patch from W. Merks-Swolfs

Mesh/meshGFace.cpp

@@ -1813,11 +1813,27 @@ static bool buildConsecutiveListOfVertices(GFace *gf, GEdgeLoop &gel,
     for(unsigned int i = 0; i < edgeLoop.size(); i++){
       MVertex *here = edgeLoop[i];
       GEntity *ge = here->onWhat();
+
+      BDS_Point *pp = nullptr;
+      if (ge->dim() == 0){
+        // Point might already be part of other loop
+        for (std::map<BDS_Point*, MVertex*, PointLessThan>::iterator it = recoverMap.begin();
+          it != recoverMap.end(); ++it){
+          if (it->second == here)
+          {
+            pp = it->first;
+            break;
+          }
+        }
+      }
+
+      if (pp == nullptr)
+      {
         double U, V;
         SPoint2 param = coords[i];
         U = param.x() / m->scalingU;
         V = param.y() / m->scalingV;
-      BDS_Point *pp = m->add_point(count + countTot, U, V, gf);
+        pp = m->add_point(count + countTot, U, V, gf);
         if (ge->dim() == 0){
           pp->lcBGM() = BGM_MeshSize(ge, 0, 0, here->x(), here->y(), here->z());
         }
@@ -1838,6 +1854,7 @@ static bool buildConsecutiveListOfVertices(GFace *gf, GEdgeLoop &gel,
           count, pp->u, pp->v, param.x(), param.y(), pp->g->classif_tag,
           pp->g->classif_degree);
         bbox += SPoint3(U, V, 0);
+      }
       edgeLoop_BDS.push_back(pp);
       recoverMapLocal[pp] = here;
       count++;