Polylines
Polylines draw lines similar to the line command we used in lesson 2, but are a lot more powerful. Let's start by drawing the same plot of land we drew in lesson 2, but this type using polylines. The polyline command is situated on the 'draw' toolbar.

1) Choose the polyline command

2) For a start point, enter 50,50

3) Now enter the next line end points:
@25,0
@0,40
@-25,0
c

Right click or hit enter to end the polyline command.

4) Try selecting any part of the area we just drew with one click of the left mouse. The lines will become dotted to show that you have selected the polyline.

You will notice that although we entered each line end point command separately, because we drew the area with the polyline command left open, AutoCAD treats the polyline as one entity regardless of the shape or direction of the lines.



See the blue squares at each corner of the drawing?, these represent each line point specified when we drew the polyine. They are also a handy quick editing tool to adjust the shape of our drawing. Try left clicking on one of the blue squares with the centre of your crosshair, the corner follows your mouse movements. Left click to reposition the corner where your crosshair is, or press the Escape key to let go. These blue squares are called Grips.

Try using the grips to dramatically alter the shape of your land layout.
(TIP- to undo any changes you make, simply select Undo from the edit drop down menu as often as required)

Advanced Polylines - Arcs
There is more to polylines than just grips, a polyline can actually be any shape or thickness. Now we'll have a play with some more interesting Polyline features.

1) Undo any changes you made to the rectangular land layout we drew, and zoom extents to be left with the layout as shown above.

2) Select the polyline command. Notice the command line is asking for a start point, choose somewhere central within the upper area of our plot of land.

3) AutoCAD now asks for a next point or we can choose further drawing options:



The options are: Arc, Halfwidth, Length,Undo,Width. To select which option we require, enter the letter from the command we require that is in UPPER case (Which is most often, but not always, the first letter of the word).

4) We are going to draw a pond on the land, so enter A for Arc.

5) Notice how the line becomes arced instantly? Select a few points and close the polyline to get something similar to the drawing shown below.



Note: when you enter 'c' for close, AutoCAD will ask you to clarify you want to use the close command and not centre (as they both begin with c). Enter CL for close which are the two upper case characters).

The arc command is obviously not just for drawing free-hand ponds! We can enter further commands within the arc command by using their upper case letters to have more control over the arc, such as specifying a radius.

Have a play with the arc command and get familiar with how it functions.

Advanced Polylines - Width

1) Now we'll draw a fence around the pond. Select the polyline command again, select a point close to the edge of the pond to begin the polyline.

2) Press W to activate the polyline width command. By default the polyline width command is set to 0. Autocad asks for a width for the start of the line, enter 0.1 then hit enter. AutoCAD now asks for the width for the end of the line, as we want it to be the same thickness, enter 0.1 again. Now just try drawing a free hand fence around the pond.

The thickness command is very useful, the more that you use AutoCAD the more reasons you'll find to use it!

Try drawing a new polyline with a starting width of 0, and an ending width of 1. A handy arrowhead pointer?

Thats about it for polylines! They may not seem so great just yet, but when we start using modify commands you'll see just how useful it is to be able to manipulate and select a whole complex shape in one go rather than selecting all the separate entities.

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