8/11/2019 _pacejka Read Me

http://slidepdf.com/reader/full/pacejka-read-me 1/3

Pacejka Car Physics Demo ( The Masked Coder 2003 )

This demo showcases my latest breakthrough in my uest !or realism in car "hysics#

$k Masked% what&s all this Pacejka stu!! all about then#

'ell% # Pacejka is the name o! the "ro!essor who has in*ented the +Magic ,ormula-algorithm which accurately models the !orces which a!!ect a tire# The +Magic ,ormula- is broken down into 3 "arts# . longitude *ersion% a /ateral *ersion and a combinationalgorithm which combines the two% making sure the !riction circleeli"se o! the summed!orces isn&t broken#

This is "retty much the industry standard !ormula !or calculating tire !orces and is used inmost commercial games and "ro!essional car sim&s alike# 1t is the holy grail !or car sims asit "ro*ides an accurate model o! tire beha*iour which enables the car sim to reach a highstandard o! realism#

The +Magic ,ormula- is based on 2 or 3 sets o! dynamic in"uts as well as coe!!icientsobtained through real world testing o! tires#

/ongtitude *ersion#

# li" .ngle# (amount o! gri" o! tire)2# ,4 5 /oad on tire# (weight#)

Coe!!icients#

0%%2%3%6%7%8%9%:%;%0

/ateral *ersion## li" angle# (.ngle between direction o! tra*el and orientation o! tire)2# ,4 5 /oad on tire# (weight#)3# Camber o! tire# (how much the tire leans#)

Coe!!icients#

.0%.%.2%.3%.6%.7%.8%.9%.:%.;%.0%.%.2%.%.2

<i*en these in"uts and the magic !ormula% 2 resulting !orces% ,= and ,> are returned#,rom these 2 !orces% you can calculate the torue on a car (rotational mo*ement)% angularrotation (trajectory)% gri" and acceleration#

8/11/2019 _pacejka Read Me

http://slidepdf.com/reader/full/pacejka-read-me 2/3

My latest demo here% showcases this in action and "ro*ides *ery smooth and accurate carmo*ement# >ou can adjust the gri" le*els o! the !ront and rear tires% (which is just aweighting !actor !or the out"ut !orces% ,= and ,>) so you can e?"eriment with understeer and o*ersteer#

1&*e ha*e released similar demo&s in the "ast% but nothing this accurate# My "re*iousdemo&s used a linear tire !riction model% which was ok% but didn&t "ro*ide me with theaccuracy 1 wanted# This latest demo does and is now a""roaching commercial standard#

My ne?t area o! de*elo"ment in car "hysics will be the interation o! the car o*er anundulating o!!road terrain# 1&*e already made big ad*ances in this area o*er my old !lu!!ydice car "hysics demo which now includes smooth wheel to landsca"e alignment% correcttake o!! on jum"s% correct sus"ension and o*erall a much better looking and handling carsim#

The Pacejka demo here just includes a !lat landsca"e to dri*e on as this best showcases the+Magic ,ormula- in action#

>ou can "er!orm skids and slides% dohnuts% :0 and 380 s"ins in this demo and kee" alook out !or the dri*er as he leans !rom side to side as the car sli"s and slides about#

There are a multitude o! camera o"tions accessed *ia keys @ 0 in conjuction with themouse and num"ad# /e!t .lt !or re*erse cam#

A @ ' and . @ change the amount o! gri" on the tires#

"ace @ "ro*ides 0 gri" !or s"ins and turns# .la dri*ing on ice#

Cursor keys dri*e the car#

Bsca"e to e?it#

,or !urther in!ormation on the +Pacejka Magic ,ormula- check these /&s#

htt"E"hors#locost9#in!o"hors2#htmhtt"E"hors#locost9#in!o"hors22#htmhtt"E"hors#locost9#in!o"hors26#htmhtt"E"hors#locost9#in!o"hors27#htmhtt"Ewww#racer#nlre!erence"acejka#htmhtt"Ewww#racer#nl"ac"lay#htm

8/11/2019 _pacejka Read Me

http://slidepdf.com/reader/full/pacejka-read-me 3/3

a*e ,un#

Masked 2003#