Error expected VLA-OBJECT at [vlax-invoke]

[BeachinIt]

(defun c:draw-triangles-on-line ()
  (setq pline (car (entsel "\nSelect a polyline: ")))
  (setq numtri (getint "\nEnter the number of triangles: "))
  (setq vertices (vlax-invoke pline 'Vertices))
  (setq num-vertices (length vertices))
  (setq spacing (/ (vlax-curve-getDistAtParam pline (vlax-curve-getEndParam pline))
                    (+ numtri 1)))
  (setq startpt (vlax-curve-getStartPoint pline))
  (setq endpt (vlax-curve-getEndPoint pline))
  (setq midpoint (polar startpt (angle startpt endpt) (/ (distance startpt endpt) 2.0)))
  (setq vertex1 (polar midpoint (/ pi 2) (/ spacing 4.0)))
  (setq vertex2 (polar midpoint (/ (* 3 pi) 2) (/ spacing 4.0)))
  (setq i 0)
  (while (< i numtri)
    (setq pt1 (vlax-curve-getPointAtDist pline (+ spacing (* i spacing))))
    (setq pt2 (polar pt1 (angle startpt endpt) (/ (distance startpt endpt) 2.0)))
    (setq pt3 (polar pt2 (/ pi 2) (/ spacing 4.0)))
    (setq pt4 (polar pt2 (/ (* 3 pi) 2) (/ spacing 4.0)))
    (command "_.pline" pt3 pt4 pt2 "" pt1 "")
    (setq i (+ i 1))
  )
  (princ)
)

 

; ----- LISP : Call Stack -----
; [0]...C:DRAW-TRIANGLES-ON-LINE <<--
;
; ----- Error around expression -----
; (AL-ENAME2OBJ ENAME)
;
; error : bad argument type <<Entity name: 1c423a40>> ; expected VLA-OBJECT at [vlax-invoke]

 

1st box is the code, the 2nd box is my console output.
 

I believe my error is on line 3, but I'm uncertain what I'm doing wrong with this.

I'm looking to place triangles on a polyline where they are evenly intersected by a selected polyline, they will also be evenly spaced.

Any help is much appreciated!

[ronjonp]

The first step to becoming a proficient programmer is learning how to debug code. Open up the VLIDE and set break on error.

 

Then load the selection:

 

There are a couple of issues with line 3: (setq vertices (vlax-invoke pline 'vertices))

vlax-invoke requires a VLA-OBJECT (vlax-ename->vla-object pline) and a polyline does not have a vertices property, it's coordinates.

 

Here is a common way to get LWPOLYLINE coordinates

(mapcar 'cdr (vl-remove-if '(lambda (x) (/= 10 (car x))) (entget pline)))

This returns ((X Y) (X Y) (X Y) (X Y))

 

Another way is like this which works on "heavy" polylines as well:

(vlax-get (vlax-ename->vla-object pline) 'coordinates)

This returns (X Y X Y X Y X Y)

 

It does not look like you're using the vertices variable for anything except setting the num-vertices variable ? An easier way to get that number is through the 90 DXF code.

(cdr (assoc 90 (entget pline)))

Edited February 24, 2023 by ronjonp

[BIGAL]

Bricscad uses Blade not Vlide but similar approach to debugging code.

 

Not sure about this with no image or dwg to compare. (command "_.pline" pt3 pt4 pt2 "" pt1 "")

 

Always post an image or dwg helps sometimes way shorter and smarter solutions are offered.

[Steven P]

"bad argument type <<Entity name: 1c423a40>> ; expected VLA-OBJECT at [vlax-invoke]"

 

Tells you everything..... Argument - entity name - but it is expecting a VLA-Object at your line vlax-invoke

Or... you are using an entity name (pline) and the line wants a VLA-Object name.

 

(setq pline_Obj (vlax-ename->vla-object pline_Ent))

 

Should do that for you.

 

 

I couldn't find 'vertices (I don't do too much with VLA) - was giving me an error at that so got vertices by entget:

 

(defun c:DTOL ()
  (defun mAssoc ( key lst )
   (foreach x lst
     (if (= key (car x)) (setq l (cons (cdr x) l)) )
   )
   (reverse l)
  )

  (setq pline_Ent (car (entsel "\nSelect a polyline: ")))
  (setq numtri (getint "\nEnter the number of triangles: "))

(setq pline (vlax-ename->vla-object pline_Ent))
;;https://www.cadtutor.net/forum/topic/24364-vertices-of-a-polyline/
(setq vertices (mAssoc 10 (entget pline_Ent)) )


;  (setq vertices (vlax-invoke pline 'vertices))
  (setq num-vertices (length vertices))
  (setq spacing (/ (vlax-curve-getDistAtParam pline (vlax-curve-getEndParam pline))
                    (+ numtri 1)))
  (setq startpt (vlax-curve-getStartPoint pline))
  (setq endpt (vlax-curve-getEndPoint pline))
  (setq midpoint (polar startpt (angle startpt endpt) (/ (distance startpt endpt) 2.0)))
  (setq vertex1 (polar midpoint (/ pi 2) (/ spacing 4.0)))
  (setq vertex2 (polar midpoint (/ (* 3 pi) 2) (/ spacing 4.0)))
  (setq i 0)
  (while (< i numtri)
    (setq pt1 (vlax-curve-getPointAtDist pline (+ spacing (* i spacing))))
    (setq pt2 (polar pt1 (angle startpt endpt) (/ (distance startpt endpt) 2.0)))
    (setq pt3 (polar pt2 (/ pi 2) (/ spacing 4.0)))
    (setq pt4 (polar pt2 (/ (* 3 pi) 2) (/ spacing 4.0)))
    (command "_.pline" pt3 pt4 pt2 "" pt1 "")
    (setq i (+ i 1))
  )
  (princ)
)

 

 

Though the triangles part wasn't quote working for me - you can adjust that though?

 

 

[BIGAL]

Need an image.

 

Like Steven P

 

(setq plent (entsel "\nPick pline"))
(if plent (setq co-ord (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget (car plent))))))
(princ co-ord)

 

[BeachinIt]

UPDATED FUNCTION from @Steven P 

(defun c:DTOL ()
  (defun mAssoc ( key lst )
   (foreach x lst
     (if (= key (car x)) (setq l (cons (cdr x) l)) )
   )
   (reverse l)
  )

;  (setq pline_Ent (car (entsel "\nSelect a polyline: ")))
  (setq pline_Ent (entsel "\nPick pline"))
  (if pline_Ent (setq co-ord (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget (car plent))))))
  (princ co-ord)
  (setq numtri (getint "\nEnter the number of triangles: "))

(setq pline (vlax-ename->vla-object pline_Ent))
;;https://www.cadtutor.net/forum/topic/24364-vertices-of-a-polyline/
;;;(setq vertices (mAssoc 10 (entget pline_Ent)) )


;  (setq vertices (vlax-invoke pline 'vertices))
;;;  (setq num-vertices (length vertices))
  (setq spacing (/ (vlax-curve-getDistAtParam pline (vlax-curve-getEndParam pline))
                    (+ numtri 1)))
  (setq startpt (vlax-curve-getStartPoint pline))
  (setq endpt (vlax-curve-getEndPoint pline))
  (setq midpoint (polar startpt (angle startpt endpt) (/ (distance startpt endpt) 2.0)))
  (setq vertex1 (polar midpoint (/ pi 2) (/ spacing 4.0)))
  (setq vertex2 (polar midpoint (/ (* 3 pi) 2) (/ spacing 4.0)))
  (setq i 0)
  (while (< i numtri)
    (setq pt1 (vlax-curve-getPointAtDist pline (+ spacing (* i spacing))))
    (setq pt2 (polar pt1 (angle startpt endpt) (/ (distance startpt endpt) 2.0)))
    (setq pt3 (polar pt2 (/ pi 2) (/ spacing 4.0)))
    (setq pt4 (polar pt2 (/ (* 3 pi) 2) (/ spacing 4.0)))
    (command "_.pline" pt3 pt4 pt2 "" pt1 "")
    (setq i (+ i 1))
  )
  (princ)
)

I used the code from @Steven P and updated line of picking the line with console output from @BIGAL.  Thank you both for looking at this post and helping btw.

I ended up choosing the level line (at the very top) and received that console output.  Complaining that I'm missing an entity name

GOAL: I'm looking to place triangles on a polyline where they are evenly intersected by a selected polyline, they will also be evenly spaced.
---|>---|>---
 

; error : bad argument type <(<Entity name: 6303b640> (4.41025118198951 6.48940258141088 0.0))> ; expected ENTITYNAME at [vlax-ename->vla-object]
: DTOL
Pick pline((3.0 4.8) (11.5999989906226 4.80416668817499))
Enter the number of triangles: 2

; ----- LISP : Call Stack -----
; [0]...C:DTOL <<--
;
; ----- Error around expression -----
; (AL-ENAME2OBJ ENAME)
;
; error : bad argument type <(<Entity name: 5e007c20> (5.24157286165867 7.15019673704534 0.0))> ; expected ENTITYNAME at [vlax-ename->vla-object]

[Steven P]

You might to use this line:

 

(if pline_Ent (setq co-ord (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget (car pline_ent))))))

 

and not

(if pline_Ent (setq co-ord (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget (car plent))))))

 

Should fix the error

[BIGAL]

Just remove the (IF  )  if happy that you always pick the right thing, I use a different way to force a correct object pick.