Please help! Lisp problem

[jlee107]

Hello, just to let you all know I only have basic knowledge of coding and I used ChatGpt to create this code. I'm trying to create a Lisp for zwcad(autocad) that could help me to increase my performance at my job. I want a block name to be automatically chosen and placed according to a length of a polyline selected on a model space after command is executed. So after I select a polyline, it should calculate a length of a polyline and find a midpoint. I want base point of a block to be an inserting point of a block and base point should be placed at midpoint of a polyline. For example if a length of a polyline I select is '8000mm', it calls a block name '7100e (8000-900 + suffix 'e')' from the block list and places that block at midpoint of selected polyline. I am certain there are block names ranging from 5400e~12200e (in increment of 100), but it doesn't seem to be able to find a block name appropriate to the length of a polyline. I've been keep getting this error message "Error: Retrieving the ID of the failed name - nil". Please help me it's urgent...

(setq selectedPolyline (car (entsel "\nSelect a polyline: ")))

(if (and selectedPolyline

         (member (cdr (assoc 0 (entget selectedPolyline))) '("POLYLINE" "LWPOLYLINE")))

    (progn

      (setq polylinePoints (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget selectedPolyline))))

      ;; Ensure there are at least two points

      (if (< (length polylinePoints) 2)

          (princ "\nError: The selected polyline must have at least two points.")

        (progn

          (setq startPoint (car polylinePoints))

          (setq endPoint (cadr polylinePoints))

          ;; Calculate the midpoint

          (setq midpoint

                (list (/ (+ (car startPoint) (car endPoint)) 2.0)

                      (/ (+ (cadr startPoint) (cadr endPoint)) 2.0)

                      0.0))

          ;; Calculate polyline length

          (setq polylineLength

                (distance (list (car startPoint) (cadr startPoint) 0.0)

                          (list (car endPoint) (cadr endPoint) 0.0)))

          ;; Calculate block name

          (setq blockName (strcat (rtos (- polylineLength 900) 2 2) "e"))

          ;; Insert block at the calculated midpoint

          (command "_.INSERT" blockName midpoint 1.0 1.0 0.0)

          (princ (strcat "\nBlock '" blockName "' placed."))

        )

      )

    )

  (princ "\nError: Please select a valid polyline.")

)

[cadffm]

Hi,

there is a special forum for Lisp, next door.

>  "I only have basic knowledge of coding"

Okay

> "and I used ChatGpt to create this code."

😞

I will not give my full support to beginners-with-chatGPTcode (not good, if you don't know the basics), but:

 Look at RTOS

 (rtos (- polylineLength 900) 2 2)

Polylineline length = 1922.00000000

result = "1022.00"

You need zero decimal numbers

 (setq blockName (strcat (rtos (- polylineLength 900) 2 0) "e"))

[cadffm]

Hi again,

back at my PC I checked the code: It will work! (with my tiny 'rtos' edit)

some comments more

(defun c:TEST nil

(setq selectedPolyline (car (entsel "\nSelect a polyline: ")))

(if (and selectedPolyline
         (member (cdr (assoc 0 (entget selectedPolyline))) '("POLYLINE" "LWPOLYLINE"))) ; Allow 2 kind of plines
     (progn
      (setq polylinePoints (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget selectedPolyline)))) ; will NOT work with POLYLINE objects"

      ;; Ensure there are at least two points
      (if (< (length polylinePoints) 2)
          (princ "\nError: The selected polyline must have at least two points.")
        (progn
          (setq startPoint (car polylinePoints))
          (setq endPoint (cadr polylinePoints))

          ;; Calculate the midpoint
          (setq midpoint
                (list (/ (+ (car startPoint) (car endPoint)) 2.0)
                      (/ (+ (cadr startPoint) (cadr endPoint)) 2.0)
                      0.0))

          ;; Calculate polyline length
          (setq polylineLength
                (distance (list (car startPoint) (cadr startPoint) 0.0)
                          (list (car endPoint) (cadr endPoint) 0.0)))

          ;; Calculate block name
          (setq blockName (strcat (rtos (- polylineLength 900) 2 0) "e"))

          ;; Insert block at the calculated midpoint
          ;;;(command "_.INSERT" blockName midpoint 1.0 1.0 0.0) ; Think about running osnaps command statements!
          (if (or
                (tblobjname "BLOCK" blockname)
                (findfile (strcat blockname ".dwg"))
              )
              (command "_.INSERT" blockName "_non" midpoint 1.0 1.0 0.0)
              (alert (strcat "Block '" blockname "' missing"))
          )

          (princ (strcat "\nBlock '" blockName "' placed."))
        )
      )
    )
  (princ "\nError: Please select a valid polyline.")
)


)

[jlee107]

Thank you for your reply and I kinda understand what the problem is now, but lisp still doesn't work and not able to load any type of block. I will ask on special forum.

[jlee107]

I have changed the code according to your suggestion. I also ran the test to check if it's retrieving proper information with a fixed value such as 8000. It does return as 7100e, but I'm still having the same issue.

[cadffm]

Try my edited code above.

Sample file attached

edit

Is it working now?

new Testfile with three different situations

Another IF to make your program more smart:

something like that:

(IF <length of polyline divideable with 100>

    (IF <matching block found>

          insert a new blockreference

          alert 'Block missing'

    )

   alert 'Invalid length'

)

[jlee107]

Thank you! It does work properly like I want it to.