;DIET.LSP  routine to reduce vertexes of a lwpoly
;          written by Yorgos Angelopoulos aggior@panafonet.gr
(Defun C:DIET (/ osm old oldpl i n nodpl pllst ptyp 
                   lastel k pcol pltp play )
 (setvar "cmdecho" 0)
 (setq osm(getvar "osmode"))
 (setvar "osmode" 0)
 (setq old(entsel "\nSelect lwpoly to diet : "))
 (setq oldpl(entget(car old)))
 (setq nodpl(cdr(assoc 90 oldpl)))
 (setq ptyp (cdr(assoc 70 oldpl)))
 (setq pcol (cdr(assoc 62 oldpl)))
 (setq pltp (cdr(assoc 6 oldpl)))
 (setq play (cdr(assoc 8 oldpl)))
 (setq pllst '())
 (setq i 0)
 (while (car(nth i oldpl))
        (if (= (car(nth i oldpl)) 10)
            (progn
            (setq pllst (append pllst (list (cdr(nth i oldpl)))))
            (setq lastel (list (cdr(nth i oldpl))))
            );endprogn
        );endif
        (setq i (+ i 1))
 );endwhile
 (setq pllst '())
 (setq i 0)
 (setq k -1)
 (while (car(nth i oldpl))
        (if (= (car(nth i oldpl)) 10) 
            (if (= k -1)
                    (progn
                          (setq pllst (append pllst (list (cdr(nth i oldpl)))))
                          (setq k (* k -1))
                    );endprogn
                    (setq k (* k -1))
            );endif
        );endif
        (setq i (+ i 1))
 );endwhile
 (setq pllst (append pllst lastel))
 (if (= ptyp 1)
   (progn
         (setq pllst (append pllst (list(nth 0 pllst))))
         (setq pllst (cdr pllst))
   );endprogn     
 );endif
 (setvar "blipmode" 0)
 (command "pline")
 (foreach n pllst (command n))
 (if (= ptyp 1)
    (command "c")
    (command "")
 );endif
 (if (= pcol nil)
     (setq pcol "bylayer")
 );endif
 (if (= pltp nil)
     (setq pltp "bylayer")
 );endif
 (command "change" "l" "" "p" "la" play "c" pcol "lt" pltp "" )
 (entdel (car old))
 (setvar "osmode" osm)
 (setvar "cmdecho" 1)
 (setvar "blipmode" 1)
 (princ)
);close defun