Filter

The filter tutorial as seen in the game.

The wire tutorial as seen in the game, showing the filter in use on the wires layer.

The filter is a building used to sort and control the flow of items. It has a single belt input and two belt output connections — one opposite of the input, and one to the right, marked by a red X.

On the wires layer, there is a single wire input. Depending on the signal provided, the filter has three modes of operation. Null and conflict disable the filter entirely, blocking any item from passing through, true will forward all input items to the output opposite, and any other signal will forward only matching items to the output opposite, while outputting the rest to the side output. In this way, false can be used to output all items to the side.

If one output is completely backed up, this will not necessarily cause the filter to back up in turn, provided that the next items were due to be sent through the other output.