Use the Attribute-from-script connection - Settings window to create a connection between a part's attribute and a script. The part's attribute will be set to the value returned from the connected script.

Attribute-to-script connections set the value of an attribute based on the value returned by the connected method. The method runs once when an instance of the part is created and again whenever any of the values it depends on change.

Attribute-to-script connections provide a way of adding a level of processing to an attribute value. Instead of taking its value directly from another attribute, as with an attribute-to-attribute connection, an attribute-to-script can take the value of an attribute and perform calculations on it.

If any values change that the attribute-to-script depends on, the connection is evaluated again and the result is assigned to the connected attribute.