Geometriesyr16 - Exemple 5

 input geometriesyr16;
 

 figureespace(-10u,-3u,10u,10u);
 Initialisation(5,35,20,800);
 color S,A,B,C,I,J,K,M[];
 S=(0,0,1);
 A=(1,0,0);
 B=(0,1,0);
 C=(-1/3,-1/2,0);
 I=1/3[C,A];
 J=1/4[S,A];
 K=3/5[S,B];
 M1=IntersectionPlanDroite(A,B,C,J,K);
 M2=IntersectionDroite(B,C,I,M1);
 path section;
 section=buildcycle(IntersectionPlanPlan(A,B,C,I,J,K),
   IntersectionPlanPlan(S,B,C,I,J,K),
   IntersectionPlanPlan(A,B,S,I,J,K),
   IntersectionPlanPlan(A,S,C,I,J,K));
 fillcolor:=jaune;
 transparence section;
 trace demidroite(K,M1) dashed dashpattern(on12bp off6bp on3bp off6bp);
 trace demidroite(I,M1) dashed dashpattern(on12bp off6bp on3bp off6bp);
 trace section withcolor orange;
 trace polygone(S,A,B);
 trace segment(A,B);
 trace chemin(A,C,B) dashed evenly;
 trace segment(S,C) dashed evenly;
 nomme.llft(A);
 nomme.lrt(B);
 nomme.bot(C);
 nomme.top(S);
 marque_p:="plein";
 nomme.lft(I);
 nomme.lft(J);
 nomme.urt(K);
 pointe(M1,M2);
 label.bot(btex M$_1$ etex,Projette(M1));
 label.bot(btex M$_2$ etex,Projette(M2));
 finespace;
 end