Edit LISP to find geometric center and ignore duplicates in a list.

[OSA]

Hi, I am still in the process of learning AUTOLISP, and would like to edit some script.  Recently I asked a question on autodesk and someone gave me this code which I am grateful for. but I have been trying to edit it for the past few days.

 

basically it selects a polyline, finds intersection points with the polyline and selected objects, then places text at points of intersection

 

the problem is 

1- many times the polyline intersects twice with an object, so it places two text objects

2-  the text should be at the geometric center of the polyline or block if necessary to transform it.

i really have tried and it was too complex for my level .. any help would be truly appreciated.

 

(vl-load-com)

(defun c:IntersNumbering ( / LM:intersections p s l o z e)
  
  (or *in-n* (setq *in-n* 0))
  
  ;; Intersections  -  Lee Mac ;; Returns a list of all points of intersection between two objects ;; for the given intersection mode.
  ;; ob1,ob2 - [vla] VLA-Objects ;;     mod - [int] acextendoption enum of intersectwith method
  
  (defun LM:intersections ( ob1 ob2 mod / lst rtn )
    (if
      (and
	(vlax-method-applicable-p ob1 'intersectwith)

	(vlax-method-applicable-p ob2 'intersectwith)

	(setq lst (vlax-invoke ob1 'intersectwith ob2 mod)
	      )
	     )
      (repeat
	(/ (length lst) 3)
	(setq rtn (cons (list (car lst) (cadr lst) (caddr lst)) rtn)
	      lst (cdddr lst))))
    (reverse rtn))
  
  ; ======================================================================================================
  
  
  (if (and (setq p (car (entsel "\nSelect a polyline: ")
			              );car
		        );setq
	   (princ "Select intersecting polylines and blocks, ")
	   
	   (setq s (ssget '((0 . "LWPOLYLINE,LINE,INSERT")))) 
	   (or (ssdel p s) t)
	   (setq *in-n* (cond ((setq f (getint (strcat "\nStart with <" (itoa (1+ *in-n*)) ">: ")))
			       (1- f))
			      (*in-n*)))
	   
	   (setq o (vlax-ename->vla-object p))
	   (setq l '()
		 z (getvar 'textsize))
	   );and
    (repeat (setq i (sslength s))
      (setq e (vlax-ename->vla-object (ssname s (setq i (1- i))))
	    l (append (LM:intersections o e acextendnone) l))))
  
  (and l
       (setq l (vl-sort l '(lambda (p1 p2) (< (vlax-curve-getdistatpoint p p1) (vlax-curve-getdistatpoint p p2)))))
       (foreach p l (entmake (list (cons 0 "TEXT") (cons 10 p) (cons 40 z) (cons 1 (itoa (setq *in-n* (1+ *in-n*))))))))
  
  (princ)
  )

 

[BIGAL]

"1- many times the polyline intersects" Using intersectwith with say a circle will give 2 points, so it may be as simple as just use the 1st point returned, The Circle would return (x1 y1 z1 x2 y2 z2) so just use (list car, cadr & caddr) of list returned.

Edited November 8, 2022 by BIGAL