Activities' durations are optimised. This button is always activated after you have created a new activity. This optimisation can affect the following situations:

• Forward calculated activities with a fixed earliest end date
• Forward calculated activities with a fixed "to end" relationship
• Backward calculated activities with a fixed latest start
• Backward calculated activities with a fixed "from start" relationship"

As optimisation is not possible for the groups in a project, this button has been deactivated in this area.

An example

To make this a little more clearer, let's work through an example. An activity starts as soon as possible and also ends as soon as possible. However, the end date cannot lie before the 20.10.2005. The setting will look like this:

The Gantt chart displays the activity as follows:

If you now deactivate the button "Optimize Duration" the Gantt chart will display your activity as follow:

Why is this so?

When the start date of an activity within a group (or also without groups in a project) is set to as soon as possible, per definition this begins with the start date of the group that displays a logical margin for an activity. As it is determined within the optimisation in Merlin that the activity at its end is fixed with a date, the work or duration is therefore calculated from this date.