In order to process rectangles and ellipses, MPSuperShape converts these shapes into closed freeform shapes. The accuracy of this conversion is controlled using the Accuracy tab on the MPSuperShape Information and Options dialog box:
The setting for the Rectangles determines the number of points (vertices) to be used on each side of the rectangle. It can range from 2 to 30. A higher number will be more accurate but it will tend to result in slower processing.
The setting for Circles and Ellipses works in terms of percentage error. This ranges from 0.001% to 5% of the radius. For example, 1% error on a 2km radius circle will result in a maximum error of 20m (0.02km). A smaller error will be more accurate but it will also tend to result in slower processing.
The appearance of rectangles, circles, and ellipses in MapPoint will depend on MapPoint's current view. MapPoint aligns shapes relative to the screen coordinates, and not map coordinates. Ie. a shape will appear to move slightly as the view moves. The best MPSuperShape can do, is to align the shape relative to map coordinates.
Rectangles and ellipses are flat Euclidean shapes. These are being projected onto a near-spherical globe. This is impossible without some distortion, although this is usually only visible on larger shapes. MapPoint ignores this distortion.