<s>
In	O
geometric	B-Application
modelling	I-Application
and	O
in	O
computer	O
graphics	O
,	O
a	O
composite	B-Algorithm
Bézier	I-Algorithm
curve	I-Algorithm
or	O
Bézier	O
spline	B-Algorithm
is	O
a	O
spline	B-Algorithm
made	O
out	O
of	O
Bézier	O
curves	O
that	O
is	O
at	O
least	O
continuous	O
.	O
</s>
<s>
In	O
other	O
words	O
,	O
a	O
composite	B-Algorithm
Bézier	I-Algorithm
curve	I-Algorithm
is	O
a	O
series	O
of	O
Bézier	O
curves	O
joined	O
end	O
to	O
end	O
where	O
the	O
last	O
point	O
of	O
one	O
curve	O
coincides	O
with	O
the	O
starting	O
point	O
of	O
the	O
next	O
curve	O
.	O
</s>
<s>
A	O
continuous	O
composite	O
Bézier	O
is	O
also	O
called	O
a	O
polybezier	B-Algorithm
,	O
by	O
similarity	O
to	O
polyline	O
,	O
but	O
whereas	O
in	O
polylines	O
the	O
points	O
are	O
connected	O
by	O
straight	O
lines	O
,	O
in	O
a	O
polybezier	B-Algorithm
the	O
points	O
are	O
connected	O
by	O
Bézier	O
curves	O
.	O
</s>
<s>
A	O
beziergon	B-Algorithm
(	O
also	O
called	O
bezigon	B-Algorithm
)	O
is	O
a	O
closed	O
path	O
composed	O
of	O
Bézier	O
curves	O
.	O
</s>
<s>
It	O
is	O
similar	O
to	O
a	O
polygon	B-General_Concept
in	O
that	O
it	O
connects	O
a	O
set	O
of	O
vertices	O
by	O
lines	O
,	O
but	O
whereas	O
in	O
polygons	B-General_Concept
the	O
vertices	O
are	O
connected	O
by	O
straight	O
lines	O
,	O
in	O
a	O
beziergon	B-Algorithm
the	O
vertices	O
are	O
connected	O
by	O
Bézier	O
curves	O
.	O
</s>
<s>
Some	O
authors	O
even	O
call	O
a	O
composite	B-Algorithm
Bézier	I-Algorithm
curve	I-Algorithm
a	O
"	O
Bézier	O
spline	B-Algorithm
"	O
;	O
the	O
latter	O
term	O
is	O
however	O
used	O
by	O
other	O
authors	O
as	O
a	O
synonym	O
for	O
the	O
(	O
non-composite	O
)	O
Bézier	O
curve	O
,	O
and	O
they	O
add	O
"	O
composite	O
"	O
in	O
front	O
of	O
"	O
Bézier	O
spline	B-Algorithm
"	O
to	O
denote	O
the	O
composite	O
case	O
.	O
</s>
<s>
Perhaps	O
the	O
most	O
common	O
use	O
of	O
composite	O
Béziers	O
is	O
to	O
describe	O
the	O
outline	O
of	O
each	O
letter	O
in	O
a	O
PostScript	B-Language
or	O
PDF	B-Application
file	I-Application
.	O
</s>
<s>
Such	O
outlines	O
are	O
composed	O
of	O
one	O
beziergon	B-Algorithm
for	O
open	O
letters	O
,	O
or	O
multiple	O
beziergons	B-Algorithm
for	O
closed	O
letters	O
.	O
</s>
<s>
Modern	O
vector	O
graphics	O
and	O
computer	O
font	O
systems	O
like	O
PostScript	B-Language
,	O
Asymptote	B-Language
,	O
Metafont	B-Operating_System
,	O
OpenType	O
,	O
and	O
SVG	B-Application
use	O
composite	B-Algorithm
Bézier	I-Algorithm
curves	I-Algorithm
composed	O
of	O
cubic	O
Bézier	O
curves	O
(	O
3rd	O
order	O
curves	O
)	O
for	O
drawing	O
curved	O
shapes	O
.	O
</s>
<s>
A	O
commonly	O
desired	O
property	O
of	O
splines	B-Algorithm
is	O
for	O
them	O
to	O
join	O
their	O
individual	O
curves	O
together	O
with	O
a	O
specified	O
level	O
of	O
parametric	O
or	O
geometric	O
continuity	O
.	O
</s>
<s>
While	O
individual	O
curves	O
in	O
the	O
spline	B-Algorithm
are	O
fully	O
continuous	O
within	O
their	O
own	O
interval	O
,	O
there	O
is	O
always	O
some	O
amount	O
of	O
discontinuity	O
where	O
different	O
curves	O
meet	O
.	O
</s>
<s>
The	O
Bézier	O
spline	B-Algorithm
is	O
fairly	O
unique	O
in	O
that	O
it	O
's	O
one	O
of	O
the	O
few	O
splines	B-Algorithm
that	O
does	O
n't	O
guarantee	O
any	O
higher	O
degree	O
of	O
continuity	O
than	O
.	O
</s>
<s>
It	O
is	O
,	O
however	O
,	O
possible	O
to	O
arrange	O
control	O
points	O
to	O
guarantee	O
various	O
levels	O
of	O
continuity	O
across	O
joins	O
,	O
though	O
this	O
can	O
come	O
at	O
a	O
loss	O
of	O
local	O
control	O
if	O
the	O
constraint	O
is	O
too	O
strict	O
for	O
the	O
given	O
degree	O
of	O
the	O
Bézier	O
spline	B-Algorithm
.	O
</s>
<s>
(	O
positional	O
continuity	O
)	O
requires	O
that	O
they	O
meet	O
at	O
the	O
same	O
point	O
,	O
which	O
all	O
Bézier	O
splines	B-Algorithm
do	O
by	O
definition	O
.	O
</s>
<s>
While	O
the	O
following	O
continuity	O
constraints	O
are	O
possible	O
,	O
they	O
are	O
rarely	O
used	O
with	O
cubic	O
Bézier	O
splines	B-Algorithm
,	O
as	O
other	O
splines	B-Algorithm
like	O
the	O
B-spline	B-Algorithm
or	O
the	O
β-spline	O
will	O
naturally	O
handle	O
higher	O
constraints	O
without	O
loss	O
of	O
local	O
control	O
.	O
</s>
<s>
However	O
,	O
applying	O
this	O
constraint	O
across	O
an	O
entire	O
cubic	O
Bézier	O
spline	B-Algorithm
will	O
cause	O
a	O
cascading	O
loss	O
of	O
local	O
control	O
over	O
the	O
tangent	O
points	O
.	O
</s>
<s>
The	O
curve	O
will	O
still	O
pass	O
through	O
every	O
third	O
point	O
in	O
the	O
spline	B-Algorithm
,	O
but	O
control	O
over	O
its	O
shape	O
will	O
be	O
lost	O
.	O
</s>
<s>
Applying	O
this	O
constraint	O
to	O
the	O
cubic	O
Bézier	O
spline	B-Algorithm
will	O
cause	O
a	O
complete	O
loss	O
of	O
local	O
control	O
,	O
as	O
the	O
entire	O
spline	B-Algorithm
is	O
now	O
fully	O
constrained	O
and	O
defined	O
by	O
the	O
first	O
curve	O
's	O
control	O
points	O
.	O
</s>
<s>
TrueType	O
fonts	O
use	O
composite	O
Béziers	O
composed	O
of	O
quadratic	B-Algorithm
Bézier	I-Algorithm
curves	I-Algorithm
(	O
2nd	O
order	O
curves	O
)	O
.	O
</s>
