ISO 13584-101:2003 specifies a particular representation category, called basic_geometry. This representation category captures the generic concept of the shape of a part. It may be associated with any of the items defined in a parts library.

ISO 13584-101:2003 also defines how representations that belong to this representation category may be exchanged within a library exchange context by means of FORTRAN programs compliant with ISO 13584-31:1999, or, by case of separate agreement between the sender and the receiver, by means of any other parametric formats.