// This is a simple script which demonstrates surf's ability to draw
// intersections of surfaces

rot_x=0.5;
rot_z=0.75;
rot_y=0.5;

transparence=10;
illumination=15;

// this is the first ellipsoid, on which we draw the intersection curve...
surface=1.3*x^2+2*y^2+2*z^2-120;

draw_surface;  // first draw the surface


// okay...then this seems to be the second ellipsoid.
cutsurface1=rotate(rotate(x^2+4*y^2+5*z^2-190, 1.3, yAxis),1.3,yAxis);

cut_with_surface;


// and save the picture...
color_file_format = ppm;  // use ppm color file format...

// the first "|" means that we write to a pipe instead of saving in a file, 
// i.e. we call image magick's convert with the image data as standard input. 
filename = "| convert -density 300x300 ppm:- eps:ellipsoidcut.eps";
save_color_image;