Topic: select pline origin

[daveland]

Does any one have a routine that allows you to select the origin of a polyline?

Example I have a boundary which is a closed polyline and i want to select a specific vertex for the starting point.  (Note: I also want to then reverse the polyline if necessary so it is going in the right direction. P.S.-I think I already have a pretty good routine for reversing.)

thanks,

Daveland

[ronjonp]

By "origin" do you mean centroid of a closed polyline?

[daveland]

I mean starting point.  In other words i want to select a vertex anywhere along a closed polyline as the starting point.

[Jeff_M]

I'm not sure about an easy coding solution, but if you use Break and select the point to break at as being on a vertex, then Pedit, select the section that had the Closing segment, join, now select the other segment. You will now have a closed pline starting at the selected vertex.

[Arizona]

That's an interesting method Jeff 

[LE]

I mean starting point.  In other words i want to select a vertex anywhere along a closed polyline as the starting point.

It won't matter if a fas or vlx file is provided?

[daveland]

I am not sure what an FAS file is but if it works in  Autodesk Land Desktop 2006 then FAS will be fine

[LE]

I am not sure what an FAS file is but if it works in  Autodesk Land Desktop 2006 then FAS will be fine

FAS & VLX are compiled lisp routines, let me look for those routines it was for an small civil routines I wrote in the past that do something like this:

Code: [Select]

ID_AREADER     [$(if,$(eq,$(getenv,"AutoAreaReaderGpoly"),"1"),!.)&Automatic Area And Polyline Direction Reader]^P'AREAREADER
               [--]
               [Change Polyline D&irection]^C^CRPOL
               [Remove Duplicate &Vertices]^C^CRVERTEX
               [Change &Starting Vertex]^C^CCHSVERTEX
       [Convert Circles Into Closed Polylines]^C^CCIRCLEPOLY


[daveland]

Sorry it didn't work either.

[LE]

Sorry it didn't work either.

Dave;

Give me some time (if you are answering to my previous post quote), to upload the routine here.... I am doing my day job now.... 

[daveland]

Hey Thanks. 
I am just finishing my day job but will check back in tomorrow.

Thanks you all for your efforts this will save me a tremendous amount of work if I can get it up and running.

I will check in tomorrow morning.

[T.Willey]

You can try this.  It's seems to work on my system.  No error checking, and not very pretty, but it did work on my test drawing.

Code: [Select]

(defun c:ReOrderPoly (/ Sel Pobj Pt PtList VertexPt PtListIndex PolyList StPos cnt tmpList)

(setq Sel (entsel "\n Select polyline: "))
(setq Pobj (vlax-ename->vla-object (car Sel)))
(setq Pt (getpoint "\n Select new starting point: "))
(setq PtList (vlax-get Pobj 'Coordinates))
(setq VertexPt 0)
(setq PtListIndex 0)
(repeat (/ (length PtList) 2)
 (vla-GetWidth Pobj VerTexPt 'StWd 'EndWd)
 (setq PolyList
  (cons
   (list
    VertexPt
    (list
     (nth PtListIndex PtList)
     (nth (1+ PtListIndex) PtList)
    )
    (vla-GetBulge Pobj VertexPt)
    StWd
    EndWd
   )
   PolyList
  )
 )
 (setq VertexPt (1+ VertexPt))
 (setq PtListIndex (+ 2 PtListIndex))
)
(foreach Lst PolyList
 (if (equal (list (car Pt) (cadr Pt)) (cadr Lst))
  (setq OldIndex (car Lst))
 )
)
(setq VertexPt 0)
(setq PtList nil)
(setq PolyList (reverse PolyList))
(setq StPos (vl-position (assoc OldIndex PolyList) PolyList))
(setq cnt StPos)
(repeat (length PolyList)
 (setq tmpList (nth cnt PolyList))
 (setq PtList (append PtList (cadr tmpList)))
 (vla-SetBulge Pobj VertexPt (caddr tmpList))
 (vla-SetWidth Pobj VertexPt (cadddr tmpList) (last tmpList))
 (setq VertexPt (1+ VertexPt))
 (setq cnt (1+ cnt))
 (if (> cnt (1- (length PolyList)))
  (setq cnt 0)
 )
)
(vlax-put Pobj 'Coordinates PtList)
(princ)
)


[LE]

OK... that works Tim (on the tests I did).... no need to post mine.

[T.Willey]

OK... that works Tim (on the tests I did).... no need to post mine.

Thanks for testing Luis.  I wouldn't use it (at least not at my current job), but it seemed fun to try and code it.

[CAB]

Tim,
Works here. Nice work.
If you wanted to add a vertex for the new start vertex it would be easy enough if straight line segment but if on an arc it's a differant story. That's why I chose the Break command like Jeff hinted at for my BreakAll routine.