Table 6.296 — DRM_Volume_Level_Of_Detail_Data

Property

Description

Class
  • <DRM Volume Level Of Detail Data>

Superclass

Subclass
  • None.

Definition

An instance of this DRM class specifies a volume that governs the switching of objects by the associated branch of a Volume-based <DRM Level Of Detail Related Geometry> or <DRM Level Of Detail Related Features> instance.

Class diagram

Figure 6.354 — DRM_Volume_Level_Of_Detail_Data

Inherited field elements

Field name

Range

Field data type

None

    

Field elements

Field name

Range

Field data type

outside1

 

Boolean

Associated to (one-way) (inherited)
  • None.

Associated to (one-way)
  • None.

Associated by (one-way) (inherited)
  • None.

Associated by (one-way)
  • None.

Associated with (two-way) (inherited)
  • None.

Associated with (two-way)
  • None.

Composed of (two-way) (inherited)
  • None.

Composed of (two-way)

Composed of (two-way metadata) (inherited)
  • None.

Composed of (two-way metadata)
  • None.

Component of (two-way) (inherited)

Component of (two-way)
  • None.

Constraints

Clarifications

1 For a <DRM Volume Level Of Detail Data> instance associated with a given branch of a volume-based level of detail aggregation, outside = TRUE if that branch is switched on when the observer is outside the volume, and off when the observer is inside the volume. If outside = FALSE, this behaviour is reversed.

2 This specifies the centre of the volume.

3 This specifies the shape of the volume.

Example(s)

  • Consider a geometric representation of a runway for an application for which increased detail is required as a viewer gets within 1000 metres of it, but for which a less detailed representation can be used outside that volume. This geometric representation can be organized as a <DRM Level Of Detail Related Geometry> instance, wherein the branch corresponding to the less detailed representation has a <DRM Volume Level Of Detail Data> link object with outside set to TRUE, specifying a parallelepiped volume that is aligned with the runway and extends 1000 metres from each edge. The more detailed representation's <DRM Volume Level Of Detail Data> link object would use the same <DRM Parallelepiped Volume Extent> and the same volume centre, but would have outside set to FALSE.

  • Consider another application, for which a geometric representation of a runway is required to provide increased detail as a viewer gets within 1000 metres of either end, but which if overflown from the side does not require detail to be switched on until the viewer is 500 metres away. In this case, the representation would have the same structure as that used in the previous example, but the parallelepiped would extend only 500 metres from either side of the runway, while extending 1000 metres from each end.

  • Consider a representation of a windowless building having opaque walls, such that nothing inside the building can be seen by an observer outside the building representation. Consequently, everything inside that building's representation can be switched on and off depending on whether an observer is inside or outside the building. This can be represented by organizing the building interior's representation with a volume level of detail organization.

    Suppose that the building interior's feature representation is being considered, so that it is being represented as one branch of a <DRM Level Of Detail Related Features> instance in a geodetic spatial reference frame, and that the interior volume of the building can be represented as a parallelepiped.

    Volume Level Of Detail Data, Example 3

    Figure 6.355 — <DRM Volume Level Of Detail Data> example

    The <DRM Volume Level Of Detail Data> specifies a parallelepiped volume of the same dimensions as the building interior, and specifies the centre of that volume. The value of its outside field indicates that the building interior's feature representation (the data represented by this branch) is active only when the viewer is inside (that is, not outside) the parallelepiped volume.