only use the 1-ring to approximate the patch if it's big enough

src/curvature.cpp

@@ -35,6 +35,8 @@ void Courbures::get_two_neighborhood(std::vector<MyMesh::VertexHandle> &out,
         flag_prop[vv] = true;
     }
 
+	if (out.size() >= 5) return;
+
     // Parcours du 1-anneau de chaque sommet du 1-anneau
 	size_t old_size = out.size();
     for (size_t i = 0; i < old_size; i++) {