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Let’s Challenge SPIDER

383 replies [Last post]
Carlos Arana
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Joined: 6 Jun 2009
Posts: 178
Hi. Has Spider project that useful for everything "jump to predecessor/succesor" button P3 has? In 2 clics, it takes you to the predecessors of an activity. It is very useful, I don’t know why it is not a feature of modern software, they seem to be focusing in making things more and more complicated instead of making common tasks more easygoing.

This is what I mean, I can get the driving sequence of an activity just by following its driving predecessors:
http://screenr.com/ZhH
Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
"You can consider the set of activities that precede current activity as the separate project with its own critical path, DRAG values, etc."

Seems like the equivalent of Longest Path, this is useful and relevant functionality.

"I want to simulate that next activity can start if any one of two preceding activities is finished. How to do this?"

Vladimir please follow the link and download the video showing this being done under SureTrak, any software can do that. This is using SF relationships and an as late as possible constraint, I suppose under "FS0 relationships only" Mike cannot simulate this.

http://rapidshare.com/files/288615256/FIFO.avi

Best regards,
Rafael
Hi Anoon,
you need not to know Spider Project. It is about potential requirements to any PM software.
Like I need to simulate this situation or to do this analysis. Is it possible?
Spider Project is just an example. I hope that somebody will suggest something really useful for all and we will discuss how it may be achieved.

There is forum for Spider Project users in Russian where people ask questions like "I want to simulate that next activity can start if any one of two preceding activities is finished. How to do this?"
Unfortunately there are few similar discussions here. I hope that this one can provoke to set really hard but still useful tasks.

Best Regards,
Vladimir
Hi Rafael,
I confirm that in Spider Project you can undo any specific action that was done earlier (like 15 actions ago) without undoing next actions.

Maybe I do not understand what is longest path. I just don’t understand the reason to compress the preceding activities if current activity has No Earlier Than constraint. I understand the usefulness of DRAG and we included this in Spider Project. DRAG shows what time each activity adds to the project duration. It can be calculated if to make activity duration equal to zero. Activity may have 10 days duration and being critical but with only 2 days DRAG because there is other subcritical path only 2 days shorter.

Spider Project can show all activities that precede current activity, it also shows driving relationships, it shows floats. You can filter the schedule by float value. You can consider the set of activities that precede current activity as the separate project with its own critical path, DRAG values, etc. It is sufficient for schedule analysis and knowing predecessors to activity with NET constraint does not help at all.
Please explain what I miss.

By the way Spider Project calculates not only activity floats but also assignment floats that may be different.

Best Regards,
Vladimir
Mike Testro
User offline. Last seen 20 hours 11 min ago. Offline
Joined: 14 Dec 2005
Posts: 4393
Hi Anoon

Whats the point of having a bit of power if you can’t abuse it now and then?

Best regards

Mike Testro
Anoon Iimos
User offline. Last seen 22 weeks 6 days ago. Offline
Joined: 22 Sep 2006
Posts: 1416
All,

I supposed Mike did a bias act on the other thread (for he is a Moderator), he just locked it when he feels that he’s about to lose. Now he wants private message, that’s unfair Mike.

Here, who can challenge Spider? I don’t know anything about Spider!

I believe Spider is not the issue! It is longest path; critical path; resource criticality; resource leveling; CPM...etc.

Rafael, I’m on your side now, if you want to ban CPM, I can make you a good coffee!

cheers!

Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
Vladimir

Undo is not the same as audit trial, undo are done in backwards sequential order, with audit trial you can see your data entry history and make changes in non sequential order, if you can see what your last 40 or 60 changes were and undo only those you select then it will be a great improvement of what our undo in Primavera Products does, I also understand Primavera undo does not works with resource leveling. If Spider Project can undo specific actions in any order then this is great, please confirm it is not sequential that it can be discretionary in any order you wish.

About Longest Path you for whatever reason might be, you might need to compress or crash the path up to a specific activity, because predecessors can also be tied to other chains, float alone do not identify the driving activities of the particular chain you are investigating. The longest path to the particular activity is not necessarily determined by those predecessors with the lowest amount of float, even when the activity is artificially constrained.

http://scheduleanalyzer.com/sa_long.htm

http://scheduleanalyzer.com/sa_long_theory.htm

“LONGEST PATH Software extends the theory of Longest Path to every activity in the schedule. Just as with Total Float, every activity in the schedule can be rated by its Longest Path Value. “ Please note Longest Path is not available in any software, Ron Winter provide this without infringing Primavera Copyright in their products, he is enhancing them is a good deal for both. I believe he only works directly with the Database, and then after the changes are done in the database you can see them in P3 until it runs any procedure that recalculates these values.

I don’t have Longest Path Software, I don’t know if it would work with SureTrak P3 files but I believe it can because here the Longest Path Software is dealing directly with the database values.

If someone can develop by their own this functionality is Spider Project, stand to the challenge and extend it to include Resource Critical Path and float plus all other simultaneous constraint sets. That I want to see, Financial Critical Path, I want all these functionality and still able to see driving constraints; predecessors/succesors logic, resources, financial, all.

Best regards,
Rafael
Rafael,

Automatic Audit Trail of Changes in Spider Project is called Protocol of Actions. You can undo any specific action. I don’t remember when this feature was added to Spider Project but many years ago. The user can define how many actions shall be stored (the depth of undo’s). There are no limitations. You can try this feature in Spider Demo.

Expected finish Constraint will be shown if to compare forward and backward schedules. You can do it at any moment if necessary.

Best Regards,
Vladimir
Rafael,
I have read about the Longest Path and did ot understand its value. If activity is restricted by No Enarlier Than constraint what driving relationships will give us? Why it is necessary to know longest path if you know activities with the minimal float.
If it is necessary to know the path from the beginning determine the activity that has no predecessors with the minimal float and filter the schedule showing only those activities that have floats equal or less. Or just define that activities with the float equal or less than ... are critical and you will see the longest path in red.
If you see the difference then explain it to me.
Vladimir
Hi Rafael,
I mentioned this task just as an example of questions that are asked in our forum. I am glad that Suretrak can do it though I did not understand about SF relationship with ALAP constraint.

Hi Carlos,
Spider Project has "jump to predecessor/succesor" function and can export/import to MS Project and P6. It has no direct export to P3 but exports to mpx that P3 understands.
Besides it exports/imports to text and databases. Any Spider table can be exported to Excel and vice versa.
Spider shows links of current activity in the diagram. Clicking on the preceding or succeding activity you will see its properties including links, Then you can click on another preceding or succeding activity and again see its properties (duration, volume, assignments, links, etc.).

Best Regards,
Vladimir
Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
Vladimir,

Thanks for your response about how to model crane use; you got it right this was my question.

I am not familiar with the use of consumable resources as Primavera SureTrak or P3 do not provide for these. I believe that Micro Planner had the concept of consumable resources; to me it seems similar to your material resource, just another name, please confirm.

I got the following functionalities missing from our software would like you to tell me if they or equivalent are available in Spider Project.

1)Automatic Audit Trail of Changes: http://www.ronwinterconsulting.com/Making_CPM_Transparent.pdf

2)Longest Path Value:
http://www.ronwinterconsulting.com/Longest_Path_Value.pdf

3)Expected Finish Constraint: this constraint calculates Remaining duration automatically between updates as the difference between the Expected Finish Constraint and the Data Date. Not a must have but handy.

Best regards,
Rafael
Hi Mike,
it is not necessary to level costs if you just want to know project cash flow. If you can work without financing then it is OK and you will know how much money you will spend until next payment.
But if your money are limited then you will depend on project income and it is nice to know project schedule that is adjusted to your financial capabilities.
When Russian Ministry of Defence planned large 10 years program they found that program cost was very uneven - expenses for one year were several times more than for another year, etc. So the program schedule was unrealistic because it will not financed this way. So they input expected limits of program financing per year and got new schedule that was approved.
Mike, computers shall help us to decide. Play what if - computers calculate faster and can try much more different options than people.

Hi Rafael,
Storage capacity can be simulated the same way. Actually we have successful experience of Just in time construction management in the middle of downtown. Project lasted one year and a half and was finished two days later than was planned in the initial schedule.
Do you mean cranes by hoisting facilities? My English is not very good, so sometimes I will ask for the explanations.
The crane is one of the project resources. And usually it is critical resource especially in the construction in the middle of downtown. We simulate its work as follows:
1) Estimate the average number of lifts in one shift,
2) Estimate the number of lifts necessary for different works (activities) during one shift,
3) Divide this number by total number and multiply by 100.
Now you know the workload of the crane on your activity.
Of course there are other activities where crane is 100% assigned because it does not lift but holds something and will not do other works in parallel.
I know queueing theory and applied it to some tasks in the past, but for project scheduling it is not necessary. I know only one practical task where it shall be applied: determination of the optimal number of trucks that shall serve the excavators in earth moving works. But it shall be done before scheduling.
Next week I will return from Germany and will answer faster.
Best Regards,
Vladimir
Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
Vladimir,

“If financing schedule is a part of your project schedule model then Spider Project will calculate project schedule taking into account financial limitations and delaying activities when there are no money to proceed.”

You are thinking out of the box. With my mindset of a general contractor, not of a developer I was wondering on the application of this functionality. Yes I accept financial constaints as real constraints, and find your approach very clever.

Let’s move to the issues on “materials” constraints. You mentioned earlier in another thread about the use of material resources as to constraint your schedule under limited available work space. But can this also be used as a way to model limited storage space at the jobsite? Let say a job in the middle of downtown or an offshore rig.

And what about limits on hoisting facilities? This is a queuing or “waiting line” problem., I have no idea on how to model that into a CPM schedule but into a GPSS (Gen. Purpose Symulation System) or the like.

Best regards,
Rafael
Mike Testro
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Joined: 14 Dec 2005
Posts: 4393
Hi Vladimir

Most software has a cost v income function but will not stop the programme if the preset parameters are exceeded.

That is left to the judgement of the manager assisted by his planner’s reports.

I do not like the idea of computers making decisions for us.

Best regards

Mike Testro
Hi Rafael,
Spider Project keeps the history of project changes and among other project tables has Performance Archive table that keeps all actual data entries.

Entering actuals you don’t play with any percent complete. You shall enter physical volumes that were done, time that was spent, materials consumed and money spent on project activities during the considered period. Besides the user can enter expected remaining volumes, durations, material requirements.

I don’t understand percent complete approach. If 40% of activity volume of work was done, 50% of activity duration was passed, 60% of material 1 and 35% of material 2 were consumed what is percent complete?

Spider Project also keeps project history and comparing two project versions you can get the reports on any changes that happened between selected dates. You can also get reports on project performance for any time period (from one date to another).

If you will have specific questions I will be glad to answer.

I also have some questions to everybody.

In Russia (and not only) some workers are paid not for the time but for the quantity of work that was done by these workers. In this case resource hour cost does not make sense. The same if resource is subcontractor - the client pays for the work and not for the time.
How to model this in Suretrak, P3, P6, etc.?

Best Regards,
Vladimir
Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
Vladimir,

For labor we pay 8 hours for a fixed production, the labor end its day when reaches the production, there are no different actual data, on the contrary and very simple a fixed production per fixed 8 hour or per day. No error with payment at all. By law we are not allowed to use piecework to evade the law and not pay labor tax. Only on rainy days an adjustment is made.

Regarding earth movement by independent truckers it is by cubic meter, these are considered individual contractors and the rate is established by a government agency.

If you move dirt on a road you must use these independent contractors, if within a site, without getting into any road you can use your own.

Here we have been for years in argument with the Workmen’s Compensation Agency that does not recognize truckers as independent contractors. We, contractors end up paying their Workmen’s Compensation based not on actual payroll but on an estimated payroll for the work based on a percentage of the payment to these individual contractors, kind of ironic.

In general we like the Workmen’s Comp idea as if you pay for it, in case of accident, you as employer have immunity, also the fee is reasonable, substantially lower than using private insurance companies. This we know because at some federal jobs we are required to use the private insurance companies and the fee is very high, and in addition as employer you do not get the immunity, being liable in case of accident.

Vladimir, different States have different laws, so there might be differences among the states. But the idea of providing you with as much information as I can is that you can understand our particular needs. I hope eventually Spider Project becomes one of the dominant CPM software here, because of its own merits, because is excellent software.

If Primavera can be all over the world, why Spider Project being a better product cannot? For this to happen you have to stop thinking only on the Russian experience, I understand your question is because Spider Team cares.

By the way on friday I was at a meeting discussing a Bid, because of the job duration we will be in need of scheduling two shift, if awarded the job, here Spider fuctionality shines as no other.

Best regards,
Rafael
Hi Rafael,
here we pay per volume units - per cubic meter, or kg, etc without transforming the price into hour costs. In any case paying for hours means that different actual data will mean wrong payment. How do you manage resource costs with your software?

Best Regards,
Vladimir
Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
Vladimir,

We call it piecework, very common here for some trades such as cement plastering and masonry block installation. I can be specific only for Puerto Rico, in the Continental US, I suppose, it is similar because we are subject to the same laws regarding minimum wage.

Here is common to pay a whole day or eight hours for a required production, is easier to model in our payroll systems. For example the installation of 350 concrete blocks means eight hours even when you finish after 5 hours. Our laws require you pay a minimum wage and report payroll per hour. Also you cannot claim these are individual subcontractors and avoid paying payroll tax such as social security, unemployment insurance, workmen’s compensation and vacations among a few others. Our local labor department recognizes these agreements if written and the result payment ends being more than the minimum wage.

Therefore in this case we get a better prediction on productivity; we schedule the resource the eight hours for the agreed production.

On the other hand we pay earth moving on trucks per a formula as established by our government agencies, these are considered to be individual contractors when they use their own trucks. Here we have to use average production based on an estimated capacity of the truck and the particular conditions of the job, such as the distance of earth moving by truck.

Best regards,
Rafael
Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
Vladimir,

You got it right because of our laws acceleration using the same labor to produce more than a "days" work is forbidden. You got to use other shift that might start earlier or use more employees (no subcontractors, no way our laws will recognize individuals as independent contractors unless specific requirements are met.

Yes after they finish the production of a single day they will leave the construction site until next day.

We will enter 8 hours work and you better pay over minimum wage for the eight hours. If latter you are proved to evade the minimum wage law the penalty will be 100% payable to the employee plus all due labor taxes and very high penalties.

I am not sure but if you allow them to work over the basic eight hour production, the remaining might be interpreted as overtime and payable at twice the rate, here in the construction business our "Mandatory Decree" does not recognize 1-1/2 pay rate. For other industries it is different, the same as for holidays.

It would be good if you get info from Mainland US Contractors, to get the big picture.

Best regards,
Rafael
Thank you, Rafael.
I know that we shall learn the needs of different markets. We have customers in 26 countries but most Spider Project users are Russian speaking.
I still don’t understand. Let’s suppose that the job for 8 hours the workers had done in 6 hours. Instead of working further they just leave the construction site? If they did not do the work in 8 hours they work until they will do the expected amount? What about the next shift?
If to enter actual information that the workers worked only 6 hours then the cost of the work will be wrong?
So acceleration is forbidden?
Best Regards,
Vladimir
Rafael Davila
User offline. Last seen 6 hours 37 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780
Vladimir,

The mathematical modeling of statistics in Spider Project is not a true Monte Carlo Simulation; it seems is neither the traditionally wrong PERT statistics, is another algorithm. Seems like the curve fitting of three job durations, one pessimistic, one most probable and one optimistic but not limited to a single critical path as original PERT was. The user assign a probability of occurrence for each and then you get X an Y values of three points in your curve. The computations are different to traditional PERT and also different to Monte Carlo Simulation. Monte Carlo Simulation is based on running the probable duration combinations hundreds or thousands of times. I have my reserves about the validity of the method without questioning the assessment of probabilities which can also be questioned for Monte Carlo. I have not seen the total job duration vs. probability curve distribution but I assume is somewhere available.

Pertmaster from the deterministic schedule can determine the distribution for your activities from a selection of distribution curves; this is very convenient when modeling thousands of activities. Spider Project implementation of probabilities to the schedule is short from what Permaster offer.

About the implementation of buffers I don’t see what is known as buffers in other software, I don’t want a substitute procedure that targets merely for early completion without the trick of a buffer activity that after float in a particular chain is consumed the reserve buffer is also consumed before the chain becomes critical, of course the buffer on the critical path might start very early to be consumed.

When I said I want to be able to model and update different schedules on parallel I meant same actual start for started but not finished activities, same actual start and finish for activities started and finished but different scenarios for the relationships, remaining duration, cost and resource loading. This is not what I am getting. I have no need for what I am getting with Spider Project in this regard.

The value of resource critical path and resource leveling algorithms is without any doubt a very relevant functionality, the most relevant, I find Spider Project stands above the competition. I am still figuring out in the 10 activities sample job you gave me what combination of prioritization can give me the same results as Spider Project. I also have to model the same again using Spider Project but not using your electronic file but my own without using driving resources. I suspect I will get the same results and Spider will again emerge as the winner, don’t take me wrong, just want to make sure as it seems too good to be true.

In my opinion, unless I get a surprise from other vendor, Spider Project is superior to what I have seen. Superior resource constraining and resource critical path keep it on top. Also don’t overlook the Resource Gantt, is great, better than a report.

I would take out some of the functionalities 98% of us do not need in order to provide with a leaner machine. I would take out cost leveling and earned value and substitute statistical functionalities with Buffers as a special type of visible activity.

Best regards,
Rafael
Hi Rafael,
looks like Nobody is willing to take your Spider Challenge at resource leveling.
Best Regards,
Vladimir
Here we use different approach.
People are paid for the quantities like per each cubic meter of concrete. If they will do more they will earn more but proportionally. This way people are motivated to work faster but there is a need for proper quality control.
The same with contractors - there are fixed price or fixed unit price contracts.
Best Regards,
Vladimir