About External Reference Control
Creo Parametric provides reference control tools for specifying system behavior when you create external references among features in a design. You can specify the external reference control settings in the Assembly tab in the Creo Parametric Options dialog box. The Creo Parametric Options dialog box opens when you click File > Options.
You can:
Specify global scope settings that apply to all components in the current session except objects that have an object-specific scope setting and objects that have a less restrictive object-specific scope control.
Specify object-specific scope settings for external references.
You can specify the external reference control settings in the active model using the External Reference Control dialog box that opens when you click change in the Reference Control line in the Model Properties dialog box. The Model Properties dialog box opens when you click File > Prepare > Model Properties.