Datasheet
26 Chapter 1: Getting Familiar with AutoCAD
If you point directly to the right, you’ll see that the rubber-banding line snaps to an
exact horizontal orientation, and you’ll see a tooltip appear at the cursor. This is a
feature called polar tracking vector, and it helps you draw in exact horizontal and ver-
tical directions, much like a T square and a triangle. The tooltip shows your cursor’s
location relative to the center point you just selected. It displays this information in
what is known as a polar coordinate. You can learn more about polar coordinates in
Chapter 2.
5. With the rubber-banding line pointing to the right, click to select a point, as shown
earlier in Figure 1.20. The prompt Specify end point of arc or [Angle/chord Length]:
appears.
6. Move the mouse, and a temporary arc appears, originating from the start point of
the arc that you just selected and rotating about the center of the arc.
As the prompt indicates, you now have three options. You can enter an angle, a chord
length, or the endpoint of the arc. The prompt default, to specify the endpoint of the
arc, lets you select the arc’s endpoint. The cursor is in Point Selection mode, telling
you it is waiting for point input. To select this default option, you need only select a
point on the screen indicating where you want the endpoint.
7. Move the cursor so it points vertically from the center of the arc. You’ll see the polar
tracking vector snap to a vertical position, as shown in Figure 1.20.
8. Click any location with the polar tracking vector in the vertical position. The arc is
now fixed in place.
As you can see, AutoCAD has a distinct structure in its prompt messages. You first
issue a command, which in turn presents options in the form of a prompt. Depending on
the option you select, you get another set of options, or you are prompted to take some
action, such as selecting a point, selecting objects, or entering a value. The prompts offer
a great deal of help by “prompting” you to take an action.
Getting Help
AutoCAD provides a good set of help options that can answer most of the questions you
might have while working on a drawing. If you’re stuck with an AutoCAD problem, give
the AutoCAD help options a try.
To get more familiar with the AutoCAD Help window, try the following:
1. Press F1 to open the AutoCAD 2010 Help window.
2. Click the Contents tab, which contains a table of contents. The other two tabs, Index
and Search, provide assistance in finding specific topics (Figure 1.21).
3. Scan down the screen until you see the topic Command Reference, and double-click
it. Both panels of the Help window change to show more topics.
38671c01.indd 26 7/8/09 12:01:00 AM