An analytical ellipse is defined by a center point and two axes. The axes don't have to be perpendicular to each other. If the lengths of both axes are equal and the axes are perpendicular to each other, a special case called a 'circle' is achieved, in which case the lengths of the axes are the radius of the circle.

Ellipse, as well as nearly all other geometric shapes derived from it define an attribute called 'Sector'. When set, two additional attributes 'Start Angle' and 'End Angle' can be defined to achieve sector like shapes. Internally, all angle attributes are represented as radians, but the user interface allows use of other standard units as well.