Repeat zones allow running nodes many times in a loop. Compared with simply duplicating a node, they support executing a node an arbitrary number of times, possibly determined when the node group is evaluated. For example, the nodes could be repeated based on the number of stories in a building generator.
When adding a repeat zone, two nodes are added, with the «zone» defined between them. The inputs connected to the Repeat Input node are read at the beginning, before starting the repetitions. Then they are passed to the inside of the zone where they can be changed, and passed to the next iteration. This process is repeated the specified number of times.
Other nodes can be connected as inputs to the inside of the repeat zone from the outside. Those are constant throughout every iteration based on their value at the current frame. However, outputs of the zone must be connected through the Repeat Output node.
Number of repetitions.