Variables and Blackboards

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FlowReactor has it’s own variable types which are tightly integrated in the whole system. To make use of them you can define variables of type FRVariables (FRFloat, FRInt, FRBoolean…) in your custom nodes. Variables of type FRVariables will be available in the node inspector and can be connected with a blackboard.

Create blackboards and variables

First we need to create a new blackboard before defining variables. As a good practice try to split your variables into different blackboards according to your objects. For example create a blackboard which contains only variables for your character, another one which contains only variables for your enemy etc.

  1. Right click in the project view and select Create / FlowReactor / New Blackboard

  2. Select the newly created blackboard and click on the + button. You can now select the type. Lets add a string type for our example and add the text “Hello Blackboard”.

Assign Blackboard

Now that you have defined your variables you can assign the blackboard to your graph.

  1. Open your graph and select Blackboard.

  2. Drag and Drop the newly created Blackboard file to the inspector.

Connect variable

Let’s connect our Debug.Log log message with the variable from the blackboard.

  1. Select the Debug.Log node.
    In the node inspector you can now click on the blackboard button next to the variable field and select the string variable we’ve created.

  2. Great! The Log variable from our Debug.Log node is now connected with the Blackboard variable.

Rename Variables

You can rename your variables in the blackboard at any time without loosing the references.


The OnVariableChanged (for example: OnFloatChanged) event nodes can be used to listen to a specific blackboard variable. It gets called as soon as it has been changed.

View connected nodes

You can inspect all nodes which are connected to a variable in a blackboard. To do this simply click on the link icon next to the variable field in a blackboard. If the node is in the current graph you can quickly navigate to it.

Save and Load at runtime

You can save Blackboards to a file during runtime – Please note: only serializeable types will be saved.
This is a great way to use them for save games. To save a blackboard to a file simply use the SaveBlackboard or SaveMultiBlackboards node. To load them back, use the LoadBlackboard or LoadMultiBlackboards node

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