Présentation de 3D_32a.jps

/syracuse/bbgraf/albums/sections_planes/3D_32a.jpg
jpegmode %quadrillage marks 400 setheight -10 8 setxrange -5.5 14.5 setyrange %% le plan de base /P1 {-9 -3} def /P2 {4 -5} def /P3 {8.5 0} def /a {-6 4.5 0} def /b {6 4.5 0} def /c {6 -4.5 0} def /d {-6 -4.5 0} def /s {0 0 11.4} def /s' {0 0 0} def /alpha 30 def /beta 165 def /vect_I {alpha cos alpha sin .5 mulv} def /vect_J {beta cos beta sin .9 mulv} def /vect_K {0 1} def /xyz2xy { 3 dict begin /z exch def /y exch def /x exch def vect_I x mulv vect_J y mulv vect_K z mulv addv addv end } def [/A /B /C /D /S /S'] [a b c d s s'] {xyz2xy} capply mapnp B C milieu /I defpoint I D A C interdroite /M defpoint S S' M paral C S interdroite /M' defpoint /fillstyle {.9 setgray fill} def [D I M'] polygone* gsave orange .8 setlinewidth mixte [A C] ligne grestore /dotscale {2 dup} def [S'] {times} plot 1.2 setlinewidth [A D C S] ligne [A S D] ligne gsave .8 setlinewidth pointilles [A B C] ligne [B S S'] ligne [M M'] ligne grestore 2 setlinewidth [-12 P2 P1 xdpoint P2 P3] ligne 12 setfontsize setTimesItalic (A) A dltext (B) B urtext (C) C drtext (D) D dltext (S) S urtext (s) S' brtext (H) P2 (0 7) ultext (I) I urtext