Resource Planning:

The time-dependant resource values (machine or human) are estimated using the amount of production, the analysis values of those productions and the time-dependant value of those productions calculated by the CPM Work Schedule.

The resource calculations should be optimized over the entire coarse of the Work Schedule. Mostly in real applications, it isn't convenient to keep the required work force available at the site or to increase or decrease the work force at hand this week or the other with respect to the Work Schedule. 

The Work Order should be optimized to homogenize the resource consumption or you should plan the resources depending upon the critical path. 

As well seen at that point, Bid, Quantity Surveying, Analysis, unit prices, work order, resource planning databases should be integrated.