The online racing simulator
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w126
S3 licensed
Quote from Forbin :However, the reality is, the AI actually drives the same car as you in LFS, with the same physics. Other games cheat in that, as JTbo mentioned, the AI behaves how the track and car makers intend it to, rather than how it should.

Forza Motorsport 2 is similar to LFS in its approach to AI, at least that's what the creators say. http://forzamotorsport.net/new ... ssreports/pitpass36-2.htm
w126
S3 licensed
At 75 Hz refresh rate it goes like 1 1 2 ...
At 60 Hz : 1 2 2 ...
At 65 Hz : 1 2 1 2 1 2 1 2 1 2 1 2 2 ... Try 65 Hz, maybe this will feel smoother, still far from perfect though.

Apart from that, using very low FOV in LFS makes it worse, because it exaggerates the movements.
w126
S3 licensed
Quote from J.B. :LFS always does two small frame steps followed by one big one, the other game is smoother.

It makes sense now. LFS performs 100 steps of physical simulation per second. This doesn't match the display refresh rate of 75 Hz. Two frames are done after every physics step, then the third one after two physics steps.
w126
S3 licensed
Have you tried changing "Full screen vertical sync", "Limit frame rate", "Maximum frame rate" and "Minimum sleep" options? http://en.lfsmanual.net/wiki/Options#Misc
w126
S3 licensed
It's very simple:
tyre longitudinal grip = (tyre longitudinal force) / (tyre normal load)
tyre lateral grip = (tyre lateral force) / (tyre normal load)

What you describe is correct (on tarmac at least), it's just load sensitivity, although whether this effect should be stronger or weaker is arguable.
w126
S3 licensed
Quote from AndroidXP :The RAFTyreExtract.exe limited me in my data gathering.

I'll just post my current ('WIP') versions of both programs here, while there is some interest in them. The new RAFTyreExtract should not have the problem mentioned (just checked with over 12 MB RAF). It also works with all 4 wheels and hopefully is more correct then the previous version, though I still know how to improve it further. The new version of MultiDim has two little new features: dimension listing option and double-click centering.
w126
S3 licensed
Quote from Niels Heusinkveld :I think I can get longitudinal and lateral forces, loads.. I suppose you also need to know slipangle and slip ratio?

The longitudinal force is not available in rFactor internals plugin API (http://forum.racesimcentral.co ... php?p=3150984#post3150984). Unless there is another source for it, you would have to try deriving it from lateral force, steering arm force and suspension/steering geometry, but pneumatic trail seems to be also necessary.
Last edited by w126, .
w126
S3 licensed
Did you try changing the FF strength setting? It seems it should influence the result of the experiments with the wheel catching the slides on its own. When the FF is not strong enough the wheel has problems overcoming its internal resistance and turning quickly enough to keep up. Obviously, this is more likely to happen with higher angle modes because the wheel has to rotate quicker in such cases.
w126
S3 licensed
Quote from Dissident :Here's an idea: create the device as an open helmet which covers the user's head and shoulders.

Whenever you need to apply forces, motors inside the device apply the forces on the user's head using the shoulders as leverage point - you can then simulate front, back, left and right forces.

I was thinking of building such a device and using components of a strong FF joystick. All its electronics could be used and the steering software (or rather a driver or a bridge between a racing sim and a device) would be just a DirectInput application.

Apart from that, we can still hope that some mass market device using galvanic vestibular stimulation will be released one day. http://www.forbes.com/personal ... x_lh_0804remotehuman.html
w126
S3 licensed
I think car action in "Death Proof" is nice. However, the dialogs are pretentious and boring. I guess I'm too old.
w126
S3 licensed
Quote from Niels Heusinkveld :I've not been that interested in rFactor after they basically said the force combining is not realistic.

Did they (ISI) say that? Where? Could you post a link?
w126
S3 licensed
Quote from ajp71 :Can any GTL/RACE owners confirm if it looks any different to the previous GP track versions or is it a straight copy and paste?

So far all we have is this single screenshot and it is very similar to GTL track.
http://forum.racesimcentral.co ... =3534394&postcount=59
w126
S3 licensed
Real suspensions springs may be progressive (i.e. have slightly more lb/in when being compressed more) instead of being totally linear.
w126
S3 licensed
Quote from atledreier :Let's hope Scawen reads these threads

Do you think he's been getting complete lines of code from Yoda in his sleep?
w126
S3 licensed
Quote from StewartFisher :The selt-aligning torque should be a factor in calculating the feedback torque, but there should also be a component from the product of the longitudinal wheel force and the scrub radius.

There is also another component originating from the lateral force and the mechanical trail, which is usually the most significant one, because the mechanical trail is usually bigger then the pneumatic trail.

Quote from AndroidXP :While I still can't completely wrap my head around it, one thing I question myself is why nKP and LFS are so different in that regard. Up to the apparent SAT limit they feel quite similar, but then they start to do completely different things. nKP goes limp while LFS doesn't really do anything at all at understeer (if it's not FWD throttle induced). Who is right? Or is neither, and we should get a little bit of easing up but not as exaggerated as in nKP?

Maybe the open wheel cars in nKP have smaller mechanical trail values and the SAT component is more visible as a result?
w126
S3 licensed
Quote from Sueycide_FD :i think the AI in the next stages need to be a little less computer heavy. i can get about 30+ cars in rFactor and a full field in GTR2 with minimum lag but in LFS manage only 6 cars

The AI cars in rFactor and GTR2 use simplified physics simulation, therefore the AI algorithms may be simpler also. Both these things are less computationally intensive than in LFS, where the AI cars are fully simulated physically and the AI has to do the same steering that we do. The approaches of LFS and ISI engine are very different, so IMO their performance shouldn't be compared directly.
w126
S3 licensed
Quote from vf1-xj220 :the main problem here is that EVERYONE wants everything free...

This is not true. It's a market and people evaluate what they get for their money and compare it with other options. The current LFS pricing scheme is what the developers wanted, obviously while staying within the market constraints.
w126
S3 licensed
I wish Bugbear would make Rally Trophy 2 instead of these mindless games.
w126
S3 licensed
Quote from Shotglass :ok now he just claimed the wheel turns faster than the tyre ... im sure he knows a bit about coding but his physics knowledge is pretty appalling

Not the whole tyre but what he said is actually true for the front part of the contact patch when accelerating, which has smaller angular velocity than the wheel hub in that case. The video was probably meant as a popular lecture and obviously things are simplified, because being precise would take too much time.
w126
S3 licensed
Quote from The Moose :The F3 car is the one with a bug and it's fixed in 1.03.

Is this http://rapidshare.com/files/18566013/nkcollision.wmv.html (http://forum.rscnet.org/showthread.php?t=284092) also fixed in 1.03?
w126
S3 licensed
When you brake in the straight line the ARBs don't generate any forces, because both wheels of the same axle have the same suspension deflection. In the other case (sideways stopping) the ARBs do work and their effect at every wheel is to make the suspension stiffer. Because the damping at every wheel is still the same, therefore the system becomes underdamped, which means longer oscillations at higher frequency.
w126
S3 licensed
The torques at the output shafts of the central differential would be equal (for open differential), but the torques delivered to front and rear wheels would be different. Isn't that what we really wanted?
Last edited by w126, .
w126
S3 licensed
Quote from Bob Smith :Those wheels (1 and 2 in the diagram) a) surely have to be the same size for it to work mechanically

You can achieve the same with additional gears (2:1 ratio for example) on one of the output shafts of the central differential or different final drive ratios of front and rear differentials. When driving in the straight line the front and rear wheels turn at the same speeds (approximately), therefore the output shafts of the central diff don't have the same speeds (the additional gears convert both torque and rotational speed), nothing unusual for a differential.
IMO all the differential settings available in LFS are possible mechanically.
w126
S3 licensed
Something related: http://www.cs.ucl.ac.uk/staff/P.Bentley/WLBEC1.pdf
Quote :Abstract. Formula One motor racing is a rich sport that spends millions
on research and development of highly optimized cars. Here we describe the
use of a genetic algorithm to optimize 66 setup parameters for a simulation
of a Formula One car and demonstrate performance improvements (faster lap
times) better than all other methods tested.

Your code could be very useful for doing similar stuff with LFS.
FGED GREDG RDFGDR GSFDG