Activity Hierarchy
Open Plan has an activity hierarchy while Primavera P6 has a flat activity collection.
P6 uses the WBS hierarchy to achieve a result similar to what Open Plan does with activity subprojects:
Open Plan:
ACT
ACT.1
ACT.1.Child
P6:
WBS
WBS.1
Child
When you export an Open Plan project that has internal subprojects (such as the example above) to P6, only the lowest activities are exported. (In the example above, “ACT.1.Child” is exported but not its parents. The "dot" characters (periods) in the activity name have no significance in P6.)
While Open Plan allows you to have resources and relationships at the subproject level, when you export to P6, only activities at the lowest level are included. For example, if you have Activity 1, Activity 1.1, and Activity 1.1.1, only Activity 1.1.1 is included in the export. Open Plan will maintain relationships between activities and resource assignments to an activity for the export as long as they are at the lowest level.