3D WBS method is the only method that allows to identify the interfaces of a project.
The three elementary tree structures of the WBS are projected on the axis of the WBS cube, and then, after the structuration, the durations estimate and the relationships definition, the schedule is calculated and the axis of the WBS cube are graduated function of the barycenter of each Product, Activity and Zone, along the time axis. It results that the distance between the tasks inside the WBS cube can be calculated, it gives the criticity of the interface. The analysis of the distances on the three axis allows also the qualify the nature of the interface which can be either Activity (temporal, logical), Product (physical or functional) and Zone (physico-functional). Interfaces can also have a complexity function of the Organization (responsible of tasks), indeed the more the organizations are different, the more the interface is complex. To be noted that an interface has a duration and happens at one date, and two tasks can be in interface only if they happens at the same time.
So, the interfaces allows:
- To identify the risks of the project;
- To define theworkpackages, by grouping the tasks containing the most of interfaces, in order to reduce the complexity of the work;
- To secure the schedule, by optimizing the interfaces, by leveling the schedule to remove them.
That is why it is so important to know them, and to understand 3D WBS method…
