As part of a job default, you can define a feature type to include a compatible unit or macro unit that will be automatically assigned when you assign the feature to a design. Since an automatically assigned unit is simply a default , it can be deleted or modified later as you work with the design in the Design Workspace. The assigned unit will inherit the life-cycle status of the feature type with which the unit is associated.

Units are associated or "pinned" to feature types using the Attributes page of the Placement Defaults dialogue box.

Attributes page (Placement Defaults dialog box)

Pinning a unit to a feature involves selecting the preferred unit from the list of matching units displayed in the Compatible Unit Matches box. If there is only one matching unit in the database, it is automatically selected and displayed with a check mark that appears dimmed. Changing the values in the Default Values box will result in a different list of matching units.

The list of matching units units displayed in the Compatible Unit Matches box is driven by compatible unit rules that are processed according to pinning logic. For more information, see Working with Compatible Unit Rules.

To prevent conflicts in values for unspecified attributes, only one unit per class code can be selected for each feature type. Associating two or more units in different class codes with the feature type is known as "multi-pinning."

When a unit is pinned, the unit will set the defaults for the feature type (in the current job default) to those that make up the unit rule. If the attribute set of the unit rule contains more attributes than the attribute set of the feature type, the extra attributes and values will be added to feature type as defaults. For example, if the feature definition for a pole specifies a height of 45 feet and no additional attributes, and if the pinned unit is based on a unit rule with attribute values for Material and Class, the feature type will acquire these added attributes and values. Pinning a unit affects only the feature type's defaults and has no effect on the attributes of features that are already included in the design.

Compatible Unit Matches list, Attributes page (Placement Defaults dialog box)