Class

• <DRM Distance LOD Data>

Superclass

• <DRM Base LOD Data>

Subclass

• None.

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.

The minimum_range field is specified in metres.

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

The maximum_range field is specified in metres; +∞ is a legal range value.

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

Class diagram

Figure 6.67 — DRM_Distance_LOD_Data

Constraints

• LOD related organizing principle
• Publishable Object

Example(s)

• Consider a <DRM LOD Related Geometry> instance which has two branches, each having an attached <DRM Distance LOD Data>.

  The first <DRM Distance LOD Data> instance has:

  minimum_range	=	100,0
  minimum_fade_band	=	10,0
  maximum_range	=	200,0
  maximum_fade_band	=	20,0

  The second <DRM Distance LOD 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.

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

  The first <DRM Distance LOD Data> instance has:

  minimum_range	=	50,0
  minimum_fade_band	=	20,0
  maximum_range	=	100,0
  maximum_fade_band	=	30,0

  The second <DRM Distance LOD 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.

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

• See <DRM LOD Related Geometry>’s examples.