing the bridge, smoking, like nothing strange is happening
Quote from gezmoor :I know that real time analysis of aerodynamics is a long way off in a sim.

Doesn't iRacing do this, abeit not in real time?

I seem to remember reading they'd put the car models in a 'virtual wind tunnel' at lots and lots of different angles, so while not actually calculating it on the fly, the sim can provide a dynamic aerodynamic affect depending on the cars speed and movement.

Does the tire temperture heat up and cool down too slow in LFS?
(56 posts, started )
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