LOD
This group node is used to allow applications to switch between various
representations of objects automatically. The children of this node typically
represent the same object or objects at varying levels of detail, from
highest detail to lowest.
The specified center point of the LOD is transformed by the current
transformation into world space, and the distance from the transformed center
to the world-space eye point is calculated. If the distance is less than the
first value in the ranges array, then the first child of the LOD group is
drawn. If between the first and second values in the ranges array, the second
child is drawn, etc. If there are N values in the ranges array the LOD nodes
should have N+1 children. Specifying too few children will result in the last
child being used repeatedly for the lowest levels of detail; extra children
will be ignored if too many children are specified. Each value in the ranges
array should be less than the previous value, otherwise results are
undefined.
FILE FORMAT/DEFAULTS
LOD {
ranges [ ] # MFFloat
center 0 0 0 # SFVec3f
}