Independent of the class hierarchy the scene manages a child-parent hierarchy of all TreeNode derived objects in the scene. The root node is the Scene object itself, which is derived from TreeNode. This hierarchy is a directed acyclic graph (DAG); or in other words a tree.

The following objects have a child-parent relationship in the scene graph:

• Transformation - A transform is a parent of a Camera, Geometry, or Light, and indicates its scale, rotation, and translation.
• Mesh - A mesh is a parent of any MeshGrid, MeshRenderer, SurfaceSmoother, TangentGenerator objects in the scene.
• Geometry - A geometry may have child SubdivisionLevel nodes.

The following classes are also part of the scene graph by virtue of deriving from TreeNode.

• Layer and ViewPort - Layers are organized in child-parent relationships independently of the scene graph, which are managed by a LayerContainer.
• LayerContainer and ViewPort
• LayerMeshData
• Material
• Picker