<s>
rFactor	B-Application
is	O
a	O
computer	B-Device
racing	B-Application
simulator	I-Application
designed	O
with	O
the	O
ability	O
to	O
run	O
any	O
type	O
of	O
four-wheeled	O
vehicle	O
from	O
street	O
cars	O
to	O
open	O
wheel	O
cars	O
of	O
any	O
era	O
.	O
</s>
<s>
rFactor	B-Application
aimed	O
to	O
be	O
the	O
most	O
accurate	O
race	O
simulator	O
of	O
its	O
time	O
.	O
</s>
<s>
Released	O
in	O
November	O
2005	O
,	O
rFactor	B-Application
did	O
not	O
have	O
much	O
competition	O
in	O
this	O
market	O
,	O
but	O
it	O
featured	O
many	O
technical	O
advances	O
in	O
tire	O
modeling	O
,	O
complex	O
aerodynamics	O
and	O
a	O
15	O
degrees	O
of	O
freedom	O
physics	O
engine	O
.	O
</s>
<s>
rFactor	B-Application
was	O
developed	O
by	O
Image	O
Space	O
Incorporated	O
(	O
ISI	O
)	O
,	O
which	O
has	O
been	O
developing	O
simulators	O
since	O
the	O
early	O
1990s	O
for	O
both	O
commercial	O
and	O
military	O
purposes	O
.	O
</s>
<s>
The	O
isiMotor2	O
engine	O
was	O
also	O
used	O
in	O
many	O
other	O
simulation	O
games	O
,	O
and	O
in	O
rFpro	B-Application
.	O
</s>
<s>
rFactor	B-Application
has	O
a	O
detailed	O
interface	O
during	O
offline	O
race	O
sessions	O
or	O
online	O
games	O
,	O
allowing	O
players	O
to	O
control	O
the	O
mechanical	O
setup	O
of	O
their	O
cars	O
,	O
chat	O
to	O
other	O
players	O
and	O
enter	O
the	O
racing	O
arena	O
in	O
their	O
vehicle	O
.	O
</s>
<s>
General	O
consensus	O
dictates	O
that	O
a	O
steering	O
wheel	O
will	O
provide	O
the	O
best	O
performance	O
gameplay	O
wise	O
,	O
though	O
a	O
joystick	B-Device
or	O
even	O
keyboard	B-Device
can	O
be	O
used	O
.	O
</s>
<s>
The	O
keyboard	B-Device
is	O
also	O
used	O
for	O
some	O
actions	O
,	O
like	O
requesting	O
pit	O
service	O
and	O
adjusting	O
brake	O
bias	O
.	O
</s>
<s>
This	O
is	O
analogous	O
to	O
buttons	O
on	O
modern	O
racing	O
car	O
steering	O
wheels	O
and	O
most	O
computer	B-Device
wheels	O
have	O
buttons	O
that	O
can	O
be	O
mapped	O
to	O
keystrokes	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
stock	O
vehicles	O
and	O
circuits	O
available	O
in	O
rFactor	B-Application
,	O
a	O
steady	O
stream	O
of	O
unofficial	O
mods	O
has	O
become	O
available	O
.	O
</s>
<s>
A	O
large	O
number	O
of	O
modifications	O
were	O
released	O
,	O
including	O
ones	O
that	O
recreated	O
seasons	O
from	O
Formula	B-Application
One	I-Application
,	O
NASCAR	O
,	O
IndyCar	O
and	O
V8	O
Supercars	O
.	O
</s>
<s>
Cars	O
from	O
the	O
racing	O
games	O
Forza	B-Application
Motorsport	I-Application
,	O
Need	B-Application
for	I-Application
Speed	I-Application
:	I-Application
Shift	I-Application
,	O
Shift	B-Application
2	I-Application
Unleashed	I-Application
,	O
Simulador	O
Turismo	O
Carretera	O
,	O
Top	O
race	O
2009	O
Simulator	O
,	O
TC2000	O
Racing	O
and	O
Test	B-Application
Drive	I-Application
Unlimited	I-Application
were	O
also	O
converted	O
into	O
rFactor	B-Application
with	O
the	O
mod	O
Shift	O
Street	O
.	O
</s>
<s>
With	O
the	O
release	O
of	O
the	O
SDK	B-Application
,	O
many	O
new	O
venues	O
were	O
created	O
and	O
released	O
as	O
unofficial	O
addons	O
to	O
the	O
game	O
.	O
</s>
<s>
Many	O
of	O
the	O
circuits	O
for	O
rFactor	B-Application
were	O
converted	O
from	O
other	O
games	O
,	O
including	O
GTR	B-Device
,	O
GT	B-Application
Legends	I-Application
,	O
TOCA	B-Application
Race	I-Application
Driver	I-Application
,	O
Grand	B-Application
Prix	I-Application
4	I-Application
and	O
Grand	B-Application
Prix	I-Application
Legends	I-Application
.	O
</s>
<s>
rFactor	B-Application
is	O
an	O
evolution	O
of	O
F1	O
Challenge	O
'	O
99–'02	O
,	O
but	O
without	O
the	O
licensing	O
of	O
Formula	B-Application
One	I-Application
circuits	O
and	O
teams	O
.	O
</s>
<s>
As	O
such	O
,	O
rFactor'''s	O
initial	O
release	O
only	O
included	O
four	O
fictitious	O
circuits	O
(	O
seven	O
as	O
of	O
v1.087	O
)	O
,	O
with	O
about	O
a	O
dozen	O
layouts	O
within	O
these	O
facilities	O
and	O
there	O
were	O
about	O
six	O
vehicle	O
classes	O
,	O
including	O
two	O
open	O
wheel	O
and	O
four	O
sedan	O
classes	O
.	O
</s>
<s>
On	O
January	O
25	O
,	O
2007	O
,	O
version	O
1.250	O
was	O
released.rFactor	O
Update	O
Version	O
1.250	O
,	O
rfactor.net,	O
25.01.07	O
On	O
October	O
12	O
,	O
2007	O
,	O
a	O
patch	O
was	O
released	O
that	O
brought	O
the	O
version	O
to	O
1.255	O
build	O
F.rFactor	O
1255	O
Patch	O
Released	O
,	O
10.12.07	O
,	O
at	O
rFactor	B-Application
newsroom	O
,	O
rfactor.net	O
rFactor	B-Application
also	O
advertises	O
an	O
advanced	O
tire	B-Application
model	I-Application
,	O
aiming	O
to	O
be	O
much	O
better	O
than	O
the	O
Pacejka	O
model	O
previously	O
used	O
in	O
most	O
simulators	O
.	O
</s>
<s>
rFactors	B-Application
tire	B-Application
model	I-Application
simulates	O
a	O
non-linear	O
tire	O
use	O
cycle	O
according	O
to	O
temperature	O
and	O
wear	O
.	O
</s>
<s>
rFactor	B-Application
has	O
extended	O
this	O
in	O
several	O
ways	O
.	O
</s>
<s>
It	O
can	O
run	O
mixtures	O
of	O
human	O
and	O
computer	B-Device
controlled	O
(	O
AI	O
)	O
vehicles	O
.	O
</s>
<s>
rFactor	B-Application
also	O
has	O
a	O
plugin-interface	O
for	O
third-party	O
addons	O
to	O
hook	O
in	O
,	O
which	O
allows	O
for	O
features	O
like	O
screen-overlays	O
or	O
radio	O
chatter	O
.	O
</s>
<s>
In	O
the	O
first	O
review	O
of	O
rFactor	B-Application
,	O
published	O
on	O
AutoSimSport	O
,	O
Jon	O
Denton	O
stated	O
:	O
"	O
What	O
the	O
tire	B-Application
model	I-Application
in	O
rFactor	B-Application
does	O
very	O
well	O
is	O
that	O
it	O
models	O
the	O
relationship	O
between	O
slip	O
angle	O
,	O
self	O
aligning	O
torque	O
and	O
cornering	O
force	O
-	O
and	O
it	O
does	O
this	O
better	O
than	O
anything	O
that	O
has	O
come	O
before	O
"	O
.	O
</s>
<s>
Writing	O
on	O
HonestGamers	O
,	O
Paul	O
Josua	O
concluded	O
:	O
"	O
It	O
's	O
a	O
little	O
unfair	O
to	O
hold	O
rFactor'''s	O
lack	O
of	O
accessibility	O
against	O
it	O
as	O
it	O
has	O
clearly	O
set	O
out	O
to	O
be	O
a	O
simulation	O
racer	O
.	O
</s>
<s>
It	O
does	O
a	O
fine	O
job	O
of	O
that	O
,	O
but	O
those	O
who	O
do	O
n't	O
demand	O
flawless	O
simulation	O
are	O
better	O
served	O
looking	O
elsewhere	O
"	O
.rFactor	O
was	O
a	O
finalist	O
for	O
PC	O
Gamer	O
USs	O
"	O
Best	O
Racing	O
Game	O
2005	O
"	O
award	O
,	O
which	O
ultimately	O
went	O
to	O
GTR	B-Device
:	I-Device
FIA	I-Device
GT	I-Device
Racing	I-Device
.	O
</s>
<s>
In	O
March	O
2009	O
,	O
ISI	O
announced	O
the	O
development	O
of	O
rFactor	B-Application
2	I-Application
,	O
which	O
includes	O
weather	O
effects	O
,	O
reflections	O
and	O
accurate	O
shadows	O
on	O
a	O
variety	O
of	O
textures	O
.	O
</s>
