Hi, My code is very simple so I suspect I missing something about the real 'examine_vertex' meaning. One example with the custom visitor and one without that produces the correct results out site the 'search' (I;d like to be able to do it with a visitor though for later steps) Simplified to just the essentials. #### With VISITOR #### IndexMap indexMap = boost::get(boost::vertex_index, m_ugraph); PredecessorMap predecessorMap(&predecessors[0], indexMap); DistanceMap distanceMap(&distances[0], indexMap); glm::dvec3 s_mid = m_ugraph[*vertex_iterator_begin].m_mid_point; double thres = 500.0f; dijkstra_threshold vis(s_mid,thres); try { boost::dijkstra_shortest_paths(m_ugraph, *vertex_iterator_begin, boost::predecessor_map(predecessorMap).distance_map(distanceMap).visitor(vis)); } catch (...) { } int total_node_count2 = 0; double total_depth2 = 0.0; for (boost::tie(vi, vi_end) = boost::vertices(m_ugraph); vi != vi_end; ++vi) { if( (double(distances[*vi])*1.1) >= std::numeric_limits<double>::max() || (std::isnan(distances[*vi])) || !(std::isfinite(distances[*vi])) ) { } else { total_depth2 += double(distances[*vi]); total_node_count2 += 1; } } #### To the total distances and the number of nodes within the radius is not correct… #### Without a visitor outside dijkstra_shortest_paths #### try { boost::dijkstra_shortest_paths(m_ugraph, *vertex_iterator_begin, boost::predecessor_map(predecessorMap).distance_map(distanceMap)); } catch (...) { } int total_node_count2 = 0; double total_depth2 = 0.0; for (boost::tie(vi, vi_end) = boost::vertices(m_ugraph); vi != vi_end; ++vi) { if( (double(distances[*vi])*1.1) >= std::numeric_limits<double>::max() || (std::isnan(distances[*vi])) || !(std::isfinite(distances[*vi])) ) { } else { if( thres > 0.0f && glm::distance(s_mid, m_ugraph[*vi].m_mid_point) < thres ) { total_depth2 += double(distances[*vi]); total_node_count2 += 1; } } ### This give you the correct results but you searched the full graph. Any ideas? Thanks