# Thread: polyline vs 2d polyline

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## polyline vs 2d polyline

I have searched for an explanation but can't find one. Can someone explain the difference between a polyline and a 2d polyline and why does Autocad have both.

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## Re: polyline vs 2d polyline

Originally Posted by rmk
I have searched for an explanation but can't find one. Can someone explain the difference between a polyline and a 2d polyline and why does Autocad have both.
If I'm not mistaken, a polyline is a 2d polyline, (I don't know of a 2d pline command).
There is a 3D polyline though, command: "3dpoly" where you can set vertices at different elevations as well as x and y coordinates.

So to recap, "pline" = 2d polyline, versus "3dpoly" = 3d polyline.

thats my take on it.

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## Re: polyline vs 2d polyline

2D Polylines are the old style polylines. They store their vertex
information inefficiently compared to the lightweight polyline, or the
"normal" polyline to which you are used.

and this

a 2d polyline wil take up more memory than a regular polyline, as the vertex information is stored differently. the current 2d polyline system is how all 2d polylines used to be stored, and cad moved towards the newer way, "regular polylines" to cut down on memory use and regen time

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## Re: polyline vs 2d polyline

Originally Posted by dzatto

2D Polylines are the old style polylines. They store their vertex
information inefficiently compared to the lightweight polyline, or the
"normal" polyline to which you are used.
That's correct, 2d polylines are legacy objects from Acad R14 and earlier.

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## Re: polyline vs 2d polyline

Thanks for trying to explain it, but it is still as clear as mud to me. is there a way to convert 2d plines to "regular" plines, or am i stuck with them. i am trying to do some data extraction and some of the lines or regular and some are 2d. any suggestions.

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## Re: polyline vs 2d polyline

Originally Posted by rmk
Thanks for trying to explain it, but it is still as clear as mud to me. is there a way to convert 2d plines to "regular" plines, or am i stuck with them. i am trying to do some data extraction and some of the lines or regular and some are 2d. any suggestions.
Simply using the polyline edit (pedit) command on a 2D polyline converts it to a standard pline.

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## Re: polyline vs 2d polyline

Originally Posted by H'Angus
Simply using the polyline edit (pedit) command on a 2D polyline converts it to a standard pline.
Or you could use the CONVERTPOLY command. This lets you do multiple plines at once. You want to convert them to "light" plines.

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## Re: polyline vs 2d polyline

Terminology only -

the new-style polylines are often called "lightweight polylines" because they require less data storage.
as a result, older polylines are occasionally referred to as being "heavyweight".

I doubt that any of this will affect your data extraction though.

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## Re: polyline vs 2d polyline

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