Class Name: External Feature Face Ring

Superclass - Feature Face Ring

Definition

The one-directional topological relationship between a Regular Feature Face and the ordered collection of one or more Feature Edges that define its outer boundary.

Primary Page in DRM Diagram:

• 12

Example

1. The outer boundary of a Regular Feature Face representing a lake is defined by 2 Feature Edges, one defining the north shore of the lake and the other defining the south shore. These 2 Feature Edges are the components of an External Feature Face Ring, which is in turn a component of the Regular Feature Face. The Feature Ring Edge Direction associated with each Feature Edge indicates its orientation with respect to the ring.

                        <Regular Feature Face>
                                  <>
                                  |
                    <External Feature Face Ring>
                                  <>
                                  |
           ---------------------------------------
           |                                     |
           |-<Feature Ring Edge Direction        |-<Feature Ring Edge Direction>
           |                                     |
           |                                     |
         <Feature Edge>                   <Feature Edge>
   

FAQs

When is an External Feature Face Ring object required?

All Regular Feature Face objects are required to have an External Feature Face Ring component, regardless of the feature topology level.

Can the same Feature Edge appear more than once in the collection of Feature Edges that are the components of an External Feature Face Ring?

Yes. If the Feature Edge is contained within the outer boundary of the Regular Feature Face, and is attached to the outer boundary of the Regular Feature Face, such that it has the Regular Feature Face on both sides, it will appear exactly twice in the External Feature Face Ring, once with each orientation.

What is the relationship between the External Feature Face Ring class and the Bordered Feature Face class?

The External Feature Face Ring class and the Bordered Feature Face class form the two halves of the bidirectional topological relationship between Feature Faces and Feature Edges. Whenever a Feature Edge appears in the collection of Feature Edge components of an External Feature Face Ring component of a Feature Face, that same Feature Face must appear in the collection of Feature Faces associated with the Bordered Feature Face component of that Feature Edge.

Constraints

• Feature Face Ring Edge Consistency

Composed of (one-way)(inherited)

• one or more {ordered} Feature Edges through Feature Ring Edge Directions

Component of (one-way)

• one Regular Feature Face