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Every task has its schedule type which is one of the following:
Fixed Work - Set the task to Fixed Work when you want the amount of work to remain constant, regardless of any change in duration or resource units.
Example: Two welders are assigned full-time (100%) to build a gate in 2 days. Work/Effort is 32 hours. If you now increase the duration of the task from 2 days to 4 days, Celoxis will reduce each welder's assignment to 50%, keeping work constant.
Fixed Duration - When you choose to make a task Fixed Duration, the task's duration remains at whatever value you enter regardless of any change in work or resource units.
Example: One welder is assigned full-time (100%) to build a gate in 2 days. Duration of this task is fixed. Thus work is 16 hours. If you now reduce this welder's assignment to 50% due to another commitment, Celoxis will reduce work to 8 hours, keeping duration constant.
Fixed Units - When you choose to make a task Fixed Units, whatever resource units you allocate, that value will remain fixed and the other two elements of the scheduling formula will be affected by changes.
Example: One welder is assigned full-time (100%) to build a gate in 2 days. Units of this task is fixed. Thus work is 16 hours. Now if you increase duration to 4 days, Celoxis will increase work to 32 hours, keeping units the same. By specifying one of these, you can control which of the scheduling formula parameter (See: Automatic Scheduling) has the most influence over the task's scheduling.
Dependencies
Dependency between tasks establishes a relation between the two such that the start or finish of one task, determines the start or finish of another (dependent) task. Once you enter dependencies between the tasks, Celoxis automatically calculates the start and finish dates for all dependent tasks. Learn more about setting dependencies here.
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If a project's start date is in the past, adding a new task today will set its start date to today with a 'SNET' constraint. If a project's start date is today or in future, adding a new task today will set its start date to the project's start with an 'ASAP' constraint. Changing Project dates, will shift all tasks with 'ASAP' or 'ALAP' constraints as appropriate.