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