Graphics Programs Reference
In-Depth Information
AutoCAD then prompts you to specify the circle's radius.
Specify radius of circle or [Diameter]:
Type
D
and press Enter if you prefer to enter the diameter rather than
the radius and you've forgotten your two-times tables — or, more seriously, if the
diameter is easier to type exactly than the radius is.
5. Specify the radius by typing a distance or clicking a point.
AutoCAD draws your circle and returns to a blank command prompt. The first point
you picked is the center. The command prompt doesn't tell you so, but if you pick a
second point instead of entering a number (or typing
D
to invoke the Diameter op-
tion), AutoCAD interprets the distance between the first and second points as the
radius value.
Arc-y-ology
Arcs
in AutoCAD are, quite simply, pieces of circles. As with circles, AutoCAD offers you
an easy way to define arcs. Just specify three points on-screen to define the arc, easy as
one-two-three. These points tell AutoCAD where to start the arc, how much to curve it,
and where to end it.
Sounds pretty easy, right? So, where's the problem? The trouble is that you nearly al-
ways have to specify arcs more exactly than is possible by using this method. AutoCAD
helps you specify such arcs, too — but the procedure ain't easy.
You can start your arc by specifying the center of the arc or the start point. If you
choose the Center option, AutoCAD prompts you for the center point first and the start
point second. AutoCAD defines arcs counterclockwise, so pick a start point in a clock-
wise direction from the endpoint. After you specify the center and start point, AutoCAD
presents several options you can choose, including the following:
Angle:
Specifies the included angle that the arc sweeps out. A 180-degree angle, for
example, is a semicircle.
Length of chord:
Specifies the length of an imaginary straight line connecting the
endpoints of the arc. Most people seldom or never use this option.
Endpoint:
Specifies where the arc ends. It's the default option and often the easiest
to use.
