anchor.diff:  SceneGraphVisitor visitor = new SceneGraphVisitor() {
   
     @Override
  -  public void visit(Spatial spat) {
  +  public void visit(Spatial spatial) {
       // search criterion can be control class:
       MyControl control = spatial.getControl(MyControl.class);
       if (control != null) {
         // you have access to any method, e.g. name.
  -      System.out.println("Instance of " + control.getClass().getName() 
  +      System.out.println("Instance of " + control.getClass().getName()
                          + " found for " + spatial.getName());
       }
     }
   
   };
  -  
  +
   // Now scan the tree either depth first...
   rootNode.depthFirstTraversal(visitor);
   // ... or scan it breadth first.
  
positive.code: = Traverse the SceneGraph
  :author: 
  :revnumber: 
  :revdate: 2016/03/17 20:48
  :keywords: spatial, node, mesh, geometry, scenegraph
  :relfileprefix: ../../
  
negative.code: 
  ----
  
  Which of the two methods is faster depends on how you designed the scengraph, and what tree element you are looking for. If you are searching for one single Geometry that is a “leaf of the tree, and then stop searching, depth-first may be faster. If you search for a high-level grouping Node, breadth-first may be faster.
  
  The choice of depth- vs breadth-first also influences the order in which found elements are returned (children first or parents first). If you want to modify user data that is inherited from the parent node (e.g. transformations), the order of application is important, because the side-effects add up.
  
  