AutoCAD 2013/2014/2015

AutoCAD 2013/2014/2015

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Distinguished Contributor
GPSJane
Posts: 179
Registered: ‎08-17-2013
Message 1 of 22 (1,231 Views)
Accepted Solution

Offset not working in one direction

1231 Views, 21 Replies
08-19-2013 10:28 AM

I have a polyline that meets itself back at the beginning. It should be closed and appears to be. I joined several lines to get the polyline. When I try to offset it I can only offset towards the inside and not the outside. Is there a reason for this or am I doing something wrong?

You've done sonething I can not determine. There are other lines under your ploylines

I've recreated your drawing and all offset commands now work.

 

 

I did get your attached dwg, and though I was not able to offset it, I had no trouble listing or otherwise selecting the object.

The problem ("Cannot offset that object.") is not unheard of, but I did not find a solution other than to recreate the geometry.

When I exploded the polyline, I did not find any "other lines under" it, but I did notice that one of the inside corners at the upper-right had three unnecessary line segments, one of which partially overlapped another.  One wouldn't think this could effectively disable the object, but...

There may have been something else going on, too, but at this point it may not be worth any more effort (unless it happens again).

If they are closed, you can EXTRUDE them as solids or surfaces.  If they're not closed, they will EXTRUDE as surfaces.  However if you are planning to form "walls" consider PRESSPULL, which will create a region between the two and automatically extrude it.

 

PressPull.gif

*Expert Elite*
JGerth
Posts: 2,226
Registered: ‎12-05-2005
Message 2 of 22 (1,227 Views)

Re: Offset not working in one direction

08-19-2013 10:33 AM in reply to: GPSJane

>> It should be closed and appears to be.

 

Appearance doesn't mean much when it comes to open or closed Plines.  What do PEdit or the Properties palette say?

 

WBlock out the pline, and post is as a dwg here so we can look at it.  Generally when I have a non-offset-able pline it's because of overlapping segments/duplicate vertices.  You could use the Properties palette and scroll though the vertex numbers and see where/how the marker jumps to.

Distinguished Contributor
GPSJane
Posts: 179
Registered: ‎08-17-2013
Message 3 of 22 (1,220 Views)

Re: Offset not working in one direction

08-19-2013 10:40 AM in reply to: JGerth

To be honest I have no idea what you just said, except the part about posting here. Ok how do I get the list of vertices to scroll through? In properties inspector I only get normal properties.

Distinguished Contributor
GPSJane
Posts: 179
Registered: ‎08-17-2013
Message 4 of 22 (1,212 Views)

Re: Offset not working in one direction

08-19-2013 10:48 AM in reply to: GPSJane

I figure out the WBLOCK thing but now I get an error here when I try to post: "The contents of the attachment doesn't match its file type."

Distinguished Contributor
GPSJane
Posts: 179
Registered: ‎08-17-2013
Message 5 of 22 (1,209 Views)

Re: Offset not working in one direction

08-19-2013 10:52 AM in reply to: JGerth
Actually does it need to be closed for offset any way?
*Expert Elite*
JGerth
Posts: 2,226
Registered: ‎12-05-2005
Message 6 of 22 (1,196 Views)

Re: Offset not working in one direction

08-19-2013 11:29 AM in reply to: GPSJane

Try zipping up the drawing and attaching that.  usually works better here....

 

to close or not to close -- you're right that it's not needed for offsetting,  but closing and open pline (or opening a closed one) may show you where the problem is.  the basic rule though on closed vs open is that you can't trust your eyes.  even a pline that starts and ends on the exact same point is not necessarily closed.

 

to step through the vetices of a pline, there are two basic ways.  Select the Pline, and in the property palette, look at the start of the Geometry section.  Click on the number that's showing, and a pair of <> arrows will appear.  click on one of them, and you'll see the geometry information change, and an 'X' marker move along the pline.  Keep clicking, and see of the X sticks in one spot, or jumps backwards.  If it does, that's your problem area to be repaired.

 

Second way would be to run the PEDIT command, select the pline, enter "E" for the Edit Vertex option, and use N (next) and P (previous) to step through the vetices.

 

One option you might want to try  with your original problematic Pline is to offseet it towards the middle, since that works, and then try offsetting _that new Pline_  to the outside while doubling the distance.  dunno - but it might work....

 

Distinguished Contributor
GPSJane
Posts: 179
Registered: ‎08-17-2013
Message 7 of 22 (1,189 Views)

Re: Offset not working in one direction

08-19-2013 11:40 AM in reply to: JGerth

JGerth thanks so much for the help.

 

The Geometry section shows insertion points for x, y and z and scale for x, y and z but no numbers or arrows. When I do PEDIT and it says 'select polyline' it just does nothing when I click on it. I don't understand! And I have a headache now.

 

Why is this so difficult?

Distinguished Contributor
GPSJane
Posts: 179
Registered: ‎08-17-2013
Message 8 of 22 (1,188 Views)

Re: Offset not working in one direction

08-19-2013 11:40 AM in reply to: GPSJane

Oh I forgot this.

 

**Master
dmfrazier
Posts: 2,757
Registered: ‎05-13-2003
Message 9 of 22 (1,187 Views)

Re: Offset not working in one direction

08-19-2013 11:41 AM in reply to: GPSJane

No, it doesn't need to be closed for offset to work in both directions, so it seems something unusual must be at play.

Since you are having trouble attaching a file (not unusual), if the polyline only has a few vertices, try entering "LIST" on the command-line, select your problem polyline, hit Enter, and then copy the results from the command-line window into a reply.  That might reveal a clue.

Distinguished Contributor
GPSJane
Posts: 179
Registered: ‎08-17-2013
Message 10 of 22 (1,184 Views)

Re: Offset not working in one direction

08-19-2013 11:48 AM in reply to: dmfrazier

I get the same problem; if I type LIST then it askes me to select an object but it does nothing just keeps asking e to select an object when I click on it. Its like I'm going backward.

 

I did attach that file above though, zipped.

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