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?
Solved! Go to Solution.
Solved! by Ron-C. See the answer in context.
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.
Solved! by dmfrazier. See the answer in context.
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).
Solved! by nestly2. See the answer in context.
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.
>> 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.
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.
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....
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?
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.
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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