On our past tutorial, we created polylines. Now we are going to edit them. The command used is PEDIT. Which means polyline edit and the subcommands are [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]:. Now lets start.
The “Close” in PEDIT command is similar to creating polylines like we did in our previous tutorial. First create an open polygon, in our example I created a four sided polygon. Type “PL” on the keyboard and create three sided open polygon as shown on Fig.1. Then type PEDIT on the command prompt and press enter. It wll promt you with Select polyline: which is asking you to select the object you wish to edit. Then point the cursor, also called the “selection box” on the polygon and click. Afterwards AutoCAD will prompt Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]:Type “C” and press enter. You wll notice that a line was created to enclose the polygon ( See Fig. 2).
Fig. 1 – Draw An Open Polygon Using Pline Command
Fig. 2 – Using Pedit to Enclose a Polygon
The purpose of the Join sub command is to join segments of lines, arcs or polylines. To make a sample, just create a series of connected lines or arcs (not polylines). Then type “PEDIT’ on the command prompt and it will prompt you: Select polyline: then select the lines you have created. Then AutoCAD will prompmt you again: Object selected is not a polyline Do you want to turn it into one?<Y> just type “Y” which means yes. Then it will prompt you again: Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: Type “J” to invoke the join command and press enter on the keyboard. Again it will prompt: Select objects: select the lines you created, I mean all the lines, one by one. You can also type “all” on the command prompt since there are no other objects affected, only the lines you have drawn then press enter two times to end the command loop.
The width subcommand is for editing the thickness of the polyline. First draw series of connected polylines. Then type “PEDIT” and select the polyline then after the prompt Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: type “W” and it will prompt you again: Specify new width for all segments: meaning you have to indicate the new thickness of the line. Type 0.4 for now and press enter. You will see that a new thickness of the line was created.
Fig. 3 – Using Pedit to Change Polyline Thickness
Vertex are endpoints of the series of lines (See Fig. 4). Here you can change the vertex position. To start, type “PEDIT” again and press enter. Select the polyline and after the prompt Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]:appears type “E” to invoke the Edit Vertex command and press enter. You will notice a an “X” mark will appear on the first vertex. Then a prompt will appear: Enter a vertex editing option [Next/Previous/Break/Insert/Move/Regen/Straighten/Tangent/Width/eXit] <N>: Type “N” to move the “X” mark then type “M” to move the vertex on its new position. When you typed “M”, AutoCAD will prompt: Specify new location for marked vertex: you will see a line dragging behind a moving “X” mark for you to specify a new location. Click your mouse to you desired place on the screen. Then type “X” to exit and press enter to terminate the command loop.
Fig. 4 – Vertex of a Polyline
Creates a smooth curve consisting of pairs of arcs joining each pair of vertices. The curve passes through all vertices of the polyline and uses any tangent direction you specify (See Fig. 5). The method is simple, just follow the example we did above.
Fig. 5 – Curve Was Created After The Polyline
This command coverts a polylines into a smooth set of curves. Make a series of polylines as shown in Fig.6. Then after that type “PEDIT” and press enter. Then select the polyline with your selection box and click. AutoCAD will prompt asking you to enter the option: Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Undo]: type “S” to invoke the spline command and press enter. Suddenly the polyline will turn into a smooth curves.
Fig. 6 – Using the Spline Polyline Will Have Smooth Curves
This command is very simple and need not elaborate. This is the same thing as Undo command on other application. In fact you can also use the undo command.
This is a command to edit a linetype where you can specify whether a linetype pattern is centered on each segment or continuous throughout the entire length of a 2D polyline. The command is like a switch which turns it off or on. Again to illustrate, create a zigzag polyline as we did above. Depending on how you set your linetype scale, if your drawing is too small or too big for the given linetype scale, you will not see the linetype if the setting is not correct. So have to adjust the linetype scale first. Type “ltscale” and change the value to 0.1 then press enter.
I assumed you already know how to change the linetype of the objects like for exampe, the polyline. Change it first to DASHED then type PEDIT and press enter. Select the polyline and click your mouse left button. When the Enter an Option prompt appears, type “L” to invoke the command Ltype gen. Then AutoCAD will prompt: Enter polyline linetype generation option [ON/OFF] <Off>: which is asking you whether you want to turn it ON or OFF. Turning it OFF will make the linetype pattern centered on each segment. Turning it ON will make it continuous throughout the entire length of a 2D polyline (See Fig. 7).
Fig. 7 – Turning Line type Generation ON or OFF
I guess this is a no brainer, it is as simple as undoing the actions you have done.