Aligning Objects by Using Object Snap Tracking

Aligning Objects by Using Object Snap Tracking
You saw how to use lines to construct an object such as the bathtub. In many situations, using these
construction lines is the most efficient way to draw, but they can also be a bit cumbersome.
AutoCAD 2008 offers another tool that helps you align locations in your drawing to existing objects
without having to draw intermediate construction lines. The tool is called Object Snap Tracking or
Osnap Tracking.
Osnap Tracking is like an extension of object snaps that enables you to align a point to the geometry
of an object instead of just selecting a point on an object. For example, with Osnap Tracking,
you can select a point that is exactly at the center of a rectangle.
In the following exercises, you’ll draw a plan view of a bathroom sink as an introduction to the
Osnap Tracking feature. This drawing will be used as a symbol in later chapters.
WARNING The Object Snap Tracking feature isn’t available in AutoCAD LT 2008. If you’re using
LT, follow along with the tutorial until you’re asked to draw the ellipse to represent the bowl of
the sink. Go ahead and draw an ellipse approximating the shape and size of the one in the tutorial.
In Chapter 15, you’ll learn about the Temporary Tracking feature, which is available in LT as well
as AutoCAD and is similar to the Object Snap Tracking feature.
A Quick Setup
First, as a review, you’ll open a new file by using the Create New Drawing Wizard. Because this
drawing will be used as a symbol for insertion in other CAD drawings, don’t worry about setting
it up to conform to a sheet size. Chances are, you won’t be printing individual symbols. Here are
the steps:
1. Choose File  New to create a new drawing for your bathroom sink. Enter Startup↵ 1↵. This
turns on the Quick Setup wizard for new drawings. Next...
2. Click the Use A Wizard button in the Create New Drawing dialog box, select Quick Setup
from the list that appears below the buttons, and then click OK.



3. In the Units screen, choose Architectural; then, click Next. Metric users can use the Decimal
option. This option performs the same operation as the Drawing Units dialog box you saw
earlier in this chapter.
4. In the Area screen, enter 48 for the width and 36 for the length. Metric users should enter 122
for the width and 92 for the length. Click Finish. This option performs the same operation as
choosing Format  Drawing Limits from the menu bar.
5. Click the Grid button in the status bar, and then choose View  Zoom  All from the menu
bar. This enables you to see your entire work area.
6. Choose File  Save As to save the file under the name Sink.
7. Enter Setup↵ 0↵ to turn off the Quick Setup wizard. Or you can leave it turned on, but be
aware that later exercises assume that it is turned off.
As you saw in steps 3 and 4, the Create New Drawing Wizard simplifies the drawing setup
process by limiting the options you need to work with.
TIP If you find that you use the same drawing setup over and over, you can create template files
that are already set up to your own, customized way of working. Templates are discussed
in Chapter 5

Aligning with Grips
Osnaps, in conjunction with grips, offer a feature similar to Osnap Tracking that lets you align a grip
with the direction of a line or an arc. Here’s how it works. Select the line to which you want to be aligned
so that its grips are displayed. Select the grip of another object that you want to edit, and then hover over
the endpoint grip of the first line you selected. As you move your cursor away from the grip, an alignment
vector appears that is aligned with the first line. Your cursor then snaps to the line and the vector
it describes. As you move the cursor, it stays along the vector described by the line.
You can also hover over the endpoint grips of two lines or a line and an arc to find their intersection. Or,
you can quickly extend the length of a line or an arc using this method. Click the endpoint grip of a line,
for example, hover over it until a cross appears, and then drag the endpoint along the direction of the
line to lengthen or shorten it. This also works with grips in a polyline.