P6 Critical Paths / Longest Path(s) With Mixed Calendars To Multiple Contract Dates

here is what I do in a situation like that 

create a new activity code call it My Path and give it a value code of CP Critical path

next add that column to the data area on the left

next filter for the last activity in the Project ONLY

in the predcessor tab at the bottom right click and select Customize Predcessor Columns

Expand the General category on the left

bring the Critical and Driving selection to the right to be displayed

Next look of the predcessor that has BOTH driving and critical boxes checked

select that activity that has both boxes checked and at the bottom select GoTo

(if there are 2 or more activities that have both boxes checked select the one with the least amount of total float)

this will add that activity into the current view

keep doing this until you gate back to the data date

now select edit and then Select All (or do a fill down for the Activity code that you just added)

right click and select Assign 

Then select activity codes and assign all of these activities to the new codes call My Path and give them the code value of CP

Now filter where for activity code

Where My Path equals CP

this is your most critical path through the project

Hi Chris,

The solution to your problem is to break it with the milestone activity so the float will be calculated correctly as long as the multiple calendar had the same start hours and same finish hours.

Example: Act 1 = 7d x 8h workweek = 5 days duration (start on Monday finish Friday)  link FS (successor) to Act 2 = 5d x 8h workweek, the float will be calculated resulting 2 days float because act 2 will start on Monday. To resolve this issue, you have to link FF to  a Finish Milestone with 5d x8h day workweek calendar then link FS to Act 2 with 5d x 8h workweek and it will be calculated as 0 float.