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Beginner User General Doubts

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Ignacio Sanchez
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Hi All,

First, great job to the developers of Spider Project; I havent used yet all its features but really looks very interesting. I have started using the demo version of Spider Project to ensure that it covers all the aspects I am looking for in this software before purchasing it.

For your information, the key elements I am looking for is to estimate manpower and equipment based on fix volumes of quantities (Fix Quantities) to be executed and based on a fix performance (Fix Productivity). The overall project duration is fixed but the time allocated for each activity is flexible. Therefore, I would like the program to optimize when the different activities are executed and with how much manpower in order to meet the total project duration and to have a level the manpower and equipment as best as possible.

Having said that, please find next the questions I have at this moment:

  1. Are Teams and Multiresources the same? I have read carefully the definition and cant see the difference. All the activities I am modelling are being executed by teams consisting on different resources (i2x labor + 1x technician + 1x machine) and they have to work together. Meaning that a team will execute 10 units per hour (for example) and all the members of the team need to work together at the same time in order to execute 10 units per hour. I am using multiresources since I think is what best fits my model. Please, let me know your thoughts.
  2. How can I let Spider to define the Quantities of each multiresource used based on a fix productivity, fix activities' quantity and fix total project duration? I am using DPH type "Productivity" since I believe this is the type I need to fix in order to let Spider optimize the quantites of multiresources. However, I note that the quantities of multiresources never change and Spider always keeps the values I set before running the calculation. As I mentioned before, I would like Spider to define the total quantites of each multiresources working on parallel in order to change the time duration of each activity to a lower or higher duration, so that the target finish date of the project is achieved and that the manpower and equipment levelling is optimized.
  3. How can I set a finish target date for the project? I am defining it on Project->Properties but it seems I am doing something wrong since it is not working. Please keep in mind that in my model I want to set a global end date for the whole project but keep each activity timelines flexible in order to be defined by Spider together with the quantity of multiresources.
  4. How does Spider define when the activity will take place? In my model, I am defining links for all the activities, so that most of the activities have two links. One link is to start with a lag of X days after another activity has started or finished and another link to finish with a laf of Y days after another activity has started or finished. This type of linking results on a window of time where the activity can be executed. If this time window is larger than what the activity requires (even considering a single multiresource/team to execute it) then I note that Spider tries to push the activity as late as possible. Is this the usual routine of Spider? or is just some coincidence of my model? In my case, I would like Spider to define when the activity will take place within the the time window available. To do so, I guess I would need to link the activities using start no sooner than X milestone and end to later than Y milestone. Is that possible?

I have uploaded the model I have created using the demo of Spider in the following link

https://wetransfer.com/downloads/4fa4ef3a023dc4fe243863b03276fcb420200202065424/5eb93b01729218b200b54eae45faed8620200202065424/5278b7

Thanks in advance for your support!

Best,

 

Ignacio

Replies

Hi Ignacio,

My answers to your questions are below.

Are Teams and Multiresources the same?

Teams and Multiresources are not the same.

Resources that belong to the same team work together and the same with resources belonging to multiresources.

But multiresources are the stable group of resources working together (like crew) and the team may include many multiresources. But the main advantage of using multiresources is the possibility at any moment reconsider the quantities and the content of the crews assigned to multiple activities. You can do the changes opening multiresource properties in the multiresource table and selecting Update Content you will change this multiresource participants at all multiresource assignments on future works. Another advantage of using multiresources will be explained in my answer to your next question.

If resources or multiresources can work on the activity independently pf each other (for example in different shifts) they shall be assigned in the different teams.

How can I let Spider to define the Quantities of each multiresource used based on a fix productivity, fix activities' quantity and fix total project duration?

Spider Project includes Skill scheduling. It means that you can define what resources or multiresources have required skill and assign to activity not resources but resource skills. Assigning skills you may define the number of resources that have required skill or total productivity of skilled resources that must be achieved.

In your sample project I created Skills A, B and C and defined that Skill A has multiresource Foundation Type A, Skill B has multiresource Foundation Type B, Skill C has multiresource Foundation Type C and assigned Skills A, B and C to activities that require multiresources Foundation Type A, B and C. I also entered required minimal productivity. Spider Project selects the number of assigned crews (multiresources) that exceeds set productivity automatically. But total productivity in this case will be always the sum of productivities of assigned resources or crews. If you want it to be certain then you shall change assigned resource workloads (like 80% of the work time).

And of course you can play with the number of assigned multiresources manually.

As Rafael Davila already wrote, you can also define the range (minimal and maximal quantities of assigned crews) and in this case Spider Project will distribute resources automatically and an activity can use one number of assigned resources at activity start and then change this number in the course of activity execution.

Total project duration is defined by activity dependencies and durations that depend on assigned resources productivities.

After project scheduling you can look for the best ways of the project duration crashing and here activity Drags can help.

How can I set a finish target date for the project?

Defining Target finish in the project properties you define the condition for backward scheduling for determining when the project must start to be able to finish at the target date.

We recommend to create project start and finish milestones and set target date for the finish milestone.

How does Spider define when the activity will take place?

Spider Project calculates project schedule basing on dependencies that were entered, activity durations set directly or calculated basing on activity volumes and assigned resources productivities, activity and resource calendars, and other constraints like resource availability, material supply and financing schedule. If activity durations, volumes, resource productivities and other parameters are not certain we recommend to apply risk analysis. You can define optimistic, most likely and pessimistic estimtes of project parameters and use Monte Carlo simulation or create three scenarios of project execution. Spider Project will calculate probability distributions of project parameters and the dates and costs that will be achived with sufficient probabilities.

We do not recommend to use Start No Earlier Than constraints if they are not determined by certain restrictions that are usually external to projects. But it is possible in activity properties.

I put your Sample project with assigned resource skills here https://files.fm/u/ur4wak98

Let us know if you will have further questions.

Best Regards,

Vladimir

Rafael Davila
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Posts: 4920

4) How does Spider define when the activity will take place? ... Is this the usual routine of Spider?

Spider uses the contiguous activity model.  

When there are competing starts and finish constraints on an activity:

  • Under contiguous scheduling the activity will be delayed as to meet all constraints while
  • Under interruptible scheduling it will be scheduled intermittent but without disclosing the details of how each segment is assigned.  

Usually it is desirable to schedule the activities as a continuous operation as intermittent work is less efficient, stopping and re-starting of an activity might mean re-mobilization of crews, the inefficiencies created might mean the duration of the segments might have to be longer than the duration of the a continuous operation. The use of interruptible option applied across the board on all activities when interruptible is desired only on some occasions is not a good idea.

There are cases when it is desirable to schedule the activity on intermittent segments because of what is known as reverse logic. Under reverse logic if you split the activity it might reduce the total job duration or because some work will start earlier it might provide some protection to prevent the activity becoming critical or delaying other activities. In some cases it might be better to fully stretch the activity and reduce workload of resources. 

If it makes sense to split the activity into several segments it should be applied only when needed and under a controlled and transparent split where you would know the scheduled start/finish, duration and float of the individual segments.

In Spider Project we have a float value for Start Flex, with Start Flex you can know how much you can stretch the activity start. If you need it to be intermittent split the activity and decide the duration of the splits and how resources will be assigned, good practice shall not allow shortcuts here.

It looks like in your example a finish predecessor link is driving some activities.  You can verify which link is driving by looking at the links table.

Rafael Davila
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Posts: 4920

3) How can I set a finish target date for the project? I am defining it on Project->Properties but it seems I am doing something wrong since it is not working.

  • You are defining the finish target date for the project in the right way.  In order to see it working you need to set calculations to backward calculation within calculation settings.
  • Direction of schedule calculation in frame Direction defines whether schedule will be calculated either Forward starting from the current date or Backward from the target finish date. Backward direction enables schedule calculation for project that necessarily requires completion at target finish date.
Rafael Davila
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2) How can I let Spider to define the Quantities of each multiresource used based on a fix productivity, fix activities' quantity and fix total project duration?

Variable quantity and workloads is a better approach when productivity per resource or multi resource is fixed.  When modeling variable resource quantities you specify the quantity range and Spider will select the quantities looking for shortest project duration. 

Rafael Davila
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Posts: 4920

Too many questions for a simple answer.  I suggest starting with the basics of resource assignments. 

1) Are Teams and Multiresources the same?

 

 

Skills leveling will allow you to model more complex scenarios where production rates are not in proportion to resource quantity.Click following links for sample files:

http://www.mediafire.com/file/0z002ilfvpl1uyd/Shifts-01.001.sprj/file

http://www.mediafire.com/file/exeye4p11ygn8vu/Shifts-02.001.sprj/file