function exportPly(obj,filename)
  volumeToExport = bwmorph3(obj.volume,'remove');
  [X,Y,Z] = ind2sub(size(volumeToExport),find(volumeToExport));
  X = X*obj.resolution(1) + obj.origin(1);
  Y = Y*obj.resolution(2) + obj.origin(2);
  Z = Z*obj.resolution(3) + obj.origin(3);
  points = ([X Y Z]);
  plywrite(filename,points);
end