Chapter 3: A Lap around the CAD Track 67

Selected object here.

Pick here to show offset directions.

Figure 3-7: Give it some thickness with OFFSET.

Circling your plate

You can use the CIRCLE command to draw a 11⁄2-inch [38mm] diameter anchor bolt on an Anchor Bolts layer by following these steps:

1.Repeat Steps 2 through 7 in the preceding section to create a new layer for the anchor bolts. Give the layer the name Anchor Bolts, assign it the color 3 (green), set it as the current layer, and then close the Layer Properties Manager.

The Layer drop-down on the Layers panel displays Anchor Bolts as the current layer.

2.On the Home tab’s Draw panel, click the Circle button.

The CIRCLE command starts, and AutoCAD prompts you to specify the center point. The command line shows

Specify center point for circle or [3P/2P/Ttr (tan tan radius)]:

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68 Part I: AutoCAD 101

3. Click in the drawing area at point 38,13 [950,325].

AutoCAD asks you to specify the size of the circle. The command line shows

Specify radius of circle or [Diameter]:

You decide that you want 11⁄2-inch [38mm] diameter anchor bolts. AutoCAD is asking for a radius. Although you can probably figure out the radius of a 11⁄2-inch [38mm] diameter circle, specify the Diameter option and let AutoCAD do the hard work.

4. Type D and press Enter to select the Diameter option.

AutoCAD prompts you:

Specify diameter of circle:

5.Type 1.5 [38] and press Enter.

AutoCAD draws the 11⁄2-inch [38mm] diameter circle. It’s on the Anchor Bolts layer and inherits that layer’s green color (see Figure 3-8).

6.Press Ctrl+S to save the drawing.

Figure 3-8: Anchor it with CIRCLE.

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Chapter 3: A Lap around the CAD Track 69

Nuts to you

Every good bolt deserves a nut. Use the POLYGON command to draw a hexagonal shape on a Nuts layer (well, what else would you call it?). Besides showing you how to draw polygons, these steps introduce you to a couple of AutoCAD’s more useful precision techniques: object snaps and Ortho mode.

1.Repeat Steps 2 through 7 in the “Drawing rectangles on the right

layers” section, earlier in this chapter, to create a new layer for the nuts and set the new layer current. Give the layer the name Nuts and assign it the color 1 (red).

The Layer drop-down list displays Nuts as the current layer.

You don’t have to create a separate layer for every type of object that you draw. For example, you could draw both the anchor bolts and nuts on a layer called Hardware. Layer names and usage depend on industry and office practices, in addition to a certain amount of individual judgment. Having too many layers is better than having too few because lumping two or more layers together is much easier than dividing the objects on one layer into two or more layers.

The Ribbon’s standard panels aren’t big enough to contain a button for every command, so AutoCAD hides the ones that don’t fit in drop-down buttons or slideout panels that you open by clicking the panel label. A small down-pointing triangle beside the panel name means that there’s a slideout with more commands available.

2.On the Home tab’s Draw panel, click the Polygon button — the one that looks like a plan of the Pentagon.

If this is the first time you’ve drawn a polygon in this editing session, its button is hiding under the Rectangle tool button. Look for the button showing a rectangle with little circles at two corners. Click the down arrow beside that button, and then click Polygon.

If a Ribbon panel has an item with a slideout list, AutoCAD remembers the last one that was used in the current session. When you close AutoCAD and restart it, all the defaults return.

The POLYGON command starts, and AutoCAD prompts you as follows:

Enter number of sides <4>:

Peek ahead to Figure 3-9 to get an idea of how the nut will look after you draw it. Four-sided nuts can be a little difficult to adjust in the real world, so we stick with the conventional hexagonal sort.

3. Type 6 and press Enter.

AutoCAD next prompts you for the center of the polygon:

Specify center of polygon or [Edge]:

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70 Part I: AutoCAD 101

In the next steps, you use one of AutoCAD’s precision drafting modes: Object Snap. We explain object snaps in detail in Chapter 7, but for now, just follow along here.

4.Click the Object Snap button on the status bar to turn on Object Snap mode. When Object Snap is enabled, the button appears light blue and the command prompt shows <Osnap on>.

As you move the crosshairs around near the anchor bolt, notice that AutoCAD tends to pull the crosshairs to certain points on existing objects.

5.Move the crosshairs over the anchor bolt you just drew.

A tooltip should show Center and pull the crosshairs to the center of the anchor-bolt circle. If you don’t see a Center object snap marker or tooltip, then right-click the Object Snap button and click Center. You may also see tracking vectors across the screen from this point — you can ignore those.

6.Click when the tooltip reads Center — not Center-Intersection or something similar — just Center.

The POLYGON command draws regular closed polygons based on an imaginary circle; the center of this imaginary circle is the point you just picked.

AutoCAD prompts you:

Enter an option [Inscribed in circle/Circumscribed about circle] <I>:

7.Press Enter to accept the default Inscribed in Circle option.

The Inscribed option draws a polygon whose corners touch the circumference of the imaginary circle. The Circumscribed option draws a polygon whose sides are tangent to the circumference of the circle. Circumscribed has nothing to do with being a Jewish male.

AutoCAD then asks you to

Specify radius of circle:

8.Turn on Ortho mode by clicking the Ortho Mode button on the status bar until you see <Ortho on> on the command line.

Ortho mode forces the crosshairs to move orthogonally — that is, in a precise horizontal or vertical direction. (We describe Ortho mode more fully in Chapter 7.)

9.Move the mouse pointer to the right so the top and bottom sides of the polygon are horizontal, but don’t click yet!

10.Type 1.5 [38] and press Enter.

AutoCAD draws the nut, as shown in Figure 3-9. It’s on the Nuts layer and inherits that layer’s red color.

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