I have a rather tricky situation. A certain activity must either finish before a certain date t0 or begin after the date t1, provided that t1 > t0. To illustrate the situation: If we cannot finish two-weeks activity before Christmass holidays (24th December), we will not even start it, and we will start the whole activity after the 5th of January.
Is it possible to implement this pattern in Primavera?
I thought about two possible solutions:
1. Assign two constraints :
Primary: Finish on or before 24 December and
Secondary: Start on or after 5 January.
Well, that doesn't work - even if I have a time to finish the activity before the 24 December, it is still postponed to 5th January. That means, that the Secondary constraint overrides the Primary.
2. Play with the Calendary
I can exclude the days from 24 December to 4 January from the Activity calendary, but that will simply "split" my Activity. The problem is that the Activity is indivisible - I cannot make a part of Activity before the 24 December and then continue the rest after the 5 January. I have to make the whole Activity either before, or the whole Activity after.
Is it possible to declare in some way or other the Activity to be a kind of Indivisible?
Thank you for your insights!
If in need of using the 1 minute activity you can fine tune the start of your successors by using a negative lag of 1 minute.
This can give some peace of mind if as a consequence successors finish date is scheduled to the first minute of "next" day.
If in need of using the 1 minute activity you can fine tune the start of your successors by using a negative lag of 1 minute.
This can give some peace of mind if successors finish date is scheduled to the first minute of "next" day.
Hi Bo,
it works if to use Spider Project.
Milestones with assigned resource are useful in many cases - some events may happen only if some resources are present or available.
Creating an activity with 1 minute duration may be used as an alternative for MSP and P6.
Best Regards,
Vladimir
Steve,
After a couple of Banks on a Friday night in Oistins Fish Market I would have believed you were right. Unfortunately I'm far away from this scenario, so not to be rude I don't think you method would work in certain software programmes (if any).
In P6 you can't assign resources to milestones as far as I recall (what is a resource meant to do in something that have the definition of time being equal to zero?)
In MSP you can assign resources to a milestone, but the milestone will start anyway in a period that is defined as non-working time for its resource's calendar. To take the example asked: The milestone could start on Dec 16th even though the resource assigned couldn't work between Dec 10th to 24th. Again, the time is zero so the resource is actually not working and as no work, the milestone can easily start/finish (instantly) in a non-working period.
You could change the milestone to an activity with just a duration of 1 minute and your solution would work.
Best regards,
Bo
Vladimir,
Thanks, I already saved a sample job using your method, a solution I did not know.
I would use perhaps a combination of methods and this can be an option for long duration interruptions that can affect any activity. Quite a saving indeed.
For the exception(s) to long duration interruptions I would still apply a separate method for the exceptions to the general rule.
Best regards,
Rafael
Hi Rafael,
you suggested good solution for Evgeny, but there is even easier solution in Spider Project that you can use for yourself.
If an activity has an exception in its calendar like Christmas vacations and shall be finished before or start later, in the scheduling options select Allow Performance Interruptions not longer than ... days and enter 2:
That's all. An example is below:
Best Regards,
Vladimir
Evgeny,
Both options shall work; both require the creation of an exception calendar, in one method assigning the calendar to the activity is enough; the other will require you to assign the resource and the calendar and will require you running resource leveling every time the schedule is run as unleveled schedule will not yield desired result under this option.
I still recommend checking the start on non-work days by temporarily creating the activities codes 2 and 4, in this way you will catch up all non-work days in between. Of course, manual checking is an option; if duration is short; I prefer manual, if duration is long and there is a possibility of calendar exceptions I prefer to model the activities. Make sure that; both activities (2 and 4) are assigned the same calendar as Activity 1 and that the link between activities uses the same calendar as Activity 1.
While in P6 you have a limited selection for assigning lag calendar in Spider Project you can assign any calendar to your links on a one by one case, and report on your link calendars on the Links Table. I am not sure P6 display lag calendar and as far as I remember from other forums is assigned using a rule across the board, the same limited rule to all links; it only suggests selecting one of four options (predecessor, successor, 24 hours or default calendar) for ALL relationships lags. Depending on your options, the lag calendar can be different to what you expect. Maybe the default will assign the correct calendar lag but what if your settings are not the default? Also, make sure you do not change the rule between updates as it will change a few, or many lag calendars. In this particular case, predecessor or successor will be valid but 24 hours or default calendar might not.
Stephen,
Thanks for the alternate, yes there are many ways to skin a cat, the more ways you know the better. Your solution adds much value to the discussion. I know of some scheduling problems that can only be solved by using resources to drive the activities as needed, in such cases I would call it unanimous winner.
PP Admin,
Please consider moving the column at the right to other tab as to provide us with valuable space; the graphics are reduced too much as compared to before this new web design. Perhaps even column at left can be included as a heading to each post adding even more space.
Best regards,
Rafael
P.S. Did any one of you noticed I used a negative lag ling between temporary activities 2 and 4?
Yes Steve, I think that your solution will also make the desired effect.
I used the Rafael's one because I am now on the summary planning and I use no ressources in it. I have just implemented the solution and it works!
Evgeny and Rafael,
Would an alternative (and perhaps simpler) method of skinning the cat be to:
1. Create a milestone called "(ACTIVITY X) STARTED" as a predecessor of (ACTIVITY X) and assign it a hobbit for a resource.
2. Make the hobbit unavailable between Dec 10 and Jan 4 (assumng that ACTIVITY X has a duration of ten weekdays).
Fraternally in project management,
Steve the Bajan
Waou! Rafael, that's a great and pretty solution!
Thank you very much!
As for your second post - actually, I was asking not about invisible but "inDIvisible" activity ;), I meant by that that the activity cannot be started before the holidays and finished after the holidays. Anyway, I don't need this "indivisibility" anymore with the help of your solution with the trigger milestone.
Thanks once again!
Evgeny
Evgeny,
About making an activity invisible we can do that in Spider Project when using multiple WBS, main WBS will be required to contain all activities but the others are not.
Best regards,
Rafael
Evgeny,
Continue playing with the calendars you are almost there, the trick is on setting a milestone that will trigger the start of your activity.
This milestone shall have a calendar equal to activity calendar but with the exceptions for the period in which activity shall not start. That is from Dec 24 minus activity duration to Jan 6. Take attention to how start dates are handled on your particular software. I created activities 2, 3 and 4 to get lower limit or start date for the exception using applicable calendar, after you know the date these are not needed. I believe your scheduling issue can be done with almost any software. Just adapt my example to your software and make sure you test it by forcing activity 1 to start before and after the period.
Best regards,
Rafael
Thank you Daniel, but unfortunatelly that's not the reply I hoped for. ;)
Of course, I cand do all that things manually to determine at any given moment whether I cand finish my activity before holidays or not. The problem is that there are some upstream milestones which are constantly adjusted and that shifts the beginning date for this activity. And there is not only one activity of this kind, but thirty of them.
That's why I was wondering if it was possible under P6 to make such kind of activity scheduling automatically.
But still thanks for trying.
Best regards
Evgeny
Evgeny,
I think your problem is not the software, but rather you should determine first whether you can finish this activity before Christmas by looking at the amount of work (Quantity), the production rates and find out if you have the resources to do it.
Once you have done your homework, then you can comfortably say that you can either finish the activity before christmas or after Christmas Holidays.
Cheers and Best regards,
Daniel