Exploring the Drawing Process

Exploring the Drawing Process
This section presents some of the more common AutoCAD commands and shows you how to
use them to complete a simple drawing. As you draw, watch the prompts and notice how your
responses affect them. Also notice how you use existing drawing elements as reference points.
While drawing with AutoCAD, you create simple geometric forms to determine the basic
shapes of objects, and you can then modify the shapes to fill in detail.
AutoCAD offers 14 basic 2D drawing object types: lines, arcs, circles, text, dimensions, traces,
polylines, points, ellipses, elliptical arcs, spline curves, regions, hatches, and multiline text. All drawings
are built on these objects. In addition, there are five 3D meshes, which are three-dimensional surfaces
composed of 3D faces. You’re familiar with lines and arcs; these, along with circles, are the most commonly
used objects. As you progress through the book, you’ll learn about the other objects and how
they’re used. You’ll also learn about 3D objects in the section on AutoCAD 3D.
Locating an Object in Reference to Others
To define the toilet seat, you’ll use an ellipse. Follow these steps:
1. Click the Ellipse tool in the 2D Draw control panel, or type El↵. You can also choose
Draw  Ellipse  Axis, End.
2. At the Specify axis endpoint of ellipse or [Arc/Center]: prompt, pick the midpoint
of the bottom horizontal line of the rectangle. Do this by opening the Osnap pop-up menu and
selecting Midpoint; then, move the cursor toward the bottom line. (Remember, Shift+click the
right mouse button to open the Osnap menu.) When you see the Midpoint Osnap marker on
the line, click the left mouse button.



3. At the Specify other endpoint of axis: prompt, point the cursor downward, and enter
1´-10˝↵. Metric users should enter 55↵.
4. Pick this as the second axis endpoint.
5. At the Specify distance to other axis or [Rotation]: prompt, point the cursor horizontally
from the center of the ellipse, and then enter 8˝↵. Metric users should enter 20↵.
Your drawing should look like Figure 3.3.
TIP As you work with AutoCAD, you’ll eventually run into NURBS. NURBS stands for Non-Uniform
Rational B-Splines—a fancy term meaning that curved objects are based on accurate mathematical
models. When you trim the ellipse in a later exercise, it becomes a NURBS curve known as a spline
in AutoCAD. You’ll learn more about polylines and spline curves in Chapter 18.