Class Name: Continuous Level of Detail Related Geometry

Superclass - Aggregate Geometry

Definition

Used to represent continuous terrain or continuous adaptive terrain, by replacing a Polygon with a set of fragmented Polygons 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 general idea is that basic Polygons have fragmented Polygons within them, and those Polygons may have subsequent fragmentation.

Primary Page in DRM Diagram:

• 4

Example

A Continuous LOD node can be fragmented into one or more Polygons, 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 Union of Primitive Geometry node will contain Polygon data. If a Continuous LOD node is encountered with the terminating_node flag set to True, that means it only has a Union of Primitive Geometry node under it.

(NOTE that this example only shows two levels of polygon fragmentation. Each Continuous Level of Detail Related Geometrycould contain component Continuous Level of Detail Related Geometries, but that would make a huge picture. Only the idea is represented here.)

FAQs

How do I find the finest fragmentation of polygons?

Follow all Continuous LOD chains. Wherever a Continuous LOD node with terminating_node set to True is encountered, that identifies the finest fragmentation of Polygons under the Union of Primitive Geometry at that Continuous LOD.

So, what do the "terminating" Polygons represent?

The combination of polygons from the Continuous LOD nodes with terminating_node set to True make up the Polygon identified under the Union of Primitive Geometry from the Continuous LOD node with terminating_node set to False.

How do I tell what the range is between fine and coarse data without a link class like Geometry Level of Detail Data?

The uniqueness of Continuous LOD data is that it is not based on range data for an entire area to blend in. Rather, the blending of data is performed typically at the IG. In source data, all potential polygon fragmentations have been identified. Therefore, it is not necessary to have range data stored in a link class.

Constraints

• No Attribute Conflicts
• Non Crossing Aggregations
• Non Cyclic Aggregations
• Precedence of Attribute Set Index
• Non Crossing Associations
• Color Mapping Restrictions
• Image Mapping Functions and Texture Coordinates
• No Model CLOD
• Non Nestable Continuous LOD

Associated by (one-way)(inherited)

• optionally, a Hierarchy Summary Item
• optionally, some Reference Surfaces

Associated with (two-way)(inherited)

• optionally, some Features
• optionally, some Geometry Hierarchies

Composed of (one-way)(inherited)

• optionally, some {ordered} Attribute Set Indices
• optionally, a Classification Data
• optionally, some Property Tables
• optionally, some Property Table References
• optionally, some Property Values
• optionally, a Reference Surface
• optionally, some Sound Instances
• optionally, a Spatial Domain
• optionally, a Bounding Volume
• optionally, a Center of Buoyancy
• optionally, a Center of Mass
• optionally, a Center of Pressure
• optionally, some Collision Volumes
• optionally, a Conformal Behavior
• optionally, a LSR Transformation
• optionally, an Overload Priority Index
• optionally, some Property Descriptions
• optionally, a Stamp Behavior
• optionally, some {ordered} Colors
• optionally, a Light Rendering Properties
• optionally, a Rendering Properties
• optionally, some {ordered} Image Mapping Functions
• optionally, a Rendering Priority Level

Composed of (two-way)(inherited)

• optionally, some Hierarchical Tables
• optionally, some Light Sources

Composed of (two-way)

• one Union of Primitive Geometry
• optionally, some Continuous Level of Detail Related Geometries

Composed of (one-way metadata)(inherited)

• optionally, a Time Constraints Data
• optionally, an Access
• optionally, some Browse Graphics
• optionally, some Cross References
• optionally, a Data Quality
• optionally, a Keywords
• optionally, a Point of Contact

Component of (two-way)(inherited)

• optionally, some Alternate Hierarchy Related Geometries through Geometry Hierarchy Data
• optionally, some Animation Related Geometries
• optionally, some Classification Related Geometries through Geometry Classification Data
• optionally, an Environment Root
• optionally, some Geometry Separating Plane Relations through Geometry Separating Plane Data
• optionally, a Geometry Model
• optionally, some Level of Detail Related Geometries through Geometry Level of Detail Data
• optionally, some Oct Tree Related Geometries through Geometry Oct Tree Data
• optionally, some Time Related Geometries through Geometry Time Constraints Data
• optionally, some Perimeter Related Geometries through Geometry Perimeter Data
• optionally, some Quad Tree Related Geometries through Geometry Quad Tree Data
• optionally, some Spatial Index Related Geometries through Geometry Spatial Index Data
• optionally, some State Related Geometries through Geometry State Data
• optionally, some Union of Geometry Hierarchies

Component of (two-way)

• optionally, a Continuous Level of Detail Related Geometry

Inherited Field Elements

Field Elements

Notes

Fields Notes

unique_descendants

 If SE_TRUE, then for any object that exists 'below' this aggregation,
 each object will appear in only one 'branch' of this aggregation.
 If SE_FALSE, then objects may appear in multiple 'branches' of this
 aggregation.

independent_topologies

 If SE_TRUE, then each 'branch' from this aggregation is its own,
 independent topology.  If SE_FALSE, then all of the branches exist
 within the same topology.

strict_organizing_principle

 If true, then each 'branch' strictly follows the rules of this
 aggregation.  If false, then each 'branch' might bend the rules a bit.
 For example, if this is a spatial aggregation, than a value of true
 indicates that objects will *not* cross the spatial extents defined
 by this aggregation relationship, and a value of false indicates
 that objects might cross those bounds.  For another example, if this
 is a time-based aggregation, then a value of true indicates that all
 branches will only contain data valid for the times specified for
 each branch, and a value of false indicates that the branches have
 the option of including data that falls outside of the specified
 time ranges for that branch.

terminating_node

 This flag identifies if the current level is the lowest level of
 fragmentation for a specific chain. Set to SE_TRUE if no other
 <Continuous Level of Detail> nodes are found below this chain's
 current level.