To control in what order a number of functions are run, the flow inputs and outputs are used. In the image below, the white lines which begin with arrows instead of round connectors are flow inputs and outputs. You can see that the flow starts with an Update node which enters an Audio Player node. This stars the audio player.
From the Audio Player node, control flows to the If Node. “If” will use the “true” output flow if the audio player is playing and the “false” output flow if the audio player has finished playing.
The Light Bulb object in the scene will be visible (light up) while audio is playing and disappear when audio has stopped.
When the flow is passed to the Light Bulb object, the connected values at the input will be sent to the corresponding object. However, to read the output of any Node, the node does not need any flow passed to it.
The Distance Node, for instance, has no flow inputs or outputs, because the distance calculation is made whenever the “distance” output is read. The distance output is read by the Compare Node which in turn is read by the if Node. The If Node will follow the “true” output flow whenever the distance between the “a” and “b” inputs is greater than 12.