In the parametric feature based design paradigm, most features possess arguments that are subsets of the boundary of the current model, subsets defined interactively by user selection of boundary entities. Any system for feature-based data exchange (FBDE) must support the exchange of such selections. In this paper we describe in detail an algorithm for supporting one-dimensional selections (sets of edges and curves) for FBDE. The algorithm is applicable to a wide class of FBDE architectures, including the Universal Product Representation (UPR) and the STEP parametrics specification.