The online racing simulator
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w126
S3 licensed
Quote from CodieMorgan :Were is africa? 0.o

Wasn't it sunk in revenge for Black Hawk Down?
w126
S3 licensed
Quote from JeffR :Note that lateral peak force is related to the component of force perpendicular to the direction of travel.

Someone might choose to describe and model tyre forces this way, but it is not the standard method of doing it used by almost everyone.
See the figure on page 2 of http://zzyzxmotorsports.com/li ... uencing-tire-modeling.pdf . I think most of published tyre data is compatible with the coordinate system described in this document.
Lateral force is perpendicular to the direction of wheel heading, not the direction of wheel travel.
w126
S3 licensed
Quote from Bob Smith :you end up with your car sliding side to side with a magnitude of the relaxation length.

That must have looked funny, as the typical value of relaxation length for lateral behaviour is around 1 m, FWIR. I must say all these things are pure theory for me, I haven't really experimented with them in code.
Here is another damping method (which you may have seen already): http://groups.google.pl/group/ ... tors/msg/509e0cfe0516548a
w126
S3 licensed
Some solution for low/0 speed and oscillation problem is described in Development of an Intermediate ... or Optimal Design Studies, formulas (7.3.8) to (7.3.12).
w126
S3 licensed
Quote from The Very End :I hope they manage to sort this crisis out, having most of the people in the current ruling government out, it got to be hard getting everything back on track.

The current government having the leading role in ruling the country is almost not affected by this. The prime minister and 'full' ministers were not on the plane. In Polish political system the president mainly represents the country and is able to veto the parliament legislation (which again may be rejected by parliament with more votes).
w126
S3 licensed
Quote from obsolum :I understand they were all very important people but still... ~3000 vs. 132?

You are definitely right. In this tragic situation it is really sad that in the lists of victims published by many Polish sites they only mention VIPs and neglect pilots, flight attendants, bodyguards etc.
Last edited by w126, .
w126
S3 licensed
Quote from Shotglass :wouldnt you only need a relatively straight forward set of 4d data to reproduce a tyre in all its behvioural characteristics?
doesnt sound too complicated to me... maybe 5d if you add aligning torque too

And normal load, camber, temperatures...

I think there is always too much talk about force combining in such discussions, as if we were Flatland citizens.
w126
S3 licensed
Quote from MadCat360 :There are, TC 22 America and scroll down.

If they were competing in WRC, their final time would've put them 24th out of 26 WRC cars (25 WRC cars competed).

You mean these 25 cars? http://www.wrc.com/jsp/index.j ... son=2010&rally_id=MEX
These are not all WRC cars. The last 2 are Peugeot 206 XS in A6 class (FWD with probably not much more than 150 hp).
Entry list: http://www.wrc.com/jsp/index.j ... son=2010&rally_id=MEX
Did they even run on the same stages exactly? Does comparing the total times make any sense?
Last edited by w126, .
w126
S3 licensed
It seems the device is produced by this Czech company: http://www.motion-sim.com/

The copy of the video you linked to and the donation links look very fishy indeed.
w126
S3 licensed
The data available from real-time official LFS interfaces are very limited, so this problem looks difficult. However, RAF contains slip fraction.
Quote :Slip fraction
-------------
This is the dynamic value of the current combined slip ratio relative
to the combined slip ratio that would provide the greatest force.

0 to 254 - slip ratio increasing up to maximum force available
255 - slip ratio exceeds the maximum force slip ratio

Obviously, it's not real-time data, but maybe it could be used to construct a model of very high-level "distilled" grip characteristics of a given car and setup.

Such a model could be a function which takes:
  • linear acceleration vector,
  • angular acceleration vector,
  • linear speed (needed for cars with downforce),
  • car orientation (e.g. up-vector, needed to take driving on banked surfaces into account, and forward-vector to distinguish between cases of moving on the same trajectory with varying amounts of drift)
and returns the slip fraction values for all four wheels.

The above data (function inputs and outputs) can be logged quite easily with simple calculations from RAF of test runs of a given car and setup with near to optimal tyre temperatures. Then the hard part would be to find a mathematical expression that approximates the function with sufficient accuracy. The inputs of the function can be retrieved in real-time from OutSim (with some simple calculations) and the AI could use the approximating function to get "predictions" of slip fraction values when driving.

This ignores real-time tyre temperature and wear, but AI could deal with cold tyres by not using 100 % of the optimal grip at the beginning and gradually going closer to the limit as tyres warm up. Also, adding steering inputs to the parameters of the function may seem useful, however, they already influence existing function parameters.
w126
S3 licensed
Quote from brt900 :cmon 2002 turbo beat mk2 escort wtf is wrong with these people i need that escort

Just one example from this forum:
http://www.lfsforum.net/showthread.php?p=1352885#post1352885
w126
S3 licensed
Quote from brandons48 :I wonder what would happen if Block completely dominated the WRC?

Hell would freeze over?
w126
S3 licensed
Using the data from CAR info binary format is for sure better than 1/4 of unsprung mass. FWIR exporting of it was added in LFS later than the discussion in this thread took place.
w126
S3 licensed
Quote from blackbird04217 :I stumbled upon PPJoy, which was mentioned on page one by someone when virtual control was first brought up. I successfully turned the wheel in LFS using my program. However, it doesn't center the wheel properly.

Have you tried calibrating it in LFS like a normal controller? I mean the steering program moving all the virtual axes through their whole ranges and then staying in neutral positions so that you can also click centering button in LFS.
w126
S3 licensed
PVM is not what you think it is probably. It shouldn't be confused with software like VirtualBox or VMware. PVM is just a library and API for writing parallel programs and a console for managing "nodes" on which these programs can run.
w126
S3 licensed
Quote from AndroidXP :
  1. Drive along the track outline and let your program automatically place track markers (your virtual marker consisting of a single coordinate on your virtual track map) every time you pass a track node. Do this for the outer and inner path of the track and you have your track marker cloud.

It seems this is not even necessary. PTH files (http://www.lfs.net/file_lfs.php?name=SMX_PTH_S2Y.zip) contain this information. I'll quote their specification below because I could not find it anywhere apart from the zip file.
Quote :PTH VERSION 0 - Path files for Live for Speed S2
=============


The nodes are given by a fixed point position (X, Y, Z) and a
floating point direction (X, Y, Z)

The node can be considered as a line perpendicular to its direction.

Outer and driving area left and right limits are given.


TYPES :
=======

1) X,Y,Z int : 32-bit fixed point world coordinates (1 metre = 65536)

X and Y are ground coordinates, Z is up.

2) float : 32 bit floating point number


FILE DESCRIPTION :
==================

num unit offset description
--- ---- ------ -----------

HEADER BLOCK :

6 char 0 LFSPTH : do not read file if no match
1 byte 6 version : 0 - do not read file if > 0
1 byte 7 revision : 0 - do not read file if > 0
1 int 8 num nodes : number
1 int 12 finish line : number
......NODE BLOCKS


NODE BLOCK :

1 int 0 centre X : fp
1 int 4 centre Y : fp
1 int 8 centre Z : fp
1 float 12 dir X : float
1 float 16 dir Y : float
1 float 20 dir Z : float
1 float 24 limit left : outer limit
1 float 28 limit right : outer limit
1 float 32 drive left : road limit
1 float 36 drive right : road limit

w126
S3 licensed
Quote from AndroidXP :That said, if you're still in search for a platform, why not use LFS?

That could be interesting. Maybe it would be possible to generate reference points based on SMX and PTH files. OutSim also contains car positions.

Quote from AndroidXP :The only thing you'd likely have to additionally invent is a virtual device that can emulate analogue steering, throttle, brake and clutch input.

PPJoy may be used for that, as described here: http://ppjoy.bossstation.dnsal ... iagrams/Virtual/IOCTL.htm
w126
S3 licensed
Quote from squidhead :i've been gathering info on Dirt 2, and I've found something peculiar... did they really drop the group B and Pikes peak rally cars AS WELL as Pikes Peak itself?

In the console version of Dirt 2 there is no Pikes Peak. The only group B cars available are Metro 6R4 and Ford RS200 (you have to unlock them), but they are in rallycross versions. It's possible to drive them on rally stages but you don't have the co-driver reading the pacenotes. Most probably this also applies to PC version unless they've added some content.
w126
S3 licensed
This may be useful: http://www.cs.cmu.edu/~baraff/sigcourse/index.html

However, doing it from scratch will take some time , so maybe you should consider playing with existing libraries like Bullet, ODE, PhysX or Havok first.
w126
S3 licensed
Quote from DaveWS :If you want to test this for yourself I'll explain. Basically take any iRacing car, say the Mazda, to the skid pad as it loads quickly and is completely flat.
[...]
Now try in the Skippy. You should find that the natural side to side motion the car naturally falls in is much slower. Why is that? Does the Skippy have significantly higher rotational inertia IRL than the Mazda?

Moment of inertia is only one factor. The other is the torque, which in this case (polar rotation) is generated by the tyres. The car having much more grip (Mazda) may also more easily generate bigger difference in lateral forces of front and rear tires (assuming 50/50 weight static weight distribution for simplicity so that these forces have approximately the same arm relative to CoM of the car) and as a result bigger torque causing the rotation. With similar polar moment of inertia to Skippy, Mazda should be able to change its orientation much more quickly.
Last edited by w126, .
w126
S3 licensed
Quote from danowat :There is no way I can see of making a custom race, quick race is limited to 2 laps, you can't select any more, also, there is no way to make a custom multiplater lobby either.

Is there no option of making a multiplayer race through system link and adding AI players to it, like in Forza 2?
w126
S3 licensed
Quote from jaxx751 :by settled I mean the load isn't changing across all four wheels. it's, for all intensive purposes, constant.

But that only means that the level of weight transfer or load transfer isn't changing. Not that there is no weigh transfer or load transfer, which are not beneficial during turning due to load sensitivity of tyres.
w126
S3 licensed
By settled do you mean there is the same normal load on front left and front right wheel for example?
w126
S3 licensed
Quote from jaxx751 :When the car settles (in this case, mid turn) it is back to the limit of the tires, and not really affected by weight transfer(assuming that the surface is flat).

Are you saying that there is no weight transfer in the middle of a turn? Is your car jet propelled with variable thrust vector?
FGED GREDG RDFGDR GSFDG