AutoCAD 2005 for Dummies

command. You use the NODe object snap mode to snap to AutoCAD point objects. In this guise, points usually are for your use in drawing and editing precisely. Other people who view the drawing probably won’t even be aware that the point objects are there.

What makes AutoCAD point objects complicated is their almost limitless range of display options, provided to accommodate the two different kinds of purposes just described (and possibly some others that I haven’t figured out yet). You use the Point Style dialog box, shown in Figure 5-12, to specify how points should look in the current drawing.

Figure 5-12: The Point Style dialog box controls the way point objects appear on- screen.

DDPTYPE is the command that opens the Point Style dialog box. You can access it from the menus by choosing Format>Point Style. The top portion of the dialog box shows the available point display styles. Most of the choices do pretty much the same thing. Just click one of the squares that says “hey, that’s a point!” to you.

  The first choice, a single-pixel dot, is hard to see on the screen, and the second choice, invisible (a stealth point?), is impossible to see. Avoid these choices if you want your point objects to show up on the screen and on plots. The single-pixel dot, which is the default display style, works well if you use point objects as object snap locations and don’t want the points obtrusive on plots.

  The remaining settings in the Point Style dialog box control the size at which points appear on the screen at different zoom resolutions. The default settings often work fine, but if you’re not satisfied with them, click the Help button to find out how to change them.

After you specify the point style, placing points on-screen is easy; the following example shows you how.

This is an example of the command-line commands to create a point:

Command: POint Enter
Current point modes: PDMODE=0 PDSIZE=0.0000
Specify a point:
 pick or type the coordinates of a location in the drawing

  PDMODE and PDSIZE in the command prompt are system variables that correspond to the point display mode and display size options in the Point Style dialog box. If you want to know exactly how the system variables correspond to the dialog box choices, you have all the makings of a successful CAD nerd. Click the Help button in the Point Style dialog box to find out more (about the system variables — not about yourself).

  If you start the POint command from the Draw toolbar or the Draw>Point>Multiple Point menu, it will repeat automatically — that is, it will prompt you repeatedly to Specify a point. When you’re finished drawing points, press Esc to finish the command for good. If the command doesn’t repeat automatically and you want to draw more points, press the Enter key to repeat the POint command and pick another location on the screen. Repeat as required: Enter, pick, Enter, pick, Enter pick… by now you should’ve gotten the point.

Chapter 6 Edit for Credit

In This Chapter

? Using command-first editing

? Selecting objects with maximum flexibility

? Moving, copying, and stretching objects

? Manipulating whole objects

? Changing pieces of objects

? Editing with grips

? Editing object properties

Editing objects is the flip side of creating them, and in AutoCAD, you spend a lot of time editing — far more than drawing objects from scratch. That’s partly because the design and drafting process is by its nature iterative, and also because CAD programs make it easy to edit objects cleanly.

  When you edit objects in AutoCAD, you need to be just as concerned about specifying precise locations and distances as you are when you originally create the objects. Make sure that you’re familiar with the precision techniques described in Chapter 4 before you apply the editing techniques from this chapter to real drawings.

Commanding and Selecting

AutoCAD offers two main styles of editing:

? Command-first editing

? Selection-first editing

Within the selection-first editing style, you have an additional choice of editing that uses actual, named commands and direct manipulation of objects without named commands. The following sections cover these editing styles.

Command-first editing

With command-first editing, you enter a command and then click the objects on which the command works. This style of editing may seem backwards to you at first unless you’re a longtime user of AutoCAD or a veteran of command-line operating systems (where you typically type the name of command and then the names of the files or other objects to which you want to apply the command). Command-first editing works well for power users who are in a hurry and who are willing to memorize most of the commands they need to do their work. It’s no surprise that command-first editing is the default style of editing in AutoCAD.

Selection-first editing

In selection-first editing, you perform the same steps — in the same order — as in most Windows applications: Select the object first, then choose the command.

Selection-first editing tends to be easier to master, which is why Windows and the Macintosh are easier for most people to use for a variety of tasks than DOS ever was. Selection-first editing makes AutoCAD more approachable for new and occasional users. 

Direct manipulation is a refinement of selection-first editing in which you perform common editing operations by using the mouse to grab the selected object and perform an action on it, such as moving all or part of it to a different place in the drawing. No named command is involved; the act of moving the mouse and clicking the mouse buttons in certain ways causes the editing changes to happen. AutoCAD supports direct manipulation through a powerful but somewhat complicated technique called grip editing. Grips are the little square handles that appear on an object when you select it. You can use the grips to stretch, move, copy, rotate, or otherwise edit the object. These grip-editing techniques can make selection-first editing almost as powerful as command-first editing. The complications arise from the fact that you can do so many things with an object after you select it.

Choosing an editing style

This chapter emphasizes command-first editing. (I also discuss grip editing at the end of the chapter.) AutoCAD is fundamentally a command-first program. AutoCAD started out offering only command-first editing and later added selection-first methods; AutoCAD 2005 inherits this ancestral