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New/Enhanced Activity Types

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Rafael Davila
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I respectfully would like to ask for a new functionality to enhance Hammocks and to create a new activity type to be called Group Activity as follows:

1-Group Activity: All its members would be summarized similar to the typical WBS activity type but not by using WBS Phases but its own Group that can include activities with different WBS from different WBS Dictionaries, in addition you would be able to add predecessor and successor links to the Group Activity. By adding predecessor or successor links to the Group Activity all members of the group would inherit the predecessors/successors links of the parent Group Activity as additional links to those of their own individual members, even when some already existing it would create an additional link. By deleting the links at Group Activity, members would be detached of their Group Activity links. You will not be able to delete Group Activity links at the individual activity but only at the Group Activity properties.

A Parent Group Activity can have within the group other Group Activities as long as the new Members do not contain within its members the parent Group Activity, this to avoid circular references.

Perhaps Group definition can be done by listing individual activities or by listing WBS or a combination. Then a Group definition based on a single WBS would be equivalent to the traditional WBS activity.

2-Enhanced Hammock; All its members would be summarized similar to the standard Hammock activity type but in addition you would be able to add predecessor and successor links to the Hammock.

Maybe the Enhanced Hammock can be modeled as a Group Activity with only two members, the SS and FF members. If such is the case then the Group Activity will substitute traditional WBS, traditional Hammock and traditional Topic Activities into a single activity type.

Because all member activities will have a SS and a FF link to the Parent Activity when looking the individual activities properties their links created by the parent avtivity, either a Group or a Hammock would be shown as a single link to the Group or Hammockin in cursive as to signal you will not be able to delete the link at the individual member but only at the Group or Hammock.

These are enhancements over some similar functionalities available in other software such as the Topic Activity in SureTrak, software I no longer use. These functionalities can be modeled using actual links functionality but with much effort and prone to error. Here the computer would be of much help. I never used much WBS nor Topic activity but convenient, easier than using many multiple links, perhaps making the logic more transparent.

Best regards,

Rafael

Replies

Rafael Davila
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Vladimir,

RE: Yes, it can be easy to find group activities to which any activity belongs. The next step is to find all other activities belonging to the group and then to find on which specific activities depends current activity dates. Since links will not exist it should be done manually and is rather complicated, isn't it?

I believe good implementation of the Pacing Hammock (just another name) can be accomplished because there exist logic to move the Pacing Hammock as well as their child or member activities. I believe Plotnick is right, something is missing but the Pacing Hammock that works as should be is feasible even if Primavera Risk falls short of disclosing full logic. Maybe I am wrong with regard to Primavera Risk and it displays full logic. I cannot afford the $9,000.00 this software costs just to figure it out, a software  believe superior to P6 but still no challenge to Spider Project.

The Pacing Hammock can be defined using a special type of link, say "Pacing Link" a functionality that would create two links between the child activity and the Pacing Hammock, a SS predecessor to child activity and a FF successor to Pacing Hammock . If you delete the pacing link you will delete these two links. The links table shall display a successor and a predecessor "Pacing Link". If you delete one the other will be automatically deleted, in this way the activity is no longer a child activity. Logic will always be visible an if you try to add an activity for which the pacing link creates a circular reference it would be rejected right away.

I do not see why if the Pacing Hammock cannot be correctly modeled if there is a well known manual algorithm based on the creation of two milestones and a hammock. This method display full logic or am I missing something and this is also banned from good practice?

No doubt any functionality can be abused, even activity duration wrongly used lead to wrong schedules, negative lag is another example, SS links another and the list is endless. If we want to immunize the CPM from any missuses we would end with nothing.

Recently I noticed what I believe are some changes into how Spider imports the Summary Task, a task I believe a subset of the Pacing Hammock as it is limited by the Outline it belongs, different to any Spider Activity under WBS Phase. I believe long ago Spider would convert MSP Summary Tasks into Spider Duration Activity, an activity type into a different activity type. Spider lacking such functionality it makes sense to me. Then it was changed to a conversion from a MSP Task into a Spider WBS Phase, this did not make any sense to me, even more was missing. Recently I tried again the conversion and got back the conversion from a MSP Summary Task to a Spider Duration Task.

Is this correct, some changes are on the working? Still it is very short of my expectations and wonder if it would be better to have nothing rather than such an incomplete conversion that always can leave out some links without the user knowing. I never had such issues with Primavera SureTrak a low cost and not so capable software.

Needless to say I will rarely use the Pacing Hammock, but might use it at times. I can mimic it with the manual algorithm after some extra effort. Still I find this alternate method rather confusing and even error prone, you might easily end up doing wrong links additions and deletions. For me the major issue with the lack of it is when very frequently the subcontractors submit their schedules in MSP format, the favorite among our subcontractors.

Is Mr. Plotnick wrong, and a Pacing Hammock that displays all predecessors/successors internal and external is not possible?

Best Regards,

Rafael

Rafael Davila
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If Group Activity type is equivalent as to create two additional milestones and a hammock I really don't see the difference, if you want to follow logic you can temporarily switch on the display of such milestones and hammock, the logic you say does not hides critical path.

http://www.youtube.com/watch?v=9fjZKW1ixRM

But it seems to me like you anticipated my further requests for such group activity to have special links to be available to the regular user like:

For each successor:

  • Hold successor ES until any number (or %) of members start/finish.
  • Hold successor ES until any number (or %) of members are left to start/finish.
  • Hold successor ES until projected cost account of members reaches a certain level.
  • Hold successor ES until projected volume of work of members reaches a certain level.
  • Hold successor until conditional formula becomes true. Conditional formula can be any of the above pre-defined for ease of use or a combination plus many other including new fields opened up by the Group Activity.
  • and a few others that are needed by some to plan their work but too much for the PMI  interests or mindset.

Maybe it is about time to break traditional CPM and PDM rules that limit out thinking. Somewhere I heard the term Conditional Scheduling, which seems like a good name for the next level, with more functionality.

Sorry for any inconvenience.

Group activity hides the links that could be created between individual activities. As I wrote in one of my posts this way makes determination of real critical pathe rather comlicated - group activity will belong to the critical path but the software can miss which activities of the group are critical.

Yes, it can be easy to find group activities to which any activity belongs. The next step is to find all other activities belonging to the group and then to find on which specific activities depends current activity dates. Since links will not exist it should be done manually and is rather complicated, isn't it?

I see many potential problems and only few potential advantages. Yes it couldbe done but will it really make the development of the project schedule more reliable and transparent? Will this feature make Spider Project easier to use and help Spider Project users to avoid potential mistakes and wrong habits?

Rafael Davila
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Posts: 4780

Vladimir,

Because this is thinking on the spot I forgot about the idea of instead of an additional pane it should be an additional tab when you click on activity properties. This tab would have 3 panes for Membership Assignment, one pane for individual activities, one pane for WBS groups and another for Groups member of a parent Group.

Following the logic indeed quite complicated, but if a group activity delays others and this is how your planning needs are then let it be.

Delays will be caused same as if no Group Activity exists if relationships are inherited by all members, just that they will be identified as belonging to individual activities as well as to member activities. This should allow for resource constraining do its magic as long as resources belonging to Group Activities per se are leveling resources. The Group Activity in reality does not add functionality to traditional logic is a marker that follows members and transmit SS and FF relationships to all members from the invisible 2 milestones of the milestones method. Is essentially the same, just the interface is different, kind of the difference between a flat database and a relational database, it saves a lot of data entry and from the standpoint of the end user this translates into efficiency.

I understand this can create a lot of redundant links. Interesting would be the issue on which links to display on Gantt and which shall not. Perhaps only links that drive the Group Activity ends shall be the only to be displayed. Yes some thinking must follow, no doubt about it.

Best Regards,

Rafael

Rafael,

imagine that you have several dozens of group activities (I understood that it is not the same as LOE, they are similar to WBS phases). When you switch to another WBS you will place them somewhere like in separate phase. Activities belonging to the group may be elsewhere in your schedule (a couple of thousands lines below as an example).

When scheduling you will see that some activity was delayed and this delay was not cause by any link and resources. You want to find why. You shall find out to what group activities your activity belongs (let's suppose thatto a dozen of group activities), whith what activities these group activities are linked, etc. Critical path will include group activities but activities that are actually critical because they are not linked with their predecessors and successors. It is complicated.

LOE activity duration is defined by other events. Linking LOE and not linking original activities hides real project logic and does not add advantages. It is more logical to link original events.

There are functions in Primavera that i do not approve. An example - activity steps.

Rafael Davila
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Where to place group activity and how to understand what activity belongs to what groups.

Where to place group activity

- where best fits your needs

how to understand what activity belongs to what groups

- with a filter to display only selectd Group Activity and its Members. If you want to see them all go to the Main WBS.

- with more complex filters

- by using report generator

- by looking at the Group Activity Properties a separate pane can display members activities while predecessors and successors will display those linked directly to the Group Activity, which can be empty as it will move with controlling member activities.

- by looking at the individual activities a separate pane will display Group Assignments while the predecessors and successors can display either only direct links or direct links plus inherited links in cursive letter, links you will not be able to edit in this pane.

- with other methods Spider Team finds suitable.

Sorry I cannot make firm statements about how P6 works but the statement about being able for LOE activities be linked directly I heard at other thread/forum so I am still wondering how it works. I might be wrong. I am avoiding other software in an attempt to make Spider my first language.

In Spider Project hammocks are activities that lasts from one event to another. You can assign costs, resources, materials, volumes to hammock activities. But their utilization is spread on hammock duration defined by other activities. Assignments may be fixed or per time unit (LOE), or per unit of volume. If hammock duration increases resource and cost utilization per hour may change if this utilization was defined as fixed or per volume unit.

You can define volume lags for links to hammocks but physical sense of these Lags is uncertain.

I already explained why I am against group activity links: imagine that you switched from one WBS to another. In this WBS activities belonging to the group belong to different WBS phases in different parts of the project. Where to place group activity and how to understand what activity belongs to what groups.

Rafael Davila
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For Owners who manage the jobs at an upper level, High Level Schedule got to be very useful. The needs of the user might vary, efficiency for me is different to what efficiency is for the Owner or to what efficiency is for the software developer.

I understand duration of hammocks are variable, but do not understand why volume of work, resources and costs cannot be defined either fixed or per a fixed rate. Perhaps using the concept of Level of Effort is not the best option if it limits the options.

Even if double links cannot be executed on hammock still Topic Activity and WBS Activity Type has been implemented before. I believe, though not sure, LOE activities in P6 can be linked with predecessors and successors similar to the Topic Activity that was available in SureTrak, this I remember.

Rafael,

I am afraid that double link to hammock is hard to define. Hammock is usually Level of Effort activity with no specific duration and volume. The same about Group activity and project phases.

We are developing new option - creating high level schedule from the detailed schedule. If this option will be applied project phases will be transformed into project activities (with resources, costs, etc.). These "activities" will be connected by many double links created automatically. But these double links will use time lags because phase volume is hard to define.

Rafael Davila
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Vladimir,

It is kind of difficult for me to follow you. Perhaps you can apply it to my sample job Double Dependency using 50% volume link to see if I can follow you. I am kind of getting lost with these milestones.

About the Twisted Hammock I understand the way around by adding 2 more links but still can leave out few activities when the real need is for a WBS Type and logic is changed on the run.

Best regards,

Rafael

Rafael,

but in Spider you can create several links with Lags from different activities to Start and to Finish of hammock activity.

Hammock starts when first dependency on Start is satisfied and finishes when the last dependency on Finish is satisfied.

Rafael Davila
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Perhaps instead of Group Activity it shall adopt the name of old Hammock, call it Hammock, a Hammock on steroids.

I never liked the idea of defining hammocks using a single SS link and a single FF link as if for some reason such as change in logic or out-of-sequence the end activity moves out it becomes twisted (not always obvious).

With a Group Activity there is no such risk if you follow good practice of including all intended members, no matter if driving or not the ends of the Group Activity.

Twisted Hammock

I would never trade my Cuba Libre on a traditional Hammock for a hundred Piña Coladas on a Hammock Chair, leave them for the tourists.

 

Hammock Chair

I believe there are enough good reasons for the Group Activity to exist.

1) As a matter of convenience, what I call efficiency.

2) As a matter of need to open up links for the use of %volume links available only in Spider Project.

3) As to avoid Twisted Hammock that leave out some activities when changes in logic or out-of-sequence events cause such effect.

Best regards,

Rafael

Rafael Davila
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Say my Group consists of 2 activities linked SS with a lag of 3 days, first one with a duration of 7 days and second one with a duration of 16 days. Their calendar is on 5 workdays per week for activity 1 and 7 days per week for activity 2, lag calendar 5 days per week and need my predecessor double link to occur at 50% of the calendar days duration of the group. How?

Links to Hammock 03

It could be applied to all and any activity of the group.

For preceding it shall be start lag, for succeeding finish lag.

Rafael Davila
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I am referring about % of volume double links. Say Group B shall start after 50% volume of Group A.

This is easy. Lag with the first group and another lag with the second group.

I don't think that double links and lags make sense in the group links.

Rafael Davila
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What about a double link between two group activities how you model this with the milestones method?

Rafael,

if one group of activities precedes another group of activities it is sufficient to create one milestone, link preceding group with this milestone and link the same milestone with succeding group. Why hammock?

For deleting all links it is sufficient to delete one milestone.

An advantage of the group activity is only when the same group has common predecessors and common successors. If not all activities of the group have the same successor another group activity shall be created and one activity will belong to several groups.

There is a case when group activity can save a couple of mouse clicks (same group has common predecessors and successors). But if the links are made to the group activity and group activity is far from activities belonging to the group it is not easy to understand what activities belong to the group.

 

Rafael Davila
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Well I am still trying to figure it out about the double link  and the milestones method.

I am trying to figure it out about the milestone method when adding or deleting a group that belong to a group activity.

A 3 activities method (minimum, 2 milestones and a hammock) versus a single activity method.

Rafael Davila
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Creating group activity in one WBS and switching to another WBS you may loose this activity or have it very far from activities belonging to the group.

When the WBS is added, no matter on which WBS you are working all the activities will be added along with their actual dependencies between activities. If you display the WBS dictionary then you will know to what WBS you must switch to see all activities and closer.

Besides I am afraid that this option will not be properly used because actual dependencies are between activities.

Yes this part of the idea, the issue is to keep the links in groups you will add or delete easily altogether.

In Spider Project you can easily create the link between one activity and selected group, or between selected group and one activity.

Yes but how about deleting the links by deleting a member Group or member WBS instead of one by one.

Hammocks show the duration between some events defined by other activities. Linking hammock with some other activity means that this succeeding activity is also linked with these events. Why not to create original dependencies?

Yes I said all can be modeled using actual functionality, as a matter of fact with no lag links. I see this one as a matter of convenience. Similar to the Topic Activity in SureTrak or the WBS activity in many other software packages.

To me it is still a matter of convenience not that the lack of it will in any way prevent you from making exactly the same model.

Rafael,

we tried to make the shedules as transparent as possible and the software as easy as possible with all necessary functionality. Creating group activity in one WBS and switching to another WBS you may loose this activity or have it very far from activities belonging to the group.

Besides I am afraid that this option will not be properly used because actual dependencies are between activities.

In Spider Project you can easily create the link between one activity and selected group, or between selected group and one activity.  Creating the milestone preceding a group of activities and linking other group of activities with this milestone you can create group links that may be deleted by deleting only one created milestone. And these links will be seen in any WBS.

Hammocks show the duration between some events defined by other activities. Linking hammock with some other activity means that this succeeding activity is also linked with these events. Why not to create original dependencies?

Please clarify the advantages of this approach.