ISO/IEC 18023-1:200x(E) — Table 6.50 DRM_Continuous_LOD_Related

Table 6.50 — DRM_Continuous_LOD_Related_Geometry

Property

Description

Class

<DRM Continuous LOD Related Geometry>

Superclass

<DRM Aggregate Geometry>

Subclass

None.

Definition

An instance of this DRM class is used to represent continuous terrain or continuous adaptive terrain, by replacing a <DRM Polygon> with a set of fragmented <DRM Polygon> instances that represent the terrain at a finer level of detail at close range (or alternatively, with a coarser level of detail at long range).

The terminating_node specifies whether the current level of fragmentation is the lowest level of fragmentation for a specific chain. This flag is set to TRUE if no other <DRM Continuous LOD Related Geometry> instances are found below this chain’s current level.

Clarifications

¹ An 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> instance on the association relationship.

² An 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> instance on the association relationship.

³ An 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> instance on the association relationship.

⁴ An 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> instance on the association relationship.

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

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

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

Class diagram

Figure 6.56 — DRM_Continuous_LOD_Related_Geometry

Inherited field elements

Field name	Range	Field data type
unique_descendants		Boolean
strict_organizing_principle		Boolean

Field elements

Field name	Range	Field data type
terminating_node		Boolean

Associated to (one-way) (inherited)

zero or more <DRM Feature Representation> instances, each with a <DRM Base Association Data> link object¹
zero or more <DRM Geometry Hierarchy> instances, each with a <DRM Base Association Data> link object²

Associated to (one-way)

None.

Associated by (one-way) (inherited)

zero or more <DRM Feature Representation> instances, each with a <DRM Base Association Data> link object³
zero or more <DRM Geometry Hierarchy> instances, each with a <DRM Base Association Data> link object⁴
zero or one <DRM Hierarchy Summary Item> instance⁵
zero or more <DRM Reference Surface> instances⁶

Associated by (one-way)

None.

Associated with (two-way) (inherited)

None.

Associated with (two-way)

None.

Composed of (two-way) (inherited)

zero or one <DRM Classification Data> instance
zero or more {ordered} <DRM Property Set Index> instances
zero or more <DRM Property Table> instances
zero or more <DRM Property Table Reference> instances
zero or more <DRM Property Value> instances
zero or one <DRM Reference Surface> instance
zero or more <DRM Sound Instance> instances
zero or more <DRM Base LOD Data> instances
zero or one <DRM Bounding Volume> instance
zero or more <DRM Camera Point> instances
zero or more <DRM Collision Volume> instances⁷
zero or more <DRM Colour> instances
zero or one <DRM Conformal Behaviour> instance
a bounded set of 0..3 <DRM Geometric Centre> instances
zero or more <DRM Geometry Topology Hierarchy> instances
zero or more {ordered} <DRM Image Mapping Function> instances
zero or one <DRM Light Rendering Properties> instance
zero or more <DRM Light Source> instances
zero or one <DRM LSR Transformation> instance
zero or one <DRM Overload Priority Index> instance
zero or one <DRM Perimeter Data> instance
zero or one <DRM Presentation Domain> instance
zero or more <DRM Property Description> instances
zero or one <DRM Rendering Priority Level> instance
zero or one <DRM Rendering Properties> instance
zero or one <DRM Spatial Extent> instance
zero or one <DRM Stamp Behaviour> instance

Composed of (two-way)

zero or more <DRM Continuous LOD Related Geometry> instances
one <DRM Union Of Primitive Geometry> instance

Composed of (two-way metadata) (inherited)

zero or one <DRM Time Constraints Data> instance
zero or one <DRM Access> instance
zero or more <DRM Cross Reference> instances
zero or one <DRM Data Quality> instance
zero or one <DRM Description> instance

Composed of (two-way metadata)

None.

Component of (two-way) (inherited)

zero or more <DRM Alternate Hierarchy Related Geometry> instances, each with a <DRM Hierarchy Data> link object
zero or more <DRM Animation Related Geometry> instances
zero or more <DRM Classification Related Geometry> instances, each with a <DRM Classification Data> link object
zero or one <DRM Environment Root> instance
zero or one <DRM Geometry Model> instance
zero or more <DRM LOD Related Geometry> instances, each with a <DRM Base LOD Data> link object
zero or more <DRM Octant Related Geometry> instances, each with a <DRM Octant Data> link object
zero or more <DRM Perimeter Related Geometry> instances, each with a <DRM Perimeter Data> link object
zero or more <DRM Quadrant Related Geometry> instances, each with a <DRM Quadrant Data> link object
zero or more <DRM Separating Plane Relations> instances, each with a <DRM Separating Plane Data> link object
zero or more <DRM Spatial Index Related Geometry> instances, each with a <DRM Spatial Index Data> link object
zero or more <DRM State Related Geometry> instances, each with a <DRM State Data> link object
zero or more <DRM Time Related Geometry> instances, each with a <DRM Time Constraints Data> link object
zero or more <DRM Union Of Geometry Hierarchy> instances

Component of (two-way)

zero or one <DRM Continuous LOD Related Geometry> instance

Constraints

Example(s)

A Continuous LOD node can be fragmented into one or more <DRM Polygon> instances, and will then have zero or more Continuous LOD nodes as subnodes. Any Continuous LOD node that contains Continuous LOD nodes under it will have the terminating_node flag set to FALSE. The <DRM Union Of Primitive Geometry> node will contain <DRM Polygon> data. If a Continuous LOD node is encountered with the terminating_node flag set to TRUE, that means it only has a <DRM Union Of Primitive Geometry> node under it.

Figure 6.57 — <DRM Continuous LOD Related Geometry> example

NOTE This example only shows two levels of polygon fragmentation. Each <DRM Continuous LOD Related Geometry> could contain component <DRM Continuous LOD Related Geometry> instances, but that would make a huge picture. Only the idea is represented here.