Brief about Constraints: 1. Constraints include limitations and prescriptions for when events must or must not yet occur that affect the logic of a schedule model. Constraints may include resource limits or usage profiles. Constraints must be carefully considered and used only when appropriate. The scheduler should remember that application of any constraint will either (a) extend the duration of the project or (b) have no effect on the project duration. Correspondingly, removal of any constraint will (a)shorten the duration of the project or (b) have no effect on the project duration. Importantly, unnecessary or inappropriate constraints included in the network, or failure to include essential constraints, may create or define an artificial critical path and eliminate the true critical path. 2. Project calendars are formulated to reflect specific events, long-running conditions, or circumstances associated with a project. A project calendar is assigned individually or globally to each activity, so that the duration of the activity may be allocated based on the characteristics of the calendar. 3. Activity, calendar and resource constraints will create discontinuous float paths. The path with the least Total Float value is called the critical or longest path. When analyzing near-critical paths it is important to review how the constraints interact with schedule calculations to give false impressions of criticality.