% D. Roegel, 7 January 2001 % roegel@loria.fr verbatimtex %&latex \documentclass{article} \usepackage{mathpple} \begin{document} etex input 3danim input 3dgeom output_res:=72; drawing_scale:=13cm; numeric b,c,d,e;b=70;c=0;d=20;e=50; % parameterized angles vardef def_T(expr inst)= new_obj_points(inst,6); % 6 points set_T_points(inst); enddef; vardef set_T_points(expr inst)= set_point(1)(0,0,0); set_point(2)(3*cosd(b),3*sind(b),0); set_point(3)(6*cosd(c),6*sind(c),0); new_vec(v_a);new_vec(v_b); vec_def_vec_(v_a,vec_I); vec_rotate_(v_a,vec_K,d); vec_prod_(v_b,v_a,vec_K); vec_rotate_(v_a,v_b,e); vec_mult_(v_a,v_a,4.5); vec_sum_(pnt(4),pnt(1),v_a); free_vec(v_b);free_vec(v_a); % Determination of I and J: % I=A + unit(AB) vec_diff(5,2,1); vec_unit(5,5); vec_sum(5,5,1); % J=A + 4*unit(AC) vec_diff(6,3,1); vec_unit(6,6); vec_mult(6,6,4); vec_sum(6,6,1); enddef; vardef draw_T(expr inst)= drawoptions(dashed evenly);draw_line(2,4);drawoptions(); draw_line(1,2);draw_line(1,3);draw_line(1,4); draw_line(2,3);draw_line(3,4); pickup pencircle scaled 2pt; draw_line(5,5);draw_line(6,6); label_obj.top(btex $A_1$ etex,1); label_obj.lft(btex $B_2$ etex,2); label_obj.bot(btex $C_3$ etex,3); label_obj.rt(btex $D_4$ etex,4); label_obj.lft(btex $I_5$ etex,5); label_obj.urt(btex $J_6$ etex,6); enddef; assign_obj("tetra","T"); new_vec(v_a);new_vec(v_b);new_vec(v_c); vec_diff_(v_a,pnt_obj("tetra",3),pnt_obj("tetra",4)); % vec(DC) vec_mult_(v_a,v_a,5); vec_diff_(v_b,pnt_obj("tetra",3),pnt_obj("tetra",2)); % vec(BC) vec_mult_(v_b,v_b,5); vec_diff_(v_c,pnt_obj("tetra",1),pnt_obj("tetra",3)); % vec(CA) vec_mult_(v_c,v_c,3); vec_sum_(Obs,pnt_obj("tetra",3),v_a); % C + 5DC vec_sum_(Obs,Obs,v_b);% C + 5DC + 5BC vec_sum_(Obs,Obs,v_c);% C + 5DC + 5BC + 3CA free_vec(v_c);free_vec(v_b);free_vec(v_a); %for i:=0 upto 20: i=8; beginfig(200+i); % Observator %set_point_(Obs)(20*cosd(3.6*i),20*sind(3.6*i),6); Obs_phi:=0;Obs_dist:=2;point_of_view_obj("tetra",1,Obs_phi); draw_obj("tetra"); endfig; %endfor; end.