Utility that shows first point of polyline?

Is there a utility that shows where the start/end point is of a polyline?
And also has the possibility to reverse it.
I use acad to genereate profile for a foam cutting machine and need to
change the direction
of the polyline.

Bert

 

The LIST command will give you the starting and end points (along with other
data).
To reverse the direction of a polyline, LWPolyline, or other object, try
REV.LSP from
http://www.turvill.com/t2/free_stuff
___

 

Type pedit at the command line and fallow the promts.

 

Paul, it hs been a while since I used Autocad. Been using Icad. Pedit in
Acad won't reverse a polyline?

 

Pedit in Acad won't reverse a polyline?

No.

Juergen

 

Hi,

Thanks for all the info.
I tried the rev.lsp
But nothing happens no output error or anything., and no reversing.
Did I do something wrong or is the tool incompatible with acad 2005?

Bert

 

How lame. It will in Intellicad.

 

It works with all versions. How are you attempting to use it?
___

 

Are you certain it isn't working? It isn't obvious on polylines using
CONTINUOUS linetype. Have you tried LISTing the polyline both before and
after using REV.LSP?
___

 

Here it also doesn't work, neiter in 2005 nor in 2004.
Try this: Draw a polyline. Start the pedit command, Edit, the marker is
visible at the startpoint of the polyline.
Now start rev.lsp, pick the polyline. No error message, nothing happens.
Start the pedit command, Edit, and the marker jumps - to the same end of the
polyline -> not reversed.

:-(
Juergen

 

Did some more experiments with REV.

First of all rev may conflict with the acad REVOLVE command.

Second: When drawing a simple poly line with a few segments it works now.

Third: With a bigger spline consisting out of a lot of segments (+/- 100) i
get:
===============
Command: (load"rev")
Command: rev
Pick an object to reverse:
At least one break point must be on polyline.*Invalid*
=================
Acad 2005

Bert

 

The conflict with REVolve (not a "vanilla" AutoCAD command) is easily fixed
by changing the name:
(defun CLREV ...
or whatever you choose. And, yes it is likely to have problems with very
complex objects; it's intended mostly for simple pipe runs or contours where
the user wants to reverse them to properly show text in complex linetypes.
___

 

Sorry, that is to say REV is defined as a shortcut in acad.pgp, and
therefore isn't a core command; REVOLVE, of course, is. To resolve any
conflict, two options exist: rename REV.LSP or change acad.pgp.

 

Here's one that will place an X (just like the pedit/edit vertex command) at
the beginning of the pline and ask if you want it reversed. The way it is
written the pline MUST be a LWpolyline, but could be modified to accept all
types.

;;Routine to show start point of pline and optionally reverse the direction
;;Jeff Mishler, November 2004
(defun c_check (/ ANS COORDS ENT ENTLST IDX NEWCOORDS OBJ newbulges)
;; Marker for point location on the screen
;; Oct. 2004 by Jeff Mishler
(defun Xmarksthespot (x y / leglen start)
(setq start (list x y)
leglen (* 0.03 (getvar "viewsize"))
)
(grdraw (polar start (angtof "135" 1) leglen)
(polar start (angtof "315" 1) leglen)
7)
(grdraw (polar start (angtof "45" 1) leglen)
(polar start (angtof "225" 1) leglen)
7)
)
(if (and (setq ent (entsel "\nSelect polyline: "))
(setq entlst (entget (car ent)))
(eq (cdr (assoc 0 entlst)) "LWPOLYLINE")
)
(progn
(vl-load-com)
(setq obj (vlax-ename->vla-object (car ent)))
(setq coords (vlax-get obj "coordinates"))
(setq idx 0
newcoords '()
newbulges '()
cnt 0)
(xmarksthespot (car coords) (cadr coords))
(initget "Yes No")
(setq ans (getkword "\nReverse?: [Yes/No]"))
(if (eq ans "Yes")
(progn
(while (< idx (length coords))
(setq newcoords (append (list (nth idx coords) (nth (1+ idx) coords))
newcoords))
(setq newbulges (append (list (- (vla-getbulge obj cnt))) newbulges))
(setq idx (+ 2 idx)
cnt (1+ cnt))
)
(vlax-put obj "coordinates" newcoords)
(setq newbulges (append (cdr newbulges) '(0.0)))
(while (/= -1 (setq cnt (1- cnt)))
(vla-setbulge obj cnt (nth cnt newbulges))
)
(redraw)
(xmarksthespot (car newcoords) (cadr newcoords))
)
)
)
)
(princ)
)
(princ "\n P_check loaded, type p_check to run......")

 

Here it also doesn't work ...

Ok, I found the error. In the function (defun prev ...) we see a line
(setq zoomit (null (ssget "c" final final)))

I modified this to
(setq zoomit (null (ssget "_c" final final)))
and now the rev.lsp works well like expected.


Juergen

 

Thank you, Jürgen,

That would explain why it worked on *some* installations and not others
(non-American English). I'll fix the one on my Web site.
___

 

Hi,

I tried it again with modified c to _c
My poly line changed color from blue to magenta and I got this error:
===================
Command: (load"revline")
Command: revline
Pick an object to reverse:
At least one break point must be on polyline.*Invalid*
===================
(I renamed rev to revline)

Bert

 

Is this one object in particular, or does this happen with all objects?

Email me a sample drawing. Please limit the drawing file to contain nothing
but your polyline that won't reverse.
Send it to
___

 

I know what it is,
plinetype was zero.
When change to 3 it works.
Regards,
Bert

 

Hi All

Plrev now works, thanks and also thanks to Jeff which posted p_check.
p_check also works, but nicely shows the begin and then asks wheter to
reverse or not,
when reversed it shows the changed beginpoint.

If plrev is better, could it be changed so that it shows also the begin
point, then ask whether to reverse,
then show the new beginpoint?

Bert