Table 6.297 — DRM_Union_Of_Primitive_Geometry

Property

Description

Class

  • <DRM Union Of Primitive Geometry>

Superclass

Subclass

  • None.

Definition

An instance of this DRM class is a <DRM Union Of Geometry> instances that is composed solely of <DRM Primitive Geometry> instances.

Class diagram

Figure 6.369 — DRM_Union_Of_Primitive_Geometry

Inherited field elements

Field name

Range

Field data type

unique_descendants

 

Boolean

strict_organizing_principle

 

Boolean

union_reason

 

Union_Reason

ordering_reason

 

Ordering_Reason

Field elements

Field name

Range

Field data type

None

   

Default field values

Default field values for DRM_Union_Of_Primitive_Geometry

Associated to (one-way) (inherited)

Associated to (one-way)

  • None.

Associated by (one-way) (inherited)

Associated by (one-way)

  • None.

Associated with (two-way) (inherited)

  • None.

Associated with (two-way)

  • None.

Composed of (two-way) (inherited)

Composed of (two-way)

Composed of (two-way metadata) (inherited)

Composed of (two-way metadata)

  • None.

Component of (two-way) (inherited)

Component of (two-way)

Constraints

Clarifications

1An association between a <DRM Feature Representation> instance and a <DRM Geometry Hierarchy> instance indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

2An association between two <DRM Geometry Hierarchy> instances indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

3An association between a <DRM Feature Representation> instance and a <DRM Geometry Hierarchy> instance indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

4An association between two <DRM Geometry Hierarchy> instances indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

5An association from a <DRM Hierarchy Summary Item> instance to a <DRM Geometry Hierarchy> instance indicates that the <DRM Hierarchy Summary Item> instance summarizes that <DRM Geometry Hierarchy> instance.

6An association from a <DRM Reference Surface> instance to a <DRM Geometry Hierarchy> instance indicates that the <DRM Geometry Hierarchy> instance organizes the geometric objects that specify the reference surface geometry of the <DRM Reference Surface> instance.

7In the case where multiple <DRM Collision Volume> components are specified for the <DRM Aggregate Geometry> instance, the union of the volumes thus specified is used in collision detection.

8A <DRM Aggregate Geometry> instance can have a <DRM LSR Transformation> component only when the <DRM Aggregate Geometry> instance is within the scope of an LSR 3D SRF.

Example(s)

  • Consider a geometric representation of an airport runway in which the runway surface is represented by a layer of polygons, overlaid by stripes (decal polygons). To ensure that the necessary rendering order is followed, the data provider creates a <DRM Union Of Primitive Geometry> instance U and attaches each <DRM Polygon> instance as a component of U, in order of increasing relative rendering priority. The <DRM Polygon> instance with the lowest relative rendering priority is attached first. After all the <DRM Polygon> instances in the underlying pavement have been attached, the <DRM Polygon> instances used to decal the pavement are attached in the order in which they will be rendered.

    If a specific method is used for the ordering, the data provider specifies it in the ordering_reason field of U. In this case, the data was created for a Z-buffer rendering system that supports layers, so ordering_reason is set to LAYERED_HIGH_QUALITY_RENDERING.

  • A <DRM Union Of Primitive Geometry> instance is a collection of <DRM Polygon> instances making up the representation of a fire hydrant.

  • A <DRM Union Of Primitive Geometry> instance is a 10 kilometre by 20 kilometre triangulated irregular network of <DRM Polygon> instances.