anchor.diff:  	std::cout << "Item uuid: " << it->getIDString() << std::endl;
   }
   ----
  -
   A convenience method exist to get an ``ItemIterator`` of the i'th item:
   [source,c++]
   ----
  
positive.code: ----
  
  or implicitly by using a unknown frame id in ``addTransform()``.
  
  [source,c++]
  ----
  EnvireGraph g;
  
negative.code: Once the item is loaded, there are two ways to add it to the graph.
  The common way is to add it using ``addItemToFrame()``:
  [source,c++]
  ----
  g.addItemToFrame(frame, octree);
  ----
  The item will remember the frame that it was added to. I.e. an item cannot be part of two frames at the same time.
  
  It is also possible to set the frame id beforehand and add the item using
  ``addItem()``.
  [source,c++]
  ----
  octree->setFrame(frame);
  g.addItem(octree);
  ----
  The item type can be a ``boost::shared_ptr`` to any subclass of ``ItemBase``.
  Item contains a typedef ``Ptr`` to make working with the pointer more convenient.
  [source,c++]
  ----
  envire::core::Item<...>::Ptr p;
  ----
  