Polylines with only one vertex.
Peter Notermans
Could anyone help me with the following problem.
A AutoCAD-operator at my company is creating polylines with only one vertex.
The person does not know how he creates those polylines.
We have got a separate application that checks to see if there are any
polylines consisting of only one vertex. This application deleteds the the
errors found.
I know that this used to be a problem in Acad R12 but it shouldend be a
problem in Acad R14.
Could anyone tell me how it is possible to create a polyline with only one
vertex?
Thanks up front.
jo...@fel.u-net.com
then stretch one vertex (endpoint) until it is at the same location as
the other.
Thomas Berger
>
> To create a polyline with 1 vertex:- create a polyline with 2 vertices
> then stretch one vertex (endpoint) until it is at the same location as
> the other.
No, this polyline would still have two vertices (at the same position).
You can create single-vertex-polylines thru programming. I have seen
some applications (among them an old Genius version) that added these
beasts to store drawing information as attached XData. You can't see or
select them manually.
--
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* Tom Berger
* ber...@architektur.uni-kassel.de
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Harold W Smith
> Hello,
>
> Could anyone help me with the following problem.
> A AutoCAD-operator at my company is creating polylines with only one vertex.
> The person does not know how he creates those polylines.
> We have got a separate application that checks to see if there are any
> polylines consisting of only one vertex. This application deleteds the the
> errors found.
> I know that this used to be a problem in Acad R12 but it shouldend be a
> problem in Acad R14.
> Could anyone tell me how it is possible to create a polyline with only one
> vertex?
>
> Thanks up front.
A polyline with one vertex?
Is it a visible entity?
If so, then it's probably a RAY.
Paste this to your command line
(cdr (assoc 0 (entget (car (entsel "\nSelect Entity")))))
If "RAY" is returned, then that's the problem....
Terry W. Dotson
> A polyline with one vertex?
> Is it a visible entity?
> If so, then it's probably a RAY.
In days of old before user dictionaries, third party software used to store
additional information in the drawing by generating a polyline with a single
vertex and storing additional information as extended entity data to the
'invisible' object.
R14 and newer versions generate a second point on these as the drawing is
converted so that you can see and erase them.
Good Luck, Terry
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Ian A. White
<ber...@architektur.uni-kassel.de> wrote:
> jo...@fel.u-net.com wrote:
> >
> > To create a polyline with 1 vertex:- create a polyline with 2 vertices
> > then stretch one vertex (endpoint) until it is at the same location as
> > the other.
>
> No, this polyline would still have two vertices (at the same position).
>
> You can create single-vertex-polylines thru programming. I have seen
> some applications (among them an old Genius version) that added these
> beasts to store drawing information as attached XData. You can't see or
> select them manually.
The main culprit for these polylines with only one vertex is AutoCAD
itself.
Essentially when you trim a closed polyline and it is trimmed in such
a way that the first segment is trimmed away, but the last segment is
left, AutoCAD happily leaves an invalid polyline. This was reported
to Autodesk when R12 first came out, but the standard line back was
that it had nothing to do with them. This also happens with LT1 and
LT2. You mention old versions of Genius. Do you know the version
numbers, as I have never seen this happen with clients who have been
using Genius for many years. AutoCAD will read in a drawing with
these invalid polylines, but will refuse to read in a DXF file with an
invalid polyline.
When I have investigated these invalid polylines, there has been no
extended entity data attached to them. They are simply polylines with
only one vertex. Adding a second vertex in the DXF file of 0,0 points
to the closed polyline that was trimmed. This is how I worked out
what was causing the problem.
--
Ian A. White, CPEng
WAI Engineering
Sydney 2000
Australia
Ph: +61 418 203 229
Fax: +61 2 9622 0450
Home Page: www.zipworld.net/~waiwhite