Usually there are more than one way of crashing an activity. And usually crashing is not linear and continious. Adding additional resource you will shorten activity duration by certain amount of time. But this resource will not be used on one activity only, so it is much more complicated. But different options may be weighted by looking at the new total cost that includes the cost of time.
Best Regards,
Vladimir
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Submitted by Rafael Davila on Wed, 2010-06-16 18:07
Agree 100%. But you still need some individual activities cost of crashing. The following to me would be practical and acceptable, no need for pretentious non linear functions, just start with normal duration and crash duration. Targeting for larger than normal does not makes sense.
The above should simplify the math and the data entry.
Best Regards,
Rafael
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Member for24 years9 months
Submitted by Vladimir Liberzon on Wed, 2010-06-16 17:43
It is necessary to define what is the cost of one day of project delay and the cost of one day of project finish acceleration.
Total cost shall be estimated taking this into consideration. And cost of crashing will increase or decrease this total cost. If crashing decreases this total cost it makes sense.
I did not suggest to estimate time cost for individual activity. For decision making you shall look at the total cost.
Best Regards,
Vladimir
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Submitted by Rafael Davila on Wed, 2010-06-16 17:24
I know about time cost and realize fixed cost will decrease with a reduction in time of the hammock activity contrary to crashing of an activity that will increase with reduction in time. But because it span across all project duration it will always be on the critical path therefore for purpose of determining where to crash is irrelevant, but it is still relevant for the determination of total crash cost, you are correct.
On the other hand the time cost related to individual activities I would consider it when determining crash cost of an activity this will vary from activity to activity and also cannot be overlooked.
I downloaded the MS Project add-on suggested by Stephen to study the walkthrough document of how to use DRAG to optimize a schedule on a sample project file. When your project starts to fall behind schedule you try to compress the schedule using other methods but crashing, these are managerial decisions no way you can pre-program into the CPM logic, and they are in essence changes in logic. It is after changes in logic no longer solve the issue when you have no other option than to crash some activities. Knowing how to crash, especially when your job is in problems is very valuable.
Many times I have given true chance to MS Project but always, very soon, it gets into my way, no matter how hard I tried, even MS Project 2010 is still a no-no. No way am I going to use it in my jobs to find in the middle it will let me down, I already know it will. I believe if Stephen techniques can be applied within Spider then why not give it a try, we already have DRAG embeded into Spider, better than an add-on.
Best regards,
Rafael
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Submitted by Vladimir Liberzon on Wed, 2010-06-16 12:39
if you will look at my presentations I always insisted on setting single project success criterion estimating the cost of the time. If cost of time is estimated and known it is easy to model it by including hammock activity or activities in the project schedule.
Best Regards,
Vladimir
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Submitted by Stephen Devaux on Wed, 2010-06-16 11:26
My pleasure! Its refreshing to chat with someone who obviously takes these issues seriously! I wish people working in industries where project time is not just measured in money, but also in human lives and suffering (e.g., pharma, health care, potable water wells) would take it as seriously!
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Wed, 2010-06-16 11:14
In the absence of sophisticated time cost trade off embedded in my software of choice I believe DRAG is quite important, otherwise you will miss the exact point when multiple paths emerge.
I already asked for the demo software you proposed, who knows maybe it will give Vladimir some ideas and we, users of Spider, benefit from it.
If compression of activities duration just add resistance then I imagine the mechanical equivalent as compressing a set of springs with different resistance and minimum length. The procedure would be like pushing the assembly from both ends.
About your book I will take a look on how to get it, believe it is available on amazon.
Thanks for taking your time,
Best Regards,
Rafael
Member for
20 years 7 months
Member for20 years7 months
Submitted by Stephen Devaux on Wed, 2010-06-16 10:28
Normally, Id be reluctant to criticize someones theoretical advice as long as there is some thats wise (and there certainly is in what youve quoted). But since youve asked for my comments, here goes:
The main thing is that the authors arent aware of DRAG. Its not their fault, because the concept only became public knowledge when my book was published (1999). And since only three PM packages (including Spider) compute it, unless theyve read my book or one of my articles, or sat through one of my courses, they could hardly be aware of it.
But DRAG really changes the whole schedule-compression ballgame -- its by far the most important concept for compressing a schedule. All the other considerations mentioned in your post may be relevant -- but number one is DRAG. For instance, lets take this one:
"3. Long duration. An activity that has a long duration offers more potential time gain from crashing it."
Long duration is meaningless without the DRAG concept. You can have a 25D task on the CP and its DRAG might only be one day. Conversely, you could have a 5D task on the CP
and its DRAG might be 5D. The latter offers the opportunity to gain 500% more time despite having only 20% of the duration.
A little over a year ago, I taught a class at a multinational DoD/aerospace contractor. When I explained DRAG, one engineer reacted dramatically. She explained that a year earlier, her team had been tasked by the client with pulling in by six weeks a mid-project task that had, from the total 5,000-activity programme perspective, over 200D of total float. The whole team flew to San Diego and met on a Monday morning. Most already had suggestions for activities they thought could be compressed. After about seven hours of tweaking, they gave the changes to their scheduler to input to the software -- and the schedule came in by one day!
After adjourning to the nearest bar, they came back and worked the rest of the week, just randomly trying things. As she put it, the concept of DRAG would probably have saved them eight person-weeks in San Diego, not to mention the airfare.
DRAG is NOT the total answer -- but it provides an "Occams razor" for selecting the best candidates for compression. Obviously, there are other considerations. One is resource elasticity: how much can an activity be compressed if resources are added? The TPC metric is DRED, or doubled resource estimated duration: how long would an activity take if resources were doubled? With doubled resources, a 20D activity may become 10D ("perfectly resource elastic"), or 13D (more likely!), or 17D, or remain 20D, or expand to 30D (e.g., building an avionics dashboard in the cockpit of a jet fighter).
Having this second estimate, based on doubling resources, provides the basis for the conversation when it turns out that a 20D task with 15D of DRAG has a DRED of 12D. We know from the DRED that the work is quite resource elastic. Now we need to find out:
(1) Do we have to double ALL its resources or just specific skills?
(2) If we added even more resources, would the duration keep shrinking until its DRAG (and DRAG Cost) disappeared?
(3) How much would the resource(s) cost?
Raphael, the subject (as you clearly understand!) is a complicated one. Since you seem so interested, I really would urge you to pick up a copy of my book -- I think youd find lots of nuggets that would interest you.
One more item thats crucial: youve got to know the cost of time on the project. Without that info, NO increase in resources (and no crashing or fast-tracking) can ever be justified because resources cost money and, if time doesnt, why would you ever pay to save it? (Of course the truth is, time on the CP (DRAG) almost always costs more than the resources that would save it!)
Finally, I know you have Spider (which, from what I know of it is a great package!). But if you also have a copy of MS Project 2007 available, I urge you to download and check out the trial version of the Project Optimizer available from Sumatra.com. Not because MSP is anywhere close to as good a product as Spider (it isnt!), but because the Sumatra folks have included a walkthrough document of how to use DRAG to optimize a schedule on a sample project file. I think that might answer a lot of your questions and you could then use the same techniques in Spider.
Hope this helps.
Fraternally in project management,
Steve the Bajan
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Submitted by Rafael Davila on Tue, 2010-06-15 18:12
There are several characteristics that mark or highlight an activity that exists on the Critical Path as a better candidate for crashing.
1. Must be on the Critical Path. Crashing noncritical activities that already have slack only buys more slack and doesn’t shorten the project duration. Only critical path activities drive the project and crashing them will shorten the project duration.
2. Precedes multiple activities. When an activity bottlenecks numerous succeeding activities, it is a great candidate to shorten. Once this activity is shortened, it allows the multiple activities to begin.
3. Long duration. An activity that has a long duration offers more potential time gain from crashing it.
4. Lower cost per period gained. Activities that cost less to crash are preferred. These include those requiring lower paid, lower skilled workers or other resources that are otherwise sitting idle.
5. Early in the project (the Sunshine Rule). If you fail in crashing the activity and it takes longer than planned, it is still early in the project. Thus you still have recovery time. Also, typically demand on resources early in the project is lower than other times, and they should be readily available.
6. Labor-intensive. When an activity is low skill labor intensive, it is easy to add people to help complete the project early. When an activity requires high skills to complete, it may be hard to find qualified individuals who are capable of completing the task.
7. Subject to common problems. Try to pick activities that are subject to higher probability of common problems. Shortening the duration lowers the exposure time and lessens the chances of having a problem.
Steps in Project Crashing:
1. Compute the crash cost per time period. If crash costs are linear over time:
Crash cost per period = (Crash cost – Normal cost) / (Normal time – Crash time)
2. Using current activity times find the critical path and identify the critical activities
3. If there is only one critical path, then select the activity on this critical path that (a) can still be crashed, and (b) has the smallest crash cost per period. If there is more than one critical path, then select one activity from each critical path such that
(a) Each selected activity can still be crashed, and
(b) The total crash cost of all selected activities is the smallest. Note that a single activity may be common to more than one critical path.
4. Update all activity times.
5. Cease crashing when
– The target completion time is reached
– The crash cost exceeds the penalty cost
If not, return to Step 2.
To the above I would add:
If optimum crashing results in crashing late activities you can factor late activities cost to crash as to artificially increase the crash cost and use this factored value on the above procedure as to obtain alternate crashing strategy. Then compare unfactored estimated costs to determine if higher cost of early crashing is justified.
DRAG metrics will tell you on the spot how much you can reduce the duration of an activity before a new additional critical path must be considered.
Stephen, please I would like to hear your comments about this procedure as until we do not have a crashing routine embedded into our software we must somehow do our best.
Best Regards,
Rafael
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21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Mon, 2010-06-14 19:23
No doubt DRAG keeps you focused on the Critical Path. I guess from now on I will keep it on my mind, just want to make the best use of this simple metrics many have not paid due attention, well at least me, until now that you brought it to the table.
About saving 90,000$/five days it might be even more in case of a mega-drug with annual sales over a billion dollars, this give me 2.73 million per day in sales x 5 = 13.65 million in sales lost forever to the generic manufacturers once patent expires. The profit got to be a fair percentage of sales. Not everybody is on the opulence; most of us must find the most economical path, brute force at any cost is not an option.
When you get into more than a single critical path, crashing become more complicated, it becomes a linear programming issue, see the following reference for a birdseye view on the issue.
Your post raises a whole bunch of issues. It would take most of a book to address them all - but I already wrote it: Total Project Control from John Wiley & Sons. If you want an abbreviated description of the TPC approach, try ProjectsatWork.com and do a search on my name for a series of articles.
Let me try to help with some of your points, though:
"Compressing the schedule have some cost, that it is a time-cost trade off issue, even if using some weightage to measure resistance to compression for each individual activity... I had the idea that efficient use of DRAG was limited to the case when required network compression is not substantial but that it can be combined with some time-cost consideration."
DRAG is simply the amount of time an activity is adding to the project duration. Id suggest that this is hugely important info for any planner to know about their project. How they use it is another matter: time/cost trade-off; time/scope trade-off; project recovery from slippage; resource justification; resource targeting; improving organizational staffing levels; even postmortem ABCP and forensic analysis.
Again, DRAG is just important critical path data; how you use it is optional.
"For the purpose of this discussion I am interested in Drag as an alternative strategy to get solutions with some consideration on cost and not merely duration."
Absolutely! The key is that time is money, often huge amounts. How much is it worth? That depends on the project and on the contract. On a cost plus contract with no time incentives or penalties, compressing the schedule can actually be disadvantageous to the contractor. (Thats one reason why no customer should ever accept a cost-plus contract without time clauses.) And a contractor who has a great scheduler should seek such clauses as an opportunity to add profit.
What is the value of pulling in a schedule? On projects I consult on (nuke outages, DoD/aerospace, pharma), the cost of time is huge! Adding $10,000 to reduce an activitys DRAG by five days can result in $90,000 or more in profit. (The number that was being tossed around in pharma eight years ago was $32... per second! In general, if the value of pulling in the schedule is estimated at only $10,000/week, and its going to cost $8,000 to reduce the DRAG by a week, thats pretty close to a wash. But theres lots of occasions when the value of reducing an activitys DRAG is dramatic. Especially during recovery.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Sun, 2010-06-13 17:55
I do not know of longest path functionality in Spider Project, therefore I could not follow your suggestion within Spider. In the following Spider Project example longest path is Activity 1 – Activity 2 – Activity 3 while critical path is discontinuous Activity 2 – Activity 3 (Activity 1 excluded as it has float).
Although I do not have P6, through PP debates I could figure out P6 misses longest path driven by resource leveling. Therefore it is kind of useless on my resource driven schedules.
Compressing the schedule have some cost, that it is a time-cost trade off issue, even if using some weightage to measure resistance to compression for each individual activity. I always believed that the use of time-cost trade off routines would be the key to determine best mathematical compression strategy. I had the idea that efficient use of DRAG was limited to the case when required network compression is not substantial but that it can be combined with some time-cost consideration. Yes near optimal solutions are acceptable, but remember they become far from near at some point.
For the purpose of this discussion I am interested in Drag as an alternative strategy to get solutions with some consideration on cost and not merely duration.
Just consider the simple case of the above 3 activities sample job projected to take 15 work days. Say we need to find the best way to reduce the schedule to 12 days under the following conditions. We would also be interested on knowing the cost even if optimum as perhaps liquidated damages might be less expensive at some point.
Reduce duration of activity 1 – one day 300$, 2nd day 250$ and 3rd day 250$ (max reduction)
Reduce duration of activity 2 – one day 325$ and 2nd day 350$ (max reduction)
Reduce duration of activity 3 – one day 200$, 2nd day 250$ and 3rd day 350$ (max reduction)
The solution would be obvious because they are all in tandem but in case of hundreds of activities the procedure could create multiple parallel paths as DRAG is being consumed.
Of course true time-cost trade off functionality will also tell you about when it make sense to increase duration of some activities with enough float when increasing duration reduces the activity cost.
Best regards,
Rafael
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20 years 7 months
Member for20 years7 months
Submitted by Stephen Devaux on Sun, 2010-06-13 10:00
"Much is being said about good scheduling practice but few about the tricks on how to tame the schedule"
Rafael, I love your expression: "(T)he tricks on how to tame the schedule"!
Here would be the functionality I would see as perhaps solving your problem. (Maybe it already exists in Spider, or maybe Vladimir can incorporate it easily.) Would a report that does the following help resolve your issues?
1. List all activities on the (new) longest path, from earliest dates to latest.
2. Subtract [start date of each activity on original schedule longest path] from [start date on each activity on new schedule longest path]. Any such activity with a value > 0 has been delayed by an earlier activity/resource/constraint.
3. Display/highlight activities where the value computed in #2 is different in Successor Y than in Predecessor X, as it indicates that the delay is due to something specific in Y (after X finishes).
4. Display DRAG and assigned resources of Y-type activities, look for the cause (which will probably be due to resource constraints), and use DRAG computation to try to recover.
5. Subtract [difference between start and finish date of each activity on original schedule] from [difference between start and finish date of each activity on new schedule]. Any such activity with a value > 0 has been delayed by some aspect within itself (resource availability DRAG?), and now has a longer duration than it did.
6. Display DRAG and assigned resources of all such activities (which now had a longer duration), look for the cause (which will probably be due to resource constraints), and use DRAG computation to try to recover.
I think this should allow very quick identification of the causes of delay, and the DRAG computation would help direct the user to where to go to reduce the impact.
It seems to me that the above process would also be of huge value in forensic analysis, allowing the user to identify the precise locations of activity delay on the as built critical path (ABCP) and their DRAGs versus DRAGs on the baseline schedule critical path.
Im curious both as to whether you think this would help, Rafael, and as to whether Spider (which really seems to have more useful scheduling functionality than any other product out there) either can do this now, or would be able to with just a tiny bit of tweaking.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Sat, 2010-06-12 20:15
We as a contractor after we develop the initial schedule the main issue become on how to recover our schedule, almost always something happens that delays the schedule and we have to recover. Perhaps the saying that activities will expand duration to available time is true; the Contractor usually waste saved time and then got to recover once again.
For months I kept asking what is driving my schedule, what is driving my schedule after resource leveling, once and again and again. Maybe Vladimir developed the functionality to display resource dependencies to get rid of me. Well now I want to know who is next into driving my schedule, or how to avoid the driver. Perhaps Longest Path theory (and second to longest) can be of help here, but if resource constraining is not taken into account it would fall kind of short to me.
Much is being said about good scheduling practice but few about the tricks on how to tame the schedule.
Best regards,
Rafael
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20 years 7 months
Member for20 years7 months
Submitted by Stephen Devaux on Sat, 2010-06-12 18:12
First, a while back now, for the first time while teaching a class, I demonstrated how to go in and optimize/recover a schedule using software to compute DRAG. (Since the company uses MS Project, I used the Sumatra add-on to MS Project.) It went over GREAT! I think actually showing people how to use is very helpful and persuasive. The customers Ive showed it to since (and I taught a class to a different engineering company a month ago when I was over my health issue and where it once again went over great) have just been blown away by it. As I get back into teaching again, I intend to incorporate it regularly.
At my suggestion, Sumatra is developing for their website a short "case study" to demo how to use it to pull in a schedule. I would recommend that Spider would do the same thing (its really an education issue), and Id be happy to help with developing that, if you are interested.
Second, resource schedule DRAG is a result of two different things: CPM schedule DRAG as well as resource availability DRAG (or from my book Total Project Control, RAD) which can change the critical path. Its very valuable to separate out the delays caused by resource availability (and its cost), as that is the way we can go about justifying the needed resources to make the resource availability DRAG go away.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Sat, 2010-06-12 17:27
I know determining best curve fitting depending on spread of input data for you will be a challenge you can solve with excellent results, but remember about the Expected Value or Mean, in case of modeling Liquidated Damages this single value will give you some sense on what direction and how much the distribution function is moving, easier and more intuitive than comparing distribution curves.
About DRAG after resource leveling this can be more complicated as with resource leveling source dependencies can shift, if it can be computed, and links are needed then perhaps Spider Project will be unique about DRAG after resource leveling. I don’t know how or if if it can be computed using resource leveling but the easy way is to challenge you.
Best regards,
Rafael
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24 years 9 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Sat, 2010-06-12 12:39
AFTER RESOURCE LEVELING ACTIVITY 6 DRAG = 1? PERHAPS AFTER CREATION OF LINK DEPENDENCIES DRAG COULD BE RECOMPUTED? SHOULDN’T IT BE 2 DAYS FOR ACTIVITY 6 AFTER RESOURCE LEVELING?
FOR THE FOLLOWING SAMPLE I USED STANDARD RESOURCE LEVELING AS OPTIMUM WOULD GIVE MINIMUM DURATION OF 7 DAYS.
Best Regards,
Rafael
P.s. Did you make some improvements on resource leveling algorithms on last update?
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Submitted by Vladimir Liberzon on Sat, 2010-06-12 12:05
I was worried about you and asked about you the people whom we know both. I am glad that you are fine and resume your activities.
DRAG is in Spider Project but we did not proceed with the cost issues. People asked what it is and how it may be used. I suggest to start the discussion on DRAG here - I expect that some of our users will participate in the discussion, others may be interested in the concept.
We have few customers in Germany. In particular you may mention Thyssen Shachtbau.
Best Regards,
Vladimir
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20 years 7 months
Member for20 years7 months
Submitted by Stephen Devaux on Sat, 2010-06-12 09:55
How are you? A long time since I saw you in Boston! You may have noticed, I havent even been on the PP site for many, many months! On top of everything else (including both teaching and studying at the university level!), I have had a number of significant health issues. (Anyone who has ever had a kidney stone will appreciate what it might be like to have one for two months!) But Im feeling much better now, though 13 kgs. lighter than when we last met.
Some questions:
1. Has the DRAG functionality been implemented fully in Spider? If yes, has there been any reaction to it?
2. Does Spider have a user base in Germany? (Im working with a German client who might, down the road, be interested.)
Hope everything is good for you.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Mon, 2010-05-24 20:24
Thanks I got it, I even tried to make an illegal move by changing the duration of a productivity type activity. The software did not apply the change and protested, similar to when trying to apply non valid changes to database tables when importing values from an external table. I will be impatiently waiting for the full English description as not to miss any detail.
Best Regards,
Rafael
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Member for24 years9 months
Submitted by Vladimir Liberzon on Mon, 2010-05-24 14:53
If this formula will be executed the duration of activity with Code 1020 will become 5 days.
Another example: Calen [Сode, 1020] = Calen [Code, А, Resource] means that Calendar of activity with code 1020 will become equal to the calendar of resource with code A that is taken from the table Resource.
Special functions:
#CurrentDate - Current Date
#DataDate - Project Data Date
#TargetFinish - Project Target Finish
#ProjCode - Project Code
#ProjVersion - Project Version
#ProjName - Project Name
Full description in English will be published soon.
Best Regards,
Vladimir
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Member for21 years8 months
Submitted by Rafael Davila on Sun, 2010-05-23 19:55
"New version of Spider Project supports not only formulae that link and calculate project fields (columns) but also formulae that link and calculate cells (or the sets of cells) of different project tables."
Can you expand on how to get access to these fields, perhaps some coding is needed. I particularly noted the issue on reference to sets of cells this is kind of something I was hoping for long time, I would like to make conditional statements based on values on other fields, at times within the same table line, at times within a set of cells within the same table, but looking at different tables is kind of a welcomed surprise.
Best regards,
Rafael
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Submitted by Rodel Marasigan on Sat, 2010-05-22 05:19
Filter is to preceding activities; it will show all paths leading to the selected activity and filter out all other paths, therefore after having created all links it might be a matter of doing the PDM calculations to the isolated paths to get local critical path and floats.
Saving the Schedule under a different name and then identify preceding paths to delete unrelated paths is not very practical because as soon as you make any changes to the schedule new possible resource links might not be available as these where filtered out. For it to be practical under resource constraining I believe it must be done by the software without eliminating other paths.
Spider for long time calculated Resource Critical Path without disclosing the created links, now as added functionality it can display the resource dependencies links.
Best Regards,
Rafael
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Submitted by Vladimir Liberzon on Fri, 2010-05-21 04:19
Thanks, I got it. So filter is to Preceding Activities of the last activities but it may not be the longest path until you trace the link. Is it correct?
Best Regards,
Rodel
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Submitted by Rafael Davila on Fri, 2010-05-21 00:27
For the moment Spider Project do not have a longest path filter per-se, the filter is a filter for all preceding (and linked) activities, it will show preceding activities only if links are visible, so if there are links that are dependencies links it will only display them if you have selected for the software to create dependencies links.
I had a previous conversation with Vladimir about longest path but he did not wanted to create a limited filter that would not filter longest path in the presence of resource dependencies and even further he want it to consider other constraints such as financial constraints. I believe the creation of resource dependencies links can be a step to it but because these can appear and disappear as the schedule moves there is the question of how useful it is.
Best Regards,
Rafael
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Member for19 years
Submitted by Rodel Marasigan on Thu, 2010-05-20 23:47
Go to Calculations/Resource Constrained Scheduling Options and mark Create Resource Dependencies. Perhaps is not a default option as for large jobs it adds to the computing time. Also go to Gantt/Options and make sure Hide Resource Dependencies is unmarked.
There is also a filter for All Preceding Activities you should learn to use, is available when you select an activity line and right click. By the way in Spider to move activities you use cut and paste no drag and drop, this prevents errors but is not what we are used to do with Primavera products.
Because of the time difference many of your questions I will reply next day but always will.
Best regards,
Rafael
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Member for19 years
Submitted by Rodel Marasigan on Thu, 2010-05-20 21:40
P6 don’t have functions of resource link to identify predecessor and successors of resource dependency therefore P6 don’t have a capability of filtering full path of non logic activities. It will show only the last activity but enable to filter critical path created by resource.
By the way, how to create resource link using resource dependency in spider project?
Best Regards,
Rodel
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Submitted by Rafael Davila on Wed, 2010-05-19 23:07
I have used the functionality for creating links quite often as soon as it became available. I noted that if you filter for predecessors of an activity when all predecessors are resource dependencies if you select create links the software can see them but if you do not select for the software to create the links then it cannot see them.
I wonder if you know if P6 longest path filter can identify longest path when it is determined by resource dependencies. Can you tell me? I do not have P6 and wonder about the filter I believe was not available under prior version P3e I used before.
I am including a sample job I would like you to tell me how the longest path to the last activity would be displayed by P6 filter, I suspect it will not be able to identify full path as to include resource dependencies. Prior to resource leveling all activities are scheduled to happen at the same time.
Sample Job with no activities linked by logic, all links are resource dependencies shown by dotted lines:
The following view is better than using graphic display of links, I frequently get lost when links span several pages. It shows all links are resource dependence links. If you unlevel the schedule then all links dissapear and the table will be empty in this sample job.
Best Regards,
Rafael
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24 years 9 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Wed, 2010-05-19 20:27
New version of Spider Project supports not only formulae that link and calculate project fields (columns) but also formulae that link and calculate cells (or the sets of cells) of different project tables.
Best Regards,
Vladimir
Member for
24 years 9 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Sat, 2010-03-20 12:26
In the new version of Spider Project it is possible to make resource dependencies visible.
The software creates artificial links that are shown by dotted arrows. If an activity is delayed because the assigned resource is not available and starts when the resource finished to perform another activity these activity become connected by resource dependency.
It makes resource constrained schedule analysis much easier.
You can select to show or to hide these links, or to show only these links hiding regular links.
Resource Critical Path is now visible as a path and not just a sequence of resource critical activities.
Another new functionality: you can use Status Date, Data Date, Target Date, etc. in formulae.
Best Regards,
Vladimir
Member for
21 years 8 months
Member for21 years8 months
Submitted by Rafael Davila on Tue, 2010-02-16 12:19
You are late with regard to the unlimited number of diagrams, I have been enjoying it science yesterday, a few more (unlimited) than the single diagram available in SureTrak under Gantt Charts.
About superfloats just got them in today’s update. Looks beautiful, goes directly to what I was looking.
Even when I already got the most important functionalities such an unsurpassed resource leveling and resource assignment functionalities plus true resource constrained float these refinements are welcomed. At times they become very useful, some help you to communicate the ideas, some help you understand and tame PDM logic.
Thank you, very much.
Best regards,
Rafael
Member for
24 years 9 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Tue, 2010-02-16 11:39
New release of Spider Project includes two new features:
1) Calculation of activity resource constrained super floats that show when activity can finish without delaying project finish if their execution will be done slower than expected (with splits, etc.).
2) Now Spider Project users can place any number of diagrams in the window under Gantt Charts. This windows is resizable, has scrolling, and you can move any selected diagram up and down the window.
Hi Rafael,
you asked for these functions. Now you can try them.
Will keep you informed on future developments.
Best Regards,
Vladimir
Member for
24 years 9 months
Member for24 years9 months
Submitted by Vladimir Liberzon on Thu, 2010-02-11 13:48
Code in Original Project is not what you expected.
When projects are consolidated in the project portfolio activity codes in different projects may be the same. Spider Project can open the portfolio as one large project and do with it everything that can be done with the project model (scheduling, levelling, any kind of calculations and reports and some additional). So there is a need for unique activity codes in the project portfolio.
These codes are assigned by the software but Spider remembers original activity codes. After portfolio calculations and analysis separate project models are sent back to their managers. They shall receive new versions of their project models with the original activity codes to be able to compare them with the previous versions, etc. So Spider Project keeps two kind of activity codes - project and portfolio.
We recommend to keep activity codes the same in all project versions. This is the key field for comparing different project versions, EV, trend analysis. If project scope was changed and new set of activities appeared we suggest to make changes not only in the current project version but also to create new baseline. The history of baselines is kept the same way as Spider keeps project archives (all previous project versions are stored as the separate files).
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
So you mean it cannot be programmed a time cost trade off that considers resource leveling?
Best regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Usually there are more than one way of crashing an activity. And usually crashing is not linear and continious. Adding additional resource you will shorten activity duration by certain amount of time. But this resource will not be used on one activity only, so it is much more complicated. But different options may be weighted by looking at the new total cost that includes the cost of time.
Best Regards,
Vladimir
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
Agree 100%. But you still need some individual activities cost of crashing. The following to me would be practical and acceptable, no need for pretentious non linear functions, just start with normal duration and crash duration. Targeting for larger than normal does not makes sense.
The above should simplify the math and the data entry.
Best Regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Rafael,
I meant something different.
It is necessary to define what is the cost of one day of project delay and the cost of one day of project finish acceleration.
Total cost shall be estimated taking this into consideration. And cost of crashing will increase or decrease this total cost. If crashing decreases this total cost it makes sense.
I did not suggest to estimate time cost for individual activity. For decision making you shall look at the total cost.
Best Regards,
Vladimir
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
I know about time cost and realize fixed cost will decrease with a reduction in time of the hammock activity contrary to crashing of an activity that will increase with reduction in time. But because it span across all project duration it will always be on the critical path therefore for purpose of determining where to crash is irrelevant, but it is still relevant for the determination of total crash cost, you are correct.
On the other hand the time cost related to individual activities I would consider it when determining crash cost of an activity this will vary from activity to activity and also cannot be overlooked.
I downloaded the MS Project add-on suggested by Stephen to study the walkthrough document of how to use DRAG to optimize a schedule on a sample project file. When your project starts to fall behind schedule you try to compress the schedule using other methods but crashing, these are managerial decisions no way you can pre-program into the CPM logic, and they are in essence changes in logic. It is after changes in logic no longer solve the issue when you have no other option than to crash some activities. Knowing how to crash, especially when your job is in problems is very valuable.
Many times I have given true chance to MS Project but always, very soon, it gets into my way, no matter how hard I tried, even MS Project 2010 is still a no-no. No way am I going to use it in my jobs to find in the middle it will let me down, I already know it will. I believe if Stephen techniques can be applied within Spider then why not give it a try, we already have DRAG embeded into Spider, better than an add-on.
Best regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Hi Guys,
thank you, I enjoyed your discussion.
Rafael,
if you will look at my presentations I always insisted on setting single project success criterion estimating the cost of the time. If cost of time is estimated and known it is easy to model it by including hammock activity or activities in the project schedule.
Best Regards,
Vladimir
Member for
20 years 7 monthsRE: New Spider Project Functionalities
"Thanks for taking your time"
My pleasure! Its refreshing to chat with someone who obviously takes these issues seriously! I wish people working in industries where project time is not just measured in money, but also in human lives and suffering (e.g., pharma, health care, potable water wells) would take it as seriously!
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Stephen,
In the absence of sophisticated time cost trade off embedded in my software of choice I believe DRAG is quite important, otherwise you will miss the exact point when multiple paths emerge.
I already asked for the demo software you proposed, who knows maybe it will give Vladimir some ideas and we, users of Spider, benefit from it.
If compression of activities duration just add resistance then I imagine the mechanical equivalent as compressing a set of springs with different resistance and minimum length. The procedure would be like pushing the assembly from both ends.
About your book I will take a look on how to get it, believe it is available on amazon.
Thanks for taking your time,
Best Regards,
Rafael
Member for
20 years 7 monthsRE: New Spider Project Functionalities
Hi, Raphael.
Normally, Id be reluctant to criticize someones theoretical advice as long as there is some thats wise (and there certainly is in what youve quoted). But since youve asked for my comments, here goes:
The main thing is that the authors arent aware of DRAG. Its not their fault, because the concept only became public knowledge when my book was published (1999). And since only three PM packages (including Spider) compute it, unless theyve read my book or one of my articles, or sat through one of my courses, they could hardly be aware of it.
But DRAG really changes the whole schedule-compression ballgame -- its by far the most important concept for compressing a schedule. All the other considerations mentioned in your post may be relevant -- but number one is DRAG. For instance, lets take this one:
"3. Long duration. An activity that has a long duration offers more potential time gain from crashing it."
Long duration is meaningless without the DRAG concept. You can have a 25D task on the CP and its DRAG might only be one day. Conversely, you could have a 5D task on the CP
and its DRAG might be 5D. The latter offers the opportunity to gain 500% more time despite having only 20% of the duration.
A little over a year ago, I taught a class at a multinational DoD/aerospace contractor. When I explained DRAG, one engineer reacted dramatically. She explained that a year earlier, her team had been tasked by the client with pulling in by six weeks a mid-project task that had, from the total 5,000-activity programme perspective, over 200D of total float. The whole team flew to San Diego and met on a Monday morning. Most already had suggestions for activities they thought could be compressed. After about seven hours of tweaking, they gave the changes to their scheduler to input to the software -- and the schedule came in by one day!
After adjourning to the nearest bar, they came back and worked the rest of the week, just randomly trying things. As she put it, the concept of DRAG would probably have saved them eight person-weeks in San Diego, not to mention the airfare.
DRAG is NOT the total answer -- but it provides an "Occams razor" for selecting the best candidates for compression. Obviously, there are other considerations. One is resource elasticity: how much can an activity be compressed if resources are added? The TPC metric is DRED, or doubled resource estimated duration: how long would an activity take if resources were doubled? With doubled resources, a 20D activity may become 10D ("perfectly resource elastic"), or 13D (more likely!), or 17D, or remain 20D, or expand to 30D (e.g., building an avionics dashboard in the cockpit of a jet fighter).
Having this second estimate, based on doubling resources, provides the basis for the conversation when it turns out that a 20D task with 15D of DRAG has a DRED of 12D. We know from the DRED that the work is quite resource elastic. Now we need to find out:
(1) Do we have to double ALL its resources or just specific skills?
(2) If we added even more resources, would the duration keep shrinking until its DRAG (and DRAG Cost) disappeared?
(3) How much would the resource(s) cost?
Raphael, the subject (as you clearly understand!) is a complicated one. Since you seem so interested, I really would urge you to pick up a copy of my book -- I think youd find lots of nuggets that would interest you.
One more item thats crucial: youve got to know the cost of time on the project. Without that info, NO increase in resources (and no crashing or fast-tracking) can ever be justified because resources cost money and, if time doesnt, why would you ever pay to save it? (Of course the truth is, time on the CP (DRAG) almost always costs more than the resources that would save it!)
Finally, I know you have Spider (which, from what I know of it is a great package!). But if you also have a copy of MS Project 2007 available, I urge you to download and check out the trial version of the Project Optimizer available from Sumatra.com. Not because MSP is anywhere close to as good a product as Spider (it isnt!), but because the Sumatra folks have included a walkthrough document of how to use DRAG to optimize a schedule on a sample project file. I think that might answer a lot of your questions and you could then use the same techniques in Spider.
Hope this helps.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Stephen,
From:
http://www.stat.mq.edu.au/Stats_docs/stat321/Wk6Handout1.pdf
http://www.stat.mq.edu.au/Stats_docs/stat321/Wk6Handout2.pdf
Criteria for Selecting Activities to Crash:
There are several characteristics that mark or highlight an activity that exists on the Critical Path as a better candidate for crashing.
1. Must be on the Critical Path. Crashing noncritical activities that already have slack only buys more slack and doesn’t shorten the project duration. Only critical path activities drive the project and crashing them will shorten the project duration.
2. Precedes multiple activities. When an activity bottlenecks numerous succeeding activities, it is a great candidate to shorten. Once this activity is shortened, it allows the multiple activities to begin.
3. Long duration. An activity that has a long duration offers more potential time gain from crashing it.
4. Lower cost per period gained. Activities that cost less to crash are preferred. These include those requiring lower paid, lower skilled workers or other resources that are otherwise sitting idle.
5. Early in the project (the Sunshine Rule). If you fail in crashing the activity and it takes longer than planned, it is still early in the project. Thus you still have recovery time. Also, typically demand on resources early in the project is lower than other times, and they should be readily available.
6. Labor-intensive. When an activity is low skill labor intensive, it is easy to add people to help complete the project early. When an activity requires high skills to complete, it may be hard to find qualified individuals who are capable of completing the task.
7. Subject to common problems. Try to pick activities that are subject to higher probability of common problems. Shortening the duration lowers the exposure time and lessens the chances of having a problem.
Steps in Project Crashing:
1. Compute the crash cost per time period. If crash costs are linear over time:
Crash cost per period = (Crash cost – Normal cost) / (Normal time – Crash time)
2. Using current activity times find the critical path and identify the critical activities
3. If there is only one critical path, then select the activity on this critical path that (a) can still be crashed, and (b) has the smallest crash cost per period. If there is more than one critical path, then select one activity from each critical path such that
(a) Each selected activity can still be crashed, and
(b) The total crash cost of all selected activities is the smallest. Note that a single activity may be common to more than one critical path.
4. Update all activity times.
5. Cease crashing when
– The target completion time is reached
– The crash cost exceeds the penalty cost
If not, return to Step 2.
To the above I would add:
If optimum crashing results in crashing late activities you can factor late activities cost to crash as to artificially increase the crash cost and use this factored value on the above procedure as to obtain alternate crashing strategy. Then compare unfactored estimated costs to determine if higher cost of early crashing is justified.
DRAG metrics will tell you on the spot how much you can reduce the duration of an activity before a new additional critical path must be considered.
Stephen, please I would like to hear your comments about this procedure as until we do not have a crashing routine embedded into our software we must somehow do our best.
Best Regards,
Rafael
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Stephen,
No doubt DRAG keeps you focused on the Critical Path. I guess from now on I will keep it on my mind, just want to make the best use of this simple metrics many have not paid due attention, well at least me, until now that you brought it to the table.
About saving 90,000$/five days it might be even more in case of a mega-drug with annual sales over a billion dollars, this give me 2.73 million per day in sales x 5 = 13.65 million in sales lost forever to the generic manufacturers once patent expires. The profit got to be a fair percentage of sales. Not everybody is on the opulence; most of us must find the most economical path, brute force at any cost is not an option.
When you get into more than a single critical path, crashing become more complicated, it becomes a linear programming issue, see the following reference for a birdseye view on the issue.
http://people.brunel.ac.uk/~mastjjb/jeb/or/netcpm.html
One of the assumptions of the model is that it assumes there are always enough resources available for crashing.
Best regards,
Rafael
Member for
20 years 7 monthsRE: New Spider Project Functionalities
Hi, Raphael.
Your post raises a whole bunch of issues. It would take most of a book to address them all - but I already wrote it: Total Project Control from John Wiley & Sons. If you want an abbreviated description of the TPC approach, try ProjectsatWork.com and do a search on my name for a series of articles.
Let me try to help with some of your points, though:
"Compressing the schedule have some cost, that it is a time-cost trade off issue, even if using some weightage to measure resistance to compression for each individual activity... I had the idea that efficient use of DRAG was limited to the case when required network compression is not substantial but that it can be combined with some time-cost consideration."
DRAG is simply the amount of time an activity is adding to the project duration. Id suggest that this is hugely important info for any planner to know about their project. How they use it is another matter: time/cost trade-off; time/scope trade-off; project recovery from slippage; resource justification; resource targeting; improving organizational staffing levels; even postmortem ABCP and forensic analysis.
Again, DRAG is just important critical path data; how you use it is optional.
"For the purpose of this discussion I am interested in Drag as an alternative strategy to get solutions with some consideration on cost and not merely duration."
Absolutely! The key is that time is money, often huge amounts. How much is it worth? That depends on the project and on the contract. On a cost plus contract with no time incentives or penalties, compressing the schedule can actually be disadvantageous to the contractor. (Thats one reason why no customer should ever accept a cost-plus contract without time clauses.) And a contractor who has a great scheduler should seek such clauses as an opportunity to add profit.
What is the value of pulling in a schedule? On projects I consult on (nuke outages, DoD/aerospace, pharma), the cost of time is huge! Adding $10,000 to reduce an activitys DRAG by five days can result in $90,000 or more in profit. (The number that was being tossed around in pharma eight years ago was $32... per second! In general, if the value of pulling in the schedule is estimated at only $10,000/week, and its going to cost $8,000 to reduce the DRAG by a week, thats pretty close to a wash. But theres lots of occasions when the value of reducing an activitys DRAG is dramatic. Especially during recovery.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Stephen,
I do not know of longest path functionality in Spider Project, therefore I could not follow your suggestion within Spider. In the following Spider Project example longest path is Activity 1 – Activity 2 – Activity 3 while critical path is discontinuous Activity 2 – Activity 3 (Activity 1 excluded as it has float).
Although I do not have P6, through PP debates I could figure out P6 misses longest path driven by resource leveling. Therefore it is kind of useless on my resource driven schedules.
Compressing the schedule have some cost, that it is a time-cost trade off issue, even if using some weightage to measure resistance to compression for each individual activity. I always believed that the use of time-cost trade off routines would be the key to determine best mathematical compression strategy. I had the idea that efficient use of DRAG was limited to the case when required network compression is not substantial but that it can be combined with some time-cost consideration. Yes near optimal solutions are acceptable, but remember they become far from near at some point.
For the purpose of this discussion I am interested in Drag as an alternative strategy to get solutions with some consideration on cost and not merely duration.
Just consider the simple case of the above 3 activities sample job projected to take 15 work days. Say we need to find the best way to reduce the schedule to 12 days under the following conditions. We would also be interested on knowing the cost even if optimum as perhaps liquidated damages might be less expensive at some point.
Reduce duration of activity 1 – one day 300$, 2nd day 250$ and 3rd day 250$ (max reduction)
Reduce duration of activity 2 – one day 325$ and 2nd day 350$ (max reduction)
Reduce duration of activity 3 – one day 200$, 2nd day 250$ and 3rd day 350$ (max reduction)
The solution would be obvious because they are all in tandem but in case of hundreds of activities the procedure could create multiple parallel paths as DRAG is being consumed.
Of course true time-cost trade off functionality will also tell you about when it make sense to increase duration of some activities with enough float when increasing duration reduces the activity cost.
Best regards,
Rafael
Member for
20 years 7 monthsRE: New Spider Project Functionalities
"Much is being said about good scheduling practice but few about the tricks on how to tame the schedule"
Rafael, I love your expression: "(T)he tricks on how to tame the schedule"!
Here would be the functionality I would see as perhaps solving your problem. (Maybe it already exists in Spider, or maybe Vladimir can incorporate it easily.) Would a report that does the following help resolve your issues?
1. List all activities on the (new) longest path, from earliest dates to latest.
2. Subtract [start date of each activity on original schedule longest path] from [start date on each activity on new schedule longest path]. Any such activity with a value > 0 has been delayed by an earlier activity/resource/constraint.
3. Display/highlight activities where the value computed in #2 is different in Successor Y than in Predecessor X, as it indicates that the delay is due to something specific in Y (after X finishes).
4. Display DRAG and assigned resources of Y-type activities, look for the cause (which will probably be due to resource constraints), and use DRAG computation to try to recover.
5. Subtract [difference between start and finish date of each activity on original schedule] from [difference between start and finish date of each activity on new schedule]. Any such activity with a value > 0 has been delayed by some aspect within itself (resource availability DRAG?), and now has a longer duration than it did.
6. Display DRAG and assigned resources of all such activities (which now had a longer duration), look for the cause (which will probably be due to resource constraints), and use DRAG computation to try to recover.
I think this should allow very quick identification of the causes of delay, and the DRAG computation would help direct the user to where to go to reduce the impact.
It seems to me that the above process would also be of huge value in forensic analysis, allowing the user to identify the precise locations of activity delay on the as built critical path (ABCP) and their DRAGs versus DRAGs on the baseline schedule critical path.
Im curious both as to whether you think this would help, Rafael, and as to whether Spider (which really seems to have more useful scheduling functionality than any other product out there) either can do this now, or would be able to with just a tiny bit of tweaking.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Stephen,
We as a contractor after we develop the initial schedule the main issue become on how to recover our schedule, almost always something happens that delays the schedule and we have to recover. Perhaps the saying that activities will expand duration to available time is true; the Contractor usually waste saved time and then got to recover once again.
For months I kept asking what is driving my schedule, what is driving my schedule after resource leveling, once and again and again. Maybe Vladimir developed the functionality to display resource dependencies to get rid of me. Well now I want to know who is next into driving my schedule, or how to avoid the driver. Perhaps Longest Path theory (and second to longest) can be of help here, but if resource constraining is not taken into account it would fall kind of short to me.
Much is being said about good scheduling practice but few about the tricks on how to tame the schedule.
Best regards,
Rafael
Member for
20 years 7 monthsRE: New Spider Project Functionalities
Hi, guys. A few comments about DRAG:
First, a while back now, for the first time while teaching a class, I demonstrated how to go in and optimize/recover a schedule using software to compute DRAG. (Since the company uses MS Project, I used the Sumatra add-on to MS Project.) It went over GREAT! I think actually showing people how to use is very helpful and persuasive. The customers Ive showed it to since (and I taught a class to a different engineering company a month ago when I was over my health issue and where it once again went over great) have just been blown away by it. As I get back into teaching again, I intend to incorporate it regularly.
At my suggestion, Sumatra is developing for their website a short "case study" to demo how to use it to pull in a schedule. I would recommend that Spider would do the same thing (its really an education issue), and Id be happy to help with developing that, if you are interested.
Second, resource schedule DRAG is a result of two different things: CPM schedule DRAG as well as resource availability DRAG (or from my book Total Project Control, RAD) which can change the critical path. Its very valuable to separate out the delays caused by resource availability (and its cost), as that is the way we can go about justifying the needed resources to make the resource availability DRAG go away.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
I know determining best curve fitting depending on spread of input data for you will be a challenge you can solve with excellent results, but remember about the Expected Value or Mean, in case of modeling Liquidated Damages this single value will give you some sense on what direction and how much the distribution function is moving, easier and more intuitive than comparing distribution curves.
About DRAG after resource leveling this can be more complicated as with resource leveling source dependencies can shift, if it can be computed, and links are needed then perhaps Spider Project will be unique about DRAG after resource leveling. I don’t know how or if if it can be computed using resource leveling but the easy way is to challenge you.
Best regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Rafael,
we do not recalculate DRAG when level resources.
We may try after introducing resource links.
Resource levelling was not changed yet though we work on some improvements on material levelling.
Thank you for noticing a problem with restoring risk distribution curve, we will make improvements soon.
Best Regards,
Vladimir
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir
BEFORE RESOURCE LEVELING ACTIVITY 6 DRAG =1
AFTER RESOURCE LEVELING ACTIVITY 6 DRAG = 1? PERHAPS AFTER CREATION OF LINK DEPENDENCIES DRAG COULD BE RECOMPUTED? SHOULDN’T IT BE 2 DAYS FOR ACTIVITY 6 AFTER RESOURCE LEVELING?
FOR THE FOLLOWING SAMPLE I USED STANDARD RESOURCE LEVELING AS OPTIMUM WOULD GIVE MINIMUM DURATION OF 7 DAYS.
Best Regards,
Rafael
P.s. Did you make some improvements on resource leveling algorithms on last update?
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Hi Steve,
I was worried about you and asked about you the people whom we know both. I am glad that you are fine and resume your activities.
DRAG is in Spider Project but we did not proceed with the cost issues. People asked what it is and how it may be used. I suggest to start the discussion on DRAG here - I expect that some of our users will participate in the discussion, others may be interested in the concept.
We have few customers in Germany. In particular you may mention Thyssen Shachtbau.
Best Regards,
Vladimir
Member for
20 years 7 monthsRE: New Spider Project Functionalities
Hi, Vladimir!
How are you? A long time since I saw you in Boston! You may have noticed, I havent even been on the PP site for many, many months! On top of everything else (including both teaching and studying at the university level!), I have had a number of significant health issues. (Anyone who has ever had a kidney stone will appreciate what it might be like to have one for two months!) But Im feeling much better now, though 13 kgs. lighter than when we last met.
Some questions:
1. Has the DRAG functionality been implemented fully in Spider? If yes, has there been any reaction to it?
2. Does Spider have a user base in Germany? (Im working with a German client who might, down the road, be interested.)
Hope everything is good for you.
Fraternally in project management,
Steve the Bajan
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
Thanks I got it, I even tried to make an illegal move by changing the duration of a productivity type activity. The software did not apply the change and protested, similar to when trying to apply non valid changes to database tables when importing values from an external table. I will be impatiently waiting for the full English description as not to miss any detail.
Best Regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Rafael,
an example: DurPlanD [Code, 1020] = 5
If this formula will be executed the duration of activity with Code 1020 will become 5 days.
Another example: Calen [Сode, 1020] = Calen [Code, А, Resource] means that Calendar of activity with code 1020 will become equal to the calendar of resource with code A that is taken from the table Resource.
Special functions:
#CurrentDate - Current Date
#DataDate - Project Data Date
#TargetFinish - Project Target Finish
#ProjCode - Project Code
#ProjVersion - Project Version
#ProjName - Project Name
Full description in English will be published soon.
Best Regards,
Vladimir
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
As per your posting #6:
"New version of Spider Project supports not only formulae that link and calculate project fields (columns) but also formulae that link and calculate cells (or the sets of cells) of different project tables."
Can you expand on how to get access to these fields, perhaps some coding is needed. I particularly noted the issue on reference to sets of cells this is kind of something I was hoping for long time, I would like to make conditional statements based on values on other fields, at times within the same table line, at times within a set of cells within the same table, but looking at different tables is kind of a welcomed surprise.
Best regards,
Rafael
Member for
19 yearsRE: New Spider Project Functionalities
Thanks Rafael,
I understand what you mean.
Best Regards,
Rodel
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Rodel,
Filter is to preceding activities; it will show all paths leading to the selected activity and filter out all other paths, therefore after having created all links it might be a matter of doing the PDM calculations to the isolated paths to get local critical path and floats.
Saving the Schedule under a different name and then identify preceding paths to delete unrelated paths is not very practical because as soon as you make any changes to the schedule new possible resource links might not be available as these where filtered out. For it to be practical under resource constraining I believe it must be done by the software without eliminating other paths.
Spider for long time calculated Resource Critical Path without disclosing the created links, now as added functionality it can display the resource dependencies links.
Best Regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Rodel,
Spider Project calculates and shows resource critical path since 1993. Showing resource links is an option.
Best Regards,
Vladimir
Member for
19 yearsRE: New Spider Project Functionalities
Hi Rafael,
Thanks, I got it. So filter is to Preceding Activities of the last activities but it may not be the longest path until you trace the link. Is it correct?
Best Regards,
Rodel
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Rodel,
For the moment Spider Project do not have a longest path filter per-se, the filter is a filter for all preceding (and linked) activities, it will show preceding activities only if links are visible, so if there are links that are dependencies links it will only display them if you have selected for the software to create dependencies links.
I had a previous conversation with Vladimir about longest path but he did not wanted to create a limited filter that would not filter longest path in the presence of resource dependencies and even further he want it to consider other constraints such as financial constraints. I believe the creation of resource dependencies links can be a step to it but because these can appear and disappear as the schedule moves there is the question of how useful it is.
Best Regards,
Rafael
Member for
19 yearsRE: New Spider Project Functionalities
Thanks Rafael,
I got the resource link but still trying to work out on how to filter longest path. Any advice?
Best Regards,
Rodel
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Rodel,
Go to Calculations/Resource Constrained Scheduling Options and mark Create Resource Dependencies. Perhaps is not a default option as for large jobs it adds to the computing time. Also go to Gantt/Options and make sure Hide Resource Dependencies is unmarked.
There is also a filter for All Preceding Activities you should learn to use, is available when you select an activity line and right click. By the way in Spider to move activities you use cut and paste no drag and drop, this prevents errors but is not what we are used to do with Primavera products.
Because of the time difference many of your questions I will reply next day but always will.
Best regards,
Rafael
Member for
19 yearsRE: New Spider Project Functionalities
Hi Rafael,
P6 don’t have functions of resource link to identify predecessor and successors of resource dependency therefore P6 don’t have a capability of filtering full path of non logic activities. It will show only the last activity but enable to filter critical path created by resource.
By the way, how to create resource link using resource dependency in spider project?
Best Regards,
Rodel
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
I have used the functionality for creating links quite often as soon as it became available. I noted that if you filter for predecessors of an activity when all predecessors are resource dependencies if you select create links the software can see them but if you do not select for the software to create the links then it cannot see them.
I wonder if you know if P6 longest path filter can identify longest path when it is determined by resource dependencies. Can you tell me? I do not have P6 and wonder about the filter I believe was not available under prior version P3e I used before.
I am including a sample job I would like you to tell me how the longest path to the last activity would be displayed by P6 filter, I suspect it will not be able to identify full path as to include resource dependencies. Prior to resource leveling all activities are scheduled to happen at the same time.
Sample Job with no activities linked by logic, all links are resource dependencies shown by dotted lines:
The following view is better than using graphic display of links, I frequently get lost when links span several pages. It shows all links are resource dependence links. If you unlevel the schedule then all links dissapear and the table will be empty in this sample job.
Best Regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
New version of Spider Project supports not only formulae that link and calculate project fields (columns) but also formulae that link and calculate cells (or the sets of cells) of different project tables.
Best Regards,
Vladimir
Member for
24 years 9 monthsRE: New Spider Project Functionalities
In the new version of Spider Project it is possible to make resource dependencies visible.
The software creates artificial links that are shown by dotted arrows. If an activity is delayed because the assigned resource is not available and starts when the resource finished to perform another activity these activity become connected by resource dependency.
It makes resource constrained schedule analysis much easier.
You can select to show or to hide these links, or to show only these links hiding regular links.
Resource Critical Path is now visible as a path and not just a sequence of resource critical activities.
Another new functionality: you can use Status Date, Data Date, Target Date, etc. in formulae.
Best Regards,
Vladimir
Member for
21 years 8 monthsRE: New Spider Project Functionalities
Vladimir,
You are late with regard to the unlimited number of diagrams, I have been enjoying it science yesterday, a few more (unlimited) than the single diagram available in SureTrak under Gantt Charts.
About superfloats just got them in today’s update. Looks beautiful, goes directly to what I was looking.
Even when I already got the most important functionalities such an unsurpassed resource leveling and resource assignment functionalities plus true resource constrained float these refinements are welcomed. At times they become very useful, some help you to communicate the ideas, some help you understand and tame PDM logic.
Thank you, very much.
Best regards,
Rafael
Member for
24 years 9 monthsRE: New Spider Project Functionalities
New release of Spider Project includes two new features:
1) Calculation of activity resource constrained super floats that show when activity can finish without delaying project finish if their execution will be done slower than expected (with splits, etc.).
2) Now Spider Project users can place any number of diagrams in the window under Gantt Charts. This windows is resizable, has scrolling, and you can move any selected diagram up and down the window.
Hi Rafael,
you asked for these functions. Now you can try them.
Will keep you informed on future developments.
Best Regards,
Vladimir
Member for
24 years 9 monthsRE: New Spider Project Functionalities
Rafael,
thank you for the proposal. I will do it.
Code in Original Project is not what you expected.
When projects are consolidated in the project portfolio activity codes in different projects may be the same. Spider Project can open the portfolio as one large project and do with it everything that can be done with the project model (scheduling, levelling, any kind of calculations and reports and some additional). So there is a need for unique activity codes in the project portfolio.
These codes are assigned by the software but Spider remembers original activity codes. After portfolio calculations and analysis separate project models are sent back to their managers. They shall receive new versions of their project models with the original activity codes to be able to compare them with the previous versions, etc. So Spider Project keeps two kind of activity codes - project and portfolio.
We recommend to keep activity codes the same in all project versions. This is the key field for comparing different project versions, EV, trend analysis. If project scope was changed and new set of activities appeared we suggest to make changes not only in the current project version but also to create new baseline. The history of baselines is kept the same way as Spider keeps project archives (all previous project versions are stored as the separate files).
Best Regards,
Vladimir