When you schedule a project, you can choose to calculate multiple critical float paths (sequences of activities) that affect the project schedule. By calculating multiple critical float paths, you can determine the most critical path in the project schedule, along with sub-critical paths that affect the completion of the most critical path.
While you can determine the critical path of activities based on total float or longest path, these methods do not offer insight into sub-critical paths that may also affect the project schedule. For example, if you choose to identify critical activities based on a maximum total float threshold, P6 Web Access will identify all activities beyond the threshold as critical even if the activities have no relationships or do not affect the project end date. Likewise, if you choose to identify critical activities based on longest path, P6 Web Access will identify the critical path of activities but will not identify sub-critical paths that affect the critical path.
On the project scheduling options Advanced tab, you can choose to calculate a specific number of critical float paths based on total float or free float. You can also choose the activity you want the float paths to end on. By choosing an activity, you can calculate multiple float paths that affect the entire project schedule, a specific part of the schedule, or a milestone in the schedule.
When you schedule the project, P6 Web Access identifies the most critical float path in the schedule and assigns those activities a Float Path value of 1. Then, depending on the number of paths you choose to calculate, P6 Web Access identifies other float paths (sub-critical float paths) that affect the most critical float path and numbers the paths in ascending order (beginning with 2) based on the criticality of the path.
After you schedule a project, you can display the Float Path and Float Path Order columns in the Activity Table on the Projects > Activities page. Group by Float Path to view the activities in each critical float path, then sort by Float Path Order to view the order in which the activities were processed.