diff --git a/network_process/src/process.cpp b/network_process/src/process.cpp
index 22c6845..36fea8c 100644
--- a/network_process/src/process.cpp
+++ b/network_process/src/process.cpp
@@ -106,6 +106,10 @@ ISNP_API void build_implicit_network_by_blobtree(const s_settings&
         {
             arrangement_cells.reserve(shells.size());
             for (uint32_t i = 0; i < shells.size(); ++i) { arrangement_cells.emplace_back(stl_vector_mp<uint32_t>{i}); }
+            shell_to_cell.resize(shells.size());
+            for (uint32_t i = 0; i < arrangement_cells.size(); i++) {
+                for (auto shell : arrangement_cells[i]) shell_to_cell[shell] = i;
+            }
         } else {
             {
                 stl_vector_mp<std::pair<uint32_t, uint32_t>> shell_links{};
@@ -125,10 +129,6 @@ ISNP_API void build_implicit_network_by_blobtree(const s_settings&
                 compute_arrangement_cells(static_cast<uint32_t>(shells.size()), shell_links, arrangement_cells);
             }
         }
-        shell_to_cell.resize(shells.size());
-        for (uint32_t i = 0; i < arrangement_cells.size(); i++) {
-            for (auto shell : arrangement_cells[i]) shell_to_cell[shell] = i;
-        }
         // post process
         {
             dynamic_bitset_mp<> active_cell_label{};