CPM is about relationships otherwise is a Bar Chart.

Some old software started to bring welcomed PDM functionality to better model real life situation but never were updated to better deal with relationships. lag calendars, lag filters, longest path value (as per Ron Winter) and better ways to report on the relationships are among the many features left out.

Spider Project is alive while others are either dead or going backwards.

Best regards,
Rafael

Thanks again, and indeed THE REAL LIFE IS NOT THAT SIMPLE.

I got the information from a forum post and yes I misunderstood it as to mean any. I dont’t have P6, good to know although you already must know I dont’t like P6, we gave it a try for a few weeks before discarding it. Let’s see what happens when many medium sized contractors and government agencies start to deal with such aberration.

What about Spider Project, do it has the option?

Best regards,
Rafael

Thanks Vladimir

Appropriate call.

To the concepts of float and lag I would like to add that both are computed upon calendars.

Different software use different calendars for lag; some use successor activity while others use predecessor, and a few like P6 let you assign an individual calendar to your relationship lags.

Float is based on the activity calendar so different activities with different calendars will show float based on different calendars.

Cordially,
Rafael

Lag is the number of time units from the start to finish of a relationship, a lag can either be positive or negative. If the relationship is not driving then it has no impact on the successor dates unless latter on it becomes a driving relationship. Think of lag as the duration of a particular relationship that might or may not be driving.

In P3 float can be defined either as:
a.The difference between early start and early finish.
b.The difference between the late start and late finish.
c.The smaller of the two.
Note that a. and b. are not necessarily equal when allowing splitting or after progress is applied.

When you impose a constraints or a project finish date the backward computations for late dates are redefined to be from this constraint date rather than from the last activity dates on the path, because the constraint date can be before the activity early dates float can be found to be negative along the particular path.

You can set open path to be critical or not as to fix the open path backward computations to start either from the dates of last activity on the open path or from the dates of the last activity on the net. This is a special type of finish constraint that will also affect your computations of float; this is applied at the network level instead of at a particular activity.

Sorry these are more complicated definitions but eventually you will have to cope with them.

Best regards,
Rafael