import solids;

size(6cm,0);

currentprojection=orthographic(0,8,2);
viewportmargin=(10,10);
currentlight=White;

revolution b=sphere(O,1);

draw(surface(b),yellow+opacity(0.3));

skeleton s;
b.transverse(s,reltime(b.g,0.5),P=currentprojection);
draw(s.transverse.back,linetype("8 8",8)+1bp+black);
draw(s.transverse.front,1bp+black);