The scene graph is the most important package in jME, as it is the API used to manage scene elements so that they can be rendered. The {@link com.jme3.scene.Spatial} class provides a common base class for all scene graph elements. The {@link com.jme3.scene.Node} class provides the "branches" in the graph, used to organize elements in a tree hierarchy. The {@link com.jme3.scene.Geometry} is the leaf class that will contain a {@link com.jme3.scene.Mesh} object (geometry data such as vertex positions, normals, etc) and a {@link com.jme3.scene.Material} object containing information on how the geometry should be shaded.