Abstract: An integrated inventory and planning system for a factory system, which builds large buildings for transportation substantially intact from one or more construction sites to building sites, is presented. The system can include a demand calculation unit, a requirements calculation unit and a scheduling unit configured to provide a schedule of operation for a factory system producing large buildings for transportation to a substantially permanent building site, wherein the schedule is based at least in part on a first calculation of the demand calculation unit and a second calculation of the requirements calculation unit.