Centerline between two polylines

[mhy3sx]

not workin in zwcad!!!

[mhy3sx]

this works 

 

;;; Centerline between two polylines
;;; version: 3.0  20260501

(defun c:CPL ( / e1 e2 obj1 obj2 len step d p1 p2 mid pts)

  (vl-load-com)

  (defun getObj (msg)
    (car (entsel msg))
  )

  (defun midpoint (a b)
    (mapcar '(lambda (x y) (/ (+ x y) 2.0)) a b)
  )

  (if (and
        (setq e1 (getObj "\nSelect first polyline: "))
        (setq e2 (getObj "\nSelect second polyline: "))
      )
    (progn
      (setq obj1 (vlax-ename->vla-object e1))
      (setq obj2 (vlax-ename->vla-object e2))

      (setq len (min
                  (vlax-curve-getDistAtParam obj1 (vlax-curve-getEndParam obj1))
                  (vlax-curve-getDistAtParam obj2 (vlax-curve-getEndParam obj2))
                )
      )

      ;; sampling resolution
      (setq step (/ len 50.0))
      (setq d 0.0)
      (setq pts '())

      (while (<= d len)
        (setq p1 (vlax-curve-getPointAtDist obj1 d))
        (setq p2 (vlax-curve-getClosestPointTo obj2 p1))
        (setq mid (midpoint p1 p2))
        (setq pts (cons mid pts))
        (setq d (+ d step))
      )

      ;; draw polyline
      (command "_pline")
      (foreach p (reverse pts)
        (command p)
      )
      (command "")

      (princ "\nCenterline created.")
    )
  )

  (princ)
)

 

Edited May 1 by mhy3sx