About Tasks

Rules for WBS Task Fields

The WBS for a project template does not contain % complete or start and finish fields so these rules generally do not apply. The duration for tasks does roll up to the parent task and project template level.

Because the values roll up to the parent task, it's generally best to edit the values for the lowest-level sub-tasks and then let the system calculate the parent task's values.

Results of promoting and demoting a WBS task:

• If a subtask is promoted to Review and all its sibling subtasks are in at least Review, then the parent task is promoted to Review.
• When a task is demoted to a state and its parent is at a higher state, the system demotes the parent to the task's state. For example, if a top level task is demoted from Review to Active, the project is also demoted to Active.
• When a task is promoted from Create to Assign, all its subtasks are also promoted to Assign.
• When a subtask is promoted to Active, the parent task is promoted to Active if it not already Active.

Restrictions on promoting and demoting a WBS task and project:

• A task cannot be demoted from Active to Assign when one of its subtasks is in Active or beyond.
• A project cannot be demoted to Assign when it has tasks that are Active or beyond.
• A task cannot be promoted to Review unless all of its child subtasks, including optional and mandatory subtasks, are promoted to at least Review.
• A project cannot be promoted to Review unless all of its tasks are to at least Review.
• A task cannot be promoted to Complete unless all of its child subtasks, including optional and mandatory subtasks, are promoted to Complete.

A project cannot be promoted to Complete unless all of its tasks are to Complete.

About Percentage Complete Calculations

The system calculates the % Complete for a project using the following formula:

Sum of (% Complete * Duration) for all subtasks divided by the sum of 
subtask days

The system then rounds that value down to the nearest value available for % Complete: 10, 20, 25, 30, etc. Similarly, the system calculates the % Complete for a task by averaging the % Complete values for all of its subtasks.A project cannot be promoted to Complete unless all of its tasks are to Complete.

About Percentage Complete Rules

Changing a task to 100% Complete promotes the task to Review. Because a task cannot be promoted to Review unless all of its subtasks are at least at Review, you cannot change a task to 100% unless all of its subtasks are at least in Review (100% Complete).

Similarly, you cannot change a project's % Complete to 100% unless all tasks are at least at the Review state (100% complete).

About Start, Finish, and Duration

When you create a task, you enter the duration for that task. ENOVIA Program Central then calculates the estimated start and finish dates based on dependencies, where in the WBS the task was created, and the project's start or finish date (depending if the project is scheduled from the start or finish of the project).

For all estimated start and finish dates, any defined dependencies and parent task schedules are used to calculate the start/finish dates for tasks. See About Task Dependencies for more details.

The duration, start, and end dates roll up to the parent task and to the project level. For example, the duration for a parent task is the duration of the longest subtask, assuming there are no dependencies and all subtasks occur in parallel. If there are dependencies, the system takes them into account when calculating the duration. The end date for the parent task is the end date for the subtask having the farthest end date and the start date for the parent task is the start date for the subtask with the earliest start date.

When changing dates for tasks, Program Central recalculates that task and subsequent tasks to calculate a new project finish date when scheduling from the project start date. When scheduling from the project finish date, Program Central recalculates the task and all prior tasks to calculate a new project estimated start date. Note that the duration stays the same when either the start or end dates are changed. In order to change the task duration, the user must change the duration manually and then reset target, correction, and closure dates.

A user can also manually enter the actual start date and end date for a task while in edit mode. If the project preference is set for the schedule to be based on actual dates, the project schedule will be recalculated each time an actual date is entered. See Setting Project Preferences.

Following are some points about manually entering a start or end date:

• When the actual start date is entered manually for a task in the Create or Assign state, the task will be promoted to Active state.
• When the actual start date is entered manually for a task in the Active, Review or Complete state, the Actual Start Date will be replaced by newly entered date.
• When an actual end date is entered, the system promotes the task to Complete. If the task is manually promoted to Complete, the system automatically enters the current date as the Actual End Date.

Scheduling Based on Project Start Date

When a project's schedule is based on a start date, Program Central does not have a fixed project end date and will push out that date if an added task, based on dependencies and the critical path, require it.

The start date for a task is based on prior tasks and dependencies. If a task is added and a dependency on the prior task is defined, Program Central uses the estimated finish date of the first task as the estimated start date for the added task.

When working with task dates, these rules apply:

• Once any of the WBS reach the Active state, Project Leads can no longer change the estimated start date for the project. Before any tasks are Active, the project start date can be changed. When it is changed, tasks that have the same start date as the project are changed to match the new project start date.
• The system skips weekend days, so if you add a task with a duration of 2 days and set its start date for a Friday, the system automatically sets the finish date for Monday.
• The duration and estimated end dates are linked so if you change the duration, the system changes the end date so it is that number of days beyond the start date. Conversely, if you change the end date, the system changes the duration accordingly.
• The duration, start, and end dates roll up to the parent task and to the project level. For example, the duration for a parent task is the duration of the longest subtask, assuming there are no dependencies and all subtasks occur in parallel. If there are dependencies, the system takes them into account when calculating the duration. The end date for the parent task is the end date for the subtask with the farthest out end date and the start date for the parent task is the start date for the subtask with the earliest.
• You can only change the estimated start date for tasks that are in the Assign state. Tasks that are Active have already been started.
• When changing the estimated start date for a task in the Assign state, you cannot change to a date that is earlier than the parent task's estimated start date. The only exception is if the parent task is also still in the Assign state, then the subtask's start date can be changed to an earlier date. Then the system changes the parent task's start date to that earlier date.

Scheduling Based on Project Finish Date

When a project's schedule is based on a finish date, Program Central uses an "as late as possible" method to determine task start dates. For example, if a project is defined to schedule from a project finish date of 6/20/2008, and you create a task at the end of the project with a task duration of 3 days, then the estimated start date for the task is 6/17/2008.

If a task is inserted as a sibling at the project level somewhere in the middle of the WBS, Program Central works back from the finish date, keeping task dependencies in mind, to recalculate the estimated start and finish dates for all tasks.

If a task is inserted as a child of another task, Program Central uses the finish date for the parent task as the estimated finish date for the inserted task, and uses the task's duration to calculate the estimated start date.

If a task is added and a dependency on the prior task is defined, Program Central uses the estimated finish date of the added task (and its duration) to re-calculate the task start/finish dates all the way back to the project estimated start date.

If you change the finish date for the project, Program Central re-calculates the finish dates for all tasks except tasks that have already started (are in the Create state). When scheduling from the project finish date, you can change the project estimated end date if the project is in the Create state. In the Active state, the estimated end date can only be postponed.

When working with task dates, these rules apply:

• Once any of the WBS reach the Active state, Project Leads can no longer change the estimated finish date for the project. Before any tasks are Active, the project finish date can be changed. When it is changed, tasks that have the same finish date as the project are changed to match the new project finish date.
• The system skips weekend days, so if you add a task with a duration of 2 days and set its finish date for a Monday, the system automatically sets the start date for Friday.
• The duration and estimated starts dates are linked so if you change the duration, the system changes the start date so it is that number of days prior to the finish date. Conversely, if you change the start date, the system changes the duration accordingly.
• You can only change the estimated start date for tasks that are in the Assign state. Tasks that are Active have already been started.
• When changing the estimated start date for a task in the Assign state, you cannot change to a date that is earlier than the parent task's estimated start date. The only exception is if the parent task is also still in the Assign state, then the subtask's start date can be changed to an earlier date. Then the system changes the parent task's start date to that earlier date.
• You cannot change the project finish date to a date earlier than the finish date of any tasks in the project. You should task with the latest finish date (and any other affected tasks) to an earlier date, then you can edit the project finish date.

About Task Constraints

Users defining a task within the WBS structure have the option to set the task constraint type to one of the following:

Even though constraint types and dates may be defined on a task, the task scheduling is still based on dependencies unless the dependencies cause the task start or finish date to conflict with its constraint at which the task constraint type will override the dependencies.

The default constraint type for a task is based on the project setting "schedule from start" or "schedule from finish". If the project is set as schedule from the start, the default constraint for a task is "As Soon As Possible". Otherwise, the default constraint for a task is "As Late As Possible". A user is able to override the default setting.

The constraint type has an effect on the task estimated start and finish date. The following use cases describe the task start and finish dates depending on how the task constraint is configured. Based on the overall project dates of 9/28/09 to 11/3/09, the use cases describe the start and finish date of each task based on the constraint type.