Defines a new project scenario. By default, the project has only one scenario called plan. To do plan vs. actual comparisons or to do a what-if-analysis, you can define a set of scenarios. There can only be one top-level scenario. Additional scenarios are either derived from this top-level scenario or other scenarios.

Each nested scenario is a variation of the enclosing scenario. All scenarios share the same set of properties (task, resources, etc.) but the attributes that are listed as scenario specific may differ between the various scenarios. A nested scenario uses all attributes from the enclosing scenario unless the user has specified a different value for this attribute.

By default, the scheduler assigns resources to tasks beginning with the project start date. If the scenario is switched to projection mode, no assignments will be made prior to the current date or the date specified by now. In this case, TaskJuggler assumes, that all assignments prior to the current date have been provided by booking.task statements.