Top Node

The Fusion node diagram configured in the Fusion panel starts at the top node. A Top Node is the root node in the Fusion Diagram. The top node is the node selected in the scene tree and is the root node of the Fusion diagram. The Top Node is fixed and cannot be deleted (from the Fusion Editor).

The nodes that can be used as top nodes are as follows.

• Predefined CGI Control templates
  
• Custom user control / Instantiated control(this one can have it’s own properties defined by user)
  
• Behavior building block template 
  
• State machine elements (States/Transitions etc)
  
• Any of 2D/3D scene nodes

To select a Top Node, click a node (in the Scene Tree) and the "Extra Scene Tree" beside it shows a link called "Fusion..."  for that particular node. When the "Fusion..." link is clicked, the Fusion Editor is displayed with the current node in the Scene Tree as the Top Node in the Fusion Diagram.

If the Fusion Editor is already currently visible, selecting any node in the Scene Tree will automatically show the Fusion Diagram of that corresponding node.

The selection of a Top Node depends on each use case. For example, the Top Node can be a button in the Scene Tree from which you want to detect click events from. Or it could be a node in the scene whose property value you want to check, in order to perform some action. Essentially, the Top Node is the node which is the source or recipient of events or values to be processed.

The Top Node only has a connector at the right side, from which all other fusion nodes can stem from. See Basic Operations on how to connect Fusion nodes.

Behaviors as Fusion nodes that can be connected to the top node are divided into the following categories. 

• Action Fusion Node
• Condition Fusion Node
• Behavior Fusion Node
• Behavior Group Fusion Node (BehaviorBuildingBlock)

Fusion nodes that can be connected other than those listed above include the reference Fusion node in the Action/Condition/Behavior Fusion node.

The color of each category (including the top node) Fusion node on the Fusion panel can be set in the Preferences.