Class Name: Distance Level Of Detail Data

Superclass - <Base Level Of Detail Data>

Subclasses

Definition

An instance of this DRM class specifies a level of detail described in terms of distance from the eyepoint to the centre of the object.

Primary Page in DRM Diagram:

• 9

Secondary Pages in DRM Diagram:

Example

1. Consider a <Level Of Detail Related Geometry> instance which has two branches, each having an attached <Distance Level Of Detail Data>.

   The first <Distance Level Of Detail Data> instance has:

   minimum_range	=	100.0
   minimum_fade_band	=	10.0
   maximum_range	=	200.0
   maximum_fade_band	=	20.0

   The second <Distance Level Of Detail Data> instance has:

   minimum_range	=	200.0
   minimum_fade_band	=	10.0
   maximum_range	=	1000.0
   maximum_fade_band	=	10.0

   If the eyepoint is moving outward and the distance reaches 90, the first branch starts fading in. At a distance of 100, the first branch has totally faded in. At a distance of 180 the first branch starts to fade out. At a distance of 190 the second branch starts fading in. The first and second branches are both seen (super-imposed) between the ranges of 190 and 200. At a distance of 200 the first branch is totally faded out, while the second branch is the only branch seen. At a distance of 990, the second branch starts fading out, and at 1000 it is completely faded out.

2. Consider a <Level of Detail Related Geometry> instance which has two branches, each having an attached <Distance Level Of Detail Data>.

   The first <Distance Level Of Detail Data> instance has:

   minimum_range	=	50.0
   minimum_fade_band	=	20.0
   maximum_range	=	100.0
   maximum_fade_band	=	30.0

   The second <Distance Level Of Detail Data> instance has:

   minimum_range	=	110.0
   minimum_fade_band	=	15.0
   maximum_range	=	500.0
   maximum_fade_band	=	10.0

   If the eyepoint is moving outward and the distance reaches 30, the first branch starts fading in. At a distance of 50, the first branch has totally faded in. At a distance of 70 the first branch starts to fade out. At a distance of 95 the second branch starts fading in. The first and second branches are both seen (super-imposed) between the ranges of 95 and 100. At a distance of 100, the first branch is totally faded out, while the second branch is the only branch seen, but hasn't completely faded in. At a distance of 110 the second branch has completely faded in. At a distance of 490 the second branch starts fading out, and at 500 is completely faded out.

3. A set of polygonal data is produced with low detail for viewing at ranges greater than 3200 metres, and organized as a <Union Of Primitive Geometry>, with a <Distance Level Of Detail Data> component specifying this viewing range so that the intended viewing distance at which these <Polygon> instances are to be used is provided.

4. See <Level Of Detail Related Geometry>'s examples.

FAQs

As a data provider, I have a branch of a distance level-of-detail-related organization for which fade bands aren't applicable. How should those fields be set?

If a target does not contain fade bands, then the minimum_fade_band and maximum_fade_band shall be set to zero (0).

Constraints

• <<Level Of Detail Related Organizing Principle>>

Composed of (two-way)

• zero or one <Location> instance (notes)

Component of (two-way)(inherited)

• zero or more <Aggregate Feature> instances
• zero or more <Aggregate Geometry> instances
• zero or more <Property Grid Hook Point> instances

Inherited Field Elements

Field Elements

Notes

Composed of Notes

Location

 This is the centre point for the LOD test.

Fields Notes

minimum_range

 This is in metres.

minimum_fade_band

 This is expressed in metres (not percent). This fade band shall
 go in the negative direction from the minimum range.

maximum_range

 This is in metres; SE_POSITIVE_INFINITY is a legal range value.

maximum_fade_band

 This is expressed in metres (not percent). This fade band shall
 go in the negative direction from the maximum range.