automatically drawn centerlines

[james.126519]

Is there a way to write a program so that it will find all of the 4-sided polylines on a particular layer, and draw a centerline parallel with the long sides of the polylines? there would potentially be hundreds of closed polylines to draw centerlines on.

I have an example file I am trying to upload, but it keeps telling me it exceeds my limit. It's only 53kb, and I don't know how to delete the old files I've had in the forum from years ago.

centerline.dwg

EDIT: Example file attached.

[Opie]

Create a new drawing, draw your example before and after, wblock that to a new drawing. You may need to place the new drawing into a compressed folder. You shouldn't but you might. Upload the zip file.

[james.126519]

When I go to upload, it says I am using 12.28MB of my 10MB limit. They are all old files from other threads, many years old. I just can not see any option to delete the old files and clear up some room.

I tried compressing the file, and it still gives me the same message.

[tedg]

When I go to upload, it says I am using 12.28MB of my 10MB limit. They are all old files from other threads, many years old. I just can not see any option to delete the old files and clear up some room.

I tried compressing the file, and it still gives me the same message.

You can go in and delete old attachments in the "Forum Actions""My Settings" tab above the page

[james.126519]

You can go in and delete old attachments in the "Forum Actions""My Settings" tab above the page

Thank you! I updated the original post with the example file.

[Tharwat]

Hi,
You did not show the where you would like to locate the centerline on 4 sides polylines in your drawing. !
Will it be on the two longest segments center point or in the center of rectangle ?

[james.126519]

Hi,
You did not show the where you would like to locate the centerline on 4 sides polylines in your drawing. !
Will it be on the two longest segments center point or in the center of rectangle ?

The red lines on the layer EPCENTER are the lines I would want added to the drawing. The drawing would already have the yellow polylines created. The centerlines would have to be lines on the EPCENTER layer.

[Tharwat]

Hopefully this is the one you are after.

(defun c:Test (/ int sel ent pts pt1 pt2 pt3 pt4 sg1 sg2 1pt 2pt )
  ;;----------------------------------------------------;;
  ;;	Author : Tharwat Al Choufi			;;
  ;; website: https://autolispprograms.wordpress.com	;;
  ;;----------------------------------------------------;;
  (and (princ "\nSelect closed polylines to draw centerline on longest segment : ")
       (setq int -1 sel (ssget '((0 . "LWPOLYLINE") (90 . 4) (-4 . "&=") (70 . 1))))
       (while (setq int (1+ int) ent (ssname sel int))
         (foreach itm (entget ent)
           (and (= (car itm) 10)
                (setq pts (cons (cdr itm) pts))
                )
           )
         (mapcar 'set '(pt1 pt2 pt3 pt4) pts)
         (and (equal (distance pt1 pt3) (distance pt2 pt4) 1e-2)
              (or (and (> (setq sg1 (distance pt1 pt2)) (setq sg2 (distance pt2 pt3)))
                       (setq 1pt (polar pt2 (angle pt2 pt3) (/ sg2 2.0))
                             2pt (polar pt1 (angle pt1 pt4) (/ sg2 2.0))
                             )
                       )
                  (setq 1pt (polar pt1 (angle pt1 pt2) (/ sg1 2.0))
                        2pt (polar pt3 (angle pt3 pt4) (/ sg1 2.0))
                        )
                  )
              (entmake (list '(0 . "LWPOLYLINE") '(100 . "AcDbEntity") '(100 . "AcDbPolyline") '(90 . 2) '(70 . 0)
                             '(8 . "EPCENTER") (cons 10 1pt) (cons 10 2pt))))
         (setq pts nil)
         )
       )
  (princ)
  )

[james.126519]

Hopefully this is the one you are after.

(defun c:Test (/ int sel ent pts pt1 pt2 pt3 pt4 sg1 sg2 1pt 2pt )
  ;;----------------------------------------------------;;
  ;;	Author : Tharwat Al Choufi			;;
  ;; website: https://autolispprograms.wordpress.com	;;
  ;;----------------------------------------------------;;
  (and (princ "\nSelect closed polylines to draw centerline on longest segment : ")
       (setq int -1 sel (ssget '((0 . "LWPOLYLINE") (90 . 4) (-4 . "&=") (70 . 1))))
       (while (setq int (1+ int) ent (ssname sel int))
         (foreach itm (entget ent)
           (and (= (car itm) 10)
                (setq pts (cons (cdr itm) pts))
                )
           )
         (mapcar 'set '(pt1 pt2 pt3 pt4) pts)
         (and (equal (distance pt1 pt3) (distance pt2 pt4) 1e-2)
              (or (and (> (setq sg1 (distance pt1 pt2)) (setq sg2 (distance pt2 pt3)))
                       (setq 1pt (polar pt2 (angle pt2 pt3) (/ sg2 2.0))
                             2pt (polar pt1 (angle pt1 pt4) (/ sg2 2.0))
                             )
                       )
                  (setq 1pt (polar pt1 (angle pt1 pt2) (/ sg1 2.0))
                        2pt (polar pt3 (angle pt3 pt4) (/ sg1 2.0))
                        )
                  )
              (entmake (list '(0 . "LWPOLYLINE") '(100 . "AcDbEntity") '(100 . "AcDbPolyline") '(90 . 2) '(70 . 0)
                             '(8 . "EPCENTER") (cons 10 1pt) (cons 10 2pt))))
         (setq pts nil)
         )
       )
  (princ)
  )

I don't know what you drink, but I owe you one!

[Tharwat]

I don't know what you drink, but I owe you one!

Its my secret so you can donate me one from HERE if you like.