3 Replies Latest reply: Mar 4, 2009 4:15 PM by 690399 RSS

    Odd float

    690399
      I have a dozen tasks as predecessor to a finish milestone.
      One of the predessor tasks is critical and driving, with
      -57 days' float. with only one successor, however, the
      milestone shows -243 days' float. When I remove the
      predecessor with -57 days' float, the milestone's total
      float goes to +5.

      I know there's
      an easy explanation, but I can't think of it. Someone hit
      me over the head with it, please....
      <br
      />Thanks, guys!

      JimS
        • 1. Odd float
          690399
          Just guessing at all possible things to try out:<br
          />
          1. Any external relationships?<br
          />2. What about retained logic for predecessors of
          the removed predecessor etc.?
          3. What
          version of Primavera? Are you on the latest
          patches?

          Cheers
          • 2. Odd float
            690399
            Float is kind of tricky here. You will have odd float
            (negative) if you applied a constraint to the
            activity. this will appear for example when you have a
            finish on or finish on or before type constraint and
            Primavera calculates that you will not be able to
            finish on time. Your negative float value indicates
            how far past the constraint your activity wants to
            push to. Aslo, LOE activities will throw you off here.
            It is my opinion that you leave LOE activities untied
            with thier successor relationship to keep them off CP.
            GL
            • 3. Odd float
              690399
              There are two primary causes of negative float on
              activities.
              1. If a Must Finish By
              constraint is assigned at the project level, this
              could cause negative float if the project cannot be
              completed by the constraint date. Check the Must
              Finish By date in Projects View, Dates tab.<br
              />
              2. If a mandatory constraint is
              assigned to an activity, this could cause negative
              float if the predecessor activities do not have enough
              time to finish. Run a schedule report to check for
              constraints.

              Other possible
              sources of negative float:
              Out of sequence
              progress. Correct the logic in the schedule or
              schedule using Progress Override or Actual Dates.

              Different Calendars on activities. <br
              />External project(s) with constraints that have
              relationship ties to the schedule. Check the Advanced
              Scheduling option "Ignore Relationships to and from
              other projects"
              Backward leveling.
              Reschedule to remove the leveling
              <br
              />If you have any further questions please contact
              support at Support at
              http://primavera.com/customer/support.asp. <br
              />
              Saryn