At times you may need to convert the line to polyline or polyline to a spline and sometimes Spline to a Polyline. You can do all of these tasks using few simple commands, let’s see how it can be done.

2019-01-02 2019-01-02. 2019-01-02 2019-01-02.

Converting Line to Polyline

You can convert Line to Polyline using “Polyline Edit” tool of AutoCAD, using this tool you can also convert an arc or spline into a polyline. However, you can’t convert circle, ellipse and elliptical arc into a polyline using this tool.

Type PE on the command line and press Enter to start polyline edit command, the command line will prompt you to select objects for making changes. Click on the object which you want to change to polyline, you can also select multiple objects by selecting Multiple from the command prompt.

Once you have made selection a new prompt will appear on the command line stating that selected object is not a polyline do you want to convert it as shown in the image below. Type Y and press enter twice to convert the object into a polyline and exit this command.

Converting Polyline to true spline

To convert a polyline into true spline type PE and press enter, then select polyline which you want to convert and select spline from prompt appearing on the command line. Press enter to exit polyline edit command.

This will convert your polyline into a “polyline spline” which looks like a spline but inherits properties of the 2D polyline.

To convert it into true spline type SPE on the command line and press Enter. This will start Spline Edit command, select “polyline spline” from drawing area and press Enter. The 2D polyline will be converted into a true spline and it will also inherit all the properties of a spline.

Converting Spline to Polyline

To convert a Spline into a polyline type PE on the command line press enter then select the spline from drawing area and press enter again. The spline will be converted into a polyline.

Alternatively, you can also use Spline Edit (SPE) command to convert a true spline into a polyline by simply selecting “Convert to Polyline” option from the command line options.

In this case when the command prompts you to specify the precision enter the default value 10 or any other value which you like. Higher the value of precision more accurate will be the converted polyline with respect to the spline but it will also create a dense polyline.

The value of precision can be set between 0 and 99.

Thanks, R.K McSwain for suggesting this tip, see more tips from him on Cadpanacea. If you have questions related to this tip let me know in comments below.

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LESSON 2-7

POLYLINES

Topics covered in this Lesson:

Polylines - creating and editing, Revision Clouds

A polyline is an object in AutoCAD that consists of one or more line (or arc) segments. A rectangle is an example of a polyline that you are already familiar with. As you've seen, it is one object that can be modified and worked with easier than four separate lines.

Polylines are created using the POLYLINE command, invoked by typing PL at the command line. To draw a simple polyline, draw it as though you are using the line command. The only difference is that it is one object instead of many.

Polylines have some unique qualities that make them very useful:

They can have width (constant or varying)

They can consist of arcs and lines.

They can be edited

They can be joined together.

They can be exploded into individual segments

Command	Keystroke	Icon	Location	Result
Polyline	Pline / PL	Home > Draw > Polyline	Creates a polyline of arcs and/or lines.
Polyline Edit	Pedit / PE	Home > Modify > Polyline Edit	Edits polyline objects
Explode	Explode / Exp	Home > Modify > Explode	Separates objects into individual components
Revcloud	Revcloud	Home > Draw > Revcloud	Draws a (rectangular by default) Revcloud

When you start the command, you will notice that there are several options available:

Command: PL PLINE
Specify start point:
Current line-width is 0.0000
Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

Remember that any time you want to choose an option, you type in the Capitol letter of that option.

One important tool is the Close option. This truly closes a polyline, which is different that just having two ends meeting at the same point - it's like welding the ends together. A closed polyline is required for extruding into 3-D space and other modifications. If you use the C option while drawing to complete your polyline, it will automatically be closed.

The Spline option allows you to draw a shape of lines using arcs and/or straight lines and then change them into one flowing curve. (Spline is also a separate command on its own.)

Also by changing the Width of a polyline, you can get some different looks to your lines. This is one way you can draw an arrow in AutoCAD:

Command: PL PLINE
Specify start point: <PICK FIRST POINT>
Current line-width is 0.0000
Specify next point or [Arc/Halfwidth/Length/Undo/Width]: W
Specify starting width <0.0000>: 1

Specify ending width <1.0000>: <ENTER>

Specify next point or [Arc/Halfwidth/Length/Undo/Width]: <PICK SECOND POINT>
Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: W

Specify starting width <1.0000>: 4

Specify ending width <4.0000>: 0

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: <PICK THIRD POINT>
Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: <PICK FOURTH POINT>

Depending upon the length of your lines, you may end up with a polyline that looks like this: