The object \Lkeyword{vecteur} allows us to define and draw a \Index{vector}.
To do so in a simple way, we use the option \Lkeyword{args} to define
its components $(x,y)$ and we specify the point from where the
vector starts with the macro \Lcs{psProjection} (or we may use a
named point).
As with points, we can save the components of a vector using the
option \Lkeyword{name}.
\begin{LTXexample}[width=7.5cm]
\begin{pspicture}(-3,-3)(4,3.5)%
\psframe*[linecolor=blue!50](-3,-3)(4,3.5)
\psset{viewpoint=50 30 15,Decran=60}
\psset{solidmemory}
%% definition du plan de projection
\psSolid[object=plan,
definition=equation,
args={[1 0 0 0] 90},
planmarks,
name=monplan]
\psset{plan=monplan}
%% definition du point A
\psProjection[object=point,
args=-2 0.75,
name=A,text=A,
pos=dl]
\psProjection[object=vecteur,
linecolor=red,
args=1 1,
name=U](1,0)
\psProjection[object=vecteur,
args=U,
linecolor=blue](A)
\composeSolid
\axesIIID(4,2,2)(5,4,3)
\end{pspicture}
\end{LTXexample}
\subsection{Some more definitions}
There are other methods to define a vector in 2D. The options
\Lkeyword{definition} and \Lkeyword{args} allow us a variety of supported
methods:
