Start-to-Finish dependancy looks odd in Gantt Chart

R

Ryan

When you create a dependancy Start-to-Finish, Project automatically draws
the (Finish) task ending immediately at the start of the other task. For my
project, the (Finish) task can only be done on certain days of the week
(Tuesdays), and only takes 1 day duration. So if my (Start) task begins on
a Friday, the (Finish) task is drawn on the Gantt chart to appear to take
place the preceding Tuesday, Wednesday, and Thursday, even though in
actuality, the task begins and ends on the preceding Tuesday. Is there any
way to fix this to make the Gantt chart draw the task accurately?

Thanks.
 
S

Steve House [MVP]

Can you go into a bit more detail as the the other links, calendars, and any
constraints you have on these tasks? When I set up a simple two task
experiment using only the information you've provided, P2003 shows the
"finish" task to start on Thurs with a 1 day duration if the "start" task is
on Fri. How are you advising project that the "finish" task can only occur
on a Tues? How does the "start" task get placed on Fri in the first place?
If I create a calendar showing Tues as the only workday in the week and
assign it as the task calendar to the "finish" task, I get it starting Tues
and the bar shows ending Fri, as you describe, but the duration remains at 1
day. ie, Tues is a work day and the task is worked on then but not
otherwise. Wed and Thur are non-working days and nothing is happening
"inside the bar" and then on Fri again nothing is happening except that once
the "start" task begins we can officially declare the "finish" task to be
complete. The bar is there over Wed and Thur just like it flows over the
weekend for a 2 week task but the task is a 1 day duration task, not a 3
days duration one, since non-working days do not count toward duration.
 
R

Ryan

Hi Steve,

Thanks for your assistance.
You'll need 3 tasks to test this (I think). Task 1 and Task 2 are normal
Finish-to-Start dependancy. Task 1 needs a duration longer than the
"tuesday" task (Task 3), I set it to 10 days (while Task 3 will be 1 day).
Task 2 then has a Start-to-Finish dependancy with Task 3. You should see
the abnormal behavior with this setup. Task 3 appears to stretch out over
multiple days, even though it has only 1 day duration. Oh and I am setting
up a special "tuesday" calendar that Task 3 uses (Tools->Change Working
Times->New. Then just assign the calendar to Task 3).

After reading your explanation I think you may be seeing the long bar as
well ("The bar is there over Wed and Thur just like it flows over the
weekend for a 2 week task but the task is a 1 day duration task"). I do not
want the bar, I want an arrow (1 day bar, several days arrow going to the
next task). If you do the same thing with all Finish-to-Start dependancies
the 1 day task bar never stretches over 1 day, even if the next task doesn't
start for several days afterwords.

If you want an explanation as to why I need my project set up like this:
We have a project with several Phases (6 to be exact), each with a main
Construction Task. The Construction tasks need to happen one right after
the next (standard Finish-to-Start dependancies). However, before each
Construction phase, the phase must be approved in a commision meeting (which
only takes place on tuesdays). This meeting needs to happen just soon
enough that the Construction phase will be able to start immediately after
the previous construction phase ends. I want the project Gantt Chart to
accurately show that this task only occurs on a Tuesday and is complete on
that day, but I want the dependancies so that it moves if Construction
phases finish early or late.

Hope that explains my problem better.
Ryan
 
S

Steve House [MVP]

I do get the same thing you do. It's related to the idea that in a Start to
Finish link, the "hinge point" if you will, is the Start time of the
predecessor and that link dictates the successor's end will always synch up
to be no earlier than to the start of the predecessor. Indeed, a
fundamental property of all links is that the link logic determines the
*earliest* (when scheduling from start) that the successor's target will
occur - FS and SS links define the earliest the successor's start can occur
in the schedule while FF and SF links define the earliest the sucessor's
finish can occur. So the earliest possible time that our task in question
can finish is Friday. Then Project works backwards, fixing the finish to
coincide with the start of its predecessor and pushing the start back into
the future until such time as the *work* covers 8 duration, i.e., actual
working, hours. We get no duration credit for Thursday or Wednesday since
no work takes place on those days. Tuesday at 5 we start to cover duration
time and will have worked back thru 8 duration hours when we get to Tuesday
at 8am. So our 1 day duration task begins Tuesday 8am and ends Friday at
8am, the end coinciding with the start time of the task that's controlling
the whole process. I grant you it would be nice to see the meeting finish
display as Tue, 5pm - makes it easier to explain to non-PM savvy managers -
but from a schedule logic standpoint that's purely cosmetic and has no
affect on the actual work schedule, critical path, budget, or what-have-you.

I wonder if the solution might be to rexamine the SF link for the meeting.
As I read your note, the first thing that popped into my mind was can the
meeting only be scheduled for the week when it looks like task 2 will begin?
What happens if task 1 gets delayed? Does task 1 HAVE to be in progress
before you can go to the meeting for approval to begin task 2 and does it
really HAVE to be the LAST Tuesday before the next phase begins or is that
just the preferred meeting? Could you perhaps hold or attend the meeting on
the first Tuesday after task 1 begins, even if its end is a few weeks away?
If I held the meeting this Tuesday, anticipating the next phase will start
this coming Friday, but then the current phase finish gets delayed is it a
problem, do we have to go back for another meeting? I may be wrong, but it
seems to me like there might be an alternate view of the situation logic.
Try this logic and links ...

Task 1 - first phase
Task 2 - approval meeting, 1 day, Tuesday only calendar, link 1SS
Task 3 - next phase, links 1FS & 2 FS

That places the meeting on the first Tuesday after task 1 begins. If task 1
has to be far enough along to provide some information needed for the
meeting, you could also have a lag time in the SS link from 1 to 2 so that
the meeting would happen on the first Tueday after task 1 is expected to be
50% or 75% complete or something like that.

Would that work?


--
Steve House [MVP]
MS Project Trainer/Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs
 
R

Ryan

Does anybody know if there's a way to do this? I would think this would be
the default behavior with Microsoft Project but for some odd reason it is
not.

Thanks.
 
S

Steve House [MVP]

You're getting hung up on the visual appearance of the bar, something that
is purely cosmetic and has no actual effect on your project's schedule. If
a task spans non-working time, the bar still extends over it. Actually, if
you look at tasks longer than 1 week so their bar extends over a weekend,
you'll see the same phenomenon where the count of the days the bar crosses
is greater than the number of days of duration. If you look at the Task
Usage views you'll see no work on any day except Tueday and even though the
task bar shows on the picture, the work for Wed, Thur, and Fri is zero.
Even though the bar extends from Tues to Fri, the extent of the task is an
artifact, not real, and the only day any work is being performed is Tuesday.

Too bad we don't have some sort of "digital White-Out" so you could paint
over the bar and make it appear to be only 1 day in length so the boss isn't
confused by it.

Hmmm - just had an idea!! Make the working hours for your Tuesday calendar
1 day plus 1 minute, for instance on the default calendar make the end of
the day 17:01 instead of 17:00 . The Tuesday task is 1 day duration, that's
still 8 hours even. But there's 8 hours and 1 minute available for it on
that day. Now in the link from the Friday task back to the Tuesday task add
a lead time (minus lag) of 1 minute. The lead time takes place during that
extra final minute of the workday on Tuesday. Now you'll see the Tuesday
task going from 08:00 to 17:00, no bar crossing Wed or Thur, the Fri task on
Fri with the link arrow flowing from it back to Tuesday. Tried it and it
works, showing just what you're seeking.


--
Steve House [MVP]
MS Project Trainer/Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs

..
 
M

Mike Glen

That's neat ,Steve! :)

Mike
You're getting hung up on the visual appearance of the bar, something
that is purely cosmetic and has no actual effect on your project's
schedule. If a task spans non-working time, the bar still extends
over it. Actually, if you look at tasks longer than 1 week so their
bar extends over a weekend, you'll see the same phenomenon where the
count of the days the bar crosses is greater than the number of days
of duration. If you look at the Task Usage views you'll see no work
on any day except Tueday and even though the task bar shows on the
picture, the work for Wed, Thur, and Fri is zero. Even though the bar
extends from Tues to Fri, the extent of the task is an artifact, not
real, and the only day any work is being performed is Tuesday.
Too bad we don't have some sort of "digital White-Out" so you could
paint over the bar and make it appear to be only 1 day in length so
the boss isn't confused by it.

Hmmm - just had an idea!! Make the working hours for your Tuesday
calendar 1 day plus 1 minute, for instance on the default calendar
make the end of the day 17:01 instead of 17:00 . The Tuesday task is
1 day duration, that's still 8 hours even. But there's 8 hours and 1
minute available for it on that day. Now in the link from the Friday
task back to the Tuesday task add a lead time (minus lag) of 1
minute. The lead time takes place during that extra final minute of
the workday on Tuesday. Now you'll see the Tuesday task going from
08:00 to 17:00, no bar crossing Wed or Thur, the Fri task on Fri with
the link arrow flowing from it back to Tuesday. Tried it and it
works, showing just what you're seeking.


.
 

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