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Spider Project Scheduling Logic Issues

3 replies [Last post]
Alexandros Kroustis
User offline. Last seen 2 years 16 weeks ago. Offline
Joined: 29 Dec 2006
Posts: 18
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Dear all,

I'm currently have 11.01.28 version of Spider Project.

In general I'm impressed with the overall performance and easiness of Spider Project.

Recently only I started working in Spider with a programme having actuals.

I noticed that there might be an error / wrong scheduling calculation and I wanted to share it with you in order to help me understand this issue, and if this calculation is different in newer versions.

 I have created a sample programme which you can find it attached here.

In this programme we have 3 activities all with 24 days duration starting 17-Feb-2020.

2 simple links between them:

  • Activity 1 --- FF (6 Days) ---> Activity 2
  • Activity 2 --- SS (0 Days) ---> Activity 3

Data date 04-March-2020, Activity 1 actuals as planned, Activity 2 changed to 90% complete, Activity 3 no actuals.

In scheduling options we have 4 options to choose in case of out of sequence execution.

First I want to mention that we currently don't have out of sequence execution above, so none of the above options would be our case.

For first link none of the activities have finished so the logic is correct and when Activity 1 will finish, activity 2 to finish 6 days later.

For the second link, Activity 2 has started and Activity 3 not yet and will start after Activity 2, the soonest possible.

I would expect Activity 2 to finish 6 days after Activity 1 finishes and Activity 3 to start just after my Data Date, that is, 05-March-2020.

I can't get the expected result with any of the above options selected:

  • Option 1 - Retained Logic: It pushes Activity 3 to start after Activity 2 finishes. Like there was link:

Activity 2 --FS0--> Activity 3


  • Option 2 - Retained Logic With Exception Of Activities In Progress: It shifts Activity 2 to finish As early as possible breaking logic between Activity 1 & 2 of FF (6 Days), and keeps Activity 3 as before with no logic at all


  • Option 3 - Ignore Preceding links if Activity is in progress: Activities 1 & 2 as Option 2 and Activity 3 to start 05-March-2020 as expected (but Activity 2 not as expected)


  • Option 4: Ignore Preceding links of activities finished: Activities 1 & 2 as expected, Activity 3 to start when the remaining of Activity 2 starts and not 05-March-2020


Can you please clarify the above simple scenario?

Is this a mulfunction of my current version, that is 11.01.28, or there is something that I don't get and you can clarify?

Link To File: test-ret-log.002.sprj

Kind Regards,

Alexandros Kroustis



Alexandros Kroustis
User offline. Last seen 2 years 16 weeks ago. Offline
Joined: 29 Dec 2006
Posts: 18
Groups: None

Hi Vladimir,


I'm just writing to confirm that this issue has been resolved in the newer version of Spider.


Kind Regards,

Alexandros Kroustis

Alexandros Kroustis
User offline. Last seen 2 years 16 weeks ago. Offline
Joined: 29 Dec 2006
Posts: 18
Groups: None

Dear Vladimir,

Yes, option 3 works as it should, but only if we had out of sequence execution as the title mentions in the options.

The programme should mention just how we want to schedule globally and not "in case of out of sequence execution".

In the above example we don't have out of sequence execution.

I would like you to send me the version that this error was fixed, if it is possible.

Kind Regards,


Hi Alexandros,

thank you for your information.

It looks like there was an error in your version that was fixed long time ago. I understood that in your version when links were restored Spider applied them to remaining parts of activities. It was noticed and fixed very fast.

I cannot repeat your examples now because in current versions everything is as expected.

But I don't understand what is wrong in the Case 3. In this case preceding links to an activity in progress (FF to activity 2) were ignored.

Let me know if you need the version where this error was fixed.

Please download current version from and try your examples.

But due to Demo restrictions it contains only two of four options of scheduling when the dependencieas are broken. Full version includes all options.

Please let me know if you will meet any problems.

Thank you and Best Regards,