Grouping nodes help to organize the scene graph, can establish relative coordinate systems,
and can contain most other kinds of X3D nodes.
Grouping nodes include the
node is also similar since it adds nodes into the current scene that loaded from another X3D scene, retrieved
via a local or online url address.
Chapter 3 slideset
and course videos
for X3D for Web Authors are available online via
X3D Scene Authoring Hints