Mline to Pline

[autolisper]

Hi All,

I am trying to draw a pline by connecting all the vertices of the mline. Below is my code, but it gives an error saying;

error: bad argument type: fixnump: 

 

(vl-load-com)

(defun c:hl_mltopline ()
  (setq	mspace (vla-get-modelSpace
		 (vla-get-activeDocument
		   (vlax-get-acad-object)
		 )
	       )
  )

  (setq	ml (vlax-ename->vla-object
	     (car (entsel "\nPick a multiline: "))
	   )
  )
  (setq coord (vlax-safearray->list (vlax-variant-value (vla-get-coordinates ml))))
  
  (setq pl_points_safearray (vlax-make-safearray vlax-vbDouble pl_points_list))
  (setq pline (vla-addlightweightpolyline mspace ))
  (entmod pline)
)

 

Could someone please help me fix this? Thanks in advance..!!

[Lee Mac]

There are many issues with your code -

• You define a variable 'coord' as the coordinates of the mline, but then supply vlax-make-safearray with the variable 'pl_points_list'.
• You are not supplying all of the required arguments for the addlightweightpolyline method, only the block container argument 'mspace'.
• The addlightweightpolyline method returns a vla-object, not an entity name which may be used with the entmod function.
• You are not declaring your local variables.
• You are not accounting for null user input.
• You are not accounting for the user selecting objects other than multilines.

 

[BIGAL]

Try this, there are other ways like entmake.

(defun c:hl_mltopline ( / mspace ent coords pline)
  (while (and (setq ent (car (entsel "\nPick a multiline Enter to exit : ")))
         (= (cdr (assoc 0 (entget ent))) "MLINE")
         )
  (setq mspace (vla-get-modelspace (vla-get-activedocument (vlax-get-acad-object))))
  (setq coords (vlax-safearray->list (vlax-variant-value (vla-get-coordinates (vlax-ename->vla-object ent)))))
  (setq tmp (vlax-make-safearray vlax-vbDouble (cons 0 (- (length coords) 1))))
      (vlax-safearray-fill tmp coords)
      (setq myobj (vla-addPolyline mspace tmp))
  )
(princ)
)

Maybe do a search next time 1st this is 3 years old and has lee's solution as well.

 

Edited January 24, 2020 by BIGAL

[autolisper]

Dear Lee,

Though I had started to explore Autolisp some years back, I could not continue my learning. Now recently I restarted exploring and its hardly a couple of months. Thanks a lot for your time and effort for pointing out the mistakes and for the advise....

[autolisper]

Dear Bigal,

Thanks for the code. I tried it. It gives the following error;

error: lisp value has no coercion to VARIANT with this type: 

 

But your code below worked exactly as I wanted...

https://www.cadtutor.net/forum/topic/63755-lisp-to-convert-a-mline-to-a-single-pline/?do=findComment&comment=525461

 

Thanks a lot..!!

 

Edited January 23, 2020 by autolisper

[Lee Mac]

13 hours ago, autolisper said:

Dear Lee,

Though I had started to explore Autolisp some years back, I could not continue my learning. Now recently I restarted exploring and its hardly a couple of months. Thanks a lot for your time and effort for pointing out the mistakes and for the advise....

 

You're most welcome.

 

On this subject, you might find this program useful.

[BIGAL]

Odd re HL_MLTOPLINE  above maybe its a Briscad thing and it works no errors draws a pline. I set the layer to another so could see it make pline ie not white colour.

 

Edited January 24, 2020 by BIGAL

[Roy_043]

7 hours ago, BIGAL said:

maybe its a Briscad thing

BricsCAD is more lenient when it comes to arguments for VL* functions.

[BIGAL]

Checked in Autocad and got error fixed, now works in Autocad and Briscad. Thanks Roy_043

 

 

Edited January 24, 2020 by BIGAL

[Roy_043]

What you have done is strange:

First you convert a variant to a list then you convert the list to a variant.

 

Also look at vlax-get/vlax-put.

[Lee Mac]

3 hours ago, Roy_043 said:

What you have done is strange:

First you convert a variant to a list then you convert the list to a variant.

 

To be fair to the OP, the safearray variants used by the coordinates property of an MLINE & LWPOLYLINE object are of different dimensions (the MLINE requires 3D coordinates, whereas the LWPOLYLINE requires 2D coordinates), and so the conversion (or some form of list manipulation if using vlax-get/vlax-put) would be required. BricsCAD may be more tolerant in this regard.

[Roy_043]

BricsCAD is not that tolerant. I was commenting on Bigal's revised code. The issue you mention does not apply there.

[Lee Mac]

23 minutes ago, Roy_043 said:

BricsCAD is not that tolerant. I was commenting on Bigal's revised code. The issue you mention does not apply there.

 

Sorry - I thought you were commenting on the OP's code, which performs the same conversion.

[BIGAL]

Quick answer from me is that I would not normally use (vla-addPolyline rather entmake or a command method as the list is xyz xyz xyz I would just make a point using list of nth's.

[ronjonp]

Code simplified per @Roy_043 suggestions.

(defun c:hl_mltopline (/ ent sp)
  (while (and (setq ent (car (entsel "\nPick a multiline Enter to exit : ")))
	      (= (cdr (assoc 0 (entget ent))) "MLINE")
	 )
    (or sp (setq sp (vlax-ename->vla-object (cdr (assoc 330 (entget ent))))))
    (vlax-invoke sp 'addpolyline (vlax-get (vlax-ename->vla-object ent) 'coordinates))
  )
  (princ)
)