Making a Preliminary Sketch

Making a Preliminary Sketch
In this section, you’ll see how planning ahead will make your use of AutoCAD more efficient. When
drawing a complex object, you’ll often have to do some layout before you do the actual drawing. This
is similar to drawing an accurate pencil sketch using construction lines that you later trace over to produce
a finished drawing. The advantage of doing this in AutoCAD is that your drawing doesn’t lose
any accuracy between the sketch and the final product. Also, AutoCAD enables you to use the geometry
of your sketch to aid you in drawing. While you’re planning your drawing, think about what you
want to draw, and then decide which drawing elements will help you create that object.
You’ll use the Offset command to establish reference lines to help you draw the inside of the tub. This
is where the Osnap overrides are useful. (See the sidebar “The Osnap Options,” later in this chapter.)
You can use the Offset tool on the 2D Draw control panel to make parallel copies of a set of
objects, such as the lines forming the outside of your tub. Offset is different from the Copy command;
Offset allows only one object to be copied at a time, but it can remember the distance you
specify. The Offset option doesn’t work with all types of objects. Only lines, arcs, circles, ellipses,
splines and 2D polylines can be offset.
Standard lines are best suited for the layout of the bathtub in this situation. In Chapter 6, you’ll
learn about two other objects, construction lines (Xlines) and rays, which are specifically designed
to help you lay out a drawing. In this exercise, you’ll use standard lines:
1. Click the Offset tool in the 2D Draw control panel, or type O↵. You can also choose Modify
 Offset from the drop-down menu.

2. At the Specify offset distance or [Through/Erase/Layer] : prompt, enter 3↵.
This specifies the distance of 3˝ as the offset distance. Metric users should enter 7 for 7 cm, which
is roughly equivalent to 3 inches.
3. At the Select object to offset or [Exit/Undo] : prompt, click the bottom line
of the rectangle you just drew.
4. At the Specify point on side to offset or [Exit/Multiple/Undo]: prompt, pick
a point inside the rectangle. A copy of the line appears. You don’t have to be exact about
where you pick the side to offset; AutoCAD wants to know only on which side of the line
you want to make the offset copy.
5. The prompt Select object to offset or [Exit/Undo] : appears again. Click
another side to offset; then, click again on a point inside the rectangle.
6. Continue to offset the other two sides; then, offset these four new lines inside the rectangle
toward the center. You’ll have a drawing that looks like Figure 3.8.
7. When you’re done, exit the Offset command by pressing ↵.