CADXChange

All LISP commands

CXDISTMeasuring and polylinesVersion 1.0.0Tested in AutoCAD

Measure a path point by point

Click along a route and see every leg's length, angle and offsets plus the running total, with Undo for the last point.

Download cxdist.lspLISP terms

How to use it

  1. Type CXDIST and click the first point.
  2. Click each following point. Choose Undo to drop the last one.
  3. Press Enter to finish and read the path length and the area it would enclose.

Good to know

  • Nothing is drawn, so it is safe to use on any drawing.

Load it in AutoCAD

  1. Save the file anywhere you like.
  2. Type APPLOAD, pick the file and choose Load.
  3. Type the command name: CXDIST.

To have it at every start, add it to the Startup Suite in the same dialog, or load a whole folder at once with the optional loader. About the optional loader

Tested in AutoCAD (full version). Other programs that run AutoLISP may work, but they are not tested.

The code

Plain text, nothing hidden. Copy it into a file named cxdist.lsp, or download it.

;;; ============================================================================
;;; CXDIST - Measure a path point by point
;;; Version 1.0.0
;;; CADXChange LISP tools - https://cadxchange.net/resources/lisp/cxdist
;;; Tested in: AutoCAD (full version). Other programs that run AutoLISP may work but are not tested.
;;; Copyright (c) CADXChange. Free for personal and commercial use; do not resell or
;;; republish it as a collection. Terms: https://cadxchange.net/legal/lisp-terms
;;; ============================================================================

;; The length of the path through PTS and, when the path is closed back to its start, the area it encloses: (length area).
(defun cx:dist-stats (pts / total i n sum)
  (setq total 0.0 sum 0.0 i 0 n (length pts))
  (repeat (1- n)
    (setq total (+ total (distance (nth i pts) (nth (1+ i) pts))) i (1+ i)))
  (setq i 0)
  (repeat n
    (setq sum (+ sum (- (* (car (nth i pts)) (cadr (nth (rem (1+ i) n) pts)))
                        (* (car (nth (rem (1+ i) n) pts)) (cadr (nth i pts)))))
          i   (1+ i)))
  (list total (abs (/ sum 2.0))))

(defun c:CXDIST ( / *error* cx:sv pts p r prec leg total)
  (setq *error* cx:err)
  (setq prec (getvar "LUPREC")
        pts  nil
        total 0.0)
  (setq p (getpoint "\nFirst point: "))
  (while p
    (if pts
      (progn
        (setq leg   (distance (car pts) p)
              total (+ total leg))
        (princ (strcat "\nLeg " (cx:num leg prec)
                       "   angle " (cx:num (* 180.0 (/ (angle (car pts) p) pi)) 2)
                       "   dx " (cx:num (- (car p) (car (car pts))) prec)
                       "   dy " (cx:num (- (cadr p) (cadr (car pts))) prec)
                       "   total " (cx:num total prec)))))
    (setq pts (cons p pts))
    (initget "Undo")
    (setq r (if (cdr pts)
              (getpoint p "\nNext point or [Undo] (Enter to finish): ")
              (getpoint p "\nNext point (Enter to finish): ")))
    (cond
      ((= r "Undo")
       (setq pts (cdr pts))
       (if (cdr pts) (setq total (- total (distance (car pts) (cadr pts)))) (setq total 0.0))
       (setq p (car pts)
             pts (cdr pts)))
      (T (setq p r))))
  (if (cdr pts)
    (progn
      (setq r (cx:dist-stats (reverse pts)))
      (princ (strcat "\nPath length " (cx:num (car r) prec)
                     ". Area enclosed if closed back to the start: " (cx:num (cadr r) prec) ".")))
    (princ "\nNeed at least two points."))
  (princ))


;;; ---- Shared helpers (used by the command above; identical in every CADXChange tool) ----

;; Close the undo step and put the system variables back.
(defun cx:end ()
  (foreach v cx:sv (setvar (car v) (cdr v)))
  (command "_.UNDO" "_End")
  (setq cx:sv nil)
  (princ))

;; Error handler: restores everything, stays quiet on Esc.
(defun cx:err (msg)
  (if (> (getvar "CMDACTIVE") 0) (command))
  (cx:end)
  (if (and msg (not (wcmatch (strcase msg) "*BREAK*,*CANCEL*,*EXIT*")))
    (princ (strcat "\nError: " msg)))
  (princ))

;; Real X as text with at most PREC decimals and no trailing zeros ("2.50" -> "2.5", "3.00" -> "3").
(defun cx:num (x prec / s)
  (setq s (rtos x 2 prec))
  (if (wcmatch s "*.*")
    (progn
      (while (= (substr s (strlen s)) "0") (setq s (substr s 1 (1- (strlen s)))))
      (if (= (substr s (strlen s)) ".") (setq s (substr s 1 (1- (strlen s)))))))
  (if (or (= s "-0") (= s "")) "0" s))

(princ "\nCXDIST loaded. Type CXDIST to start.")
(princ)

Version history

Version 1.0.0 · October 27, 2026

First release.

More commands: Measuring and polylines