Using the LINE Command

Perhaps the most common object in a typical AutoCAD drawing is the line. In addition to representing the shortest distance between two points, lines serve a myriad of other useful purposes. Centerlines locate other geometry; border lines indicate an area’s constraints; and dashed lines represent objects or boundaries that are not visible from a given point of view. All these lines are usually further identified functionally by their linetype—the periodic pattern of interruptions in the line’s continuity. Normal continuous lines are representative of things such as walls or the sides of objects. Lines are very versatile, and drawing a line is one of the most basic operations in AutoCAD.

In the following exercise, you will learn the basics of using the LINE command as you begin drawing a fixture base.

Exercise 7.1 Using the LINE Command to Draw a Fixture Base

In the preceding exercise, you used several different methods to specify coordinate point entry while using the LINE command. You also saw how the coordinate display, which is located on the status bar at the bottom of AutoCAD’s display, can be helpful in locating both absolute and relative coordinate points. Keep in mind that, depending on how your increment snap is set up and the value of the actual points, the snap feature can make finding many points much easier. For points that do not lie on your current snap pattern, direct coordinate entry through the keyboard is the only practical method of having line segments begin and end exactly where you want.

In the following exercise, you will continue to use the LINE command as you outline the fixture base. After establishing the first corner of the base, you will use the efficient direct distance method for entering points that are orthogonal to the previous point.

Exercise 7.2 Using the LINE Command to Draw the Fixture Base Outline

1.	Continuing from the previous exercise, change the current layer to OBJECT. See Figure 7.3 to identify the following points. Figure 7.3. Points used to draw the fixture base.
2.	First, you will deliberately enter the wrong point to see how easy it is to recover from such a mistake. Begin the LINE command, type the coordinate 150,48 , and press Enter. Note that the point falls short of the right centerline. The X coordinate is incorrect.
3.	To recover from your mistake, use the LINE command’s Undo option by typing U and pressing Enter. Then reenter the point at by typing 156,48 and pressing Enter.
4.	Now with ORTHO on and the cursor placed to the left of the previous point, use direct distance entry to specify the point at by typing 108 and pressing Enter. Note From now on in this chapter’s exercises, the instruction to “enter 80,” for example, will mean that you are to type 80 and press Enter. The instruction “enter 80” or “enter Line” (without the double quotation marks) means the same as “type 80 and press Enter” or “type Line and press Enter.”
5.	Move the cursor above the preceding point and enter 80 to draw a line segment to .
6.	Move the cursor to the right of and enter 108 . The line segment is drawn between and .
7.	Now close the outline by using the Close option of the LINE command (type C and press Enter). This closes to the start point and ends the LINE command.
8.	The line segment from to was drawn by mistake; it is not wanted. At the Command: prompt, issue the U command by typing U and pressing Enter. Note that, because the LINE command is no longer in progress, all four line segments completed during the LINE command are erased. At the Command: prompt, issue the REDO command by entering REDO . All four segments are redrawn. Tip You can use the REDO command to recreate the sequences undone by an UNDO.
9.	To erase the last line segment, issue the ERASE command by entering E . At the Select objects: prompt, type L and press Enter. Note that the last completed line segment is highlighted. Now, with the Select objects: prompt still current, press Enter. The line is erased. Your drawing should now resemble Figure 7.4. Figure 7.4. The fixture base with primary outline and center lines.
10.	If you are continuing with the next section, leave this drawing open.

The LINE Command Options

The LINE command is straightforward and easy to use. It offers the following features:

• Specify first point: At this prompt, your input places the first point of the first line segment. If you press Enter at the Specify first point: prompt, the line segment will start from the last specified endpoint of the last drawn line segment or arc.

• Specify next point: At this prompt, your input places the point to which the current line segment is drawn.

• [Close/]: After two successive line segments have been drawn, you can type C (Close) to close the series. A line is drawn from the last endpoint to the first point of the series.

• [Undo]: At any Specify next point: prompt, you can type U (undo) to undo the last line segment drawn. Repeating the U option will step back through multiple line segments.

Keep in mind that the LINE command draws individual lines or line segments whose only relationship to one another is that the endpoint of one segment shares the same coordinate as the start point of the next segment.

You can end or exit the LINE command at any time by pressing Esc or by pressing Enter at any Specify next point: prompt.