Class Name: Connected Geometry Edge

Superclass - SEDRIS Abstract Base

Definition

A topological relationship between a Geometry Node and an ordered set of Geometry Edges, indicating that the Geometry Node connects the Geometry Edges.

Primary Page in DRM Diagram:

Example

  1. Consider a Geometry Edge representing part of the boundary of a Geometry Face, which in turn represents a lake. The Geometry Edge naturally contains two Geometry Edge Terminal Nodes, which in turn contain Geometry Nodes.

    In order to supply clean, high-level topological information, the data provider gives each of these Geometry Nodes a Connected Geometry Edge component, which relates it back to the Geometry Edge of which it is a part. This allows a consumer, encountering one of the Geometry Nodes, to determine what edges it participates in.

FAQs

When is a Connected Geometry Edge object required?
A Geometry Node object is required to have a Connected Geometry Edge component whenever it is the endpoint of one or more Geometry Edges. This requirement holds at all geometry topology levels. Also, if a Geometry Node is not the endpoint of any Geometry Edge, it must not have a Connected Geometry Edge component.

Why would a Geometry Node have more than one Connected Geometry Edge component?
At geometry topology levels 0 through 3, all of the Geometry Edges connected to a Geometry Node are located in the same topological surface; consequently, they can be ordered around the Geometry Node. However, at geometry topology level 4, Geometry Edges can connect to a Geometry Node from any direction in 3-dimensional space. When the Geometry Edges connected to a Geometry Node are not all located in the same topological surface, the Geometry Edges must be organized into subsets, one for each separate topological surface, and the Geometry Node must have a separate Connected Geometry Edge component for each such subset.

Can the same Geometry Edge appear more than once in the collection of Geometry Edges associated with a Connected Geometry Edge?
Yes. If a Geometry Edge forms a loop, so that its Geometry Edge Starting Node and its Geometry Edge Ending Node are the same Geometry Node, that Geometry Edge will appear exactly twice in the collection of Geometry Edges associated with the Connected Geometry Edge.

What is the relationship between the Connected Geometry Edge class and the Geometry Edge Terminal Node classes?
The Connected Geometry Edge class and the Geometry Edge Terminal Node classes (Geometry Edge Starting Node and Geometry Edge Ending Node) form the two halves of the bidirectional topological relationship between Geometry Nodes and Geometry Edges. Whenever a Geometry Edge appears in the collection of associated with a Connected Geometry Edge component of a Geometry Node, that same Geometry Node must be associated with either the Geometry Edge Starting Node, or the Geometry Edge Ending Node component of that Geometry Edge, and vice versa.

Constraints

Associated to (one-way)

Component of (one-way)

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