Ellipse Construction, Continued
Parallelogram
The parallelogram method of constructing ellipses inscribes the ellipse within
ellipses
a parallelogram. You may use conjugate diameters or the major and minor
axes to formulate the parallelogram so long as the sides of the parallelogram
are parallel to the diameters or axes.
To draw an ellipse by the parallelogram method, use this table;
Step
1
Action
Given the major and minor axes or the conjugate diameters AB and
CD, draw a rectangle or parallelogram . Make sure all sides are
parallel to their respective sides.
2
Divide the distance between AO and AJ into the same number of
equal parts.
3
Starting at the ends of the minor axis CD, lightly draw straight lines
through each point. The lines intersect forming the circumference
of the ellipse.
4
Lightly sketch the outline of the ellipse. Darken the outline using
french curves.
Figure 2-51 illustrates the procedure for drawing an ellipse inscribed within a
parallelogram.
Figure 2-51.—The
parallelogram method.
2-53
