% geombasic.mp % L. Nobre G. % 2003 input featpost3Dplus2D; verbatimtex \documentclass{article} \usepackage{beton} \usepackage{concmath} \usepackage{ccfonts} \begin{document} etex % Kind of graph that physicists do a lot. Play with the angles % and h a little to see what happens. Change the point of view f. % Change the position of symbols using the last argument of angline. beginfig(1); f := (3,5,2); Spread := 155; ShiftV := origin; gamma := 30; theta := 15; phi := 40; h := 1.2; p := 0.75; ppp := 0.8; mythick := 0.9pt; color c[], n[], H; c0 := (0,0,0); n0 := (cosd(gamma),0,sind(gamma)); n1 := (cosd(gamma+theta),0,sind(gamma+theta)); n2 := (cosd(gamma)*cosd(phi),cosd(gamma)*sind(phi),sind(gamma)); n3 := (cosd(gamma+theta)*cosd(phi), cosd(gamma+theta)*sind(phi),sind(gamma+theta)); n4 := (cosd(phi),sind(phi),0); H := h*(-sind(gamma),0,cosd(gamma)); c1 := (0,0,Z(p*n1)); c2 := (0,0,Z(p*n2)); c3 := (1,0,0); c4 := (0,0,1); c5 := (X(H),0,0); pickup pencircle scaled 1.25pt; drawarrow rp(c0)..rp(n0); drawarrow rp(c0)..rp(n3); drawarrow rp(c0)..rp(H); label.urt(btex $\vec{n}_0$ etex,rp(n0)); label.urt(btex $\vec{n}$ etex,rp(n3)); label.lft(btex $\vec{H}$ etex,rp(H)); pickup pencircle scaled mythick; cartaxes(1,1,1); % draw rp(c0)--rp(p*n1) dashed evenly scaled 2; % draw rp(c0)--rp(p*n2) dashed evenly scaled 2; draw rp(c0)--rp(c5)--rp(H) dashed evenly scaled 1.5; % draw rp(c1)..rp(p*n1) dashed evenly scaled 2; draw rp(c1)..rp(p*n3) dashed evenly scaled 1.5; % draw rp(c2)..rp(p*n0) dashed evenly scaled 2; % draw rp(c2)..rp(p*n2) dashed evenly scaled 2; draw rp(c0)..rp(n4) dashed evenly scaled 1.5; angline(c3,n0,c0,ppp,btex $\gamma$ etex,lft); % angline(n0,n1,c0,p,btex $\theta$ etex,rt); % angline(p*n0,p*n2,c2,X(p*n0),btex $\phi$ etex,lrt); % angline(p*n1,p*n3,c1,X(p*n1),btex $\phi$ etex,ulft); % angline(n2,n3,c0,p,btex $\theta$ etex,urt); angline(c4,H,c0,ppp,btex $\gamma$ etex,top); angline(n4,n3,c0,p,btex $\gamma+\theta$ etex,lft); angline(n4,c3,c0,p,btex $\phi$ etex,llft); endfig; verbatimtex \end{document} etex end.