Accessing polyline vertices in AutoLisp

[Saurabh Manohar]

Hi everybody,
I am trying to access th vertices of a polyline in lisp. Earlier (upto r13)
I beleibve the method was (entnext e1) where e1 is my polyline entity got by
(car (entsel)) . But now in R14 and R2000 it give me nil. and (entget
(entnext e1)) give me an error ; error: bad argument type: lentityp nil
How do I access vertices of a polyline in R2000.
Also if I use AutoLISP to calculate some data, can I return a value to a VBA
call?

Thanks in advance.

Saurabh Manohar

[Tom Berger]

Saurabh Manohar wrote:
> Hi everybody,
> I am trying to access th vertices of a polyline in lisp. Earlier
> (upto r13) I beleibve the method was (entnext e1) where e1 is my
> polyline entity got by (car (entsel)) . But now in R14 and R2000 it
> give me nil. and (entget (entnext e1)) give me an error ; error: bad
> argument type: lentityp nil How do I access vertices of a polyline in
> R2000.

With the POLYLINE entity it is still the same procedure as it was in R13
and earlier. For LWPOLYLINE entities you need to walk through the
multiple DXF-group entities for the vertices (there is a (10 x y z)
entry for each vertex, ASSOC only gives you the first entry).

Tom Berger

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[TomD]

Here are the two routines I typically use for getting vertices out of
PLines. These should be carefully reviewed/tested if you're going to use
them. I believe they have some limitations, though I don't remember exactly
what they are. I wrote these, but I'm NOT a programmer.

;get Poly/LWPoly point list
(defun plplst ( plnam / plist subent vertex plist subent )
(setq subent (entnext plnam)
plist (list (dxfn 10 subent)) ;THIS LINE REVISED 12/2/97 by TLD
subent (entnext subent)
);setq
(while (/= (dxfn 0 subent) "SEQEND")
(setq vertex (trans (dxfn 10 subent) 0 1)
plist (append plist (list vertex))
subent (entnext subent)
);setq
);while
plist
);defun - returns list of all vertex coords of plnam (must be Heavy Poly)
(defun lwplplst ( plnam / elst plist )
(setq elst (entget plnam))
(while elst
(if (= (caar elst) 10)
(setq plist (append plist (list (cdar elst)))
elst (cdr elst)
);then
(setq elst (cdr elst));else
);if
);while
plist
);defun - returns list of all vertex coords of plnam (must be LWPoly)

As for returning lisp values to VBA, there isn't a *good* way. You might
want to check out the autodesk.autocad.customization.vba NG. There are some
real wizards there that can certainly point you in the right direction.

"Saurabh Manohar" <saurabh...@vsnl.net> wrote in message
news:asljcg$hn4$1...@news.vsnl.net.in...