Drawing Curves - Mastering AutoCAD for Mac - page 470

Drawing a True Spline
The following steps describe the process used to create a spline curve. You don't have to create
them now. Make a note of this section, and refer to it when you need to draw and edit a spline.
Here are the steps:
1. Choose the Spline tool on the Tool Sets palette, or type SPL ↵.
2. At the Specify first point or [Method/Knots/Object]: prompt, select a point to
start the curve. (Figure 17.20.) The prompt changes to Enter next point or [start
Tangency/toLerance]:.
FIGURE 17.20
Start the spline
curve at the fi rst
data point and
then continue to
select points.
Click a point to
start the spline.
3. Continue to select points until you've entered all the points you need. As you pick points,
a curve appears, and it bends and fl ows as you move your cursor. In Figure 17.20, a Center
object snap was used to select the donuts that appear as dots in the survey plan.
4. After you've selected the last point, press ↵ to exit the Spline command.
If you prefer, you can control the tangency of the spline at its fi rst and last points. The follow-
ing steps describe how the Tangency option can be used:
1. Start the spline just as before, and select the start point. At the Enter next point or
[start Tangency/toLerance]: prompt, type T ↵.
2. The prompt changes to Specify start tangent:. Also, a rubber-banding line appears
from the first point of the curve to the cursor. Select a point indicating the tangency of the
first point.
3. Continue to select the other points of your spline. After you've selected the last point,
type T ↵.
4. Use the cursor to indicate the tangency of the spline at the last point.
You now have a smooth curve that passes through the points you selected. These points are
called the fi t points. If you click the curve, you'll see the grips appear at the location of these fi t