Finish to Finish tasks

[Chris]

Dear All,
I'd welcome some help please.Would

I have 2 projects A, B, each with 5 tasks 1,2,3,4,5 each with different
durations for projects A and B. Each task within the project has a Finish to
Start link. Each task should start straight after its predecessor (i.e.
within 24 hours).

Tasks A3 and B4 must finish at the same time, so I have assumed that they
would use a Finish to Finish link. However, although this seems to work it
stops the neat stacking of tasks B1,B2,B3 and B4, they become disjointed with
large gaps between some of their ends and the start of the next task.

Tasks B1, B2, B3 have no date constraints on them so I'm wondering how I can
get this smooth move between those tasks whilst retaining the Finish to
Finish constraint (which also does not have a date constraint).

Many thanks for help / views in advance.
Chris

 

[Dave]

First of all, a finish-to-finish link from A to B does not mean that
they finish at the same time. It means that B cannot finish until A
has. You need to understand the concept of the link driving the
successor teak, not forcing it.

Secondly, you state that the successor tasks must start within 24 hours
of the end of the predecessor. If A3 and B4 must finish at the same
time then that constraint imposes constraints on the sum of the
durations of the predecessor tasks. Consequently, the 24 start window
and concurrent finishing will be incompatible conflicting constraints
for many combinations of durations.

You say that tasks 1,2,3,4 and 5 are all linked FS. Is that because
that is the order they absolutely have to be done in, or is that because
that is the order you want them to be done in? As with the FF link,
these links do not determine when a task will start but what has to
happen before the task can start.

If you want B4 to finish on the same date as A3, then you could paste a
link to the finish date of A3 to the finish date of A4. To do this,
select the finish date of A3 then from the menu, select Finish/Copy Cell.

Then select the finish date of B4 and from the menu select Edit/Paste
Special/Paste Link.

Now if A3 moves into the future B4 will follow.

If you want B4 to follow A3 just copy a link from the finish of B4 to
the finish of A3 by reversing the steps above.

 

[Chris]

Hi Dave,

That's very useful - some very good pertinent points, particulalry about
some permutations of durations not allowing such a run of tasks.

In fact you've answered 2 questions as the paste a finish date between tasks
is particulalry useful.

Many thanks
Chris