closed polyline issue

[rmk]

why is it when you draw a polyline and using the endpoint osnap to pick the endpoint of the first line you drew, it's not a closed figure.

after drawing this, i selected the supposed closed figure and go to properties, it shows it's not a closed figure. i've even set the units to maximum decimal place
and id'd both endpoints and the coordinates are exactly the same.

I know you can select close and close the figure, and you can pick yes to close it in the properties dialog, just curious as to why this occurs.

i ran across this when trying to create parcels from what i thought were closed figures, but it fact they weren't.

thanks for any input.

[Ed Jobe]

Why? Its just the nature of the beast. The way you're doing it, you just have two vertices stacked. There's still no segment between the vertices. The only way to have a closed loop is to end with the CLOSE option.

[rmk]

thanks Ed, that makes sense. stacked vertices....i would never have thought of that. i'v had issues with feature lines as well, probably because of this very reason.

I'll never look at a closed polyline the same ever again.

once again, thanks for the info.

[rkmcswain]

To add to what @Ed Jobe said, it's the way polyline entities were designed. There is a flag that is set when a polyline it truly closed, and without it, it's not closed as far as AutoCAD is concerned. And any 3rd party tool that is looking for a closed polyline should honor this flag also.

If you had a drawing full of polylines that appear closed, but really are not, there are 3rd party tools to convert them all to true closed polylines (such as ToolPac's "Check Closing" tool)