Tool parameters can either be required or optional. Optional parameters have "(optional)" automatically appended to their label, as illustrated below. You cannot change this text, but you can change an optional parameter to a required parameter.
To change the parameter type
- In the Catalog window or ArcToolbox window, right-click the model tool and click Properties. Or do one of the following:
- In the ModelBuilder menu, click Model > Model Properties.
- Right-click anywhere on the model diagram and click Model Properties.
- Click the Parameters tab.
- Select the parameter and click in the Type cell for that parameter.
- Choose Required or Optional from the drop-down list and click OK.
