This feature is still experimental. Please report issues and use cases on the Support Forum

You can use Feedback connections as a simple why to take values from nodes at the end of the workflow and bring them back to nodes at the beginning of the workflow, effectively creating a feedback loop without using a Loop with Shift terminals.

To mark a Connection as Feedback connection, right-click the connection that you want to use as the feedback and select Feedback connection. The connection will now be dashed instead of solid.


The sheet can now be run by pressing the play button. Every time the play button is pressed, one iteration will complete. To automatically run the sheet, press the repeat button. Press the repeat button again to stop iterating.


How it works

When a connection is marked as a Feedback connection, the connection is removed from the topological sort and will not impact the order that the nodes are executed in. However, when a node is executed, it will still try to update the Feedback connection and use the value from the terminal of the node that it is connected to.

Not all nodes can support this feature because on the first execution of the sheet, the value from the Feedback connection could be undefined. Nodes need to be either able to operate on (ignore) bad values or the value of the Feedback connection needs to be initialized to something that can be used.

For example, in the above workflow, the result terminals of the Sum nodes are initialized to 0. On the first execution of the sheet, the Feedback connection has a value of 0, which is an acceptable value that the Sum node can operate on.