AutoCAD For Dummies. Ralph Grabowski

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      You move the viewpoint in, or zoom in, to see a closer view of objects in the drawing; you move the viewpoint out, or zoom out, to see a more expansive (not expensive) view. If you watch TV or movies or own a camera, you should understand zooming.

      Panning refers not to looking for gold but to looking at a different part of a drawing without changing the magnification of the view. If you zoom in so that part of the drawing is no longer shown onscreen, you’ll pan around in the drawing to see other parts, without zooming in and out. Think of the monitor as a window through which you look at part of the drawing. Now reach through the window and slide the drawing around until you see a different portion of it through the window.

      

Panning and zooming do not change the size or position of objects in the drawing. The actions change only how you see them.

      In fact, you not only can zoom and pan in the drawing but also, in most kinds of drawings, you must zoom and pan frequently to be able to draw and edit effectively.

      Why do you need to pan and zoom often? For starters, though many architectural drawings plot out at 3 feet by 2 feet, you probably aren’t fortunate enough to own a monitor of that size with sufficient resolution to be able to see every little detail.

Early releases of AutoCAD came with a sample drawing of the solar system done to scale. When first opened, it showed circles for each planet’s orbit. Zooming in revealed the moon’s orbit around Earth, then a crater on the moon, then the lunar landing module, and finally writing on the plaque mounted on a leg of the lunar lander.

      In addition, technical drawings are jam-packed with lines, text, and dimensions. As discussed in Chapter 8, drawing with precision is essential to following best practices for AutoCAD drawings. Frequent zooming and panning enables you to better see detail, to draw more precisely because you can see what you’re doing, and to edit more quickly, because object selection is easier when the screen isn’t cluttered with objects. This chapter describes the most useful display control features in AutoCAD.

Panning and Zooming with Glass and Hand

      AutoCAD makes panning easy, by offering scroll bars and real-time panning. In real-time panning (as opposed to pretend-time panning?), you can see objects moving on the screen as you drag the mouse upward and downward or back and forth with the middle button held down. Of course, the viewpoint is moving, not the objects.

      Both panning and zooming change the view — the current location and magnification of the AutoCAD depiction of the drawing. Every time you zoom or pan, you establish a new view. You can give names to specific views so that returning to them is easy, such as a title block or a bill of material, as I demonstrate in the later section “A View by Any Other Name.”

      You can gain a better sense of panning and zooming in a drawing when you’re looking at a drawing. Draw some objects on the screen, or open an existing drawing, or launch a sample drawing in AutoCAD.

      If you haven’t done so already, you can download sample files from www.autodesk.com/autocad-samples. (You can ignore the version numbers.) The AutoCAD LT sample files are also online at www.autodesk.com/autocadlt-samples. Note that LT drawings can be opened by standard AutoCAD and vice versa.

      The wheel deal

Later in this chapter, I cover in detail various commands and options in AutoCAD for panning and zooming — if you have a wheel mouse, however, you’ll rarely need to use the other methods, especially when working in 2D drawings. If you don’t have a wheel mouse, run out and buy one now because the small cost will be more than offset by your increased productivity. The following three actions usually suffice for almost all panning and zooming needs:

       Zoom in, zoom out: Roll the scroll wheel forward and backward.

       Pan: Hold down the scroll wheel (or middle button) as you move the mouse. (The scroll wheel is also considered a button.)

       Zoom to the extents of the drawing: Double-click the scroll wheel. This method is particularly useful when you accidentally press Enter at the wrong time during a Move or Copy operation, as described in Chapter 11.

      

Using the scroll wheel (or middle button on a mouse that has three buttons) for zoom and pan operations depends on the 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.

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