\definecolor{Tan}{cmyk}{0.14,0.42,0.56,0}

\psset{lightsrc=50 10 30}

\psset{viewpoint=100 -30 25 rtp2xyz,Decran=75}
\begin{pspicture*}(-5,-3)(5,10)
\psframe*[linecolor=cyan!30](-5,-3)(5,10)
\psSolid[object=grille,base=-8 8 -8 8,action=draw**,ngrid=4,linecolor=red]%
\psSolid[object=new,RotX=0,RotY=0,RotZ=30,unit=0.2,fillcolor=Tan,grid,
    sommets= (sommets_chair.dat) run,
    faces={(faces_chair.dat) run}]%
\end{pspicture*}