Class Name: Internal Feature Face Ring

Superclass - <Feature Face Ring>

Subclasses

Definition

An instance of this DRM class specifies the one-directional topological relationship between a <Feature Face> and the ordered collection of one or more <Feature Edge> instances that define one of its inner boundaries (i.e., a "hole" within the <Feature Face>).

Primary Page in DRM Diagram:

• 12

Secondary Pages in DRM Diagram:

Example

1. An island within a lake is represented by a <Regular Feature Face>. The shoreline of the island is represented by a single <Feature Edge>, and the lake is represented by another <Regular Feature Face>. The <Feature Edge> that specifies the shoreline of the island is the sole edge of an <Internal Feature Face Ring> component of the <Regular Feature Face> representing the lake. The <Edge Direction> associated with the <Feature Edge> indicates its orientation with respect to the <Internal Feature Face Ring>.

   

FAQs

When is an <Internal Feature Face Ring> instance required?

An <Internal Feature Face Ring> instance is required whenever a <Feature Face> contains a "hole" within its outer boundary, regardless of the feature topology level. All <Universal Feature Face> instances are required to have at least one <Internal Feature Face Ring> component.

Can the same <Feature Edge> appear more than once in the collection of <Feature Edge> instances that are the components of an <Internal Feature Face Ring>?

Yes. If the <Feature Edge> is contained within the boundaries of a <Regular Feature Face>, and is attached to an inner boundary of the <Regular Feature Face>, such that it has the <Regular Feature Face> on both sides, it will appear exactly twice in the <Internal Feature Face Ring>, once with each orientation.

Constraints

• <<Face Ring Edge Consistency>>

Associated to (one-way)(inherited)

• one or more {ordered} <Feature Edge> instances through <Edge Directions>

Component of (two-way)

• one <Feature Face> instance

Inherited Field Elements