Does "overkill command" not delete a line that is not exactly overlap??
Yes. Read about it in Help, which specifically mentions an Arc drawn over a portion of a Circle.
Kent Cooper, AIA 
Hi,
He's talking about two type of polyline segments ...
That means that polylines that totally overlapped or duplicate each other will be deleted with overkill and just keep one segment . also if it's partially overlapped will be combined to one polyline segment and of course depending on you overkill dialog options . zero-length polylines segments means that it have a start point and an end point but have zero-length . also Zero-length objects can be introduced inadvertently when importing data from other applications or when digitizing map data.
Imad Habash
>> overlapping pointed object without dimension are deleted. Right ?
either you try it or post here an example ( CAD dwg file ) for testing ?
Imad Habash
@Anonymous wrote:
Overlapping and zero-length polyline segments are deleted.
→ Directly in other word , overlapping pointed object without dimension are deleted. Right ?
If by "pointed object without dimension" you mean a POINT entity such as is drawn with the POINT or MEASURE or DIVIDE commands, "overlapping" on other kinds of objects, then no, those would not be deleted [unless there are more than one of those in the same place].
A zero-length polyline segment is one with both ends at the same place -- not a separate object, but a segment within a Polyline. To demonstrate, start a PLINE command, pick a point, continue, and somewhere along the way, pick exactly the same point twice in a row [whether by Object Snap or with positional Snap turned on], and continue further. Finish the Polyline, then select it, and in the Properties palette, look at the Geometry section, Current Vertex slot:
If you pick on the little up pointer at the right, you can watch the X marker of the current vertex move around the Polyline. When it gets to that place where you picked twice, the next pick on the up pointer will raise the vertex number, but the X will not move. That's a zero-length segment--two adjacent vertices in the same place.
Use Overkill on the Polyline, with the "Optimize segments within polylines" option checked, and it will report "1 overlapping object(s) or segment(s) deleted." Select the Polyline again, and run through the vertices, and it won't "hang" at that vertex location any more.
Kent Cooper, AIA
@Moshe-A wrote:
.... zero-length polyline's segments mean a polyline object that exist in database that has no length (not even 1 segment) zero length. it's not shown on screen.
....
It doesn't necessarily mean the entire Polyline has no length, only a segment somewhere within it. And a Polyline with no overall length could have any number of vertices all in the same place, and would still show on-screen, looking like a point [except if PDMODE is set to make Points look different, such a Polyline would not take on that look].
Kent Cooper, AIA
@Anonymous wrote:
.... [responses in blue] ....
1. A zero-length polyline segment is one with both ends at the same place.
→ there are only two ways to locate both end of an object at same point.
A--------------------------B
• make an object so small that both ends A and B merge with each other to get a same location. OR
• make a loop of an object so that A and B meet at same location.
I wasn't talking about both ends of an object, but both ends of a Polyline segment, which is [usually] one part of a larger object.
A-------------B--------------C
There could be two Polyline vertices both at B, which would define a zero-length segment from B to B between segments with length from A to [the first one at] B and from [the second one at] B to C. These are often referred to as "coincident vertices." OVERKILL, when set to optimize Polylines, will eliminate one of those coincident vertices at B. Such a possibility is not limited to intermediate locations, but can exist at ends, too [there could as easily be two (or more) coincident vertices at A and/or C].
2. Not a separate object.
→ both ends are of single object only.
[See above -- not about an object, but a segment within an object.]
3. segment within a polyline.
→ segment is one single line and it is the part of one polyline object. Right ?
Right, except that a Polyline segment can be either a line segment or an arc segment.
Kent Cooper, AIA
@Anonymous wrote:
....
2. There could be two Polyline vertices both at B,
→ • but there is only one polyline A-------------B--------------C, how can you say it two polyline ?
• I think you should say B is the common point of the two segment
AB and BC. Rights?
I didn't say it's two Polylines. I said there can be two coincident Polyline vertices at the same location within one Polyline. Please read more carefully. The vertices of such an overall Polyline would be at A, B, B again, C. Go back to Message 6, and follow carefully the "To demonstrate" instructions in the second paragraph. If you do that, and still don't understand, write back. I don't know how much more clearly it can be explained.
Badly drawn Polylines can have any number of vertices at the same location, and can even retrace back over themselves. It is possible that a Polyline that has that A---B---C appearance could have vertices at A, A again, A again, A again, B, C, C again, C again, B again, A again, B again, C again, A again. [Etc.]
Kent Cooper, AIA
