AutoCAD 2002 Bible

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Understanding arc options

Arcs have many options. Making sense of them may seem overwhelming, but once you understand the parts of an arc and AutoCAD’s terminology, you can choose the options that suit your needs. Figure 7-3 shows the parts of an arc that you can use to draw an arc. Refer to these parts as you read through the arc options.

Figure 7-4 shows the flow of the arc options. When you start the ARC command, you have two options, Start point and Center. Depending on which you choose, more options become available.

You can also press Enter at the first arc prompt to draw a second arc starting from the endpoint of a previous arc, line, polyline, and so on. The new arc continues in the same direction as the end of the first arc. The only other prompt is the endpoint.

Drawing arcs

To draw an arc, choose Arc from the Draw toolbar and follow the prompts. As with circles, object snaps are often helpful when drawing arcs.

When drawing an arc using the Start, End, and Radius options, the three specifications actually define two possible arcs, one minor and one major. AutoCAD draws the minor arc by default, in the counterclockwise direction. (A minor arc is less than half a circle.) If you enter a negative number for the radius, AutoCAD draws the major arc (which is more than half a circle). The options requiring an angle also define two possible arcs, one drawn counterclockwise and one drawn clockwise. AutoCAD draws the counterclockwise arc by default. If you type a negative number for the angle, AutoCAD draws the arc clockwise.

Скачать в pdf «AutoCAD 2002 Bible»