Alex, haha this is me. trying to solve something that si not my problem. well i believe learning from mistakes, even other’s mistake.
so i try to replicate teh problem, but still cannot.
I create 2 activities A adn B with FS0
progress successor with AS and AF, DD to the future.
No prob, B shows the AS/AF as before DD and A the pred scheduled to start on DD.
Then try with ZTF for A, also no prob.
Then try with ZTF for B, also no prob.
In both the ZTF options, same result as without ZTF.

Can give me the scenario for your replicated "problem" case? I wanna try to get the "problem" and understand why.

Alex,
Just to make sure I understand correctly,
If I have 2 activity A and B, A is predecessor of B with FS logic.
If pred A has not finish, whatever AS/AF i enter for B, the Gantt will never show B to finish before the Datadate?

But I dont have that problem. FYI, I m using P3.1, retain logic. (how can i attached a screen capture to show?)

as for "resource logic", do share with me with regards to "How to aviod it ... its depend on your experience in the schedule and logic and P3."

always learning... if there is a better way, must learn, adapt and change for the better...

thanks.

Dear All,
It is interesting to read about what is considered right logic and what is wrong...
To me, that "Plan the work, and Work the plan" is the key to the right logic. The logic is in place to create a plan.
Next stage is the excutioner of the work to work the plan. So "resource logic" can be correct logic in the sense of planning your (limited workforce) team movement.

Unfortunately, there are still many organisations which have "Plan the work " which in my opinion is not planning, but just painting nice pictures (charts and schedules).

Dear All

Let me put another dimension into this topic.

A lot of the time logic is put in because of

1. Resource Constraints
2. Clients Requirement to have a critical path where total float is less than x days


Because of these reason logic is being put in without its true relationship. As a result, when updating the scheudle problem apprear everywhere.

And because the Baseline is already fix(Approved) at that point, it is impossible to change the baseline and logic, what should/can the planner do??

Cheers

Alex

Hi Alex,

You’re quite right. The "relationship" element, however, is something that has always been a bit "fluffy" - especially in the world of Design Planning. In the world of construction, be it buildings, railways, waterworks etc, there are very definite and true logic relationships - as per your example. However, it must be realised that none of the software recognises the context of the activity descriptions. ie. it doesn’t understand that you physically cannot have finished washing the dishes until you have finished stuffing-your-face.The problem, though, is that you are telling the software that you have. So, you now have a conflict that needs to be resolved as to what is true:

In order to resolve the conflict, you have to go through a series of questions, such as:

1)Is the relationship correct? If the relationship is correct, then the operator is doing something wrong.
2) If the operator is doing something wrong, then what is he doing wrongly? Is he inputting incorrect dates for the Actuals, or has he just forgotten to correctly update the predecessor?

The software cannot answer those questions using anything other than its in-built algorithms. In this case, it chose to assume that the predecessor relationship was correct, and that the predecessor dates were cardinal - thus it automatically moved the successor Actuals to the logically derived time-line. However, it there is still nothing to determine that the software’s choice of action was correct. When our colleague input the Actuals, I would have thought that the software would have warned him that he was about to contravene the logic - thus giving him the choice. Did it do this? If not, then you could argue that the software is not exactly being helpful, if not actually being completely wrong, relative to "real-life".

To take your example to the almost ridiculous extreme of logical interpretation, you could argue that, when eating a KFC, you don’t actually use dishes - but the dishes remaining from breakfast have yet to be done. Therefore, in reality, there is no TRUE relationship between the two activities, but you might PLAN to do them after eating the KFC. So, in order to correctly drive the PLAN, you are forced to introduce the relationship based on how you expect to execute the activities.

Alex: ’tis an interesting debate on planning practice. Feel free to comment and introduce us to your ideas.

Cheers.

James.

Hi Andy,

I appreciate what you’re saying - and I know that all this software stuff has its own "operating characteristics" wot one has to learn (years). My contention, however, is that the input of an ACTUAl is the cardinal data. All other data will automatically amend in accordance with that input. Yes, one of your results will perhaps be an out-of-sequence activity.

Methinks we need someone else’s input on this one.

Cheers.

James.

Hi Andy,

To me, the logic linking would seem irrelevant if you have input Actual Start and Actual Finish dates. In my mind, such inputs would over-ride any others. OK, I’m translating my MSP experience, and I stand to be corrected, owing to the fact that my P3e experience is miniscule in comparison to my MSP knowledge.

James.