Graphics Programs Reference
In-Depth Information
The Point Selection cursor
appears whenever AutoCAD expects point input. It can also
appear in conjunction with a rubber-banding line. You can either click a point or enter a coor-
dinate through the keyboard.
The Object Selection cursor
tells you that you must select objects—either by clicking them
or by using any of the object-selection options available.
The Osnap (object snap) marker
appears along with the Point Selection cursor when you
invoke an osnap. Osnaps let you accurately select specific points on an object, such as end-
points or midpoints.
The tracking vector
appears when you use the Polar Tracking or Object Snap Tracking feature.
Polar Tracking aids you in drawing orthogonal lines, and Object Snap Tracking helps you align
a point in space relative to the geometry of existing objects. Object Snap Tracking works in con-
junction with osnaps. You'll learn more about the tracking vector in Chapters 3 and 4.
If you're an experienced AutoCAD user, you may prefer to use the old-style crosshair cur-
sor that crosses the entire screen. You can change the size of the crosshair cursor through the
Cursor And Selection settings in the Application Preferences dialog box. See Appendix B on the
companion website for more on the Preferences settings.
Choosing Command Options
Many commands in AutoCAD offer several options, which are often presented to you in the
Command window in the form of a prompt. This section uses the Arc command to illustrate the
format of AutoCAD's prompts.
Usually, in a floor-plan drawing in the United States, an arc is drawn to indicate the direc-
tion of a door swing. Figure 2.12 shows a drawing that includes other standard symbols used in
architectural-style drawings.
Here, you'll draw the arc for the door you started in the previous exercise:
1.
Click the 3-Point Arc tool in the Tool Sets palette. The Specify start point of arc
or [Center]: prompt appears, and the cursor changes to Point Selection mode.
Examine the Specify start point of arc or [Center]: prompt in the Command
Line palette. The start point contains two options. The default option is the one stated in
the main part of the prompt. In this case, the default option is to specify the start point of
the arc. If other options are available, they appear within square brackets. In the Arc com-
mand, you see the word Center within brackets telling you that, if you prefer, you can
also start your arc by selecting a center point instead of a start point. If multiple options
are available, they appear within the brackets and are separated by slashes (/). The
default is the option AutoCAD assumes you intend to use unless you tell it otherwise.
2.
Type
C
↵ to select the Center option. The Specify center point of arc: prompt
appears. Notice that you had to type only the C and not the entire word
Center
.
When you see a set of options in the Command Line palette, note their capitalization.
If you choose to respond to prompts by using the keyboard, these capitalized letters are
all you need to enter to select the option. In some cases, the first two letters are capitalized
to differentiate two options that begin with the same letter, such as LAyer and LType.
