Thanks for those.. Even though they have to be taken with a grain of salt, you seem to know what you are doing so I'm sure they're 'close enough to say something about' ..

Thats one big drop! I don't *know* but I think this isn't so bad in reality, but I could be wrong.. 0.2G drop sure feels like a lot in LFS: some fun powersliding in a FZ50 only lasts 1 lap or less before I spin with overheated rears But if this does turn out to be real, I'll shut up of course

So we have the 'game data', now the even harder part, real data.. :o

great work! How much work is it to do this for a street tyre car as well? :O Its cool what you can get out of RAF files it seems..

top stuff!
/N

Hi all,

I'm trying to find documents on 'rubber grip vs temperature' but all the pdf's that seem like they might contain some info cost $ to buy online.. I think that the road tyres loose too much grip with temperature. Around 90/100c it really has reduced a lot, although its hard to say if this is the 'general tyre model issue' (that Scawen is aware of ) or the tyres loosing too much grip with temperature.

Does anyone have some data on grip vs temp of tyres?

LFS isn't doing itself justice atm I feel.. It has great potential but, even though its not as bad as S1, some big flaws in physics.. However, Scawen knows about the issues so I think the only thing we must do is wait for either an update to appear, or if thats not within a while, try to tell little Leo to bug his daddy into improving the tyres

Perhaps a M$ employee tried GPLproxy.. :o

Scawen at the town hall:

"Hi, I'd like to report our new baby Leo to the registers!"

"Ahh that's your second one eh mr Roberts"

"eh?"

"At least Leo won't be bullied at school unlike 'LFS' which is a really strange name.."

"err"

....

Also note that there is a bug in the current version of LFS, where you lock the inside front tyre only, you don't hear it squeek. Only when both are locked do you hear noise. This leads to many flatspots if you don't do your 'near limit braking' in a straight line.

I'm a man of compromise.. Nurby and Bathurst both then?

Even though LFS is not GPL, the principles apply. I read this the other day and it still is a good guide. If you're new or experienced, reading this will never be a waste of time:

http://www.asrg.org/gpl/gplac/rec_dvr_beh/rec_driver_beh.htm

Have a go at these:

http://www.lfsforum.net/showthread.php?t=4272

(don't install super front tyres!)

There are things that need improving, but there are also things that make LFS the only sim that I can connect to. Being a bit over the top doesn't scare me too much. I tried some F3 and GP2 Rfactor action and I just can't attack; there is little feel near the limit for whatever reason. With LFS I just 'do it' and stay alive.. Of course my laptime sucks after a moment but I can explore the 'limit region' a lot better than with any sim!

Vid attatched.. Can anyone do that 9 out of 10 times in RF? Is it just me or do we all agree?

I actually prefer to set Vsync on as it gives me 100% smooth 60fps all the time (well, when by myself anyway) and no 'screen tearing'.

aah top stuff, I actually had media player classic, but didn't expect it to have this option!

Thanks!

N

hi guys,

Looking at many video's lately it is so obvious that a lot of them have dodgy aspect ratio. Sometimes very obvious, sometimes its 1.22 /1 instead of 1.3 /1.

I found a fairly decent 100mb video of the 2 RUF CTR @ Nurby (drifting) vids but it has the wrong aspect ratio. Loads of vids on Google Video are wrong too!

So I found this program "Videoperspective" which can supposedly change aspect ratio and recode... Well, in the preview screen it does change the video aspect ratio, but recoding, that RUF still has oval wheels

Isn't there some intelligent media player plugin that can change its aspect ratio?

It will be interesting to see a physics update when Scawen is ready with it.

Meanwhile I've uninstalled all ISI games. I would bet a pint on its tyre model being more flawed than that of GPL. Sure it does flashy suspension settings, brake duct cooling and suspension modelling, but the tyres ARRGGG the tyres. I couldn't handle it anymore! Meanwhile I've put my faith on Scawen and Stefano.. (and Kaemmer)

2006 might be very good if two out of those three come out with something new

I see you drive with less than 50% steering sensitivity? Have you tried it at 50? much better imo! (or is it speed sensitivity you have enabled..)

Sata 150 or 300 doesn't matter in real life.. its like fitting a speedometer dial that goes to 500km/h in the cars in LFS.. They just don't reach it no matter what the dial goes up to..

Manual gears are an absolute requirement for racing imo. Deciding yourself what gear you're in and when you shift plays a big role in keeping the car balanced through a lap.

I get almost as pissed of from auto gears than from the ISI physics engine

Thanks for that quote from Scawen, at least that explains his lack of response to the matter.. At least he's 'on it' (as expected but nice to confirm.

Lets try to stay on topic guys

Some more observations on LFS in general..

0)Effect of small changes. I recall messing with tyres in RACER that relatively small changes could have a noticable effect. Perhaps sims can feel 'quite wrong' when values are 'not astronomically wrong'.

1) Drifting. Much hated but its possible in real life and some videos show that drifting in LFS doesn't seem too far off. This is slightly odd as one would expect the tyre model, if wrong in the area that I think it is (first post), drifting to be harder somehow. Why is it easier than other sims to keep a slide (suggesting more constant lateral grip with wheelspin) when the tyres loose lateral grip so easy and start sliding? Sounds contradictory..

2) lateral vs longitudinal grip. Based on limited information it seems that cars pull slightly more longitudinal G (braking/accelerating) than lateral G. (cornering). It seems that this is not the case in LFS. When small changes have noticable effect perhaps road car performance along the lines of 1G lateral and 1.2G longitudinal would improve things considerably

3) Buildup and peaks. Another thing I notice when driving LFS is that you enter 'slip / slide' status without having the idea that the forces and grip build up. You simply seem to go from a left to a right slide (I don't mean huge oversteer slide, but just not in a 'stick' zone as you leave skid marks and warm the tyres.. where real tyres would expected to be in their 'stick' zone. Its hard to say but perhaps the buildup of available long. and lat. force with small slip angles or ratios is too sudden? (see pics attatched). LFS also doesn't have the longitudinal peak. Now its debatable if threre really is a noticbale peak in real life, you would assume there would be a small difference. Now a locked tyre in LFS slows you down best, until it overheats..

--
I really don't know it all for sure..

Bob, indeed, there will probably be some loss of lateral grip, and the wheelspin will result in some forwards force. The interesting thing is that both ends of the scale produce the same basic effect (car wants to oversteer) yet the difference can be considerable.

How does beta testing LFS work? I've rarely seen Scawen talk about physics / tyre models. I can understand that as everyone here probably has a different opinion about what is wrong and what isn't, but surely there must be something more constructive some players can mean for LFS. I doubt beta testers have insight in the inner workings of the tyre model?

Its hard not to have any control over what happens with LFS physics, as S1 and S2 alpha are so amazing in dynamic feel and 'instant response' and the feeling of being connected, yet are pretty far off when it comes to tyres, providing it is not some strange weight transfer bug..

Edit: URL fixed

Yo Folks,

Yes, lets try to objectively keep the LFS physics against the light. So instead of 'I feel this' and 'I feel this is realistic', lets see how we can attatch some proper numbers and facts to what we think and feel.

This Lx type video was posted in the 'racing' subforum but I think its worth an attempt at an analytical physics debate, not going by 'feel' but going by videos / numbers.

Here is the vid:
http://www.westfield-sportscar ... tvid/misanomegabusa2.mpeg

Interesting because there is both 'sane keep it gripping' driving and 'insane try to slide the car around' stuff in one video.

Here are my observations, perhaps something can be concluded out of them..

1) It seems that he does the sliding in 2nd and perhaps once even in 1st gear

2) when not deliberatly sliding and/or in higher gears the car NEVER requires opposite lock to keep it on the track despite what seems to be full throttle.

3) the first slide (1m04) isn't really initiated by throwing the car into the turn but just by using a lot of throttle on turn in, in 2nd gear (I think). Perhaps the sudden transition from lift off to throttle unsettles the car.

4)lateral (sideways) grip barely seems to drop with wheelspin. Once he unsettles the car with power on corner entry it seems more forward force from the outside rear tyre that cause yaw torque than loss of lateral grip that causes yaw slide.

5) at 1m20 he gets mid turn oversteer again with power, not really assisting it with the steeringwheel. (I tend to flick the car into turns)

6) The oversteer seems brief as it seems to be a full throttle corner exit but the sliding stops before exitting the turn...

7) The corner exit at 1m31ish is interesting as its one of those oversteer guaranteed things in LFS, yet his car is planted..

8) 1m45 he really seems to want a slide but has trouble getting one going After his first correction a big slide is no longer possible.

9) 2m25 he gets nicely sideways under max power.

Now I think I can make something out of this. Based on the tyre model discussions, most notably the 'new' model by Todd Wason, it seems that traditional combining of longitudinal and lateral forces isn't quite realistic. Now this is just another debate with people being against and people being pro but I think I can now sketch a bit what happens in real life and what happens in sims, notably LFS.

I'm the non-expert on this but I'll give common sense a shot. During opposite lock in LFS, you turn against the corner. If you wouldn't, the lack or rear sideways grip will make you spin. You seem to balance the forces around the car centre of gravity by steering the 'wrong way'. This makes the front tyres roll more or less in the direction the car is traveling at, which basically stops them from wanting to enter the turn. Now what seems to be the case in LFS, when you get wheelspin there is a considerable drop in lateral grip. This seems to be what causes oversteer.

Now I *think* I'm beginning to understand what happens in reality. It isn't so much the drop in lateral force that causes oversteer, it is the torque from mostly the outside driven tyre around the car centre of gravity that tries to push it around.

Tyre models are tricky to understand as there is always a combination of longitudinal and lateral forces at play. With risk of being totally wrong I've attatched a sketch which hopefully nods in the right direction. I'm only looking at pure lateral force in LFS (assuming longitudinal force is relatively small) and looking at pure longitudinal force in the 'real(??)' sketch, assuming lateral grip stays relatively constant, more or less based on drifters pulling about 90% lateral G compared with non drifters, which I heard somewhere, and have no idea whether that is actually true..

Would it seem plausible that such a thing is happening in LFS? I think it might explain its handling to some extent. Imagine driving LFS with the sketch on the right being the case and lateral grip being relatively constant.

Ever so slight slalom turning in LFS tends to cause oversteer by the bucketload. With more constant lateral grip you would certainly not get the oversteer simply because the amount of rear lateral grip available is not much less than what the fronts have available. You would only get oversteer when applying a lot of power in a turn. You would force the rear around the front instead of passively having it overtake the fronts because they have no grip. I.E. you would actually have GRIP on the outside rear tyre that causes oversteer (as the grip causes forward force) instead of LOOSING sideways grip.

Any constructive thoughts on this one?

Last edited by Niels Heusinkveld, Tue, 31 Jan 2006 10:25.

If they do Kyalami next year it'll be even better

I'm getting really anxious for a physics patch.

What is also interesting in LFS is how easy you put down skid marks. This must be coupled to 'excessive slip' in the sim somehow and it just seems that tyres leave their 'stick' zone without any effort. Anyway, with no words from Scawen's keyboard I'm afraid we have to wait and see. He clearly is good enough as a programmer but is he methodic in his approach for the most realism? I have good hopes, but then again, S1 and S2 alpha are so far from realism that I doubt I would release them in that state. How good is the programmers approach to realism when the difference from S1 to S2 was noticable, but certainly not close to realism? Its up to Scawen to take away the doubts, hopefully sometime this year!

My current Lx4 setup is here http://lfsforum.net/attachment ... tid=4843&d=1136598327 I find it fairly realistic to drive this way, but its masking the problems, not solving them.

Dressed booth babes?!? booh!!