Drawing a Polyline is very similar to drawing a line in AutoCAD but the only difference is that it consist of two or many series of lines or line segments that is why it is called “poly”. This command is very useful and have many application in making your drawing specially complex curves. This is similar to a french curve or a flexible curve, a tool used in manual drafting. It creates curves that cannot be made by an arc. So with out much ado lets start.
Again to start with, there are two options in invoking the command, one is typing PLINE on the command prompt or clicking the icon on the menu just as in the screen below (Fig 1).
The outcome will be the same. Just click the PLINE icon on the menu then AutoCAD will prompt: Specify start point: which is telling you to start polyline somewhere on the screen. This time just point your mouse and click on the center of the black screen. After clicking the command prompt will say: Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: which is obviously telling you to point your mouse to another area in the screen to create the line. But enclosed in the bracket are options on what kind of polylines you want to create. We will deal with that later and just focus on the basics first. So to specify the next point, just point your mouse cursor again opposite the first point you just created dragging the white rubber like polyline then click. Then the command prompt will tell you again: Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Repeat the moving of your cursor and clicking of mouse until you made three connected lines then press the ‘enter’ key to terminate the command (See Fig 2).
Now you’ve made your first set of polylines. But it doesn’t look complex isn’t it? and where are the curves? looks like I’ve lied to you but wait, we are not finished yet. After making the lines, we can modify it and change it’s property. Just type the command PEDIT in the commnad prompt. Again AutoCAD will tell you in the command prompt: Select polyline: then select the polyline you have made. Again AutoCAD will say: Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: For the meantime lets see how will it turn to a curve. Type ‘Spline’ or just ‘S’ on the command prompt. Then you will be surprised that it turns into a curve (See Fig. 3)
Actually you can play around and experiment with the other options in the bracket. Just repeat the process we have made. And for the sake of elaboration, I’ll add the here what are some of the other options are for. For the ‘Close’ option, the polyline will create another line to convert the polyline into a polygon. On the ‘Join’ command, this is for converting ordinary segment of lines into polyline. Unlike ordinary line segments, polyline is one object, meaning one entity. You can test it by deleting ordinary line segmants and compare it when deleting polyline. And for the rest of the option, I’ll explain it in detail in my other post.