elements are made up of edges that connect to each other at node points. The connections between nodes and edges are described with the element.
An element will contain a list of child elements. Each one models a branch of the vessel. Each edge contains a collection of sequentially connected elements. Connecting these points represents the centerline. The d value of each point is equal to the radius of the segment at that point. The elements also include a unique ID value and a user-defined name.