AutoCAD For Dummies. Ralph Grabowski

setting of the obscure AutoCAD system variable named MBUTTONPAN. When MBUTTONPAN is set to its default value of 1, you can use the scroll wheel or middle button to pan and zoom. If you change MBUTTONPAN to 0, clicking the scroll wheel or middle mouse button displays the Object Snap menu at the cursor, as it did in earlier AutoCAD releases. If you can’t zoom or pan using the scroll wheel or middle mouse button, set MBUTTONPAN to 1. When MBUTTONPAN is set to 1 you can press Shift+right-click to display the Object Snap menu at the cursor. I discuss Object Snaps in Chapter 8.

      

If you used the software that came with the mouse to change the function of the middle button, you might not be able to pan with it. To fix this, redefine the function of the middle button to its default.

      

Before using the mouse wheel to zoom in, position the cursor over the area you want to zoom into. AutoCAD uses this as the center of the zoom. This way, the area of interest doesn’t disappear as you get in close.

      Navigating a drawing

      You may believe that AutoCAD is all about drawing and, occasionally, even about erasing. If so, you may be surprised to read that two of the most frequently used commands in all of AutoCAD are Pan and Zoom although the hands-down favorite is Undo. You can find these two commands in a couple of convenient places in AutoCAD:

       On the Navigation bar: The Navigation bar contains both Zoom and Pan buttons. Figure 5-1 shows the upper-right corner of the AutoCAD window with the Navigation bar in its default location, linked to the ViewCube. Because the ViewCube is more useful in 3D drawing, I tell you about it in Chapter 21.

       In the Navigate and Navigate 2D panels on the View tab on the Ribbon: These two panels contain a Pan button and a drop-down set of Zoom tool buttons. This location is not the most convenient for frequently used commands — and to make matters worse, this panel may not even be visible. To display it you must right-click anywhere in the View tab, click Show Panels, and then click Navigate.If you’re primarily creating 2D drawings, you can remove some of the 3D related viewing tools from the Navigation bar or turn off the ViewCube itself, either for the drawing session or permanently. Choose a method:

       Turn off navigation buttons. Open the Navigation bar menu by clicking the down arrow in its lower-right corner (refer to Figure 5-1) and deselect SteeringWheels, Orbit, and ShowMotion.

       Turn off the ViewCube or the Navigation bar (or both) in the current viewport. From the User Interface panel on the View tab, click User Interface and deselect ViewCube or Navigation bar or both.

       Turn off the ViewCube permanently. Open the Options dialog box (choose Options from the Application menu or type OPtions) and select the 3D Modeling tab. In the Display Tools in Viewport section, under the Display the ViewCube line, deselect the two options 2D Wireframe Visual Style and All Other Visual Styles.

      FIGURE 5-1: Belly up to the Navigation bar.

      

In AutoCAD, unlike in most other Windows programs, panning and zooming are usually more convenient and faster than scrolling. If you want the traditional Windows scroll bars on the right and bottom edges of the drawing window, you can turn them on. Choose Options from the Application menu (or type OPtions) to display the Options dialog box. On the Display tab, select or deselect the Display Scroll Bars in Drawing Window check box. The default, and most users’ preference, is not to use scroll bars, thereby regaining the screen space they occupy. That’s why you don’t see them in most figures in this book.

Zoom, Zoom, Zoom

      Because zooming is a frequent activity in AutoCAD, you should know some alternative ways to zoom.

      In addition to using the mouse’s roller wheel and the Zoom button on the Navigation bar (as I describe earlier in this chapter), you’ll find tool buttons for all the Zoom options in the Navigate panel on the View tab.

      

As mentioned, the Navigate panel on the View tab is turned off by default.

Click the small down arrow in the lower-right corner of the panel and a menu with the other options opens, as shown in Figure 5-2.

      The Zoom command has 11 options. The most important ones are described in this list:

        Extents and All: The Zoom Extents button (with the four-headed arrow and the magnifying glass) zooms out just far enough to display all objects in the current drawing. The Zoom All button (the sheet with the folded-over corner) does almost the same thing: It zooms to display the rectangular area defined by the drawing limits set with the LIMITS command, or it zooms to show the extents — whichever is larger. These two options are especially useful when you zoom in too close or pan off into empty space and want to see the entire drawing again. Limits and extents are slightly different. Limits are set by the Limits command. You can configure AutoCAD to not allow you to draw anything outside the limits, but this usually causes more problems than it solves. Extents are defined by the smallest imaginary rectangle that will just surround every object in your drawing. A good April Fool’s trick is to sneak up to another person’s computer and draw a tiny circle by typing the location coordinates as something like 10000,10000. The next time the person does a Zoom Extents, the drawing will seem to disappear. Use Zoom All or Zoom Extents and then save the drawing before you close it to ensure thatThe next person who opens the drawing can see the full drawing as soon as the person starts working.FIGURE 5-2: A menu for magnifying.Any objects that you accidentally copied beyond the drawing limits show up so that you can delete or move them.The drawing preview that appears in the Select File dialog box and on the Start screen displays the full drawing rather than a tiny, unidentifiable corner of it.

        Window: This option, which is useful for zooming in quickly and precisely, zooms to a rectangular section of the drawing that you specify by clicking two points. The two points define the diagonal of a window around the area you want to see. The Zoom command’s Window option is not a click-and-drag operation, unlike in most other Windows programs and — confusingly — unlike in the Zoom/Pan Realtime Zoom Window option. To use the Zoom command’s Window option, you click to specify one corner, release the mouse button, and then click another corner.

        Realtime: Enables you to zoom in and out by starting a real-time zoom and then dragging the magnifying-glass cursor up (to zoom in) or down (to zoom out).

        Previous: Use this option to undo the last zoom or pan sequence (or both), returning to where you started. You can repeat this option to step through previous views, even if you create or edit objects after changing the view.

        Object: This option zooms in close enough to show selected objects as large as they can be displayed onscreen. Using Zoom Object is similar to examining selected objects under the AutoCAD microscope.

      

Entering the keyboard command sequences Z A, Z P, or Z W (note the mandatory space between the letters) is usually faster than trying to find the corresponding zoom tools on the Ribbon or various toolbars. Z is the command alias for the Zoom command, while A, P, and W start the All,