The SEDRIS Data Representation Model
APPENDIX A - Classes
Polygon

Class Name: Polygon

Superclass - <Surface Geometry>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies a bounded portion of a plane, defined by a set of three or more <Vertex> components listed in counterclockwise order. The final segment connecting the last <Vertex> component to the first <Vertex> component is implicit, not explicit. That is, the first <Vertex> component is not duplicated to also appear as the last <Vertex> component of the <Polygon> instance.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

Example

  1. A <Polygon> instance represented by multiple subfaces each of which are other <Polygon> instances is depicted in Figure 6.38.

    Polygon, Example 1, Diagram 1

    Figure 38 — <DRM Polygon> polygon subfacing example

    The resulting DRM objects are depicted in Figure 6.39.

    Polygon, Example 1, Diagram 2

    Figure 39 — <DRM Polygon> example

    In processing these subfaces, the traversal and drawing order of the DRM objects is depth first.

FAQs

No FAQs supplied.

Constraints

Associated with (two-way)

Composed of (two-way) (inherited)

Composed of (two-way)

Composed of (two-way metadata) (inherited)

Component of (two-way) (inherited)

Component of (two-way)

Inherited Field Elements

This class has no inherited field elements.

Field Elements

SE_Polygon_Flag polygon_flags; 4

Notes

Associated with Notes


Geometry_Face

A <Geometry Face> instance associated with a <Polygon> instance represents the topology of the specified face (front or back) of that <Polygon> instance.

Composed of Notes


Union_Of_Primitive_Geometry

A <Primitive Geometry> instance P has a <Union Of Primitive Geometry> component only when P can be decomposed into nested <Primitive Geometry> instances.

EXAMPLE  A <Polygon> instance can be decomposed into multiple <Polygon> instances representing subfaces.


Polygon_Control_Link

If a <Polygon> instance is subject to dynamic control (that is, if its flags can be turned on and off), it has a <Polygon Control Link> component to express that control mechanism.

Fields Notes

polygon_flags

The polygon_flags field specifies the set of SE_Polygon_Flag members applicable to the <Polygon> instance. For a <Polygon> instance with a <Polygon Control Link> component X, the value of the polygon_flags field is obtained from X.


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Last updated: July 26, 2006 Copyright © 2006 SEDRIS