8.21.1 planeSection class: A class describing a general 2D section.

The 2D section is the area inside a closed curve in the (x,y) plane. The curve is decribed by a finite number of points and by straight segments connecting them.

The planeSection class has this constructor:

class planeSection( F)
Initialize a plane section.

Initialization can be done either by a list of points or a set of line segments.

1. By Points Each point is connected to the following one, and (unless they are very close) the last one back to the first. Traversing the resulting path should rotate positively around the z axis to yield a positive surface.

2. By Segments It is the responsibilty of the user to ensure that the segments form a closed curve. If not, the calculated section data will be rather meaningless.

planeSection objects have the following methods:

sectionChar( )