Inter Project Links and Critical Path Analysis

you have several options

option #1

create a new activity code call it current CP for current critical path for the code values add one called CP name current criticla path

go to the data and add that new code as a column.

in the predecessor window right click and select Customize Predecessor window and expand tge General category and select Project ID, critcal and driving and bring them to the right as selected Options.

Expand the durations available options category and select total float.

Filter for only the last activity in the project 

go to the predecessor window

Look for the predecessor activity that has both the driving AND critical boxes checked if that predecessor belongs to this project then at the bottom click on the GoTO. If the predecessor activity that has both driving and critical boxes checked but DOES NOT BELONG to this project then select the predecessor activity that BELONGS to this project and has the LEAST amount to toal float and click on GoTo keep doing this until you get to the data date. You will be left with the critical path ONLY for this project.

IN the first activity up top in the new column that you just added fill in the value of CP then do a fill down for the rest of the activities assigning all of them the CP value

now you can filter for this CP code and get your data 

option #2

go to schedule F9 then options then check ignore realtionships to and from external projects

recaclauate the schedule 

filter for the longest path if that does not work then

create a new activity code call it current CP for current critical path for the code values add one called CP name current criticla path

go to the data and add that new code as a column.

in the predecessor window right click and select Customize Predecessor window and expand tge General category and select Project ID, critcal and driving and bring them to the right as selected Options.

Filter for only the last activity in the project 

go to the predecessor window

Look for the predecessor activity that has both the driving AND critical boxes checked click on GoTo keep doing this until you get to the data date. You will be left with the critical path ONLY for this project.

IN the first activity up top in the new column that you just added fill in the value of CP then do a fill down for the rest of the activities assigning all of them the CP value

now you can filter for this CP code and get your data 

If you want to highlight driving activities to end of job for any given project just setup critical float value equal to such job schedule margin.

Please be reminded Longest Path Theory was developed long ago and breaks under resource leveling and constraints.

P6 -What are critical path activities?

If your database is large but the calculation engine is poor you have large but poor database.

• A well planned portfolio shall provide for reasonable schedule margin for all jobs.
• Initially no project shall be critical, that would be a self defeating strategy.  Still you need to know how close to critical every job is at any time.
• Project Delivery is a contractual milestone to be considered under portfolio resource leveling.
• Not all machine allocations are necessarily spatial resources. 
• Most old CPM software based on theories of the 60's cannot deal with spatial resources.  Many schedulers do not even know about spatial resource models.
• Some machines might be similar and can have different production rates, in such case software shall dynamically adjust activity duration to productivity of assigned machine. Insane if by manual adjustments, in such case automatic Skill scheduling is a better approach.
• Use of spatial resources might be in order at times.
  

  It makes no sense to schedule within same day same machine to Projects A&B in alternate sequence A-B-A-B-A-B-A-B-A-B-A-B as regular renewable resource leveling might.  Better use spatial resource leveling to get control A-A-A-A-A-A-B-B-B-B-B-B. Because a shop might have at any given time hundreds of activities scheduled for a single machine, adjusting the sequence using manual methods can be a nightmare.

• Job Shop scheduling can be a real challenge.

The following image is for a simple portfolio where there are no spatial resources considered.  It illustrates planning with schedule margin. Schedule margin activities are hammock activities that span from current schedule End of Job to Project Delivery milestone.

In Portfolio View better filter for spatial resource if activities are assigned Machine Tools as a Spatial Resource.

• Jobs may be sequenced at a machine to reduce the number of setups on the machine. In such case these activities are assigned a Spatial Resource.
• http://optisol.biz/machine-shop-scheduling/
• http://www.pmknowledgecenter.com/node/104
• Spatial resources are required by a group of activities, rather than a single activity as renewable resources. The spatial resource is occupied from the first moment an activity from the group starts until the finish of all activities from that group. Examples are dry docks in a ship yard or a freezing machine in the Westerscheldetunnel.
• Spatial resources can be modeled as consumable resources. 
• Manual leveling of Spatial Resources by using hard links is not an efficient way of scheduling such resources.

Hi Jon,

If Primavera is the tool you are using I would simply select the specific activity to which your project refers i.e. the last activity in the project you are interested in. Do this by opening the scheduling option (F9) and then opening advanced options, select Calc multiple float paths and then select the specific activity in which you are interested in. Also tick 'ignore relationships to and from other projects' in the general tab and schedule.

This should allow you to see what the CP is on any specific project ending on any specific machine or the sequance through a set of machines ending in a specific job.

In MSP you may have to temporarily decouple th link to externally linked projects to get the view you want.

Jon,

There is a precise answer, but it depends on how (and using what software) you are modeling the interproject relationships.  What software are you using?