The present invention is a constraint-based planning tool that specifically addresses the needs of complex discrete and process industries by providing a computationally efficient method and system for fulfillment of customer orders in a supply chain. By comprehensively synchronizing and optimizing the flow of materials through the enterprise, the present invention creates a feasible plan for manufacturing operations that simultaneously optimizes both material and capacity constraints by planning and scheduling multiple customer orders, planning for use the various resources located in remote locations needed to fulfill such orders, and scheduling the used resources for replenishment at appropriate times so that the resources meet the needs of the orders.