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3 Replies Latest reply: Mar 4, 2009 2:15 PM by 690399 RSS

Odd float

690399 Newbie
Currently Being Moderated
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 Newbie
    Currently Being Moderated
    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 Newbie
    Currently Being Moderated
    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 Newbie
    Currently Being Moderated
    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