% D. Roegel, 7 January 2001 % roegel@loria.fr verbatimtex %&latex \documentclass{article} \begin{document} etex input 3danim input 3dgeom output_res:=72; drawing_scale:=10cm; numeric lsa,lsb,lsc,aasc,aasb,absc; lsa=9;lsb=8;lsc=4;aasc=60;aasb=40;absc=30; vardef def_T(expr inst)= new_obj_points(inst,19); % 19 points set_T_points(inst); enddef; vardef set_T_points(expr inst)= save hp,kp,sa,sc,inter; set_point(1)(0,0,0); % S set_point(2)(lsa,0,0); % A set_point(4)(lsc*cosd(aasc),lsc*sind(aasc),0); % C vec_diff(5,2,1); vec_unit(5,5);vec_mult(5,5,lsb*cosd(aasb)); vec_sum(5,5,1); vec_diff(6,4,1); vec_unit(6,6);vec_mult(6,6,lsb*cosd(absc)); vec_sum(6,6,1); new_plane(hp)(1,1,1); new_plane(kp)(1,1,1); new_line(sa)(1,2); new_line(sc)(1,4); new_line(inter)(1,1); def_orth_pl_l_p_(hp)(sa)(pnt(5)); def_orth_pl_l_p_(kp)(sc)(pnt(6)); if def_inter_l_pl_pl(inter)(hp)(kp): % there is an intersection if def_point_at(3,-lsb,1)(inter): else: message "PROBLEM"; fi; new_plane(sac)(1,2,4); if def_inter_p_l_pl(13)(inter)(sac): else: message "PROBLEM";fi; free_plane(sac); else: message "PROBLEM"; set_point(3)(1,1,1); fi; def_right_angle(7,8,9,5,1,3); def_right_angle(10,11,12,6,1,3); def_right_angle(14,15,16,13,6,3); def_right_angle(17,18,19,13,5,3); free_line(inter);free_line(sc);free_line(sa); free_plane(kp);free_plane(hp); enddef; vardef draw_T(expr inst)= draw_line(1,2);draw_line_extra(1,4)(-.1,2);draw_line(1,3); draw_line(2,3);draw_line(3,4); draw_line_extra(3,13)(-0.5,1); drawoptions(dashed evenly); draw_line(2,4);draw_line(3,5);draw_line(3,6); draw_line_extra(3,13)(1,2); draw_line(13,6);draw_line(13,5); drawoptions(); draw_double_right_angle(7,8,9,5); draw_double_right_angle(10,11,12,6); draw_double_right_angle(14,15,16,13); draw_double_right_angle(17,18,19,13); label_obj.bot(btex $S$ etex,1); label_obj.rt(btex $A$ etex,2); label_obj.ulft(btex $B$ etex,3); label_obj.llft(btex $C$ etex,4); enddef; square_angle_size:=0.35; assign_obj("tetra","T"); %for i:=0 upto 20: i=0; beginfig(100+i); % Observator set_point_(Obs)(20*cosd(3.6*i-150),20*sind(3.6*i-150),6); Obs_phi:=90;Obs_dist:=2;point_of_view_obj("tetra",1,Obs_phi); draw_obj("tetra"); endfig; %endfor; end.