Explaining Polyline Sub Commands in AutoCAD

This is a continuation of my previous post AutoCAD for Dummies: How to Draw a Polyline. I’ll explain further the sub commands [Arc/Close/Halfwidth/Length/Undo/Width]:

Arc

This command is used if you wanted to create an arc from the last point of the open polygon you created connecting it to the first point. First create an open four sided polygon. Type “Pline” in the command prompt and create an open polygon, see Fig. 1. Then looking on the last AutoCAD prompt: Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: type “A” or “ARC” then press enter. An elastic arc will appear which you can stretch until the endpoint of the arc reach the first point to connect it. This time you can use OSNAP just to simplify the sample drawing. Press the “shift” button and press the right mouse button (while holding the shift button) to invoke the osnap menu. Select endpoint and drag your cursor to the first point and click your left mouse button. Then press enter to terminate the command loop (see Fig 2).

    autocad polyline icon

Fig. 1 – Draw An Open Polygon Using Pline Command

    autocad polyline icon

Fig. 2 – An Arc was Drawn

Closed

The Close option as I’ve said before in my previous post, it will automatically enclose an open polygon created by the polyline or “pline” command. To demonstrate, first create a series of lines, create a four sided polygon but don’t close the polygon yet. Leave it as shown in Fig. 1.  To create the line type “pline” in the command prompt, then create the open polygon. Then looking on the last AutoCAD prompt: Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Type “close” or “c” in the command prompt and a line will be created connecting the last line you made to the first point to enclose the polygon (See Fig. 3).

    autocad polyline icon

Fig. 3 – The Polygon Was Enclosed

Width

This command enables you to specify the width of the line and can be made with a tapered shape. To set the width, type “pl” on the command prompt and press enter. Click your cursor on the black drafting screen as if making a line, then when AutoCAD prompt you  with this : Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: type “w” to invoke the “width” command and press enter, then AutoCAD will prompt again: Specify starting width <0.0000>: which is telling you to specify the width of the starting point of the line. Type 0.1 and press enter. Again it will prompt you again:  Specify ending width <0.0000>: which is asking you to specify the width of the end line ( See Fig. 4). Type 0.4 and press enter. Now you can see a stretching tapared polyline. Click your cursor on the desired place on the screen to create the line.

    autocad polyline icon

Fig. 4 – Tapering Polyline

Length

This command is just to specify the exact length of the polyline instead of dragging the cursor on the screen and clicking it where ever you want. This is pretty much the same as the above example.  Just type “PL” on the command prompt then press enter and click your first point on the screen. When prompt shows up type “L” then press enter again. Specify the length you wish to create. That’s it.

Undo

This command is used to undo the polylines while you are in the process of drawing a polylines incase you made a mistake.

Halfwidth

This command is the same as Width. The only difference is that it specifies the width from the center of a wide polyline line segment to one of its edges (See Fig. 5). You can start doing it by following the example I made above.

    autocad polyline icon

Fig. 5 – Halfwidth Polyline

1 comment so far ↓

#1 alsreerh on 10.12.08 at 4:03 pm

thank you very much

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