When first created, a scenario is identical to its parent. To modify or run a scenario, it must first be made the current Workspace scenario by selecting it within the Scenario Manager window, then clicking on the Load As Current Scenario button. (The name of the current scenario is displayed in both the Scenario Manager window and in AFT Arrow’s Status Bar.) Once a scenario is the current scenario, changes may be made to differentiate it from its parent using any of AFT Arrow’s editing tools and functions. When an attribute is changed within a scenario it breaks the link for this attribute. Subsequent changes in the scenario’s ancestors will no longer affect this attribute.

Properties of a scenario that may differ from its ancestors include:

• Presence and location of objects -- one may add or delete pipes and junctions within a scenario and the workspace locations may vary from scenario to scenario

• Pipe and junction Properties -- all values set in the Properties windows

• Fluid Properties -- fluid selected, system data

• Solution Control -- solution method, tolerances, relaxation

• Output Control -- Output window content and formatting

• Cost Settings -- application of cost data

• Goal Seek & Control (GSC Module Only) -- Application of variables and goals can change between scenarios. The actual variables and goals are the same in all scenarios.

• Libraries Manager -- The connected library content can be varied between scenarios

• Visual Report Control -- Visual Report content and color maps

• Model Data Control and User Options applies to all scenarios.

• Sizing Settings (ANS Module Only) - All input in the Sizing window. Candidate Sets and Design Requirements are the same in all scenarios, but they may be applied differently.