1 \section{\Index{Solid strip
}}
3 The strip is a folding screen positioned horizontally on the floor. The base of the folding screen is defined in the plane $Oxy$ by the coordinates of its vertices by the parameter
\Lkeyword{base
}:
5 \psSolid[object=ruban,h=
3,base=x1 y1 x2 y2 x3 y3 ...xn yn,ngrid=n
](
0,
0,
0)
%
8 \subsection{A simple
\Index{folding screen
}}
9 \begin{LTXexample
}[width=
9.5cm
]
10 \psset{lightsrc=
10 0 10,viewpoint=
50 -
20 30 rtp2xyz,Decran=
50,unit=
0.75}
11 \begin{pspicture
}(-
5.5,-
4.5)(
7,
5)
12 \psSolid[object=grille,base=-
4 6 -
4 4,action=draw,linecolor=gray
](
0,
0,
0)
13 \psSolid[object=ruban,h=
3,fillcolor=red!
50,
19 \axesIIID(
0,
2,
0)(
6,
6,
4.5)
24 \subsection{A sinusoidal folding screen
}
25 \psset{lightsrc=
10 30 10,viewpoint=
50 50 20 rtp2xyz,Decran=
50}
28 \begin{pspicture
}(-
10,-
6)(
12,
8)
29 \defFunction{F
}(t)
{2 t
4 mul cos mul
}{t
20 div
}{}
30 \psSolid[object=grille,base=-
6 6 -
10 10,action=draw,linecolor=gray
](
0,
0,
0)
31 \psSolid[object=ruban,h=
2,fillcolor=red!
50,
33 base=-
200 200 {F
} CourbeR2+,
%% -200 5 200 {/Angle ED 2 Angle 4 mul cos mul Angle 20 div } for,
35 \axesIIID(
5,
10,
0)(
7,
11,
6)
40 \subsection{A
\Index{corrugated surface
}}
41 This is the same object as before with an additional rotation of $
90^
{\mathrm{o
}}$ around $Oy$.
43 \psset{lightsrc=
10 30 10,viewpoint=
50 50 20 rtp2xyz,Decran=
30}
46 \begin{pspicture
}(-
14,-
7)(
8,
5)
47 \defFunction{F
}(t)
{t
4 mul cos
}{t
20 div
}{}
48 \psSolid[object=grille,base=
0 16 -
10 10,action=draw,linecolor=gray
](
0,
0,
0)
49 \psSolid[object=ruban,h=
16,fillcolor=red!
50,RotY=
90,incolor=green!
20,
51 base=-
200 200 {F
} CourbeR2+,
53 \axesIIID(
16,
10,
0)(
20,
12,
6)
57 We can then imagine it to be like a corrugated iron roof of a shed.
60 \subsection{An asteroidal folding screen: version
1}
62 The contour of the folding screen is defined within a loop:
64 base=
0 72 360 {/Angle ED
5 Angle cos mul
5 Angle sin mul
65 3 Angle
36 add cos mul
3 Angle
36 add sin mul
} for
67 the blueish surface on the bottom is defined with the help of a polygon, where the vertices are calculated by the command\\
68 \verb+
\psPoint(x,y,z)
{P
}+
70 \multido{\iA=
0+
72,
\iB=
36+
72,
\i=
0+
1}{6}{%
71 \psPoint(
\iA\space cos
5 mul,
\iA\space sin
5 mul,
0)
{P
\i}
72 \psPoint(
\iB\space cos
3 mul,
\iB\space sin
3 mul,
0)
{p
\i}
74 \pspolygon[fillstyle=solid,fillcolor=blue!
50](P0)(p0)(P1)(p1)(P2)(p2)
75 (P3)(p3)(P4)(p4)(P5)(p5)
78 \psset{lightsrc=
10 0 10,viewpoint=
50 20 30 rtp2xyz,Decran=
50}
79 \begin{LTXexample
}[width=
7.5cm
]
81 \begin{pspicture
}(-
9,-
5)(
9,
7)
82 \multido{\iA=
0+
72,
\iB=
36+
72,
\i=
0+
1}{6}{%
83 \psPoint(
\iA\space cos
5 mul,
\iA\space sin
5 mul,
0)
{P
\i}
84 \psPoint(
\iB\space cos
3 mul,
\iB\space sin
3 mul,
0)
{p
\i}
86 \pspolygon[fillstyle=solid,fillcolor=blue!
50](P0)(p0)(P1)(p1)(P2)(p2)(P3)(p3)(P4)(p4)(P5)(p5)
87 \defFunction{F
}(t)
{t cos
5 mul
}{t sin
5 mul
}{}
88 \defFunction{G
}(t)
{t
36 add cos
3 mul
}{t
36 add sin
3 mul
}{}
89 \psSolid[object=grille,base=-
6 6 -
6 6,action=draw,linecolor=gray
](
0,
0,
0)
90 \psSolid[object=ruban,h=
1,fillcolor=red!
50,
91 base=
0 72 360 {/Angle exch def Angle F Angle G
} for,
92 num=
0 1 2 3,show=
0 1 2 3,ngrid=
2](
0,
0,
0)
93 \axesIIID(
5,
5,
0)(
6,
6,
6)
98 \subsection{An asteroidal folding screen: version
2}
100 The bottom of the pot is defined by the object
\Lkeyword{face
} with the option
103 \psset{lightsrc=
10 0 10,viewpoint=
50 -
20 20 rtp2xyz,Decran=
50}
104 \begin{LTXexample
}[width=
7.5cm
]
106 \begin{pspicture
}(-
9,-
4)(
9,
7)
107 \defFunction{F
}(t)
{t cos
5 mul
}{t sin
5 mul
}{}
108 \defFunction{G
}(t)
{t
36 add cos
3 mul
}{t
36 add sin
3 mul
}{}
109 \psSolid[object=face,fillcolor=blue!
50,biface,
110 base=
0 72 360 {/Angle exch def Angle F Angle G
} for,
](
0,
0,
0)
111 \psSolid[object=grille,base=-
6 6 -
6 6,action=draw,linecolor=gray
](
0,
0,
0)
112 \psSolid[object=ruban,h=
1,fillcolor=red!
50,
113 base=
0 72 360 {/Angle exch def Angle F Angle G
} for,
115 \axesIIID(
5,
5,
0)(
6,
6,
6)