• derived nodes inherit all messages from their base classes
  
• see reset method for default settings
  
• the first range value defines when the first child is selected
  
• all subsequent range values define the selection of the next child
  
• the last range value defines when the last child is unselected
  
• the total number of range values should be the number of children plus one
  

constructor levelOfDetail

1 set the range to the first child as 0.0
2 initialize a range variable to 50.0
3 for each child

3.1 set child number plus one range to the variable
3.2 double the range variable

destructor ~levelOfDetail

method reset

method message

1 set the distance at which a child is switched on
2 set the distance for each child plus switch off distance

method app

1 get the world viewer
2 find the viewer with respect to this node
3 find the distance to the viewer
4 set selected to OFF
5 for each range value minus the last one

5.1 if distance greater than range, then set selected to that child

6 if distance greater than last range, then set selected to OFF
7 if selected has changed

7.1 set sw value

method appTraverse

1 start timing
2 execute app method
3 call appTraverse recursively on selected child
4 end timing