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Late Resource Curve above Early Resource Curve

8 replies [Last post]
Benjamin Feng
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Joined: 9 Nov 2012
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Hi All,

Whilst I'm sure this topic has been consistently repeated, I would like to ask this again as I have yet been able to find a resolution:

Background:

I am currently in the midst of doing a rebaseline with revised contractual milestone dates

Key Notes:

1. Resources loaded on LOEs

2. No Negative Floats on all activities

3. Resource Curves applied on some of the resources

 

Observations:

1. Late start for LOE activities earlier than Data Date (Same as Actual Dates) for started activities

2. Remaining Late Units start before data date

3. Late Resource Curve above Early Resource Curve

 

I would like to seek your advice on how to resolve this so as to have the remaining late curve below the remaining early curve where it is supposed to be.

Regards,

Benjamin

Replies

Rafael Davila
User offline. Last seen 2 weeks 4 days ago. Offline
Joined: 1 Mar 2004
Posts: 5229

Try checking external links, I do not use P6 but understand external links can create constraints. Check the Advanced Scheduling option "Ignore Relationships to and from other projects.

Other possible source can be due to Out-Of-Sequence progress and the calculation options, in such case I suggest to correct the logic in the schedule.

This can also be caused by a BUG. If multiple calendars can produce negative float without any constraint then it can create situations in which this can happen.

P6 float Calculations photo Float - Paul Harris on P6 Float Calculations_zpsvnhca2ew.png

There are many ways in which P6 can mess with the late dates.

Good Luck

Benjamin Feng
User offline. Last seen 16 weeks 1 day ago. Offline
Joined: 9 Nov 2012
Posts: 19
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Hi Rafael,

Did a quick check and made sure that the "Must Finish By" is empty.

However, results are still the same.

 

Regards,

Benjamin

Rafael Davila
User offline. Last seen 2 weeks 4 days ago. Offline
Joined: 1 Mar 2004
Posts: 5229

Check for a global constraint for project finish.

The Case Against “Must Finish By”

http://www.primaverascheduling.com/the-case-against-must-finish-by/

Benjamin Feng
User offline. Last seen 16 weeks 1 day ago. Offline
Joined: 9 Nov 2012
Posts: 19
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Hi,

As previously mentioned, all weightage units have been loaded as nonlabor units on LOEs.

None of these activities have constraints / negative floats and all have been loaded with a "linear curve".

However, a "twisted banana" curve still appears as a result.

4499
capture.png

 Regards,

Benjamin

Rafael Davila
User offline. Last seen 2 weeks 4 days ago. Offline
Joined: 1 Mar 2004
Posts: 5229

Twisted Banana Curve happens when the software tweaks late dates into the impossible, late earlier than early.  Because date constraints can be applied to non critical activities this might happen in the absence of negative float but a reduced positive float.

Doubly twisted banana curve must hurt!

Twisted Banana photo Twisted Banana Curve_zpsphllmkcw.jpg

A better approach to calculation and disclosing of negative float is to make it a separate calculation field to total float using separate late date fields for purpose of this calculation. When the activity constraint is unfeasible then early dates are set equal to late dates for calculation of total float.  Because in this way late dates will never be before early dates except for the calculation of negative float the S curve will represent a feasible scenario, not Back to the Future.

Zoltan Palffy
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if you have a lot of activites riding the data date you are going to get this. filter for the activites riding the data date and put a backend loaded curve on them 

Benjamin Feng
User offline. Last seen 16 weeks 1 day ago. Offline
Joined: 9 Nov 2012
Posts: 19
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Hi,

Thanks for your suggestion.

I have carried out the suggested changes and the findings are as follows:

1. Resource Curves have been assigned to all LOEs - Still facing the problem of remaining units before data date.

2. Late start of these in progress LOEs appear to be tied to Actual Start Dates.

 

As a result, we are still seeing the Late Remaining Curve appearing above the Early Remaining Curve.

 

Regards,

Benjamin

Zoltan Palffy
User offline. Last seen 12 weeks 3 days ago. Offline
Joined: 13 Jul 2009
Posts: 3089
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ALL LOE's must have an associated curve assigned to them or ALL of the resources will put on the data date.

go to the activity then the resources tab then right click and select Customize Resource Columns 

expand the General category and select curve

now you can select how you want the resources distributed over the activity. The default of an activity is Linear there is NO default for a LOE. You can choose bell shaped or whatever you want.

Now instead of doing this for each activity go to tools global change

select new

up top under Select Subject Area make sure that it says Activity Resource Assignments

then for the parameters make it like this

where  Resource     equals     (whatever you resource is) 

then    Curve             =         Linear

then on the right select change 

then on the bottom select commit changes