What Ductwork Does
Ductwork is a "simple" duct-metaphor item distribution network mod. In other words, gives Minecraft players a new way to move items around their world.
This mod provides three blocks which together implement a slight superset of the features of the Minecraft Item Hopper, enabling greater flexibility and improved game performance. Ductwork item movement networks are often more space and resource efficient than Hopper versions. Another core goal of the Ductwork mod is to deliver stable item movement similar to that of Hoppers and suitable for use in sorting systems and other complex machines, even in cases where Hoppers and Ductwork blocks are intermingled.
The Duct is the workhorse of a Ductwork network. Ducts accept items from up to five adjacent blocks, and deliver items to the block they are facing. Ducts cannot be locked and do not extract items from other blocks, so they make minimal use of game resources.
A Damper is a specialized Duct which accepts items from the block behind it and delivers items to the block in front of it. Unlike the basic Duct, a Damper can be locked via Redstone and will obstruct item movement while it remains locked. Dampers can also be temporarily locked or unlocked by the player (shift-right-click on them with an empty hand), until the next time an adjacent block changes state.
Dampers have a feature quite unlike Hoppers: when and only when a Damper is closed (powered), items can be extracted through the side of the Damper. This means you can easily create a system where items can be reliably diverted via a redstone signal, even when the Damper already has a full inventory.
Collector blocks suck items from the inventory or space behind them like a Hopper, but unlike a Hopper they can be oriented in any direction. Collectors deliver items from their inventory into the block in front of them just like other Duct blocks. Redstone wire can be placed on the top surface of any Collector block with an upward-facing intake.