Chapter 3: A Lap around the CAD Track 73
Figure 3-10: The Zoom/Pan Realtime right-click menu.
4.Click and drag to pan the drawing until the plate is more or less centered in the drawing area.
You’re not moving the plate, although it may look like it. You’re moving your viewing position while the plate stays put. Never move drawing objects if you just want to view them from a different position.
You can use the right-click menu to toggle back and forth between Zoom and Pan as many times as you like. If you get lost, choose Zoom Original or Zoom Extents to return to a recognizable view.
5.Right-click in the drawing area and choose Exit from the Zoom/Pan Realtime menu.
The hand pointer returns to the normal AutoCAD crosshairs.
If you have a wheel mouse, you can zoom simply by rolling the wheel back and forth. To pan, press and hold the wheel (yes, the wheel is also a button) and drag the view around. These actions can be performed even when another command is active.
Modifying to Make It Merrier
When you have a better view of your base plate (which we talk about in the preceding section), you can edit the objects on it more easily. In the following sections, you use the ARRAY command to add more anchor bolts, the STRETCH command to change the shape of the plate, and the HATCH command to add crosshatching to the column. (As always, we cover these commands in detail later in the book.)
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74 Part I: AutoCAD 101
Hip-hip-array!
Using the ARRAY command is a great way to generate a bunch of new objects from existing objects at regular angles or spacing. The array pattern can be rectangular (that is, columns and rows of objects), polar (in a circle around a center point, like the spokes of a wheel around its hub), or it can follow
a path.
AutoCAD 2012 introduced a sophisticated new method of arraying objects, and AutoCAD 2013 improved on it. We explain it in detail in Chapter 18. In this chapter, we introduce the simpler, old-style array feature. The newer version is more powerful, but the older version is simpler. For our purposes now, the simpler one is adequate.
In this example, you use a rectangular array to create three additional anchor bolts:
1.Type –ARRAY and press Enter (don’t omit the hyphen!).
Typing a hyphen in front of a command name tells AutoCAD you want to use the command line rather than a dialog box to specify values for the array.
The old-style ARRAY command starts at the command line, and AutoCAD prompts you to select the objects you want to array.
2.Click the anchor bolt and then click the nut.
If you encounter any problems while trying to select objects, press the Esc key a couple of times to cancel the command; then restart the – ARRAY command and try again.
AutoCAD continues to prompt you at the command line:
Select objects: 1 found, 2 total
3.Press Enter or right-click to end object selection.
You specify the parameters of an array by first telling AutoCAD whether you want a rectangular or polar (circular) array. A rectangular array creates regularly spaced rows and columns. Next, you specify the number of rows and the number of columns, and then the spacing between rows and the spacing between columns.
AutoCAD prompts:
Enter the type of array [Rectangular/Polar] <R>:
4. Type R and press Enter to accept a rectangular array.
AutoCAD prompts:
Enter the number of rows (---) <1>:
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Chapter 3: A Lap around the CAD Track 75
AutoCAD wants to know how many rows and columns you want. Because the source object is included in AutoCAD arrays, you must specify two rows and two columns of bolts.
5.Type 2 and press Enter. At the next prompt for the number of columns, type 2 and press Enter again.
AutoCAD prompts:
Enter the distance between rows or specify unit cell (---):
Almost done! To complete the array you tell AutoCAD the spacing between rows and columns.
6.Type 24 [600] and press Enter. At the Enter distance between columns prompt, type 24 [600] and press Enter again.
AutoCAD adds the additional objects to the drawing, as shown in Figure 3-11.
7.If anything looks wrong, type U or click Undo to delete the array and start again.
Unfortunately, the command line is not as forgiving as a dialog box!
8.Press Ctrl+S to save the drawing.
Figure 3-11: Buttoned-down base plate.
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76 Part I: AutoCAD 101
Perfect! Except that nutbar engineer (hey, we resemble that remark!) has decided the column needs to be 18 x 18 inches [450 x 450mm] rather than 12 x 18 inches [300 x 450mm — unfortunately, there are just as many metric nutbars as imperial ones]. And that means the base plate is too small, and the anchor bolts are in the wrong place, too. If you were working on the drawing board, you’d be getting out an eraser right about now and rubbing out all your efforts. If you were lucky, you’d have an electric eraser. At some point, you simply tore up the paper and started over. AutoCAD to the rescue!
The drawing afd03c-i.dwg [afd03c-m.dwg] contained in the afd03.zip download adds the remaining anchor bolts.
Stretching out
The STRETCH command is powerful but a little complicated — it can stretch or move objects, depending on how you select them. The key to using STRETCH is specifying a crossing selection box properly. (Chapter 10 gives you more details about crossing boxes and how to use them with the STRETCH command.)
Follow these steps to stretch the column and base plate:
1.On the Modify panel, click the Stretch button — the one with the corner of a rectangle being stretched.
The STRETCH command starts, and AutoCAD prompts you to select objects. This is one of those times (and one of those commands) that really does require you to look at the command line:
Select objects to stretch by crossing-window or crossing-polygon...
Select objects:
2.Click a point above and to the right of the upper-right corner of the plate (Point 1 in Figure 3-12).
3.Move the crosshairs down and to the left.
The pointer changes to a dashed rectangle enclosing a rectangular green area, which indicates that you’re specifying a crossing box. AutoCAD prompts you at the command line as follows:
Select objects: Specify opposite corner:
4.Click a point below the plate, roughly under the center of the column (Point 2 in Figure 3-12).
The crossing box must cut through the plate and column in order for the STRETCH command to work (refer to Figure 3-12).
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Chapter 3: A Lap around the CAD Track 77
Point 1
Point 2
Figure 3-12: Specifying a crossing box for the STRETCH command.
AutoCAD prompts you at the command line:
Select objects: Specify opposite corner: 7 found
Select objects:
5.Press Enter to end object selection.
AutoCAD prompts you to specify the base point.
6.If they’re not already on, turn on Snap mode, Ortho mode, and Object Snap by clicking their respective buttons on the status bar until they appear highlighted.
7.Move your mouse pointer over the lower-right corner of the plate, and click when you see a square box with an Endpoint tooltip.
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78 Part I: AutoCAD 101
This point serves as the base point for the stretch operation. Chapter 11 describes base points and displacements in greater detail. As before, if you can’t get it to snap to the endpoint, right-click the Object Snap button and select Endpoint.
AutoCAD prompts you at the command line:
Specify second point or <use first point as displacement>:
8.Move the crosshairs to the right until the tooltip shows a displacement of 6 [150] units to the right, and then click in the drawing space (see Figure 3-13).
AutoCAD stretches the column and plate by the distance that you indicate and moves the anchor bolts that were completely inside the crossing window rectangle, as shown in Figure 3-13.
Figure 3-13: Stretching the base plate.
If your first stretch didn’t work right, press Ctrl+Z and try again. STRETCH is an immensely useful command — one that makes you wonder how drafters used to do it all with erasers and pencils — but it does take some practice to get the hang of those crossing boxes.
9. Press Ctrl+S to save the drawing.
The drawing afd03d-i.dwg [afd03d-m.dwg] contained in the afd03.zip download is the stretched version of the base plate.
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