Hello I am wondering if there is ongoing work around the notion of embeddings of the Boost Graph Library. In the CGAL project which deals with geometric data structures we have written specializations of the graph_traits for the polyhedral surface, the halfedge datastructure, 2D triangulations, and arrangements. This allows to run BGL algorithms directly on CGAL data structures. http://www.cgal.org/Pkg/BGL. As these graphs are always embedded, that is as there is a circular order of edges we introduced a HalfedgeGraph concept http://www.cgal.org/Manual/latest/doc_html/cgal_manual/BGL_ref/Concept_Halfe... where one has global functions in order to walk along the border of a face, and go from an outgoing edge via the opposite incoming edge to a neighbor face. Would any of these ideas be interesting for the maintainers of the BGL. best regards, andreas -- Andreas Fabri, PhD Chief Officer, GeometryFactory Editor, The CGAL Project phone: +33.492.954.912 skype: andreas.fabri