The planning and control activities concerning the same time-period are dealt with on the same level of aggregation. In this way, the resource constraints and the order requirements are jointly analysed on several levels of aggregation. In order to integrate production planning aspects into process planning decision making, it is necessary that a feasible finite capacity planning concept is developed that is able to handle uncertainty and incompleteness of project plans. Capacity planning is a view on aggregate order planning that considers the capacity and the availability constraints of the resources. Production planning performs the loading of orders into predefined time-buckets of aggregated resource groups.
Process planning performes the allocation of resources to predefined process steps.
Among other reasons, it is, therefore, hard or even impossible to perform project planning and production planning concurrently. Performing production planning in an activity-oriented way makes it easier to integrate these two manufacturing planning tasks. As a result of this, the aggregate groups of resources are configured according to the requirements of the individual orders to be planned. Capacity plans of the AG s are drawn up in order to be able to analyse the influence of the capacity constraints on performing the orders in time. The capacity plans of the AG s are derived from the capacity plans of the physical resources and the relations between them.