Axis Endpoint

Defines the first axis by its two endpoints. The angle of the first axis determines
the angle of the ellipse. The first axis can define either the major or the minor
axis of the ellipse.

Distance to Other Axis

Defines the second axis using the distance from the midpoint of the first axis to
the endpoint of the second axis (3).

Rotation

Creates the ellipse by appearing to rotate a circle about the first axis.

Move the crosshairs around the center of the ellipse and click. If you enter a value,
the higher the value, the greater the eccentricity of the ellipse. Entering 0 defines
a circular ellipse.

Arc

Creates an elliptical arc.

The angle of the first axis determines the angle of the elliptical arc. The first
axis can define either the major or the minor axis depending on its size.

The first two points of the elliptical arc determine the location and length of the
first axis. The third point determines the distance between the center of the elliptical
arc and the endpoint of the second axis. The fourth and fifth points are the start
and end angles.

Axis Endpoint

Defines the start point of the first axis.

Rotation

Defines the major to minor axis ratio of the ellipse by rotating a circle about the
first axis. The higher the value from 0 through 89.4 degrees, the greater the ratio
of minor to major axis. Values between 89.4 degrees and 90.6 degrees are invalid because
the ellipse would otherwise appear as a straight line. Multiples of these angle values
result in a mirrored effect every 90 degrees.

Start Angle

Defines the first endpoint of the elliptical arc. The Start Angle option also changes
Parameter mode to Angle mode. The mode controls how the ellipse is calculated.

Parameter (specialized option)

Requires angular input, but creates the elliptical arc using the following parametric
vector equation for the angle of each endpoint:

p(angle) = c + a * cos(angle) + b * sin(angle)

where c is the center of the ellipse and a and b are the negative lengths of its major and minor axes, respectively.

• End Parameter: Defines the end angle of the elliptical arc by using a parametric vector equation.
  The Start Parameter option toggles from Angle mode to Parameter mode. The mode controls
  how the ellipse is calculated.
• Angle: Defines the end angle of the elliptical arc. The Angle option toggles from Parameter
  mode to Angle mode. The mode controls how the ellipse is calculated.
• Included Angle: Defines an included angle beginning at the start angle.

Center

Creates an ellipse using a center point, the endpoint of the first axis, and the length
of the second axis. You can specify the distances by clicking a location at the desired
distance or by entering a value for the length.

Distance to Other Axis

Defines the second axis as the distance from the center of the ellipse, or midpoint
of the first axis, to the point you specify.

Rotation

Creates the ellipse by appearing to rotate a circle about the first axis.

Move the crosshairs around the center of the ellipse and click. If you enter a value,
the higher the value, the greater the eccentricity of the ellipse. Entering 0 defines
a circle.

Isocircle

Creates an isometric circle in the current isometric drawing plane.

Radius

Creates a circle using a radius you specify.

Diameter

Creates a circle using a diameter you specify.