Class Name: Face Direction
Definition
Link data that indicates which side (front or back) of a
Feature Face is associated with an
Areal Feature.
Primary Page in DRM Diagram:
Example
- An Areal Feature represents a grass-covered
region, consisting of a single Regular
Feature Face. The Face Direction link data
on the relationship between them would be set to true, indicating that the
front (i.e., the top) side of the face corresponds to the
Areal Feature.
FAQs
- What if both sides of a Feature Face are
associated with the same
Areal Feature?
- In such a case the Feature Face would appear
twice in the collection of Feature Face
components of the Areal Feature, once with the
Face Direction set to TRUE (front), and once
with the Face Direction set to FALSE
(back).
- What if the two sides of a Feature Face
are associated with different
Areal Features?
- In such a case the Feature Face would appear
once in the collection of Feature Face
components of each of the two Areal Features.
For the Areal Feature corresponding to the
front side of the face, the Face Direction
would be set to TRUE, while for the
Areal Feature corresponding to the back side of
the Feature Face, the
Face Direction would be set to FALSE.
- How does Face Direction relate to the
feature topology level?
- At feature topology levels 0 through 3, Face
Direction must always be TRUE (front). Only a feature topology level 4
can the back side of a Feature Face be
associated with an Areal Feature.
Constraints
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