A reference is created when one element of a CAD design makes use of another element of a design as part of its definition. When all references exist inside a single CAD model, the references are considered internal. When one model makes use of design or construction elements of a second model, this reference is considered to be external.

When an external reference is created and managed by Windchill, it is represented by a reference link in Windchill.

Windchill is capable of locating all drawings referenced by a drawing model and automatically relating them to the part of the model. In some cases, you can distinguish manufacturing drawings versus conceptual drawings by using a link in the database, rather than using the calculated relationship. The preference Create Content Links for Drawings controls whether the auto associate action creates a link in the database. The default value is no.

The Windchill Workgroup Manager for CATIA V5 provides enhanced link support. This support allows for a broader range of dependency link detection as well as unknown link types retaining their dependency when a structure is checked into Windchill.

If Windchill Workgroup Manager for CATIA V5 cannot determine a link type for a particular document during checkin, any document referenced by an unclassified link is prevented from being removed because the CATIA API cannot guarantee that the success of the rename.

Any alternate shape representations associated to an object are stored in Windchill as secondary content.