;;===========================================================
;; PolyDir.LSP v1.0 (03-05-02) John F. Uhden, Cadlantic
;; This is freeware dedicated to Noah (?) and Cliff Middleton
;;
(defun C:PolyDir ( / @delta @cv_parse_list @polydir 2pi e ans)
   ;;-----------------------------------------------------------------------
   ;; This function returns the deflection angle (in radians) of two angles:
   ;;
   (defun @delta (a1 a2)
      (cond
         ((> a1 (+ a2 pi))
            (setq a2 (+ a2 2pi))
         )
         ((> a2 (+ a1 pi))
            (setq a1 (+ a1 2pi))
         )
      )
      (- a2 a1)
   )
   ;;-------------------------------------------------------------
   ;; Function returns a list of 3D points from a continuous list
   ;; as returned by (vlax-safearray->list (vlax-variant-value X))
   ;;
   (defun @cv_parse_list (data n / item new)
      (foreach element (reverse data)
         (setq item (cons element item))
         (if (= (length item) n)
            (setq new (cons item new) item nil)
         )
      )
      new
   )
   (defun @polydir (e / ent etype object coords flag i p1 p2 p3 sum)
      (cond
         ((/= (type e) 'ENAME) nil)
         ((not (vl-position (setq etype (cdr (assoc 0 (setq ent (entget e))))) '("AECC_CONTOUR" "LWPOLYLINE" "POLYLINE")))
            (prompt (strcat " Object selected is a(n) " etype))
         )
         ((and (setq flag (cdr (assoc 70 ent)))(> (boole 1 16 flag) 0))
            (prompt " Object selected is a 3DMESH")
         )
         (1 (setq object (vlax-ename->vla-object e)
                  coords (vlax-get object "Coordinates")
                  coords (@cv_parse_list coords (if (= etype "LWPOLYLINE") 2 3))
                  i 1
                  sum 0.0
            )
            (and
               flag
               (= (logand 1 flag) 1) ; closed
               (setq coords (reverse (cons (car coords)(reverse coords))))
            )
            (repeat (- (length coords) 2)
               (setq p1  (nth (1- i) coords)
                     p2  (nth i coords)
                     i   (1+ i)
                     p3  (nth i coords)
                     sum (+ sum (@delta (angle p1 p2)(angle p2 p3)))
               )
            )
            (if (minusp sum) "CW" "CCW")
         )
      )
   )
   (setvar "errno" 0)
   (setq 2pi (* pi 2))
   (while (/= (getvar "errno") 52)
      (if (setq ans (@polydir (setq e (car (entsel "\nSelect a polyline: ")))))
         (princ ans)
      )
   )
   (princ)
)