This procedure assumes you have already drawn a Direction Modifier and the Edit Direction Modifier <name> dialog box is displayed.

To set Direction Modifier parameters:

1. Enter a name for the Direction Modifier in the Name box (or leave it as it is if you are happy with the existing name).
2. In the Action portion of the dialog, select one, two or all of the following options, depending on how the Direction Modifier should affect Entities:
   • Change Entity Type to – select an Entity or Supply Type from the adjacent drop-down list.
   • Change target – the Direction Modifier must be linked to other targets for this to work. If chosen, select one of:
     • Specify Links – links must be specified on the Links tab.
     • Revert to final destination – Entities will continue to their Final Destination.
   • Change final destination – Final Destinations must be added to the Direction Modifier for this to work.
3. In the Scope portion of the dialog, enter a percentage value between 0 and 100 in the box labelled Percentage of entities to affect.
   • For Direction Modifiers associated with Availability Profiles, percentages apply to the numbers of Entities within them.
   • For Direction Modifiers associated with Event Profiles, percentages apply to the numbers of Entities specified by their Event Profiles every time-step, regardless of the number of Entities in the Direction Modifiers.
4. For Legion 2023 and subsequent updates, each Direction Modifier can affect entities inside Mesoscopic Transition Zones (MTZs) that overlap it. Controls to manage this are only enabled if a Direction Modifier overlaps and MTZs.
   • In the Scope portion of the dialog, select an option from the Mesoscopic? drop-list.

     Option	Meaning
     No, only Microscopic entities	Mesoscopic entities in overlapping MTZs are ignored. This is the default when no MTZs are overlapped.
     Yes, only Mesoscopic entities	Only Mesoscopic entities in overlapping MTZs are affected. Regular entities are ignored. This is the default when MTZs are overlapped.
     Yes, Microscopic and Mesoscopic entities	All entities inside and outside overlapping MTZs are affected.

   • Note: Only new Direction Modifiers automatically affect mesoscopic entities. Existing models will not affect mesoscopic entities unless you specifically activate this in each Direction Modifier. This is so the behaviour of legacy models does not change.
     Note: To be modified, mesoscopic Entities must still match a Direction Modifiers Filter.
   • If a Yes option is chosen, the Manage MTZs… button is enabled.
   • This button opens a selection dialog, for choosing which overlapping MTZs can be affected, and which will be excluded.
     
   • By default, all overlapping MTZs are in the Affect these MTZ list; move any unrequired MTZs into the Exclude these MTZ list.
     Tip: Geometric modifications (vertex manipulation, move, scale, rotate, trim, mirror, array, copy/paste) to Direction Modifiers and MTZs can change object overlap. Direction Modifiers automatically adjust their MTZ behaviour as overlap changes.
5. Select an Availability Profile or Event Profile from the drop-down list labelled Profile.
6. To have this Direction Modifier to ignore entities already affected by this or other Direction Modifiers:
   • Go to the Advanced tab.
   • Tick the box labelled Ignore Entities already affected by any of these Direction Modifiers.
   • Drag, or use the >, >>, < and << buttons to move Direction Modifiers from the Available list to the Selected list.
7. To apply conditions to the Direction Modifier, check the box labelled use condition to enable the Condition tab. See Conditions in Models and in particular, "To set up a Condition:" in Setting up Conditions for further information.
   • To apply any restrictions to the condition, enter values for the following restrictions (details in Restrictions):
     • Time before action
     • Minimum activity period
     • Maximum activity period
     • Minimum time between actions
8. Click on the Entity Filter tab and complete the Filtering parameters (for further information on filtering, see Specifying Filter Settings).
9. Click on the Links tab and complete the link details (for further information, see Linking Methods).
10. If applicable, click on the Target Rules tab and set up the appropriate rules. See Setting Target Rules for full instructions.
11. If the box labelled Change final destination is ticked, click on the Final Destinations tab and click the Add Destination button, otherwise proceed to step 15.
    • The Select final destinations dialog is displayed.
12. Expand the object trees within the dialog box and select one or more destinations (press and hold the <Ctrl> key while clicking to select more than one).
13. Click OK to add the destination(s).
14. To distribute Entities evenly across your destinations, click Uniform Distribution. To input the distribution manually, click next to each destination name and drag the distribution bar to set the percentage (they must equal 100%).
    
15. Click OK to return to the main Parameters tab.
16. Click Apply or OK to save the parameters.