Although ellipse templates greatly reduce construction time for an ellipse,
you should know how to construct an ellipse using other methods. You may
use the foci, trammel, concentric diameter, conjugate diameter, or
circumscribed parallelogram method of ellipse construction.
An ellipse is created by moving a point so that the sum of its distances from
two points (the foci) is constant and equal to the major axis. The foci serve
as focal points for the rotation of the circumferential points. The major axis
is its longest diameter. The shortest diameter is the minor axis. The ellipses
formed is a basic, uniform, noncircular, closed curve. An ellipse may also
be a conic section if formed by an oblique cutting plane on a solid.
Figure 2-45 shows ellipse terminology.
Figure 2-45.Ellipse terminology.
Continued on next page