fix crash

contrib/HighOrderMeshOptimizer/OptHomFastCurving.cpp

@@ -969,7 +969,7 @@ void curveMeshFromBndElt(MEdgeVecMEltMap &ed2el, MFaceVecMEltMap &face2el,
     foundCol = getColumn3D(face2el, p, baseFace, baseVert, topPrimVert,
                            blob, aboveElt);
   }
-  if (!foundCol) return;                                                        // Skip bnd. el. if top vertices not found
+  if (!foundCol || blob.empty()) return; // Skip bnd. el. if top vertices not found
   DbgOutputCol dbgOutCol;
   dbgOutCol.addBlob(blob);
   dbgOutCol.write("col_KO", bndElt->getNum());