With the SF relationship, when you update the duration to 4 days it keeps the Opening Day on the Friday and rather moves the Prepare for Store Opening task start date earlier as it adds to the duration. The same scenario, you set the tasks up using a SF dependency and then realise that you need 4 days instead of 2 days to prepare. If you realise that you need 4 days to prepare and change the task Prepare for Store Opening duration to 4 days it will push the Opening day task into the following week which you cannot have happen. Prepare for Store Opening runs over Wednesday and Thursday and is linked (FS) to Opening Day which is on the Friday. The task Opening Day cannot move and must happen on the Friday. Opening day is planned for a Friday and you need 2 days to prepare. You have two tasks, Prepare for Store Opening and Opening Day. To explain the use of a start to finish (SF) dependency I will also explain how it differs from a FS dependency The output of package one and the input of package two must occur together.Ĭonsider this simple example which you can test in Microsoft Project to see how it works practically. Task 1, although it has completed it target action on time and is ready to transfer, will remain "active" until the next package starts. However, the next work package, task 2, which contains the receiving resources-both equipment and personnel-are not there and are not ready to start. It successfully hoists the object up to the 35th floor and has successfully positioned itself for transfer. The work package that contains the resources-human and equipment-to operate the crane is task 1. The assumed logic here is a must versus a can.Ī rough example might be the use of a crane to hoist a heavy object onto the 35th floor of a building under construction. In a SF dependency with a two day lead, task 2 must start two days before task 1 finishes else, task 1 cannot finish. The assumed logic with this schedule is task 2 can start within two days of task 1 finish, but it can start earlier if resources allow and can start later if you are slipping for other reasons.
For example, the FS dependency with a two day lead is saying that task 2 is scheduled to start two days before task 1 is scheduled to finish. The difference comes down to the logic of the constraint. A SF dependency will look exactly like a FS dependency with a lead in units of time if you are looking at the network diagram (notwithstanding the arrows).