diff --git a/src/libslic3r/CMakeLists.txt b/src/libslic3r/CMakeLists.txt
index 591639685..389a67a9a 100644
--- a/src/libslic3r/CMakeLists.txt
+++ b/src/libslic3r/CMakeLists.txt
@@ -428,6 +428,8 @@ set(lisbslic3r_sources
     ClipperZUtils.hpp
     FlushVolPredictor.hpp
     FlushVolPredictor.cpp
+    FilamentGroup.hpp
+    FilamentGroup.cpp
 )
 
 if (APPLE)
diff --git a/src/libslic3r/FilamentGroup.cpp b/src/libslic3r/FilamentGroup.cpp
new file mode 100644
index 000000000..2a2e6cc0d
--- /dev/null
+++ b/src/libslic3r/FilamentGroup.cpp
@@ -0,0 +1,279 @@
+#include "FilamentGroup.hpp"
+#include "GCode/ToolOrdering.hpp"
+
+namespace Slic3r
+{
+    int FilamentGroup::calc_filament_group(const std::vector<std::vector<unsigned int>>& layer_filaments)
+    {
+        std::set<unsigned int>used_filaments;
+        for (const auto& lf : layer_filaments)
+            for (const auto& extruder : lf)
+                used_filaments.insert(extruder);
+
+        m_filament_labels.resize(used_filaments.size());
+        m_used_filaments = std::vector<unsigned int>(used_filaments.begin(), used_filaments.end());
+        std::sort(m_used_filaments.begin(), m_used_filaments.end());
+
+        if (m_filament_num <= 1)
+            return 0;
+        if (m_filament_num < 10)
+            return calc_filament_group_by_enum(layer_filaments);
+        else
+            return calc_filament_group_by_pam(layer_filaments,300);
+
+    }
+
+    int FilamentGroup::calc_filament_group_by_enum(const std::vector<std::vector<unsigned int>>& layer_filaments)
+    {
+        auto bit_count_one = [](int n)
+        {
+            int count = 0;
+            while (n != 0)
+            {
+                n &= n - 1;
+                count++;
+            }
+            return count;
+        };
+
+        uint64_t max_group_num = (1 << m_filament_num);
+        int best_cost = std::numeric_limits<int>::max();
+        std::vector<int>best_label;
+
+        for (uint64_t i = 0; i < max_group_num; ++i) {
+            int num_to_group_1 = bit_count_one(i);
+            if (num_to_group_1 > m_max_group_size[1] || (m_filament_num - num_to_group_1) > m_max_group_size[0])
+                continue;
+            std::set<int>group_0, group_1;
+            for (int j = 0; j < m_filament_num; ++j) {
+                if (i & (1 << j))
+                    group_1.insert(m_used_filaments[j]);
+                else
+                    group_0.insert(m_used_filaments[j]);
+            }
+
+            if (group_0.size() < m_max_group_size[0] && group_1.size() < m_max_group_size[1]){
+
+                std::vector<int>filament_maps(m_filament_num);
+                for (int i = 0; i < m_filament_num; ++i) {
+                    if (group_0.find(m_used_filaments[i]) != group_0.end())
+                        filament_maps[i] = 0;
+                    if (group_1.find(m_used_filaments[i]) != group_1.end())
+                        filament_maps[i] = 1;
+                }
+
+                int total_cost = reorder_filaments_for_minimum_flush_volume(
+                    m_used_filaments,
+                    filament_maps,
+                    layer_filaments,
+                    m_flush_matrix,
+                    get_custom_seq,
+                    nullptr
+                );
+
+                if (total_cost < best_cost) {
+                    best_cost = total_cost;
+                    best_label = filament_maps;
+                }
+            }
+        }
+
+        m_filament_labels = best_label;
+
+        return best_cost;
+    }
+
+    int FilamentGroup::calc_filament_group_by_pam(const std::vector<std::vector<unsigned int>>& layer_filaments, int timeout_ms)
+    {
+        //calc pair counts
+        std::vector<std::vector<int>>count_matrix(m_filament_num,std::vector<int>(m_filament_num));
+        for (const auto& lf : layer_filaments) {
+            for (auto iter = lf.begin(); iter != lf.end(); ++iter) {
+                auto idx1 = std::find(m_used_filaments.begin(), m_used_filaments.end(), *iter)-m_used_filaments.begin();
+                for (auto niter = std::next(iter); niter != lf.end(); ++niter) {
+                    auto idx2 = std::find(m_used_filaments.begin(), m_used_filaments.end(), *niter) - m_used_filaments.begin();
+                    count_matrix[idx1][idx2] += 1;
+                    count_matrix[idx2][idx1] += 1;
+                }
+            }
+        }
+
+        //calc distance matrix
+        std::vector<std::vector<float>>distance_matrix(m_filament_num, std::vector<float>(m_filament_num));
+        for (size_t i = 0; i < m_used_filaments.size(); ++i) {
+            for (size_t j = 0; j < m_used_filaments.size(); ++j) {
+                if (i == j)
+                    distance_matrix[i][j] = 0;
+                else {
+                    //TODO: check m_flush_matrix
+                    float max_val = std::max(m_flush_matrix[0][m_used_filaments[i]][m_used_filaments[j]], m_flush_matrix[0][m_used_filaments[j]][m_used_filaments[i]]);
+                    float min_val = std::min(m_flush_matrix[0][m_used_filaments[i]][m_used_filaments[j]], m_flush_matrix[0][m_used_filaments[j]][m_used_filaments[i]]);
+
+                    double p = 0;
+                    distance_matrix[i][j] = (max_val * p + min_val * (1 - p)) * count_matrix[i][j];
+                }
+            }
+        }
+
+        KMediods PAM(distance_matrix, m_filament_num,m_max_group_size);
+        PAM.fit(timeout_ms);
+        this->m_filament_labels = PAM.get_filament_labels();
+
+        int cost = reorder_filaments_for_minimum_flush_volume(
+            m_used_filaments,
+            this->m_filament_labels,
+            layer_filaments,
+            m_flush_matrix,
+            get_custom_seq,
+            nullptr
+        );
+
+        return cost;
+    }
+
+
+    void KMediods::fit( int timeout_ms)
+    {
+        std::vector<int>best_medoids;
+        std::vector<int>best_labels;
+        int best_cost = std::numeric_limits<int>::max();
+
+        FlushTimeMachine T;
+        T.time_machine_start();
+
+        int count = 0;
+        while (true)
+        {
+            std::vector<int>medoids;
+            std::vector<int>labels;
+            if (count == 0)
+                medoids = initialize(INIT_TYPE::Farthest);
+            else
+                medoids = initialize(INIT_TYPE::Random);
+
+            labels = assign_label(medoids);
+            int cost = calc_cost(labels, medoids);
+
+            for (int i = 0; i < m_filament_num; ++i) {
+                if (std::find(medoids.begin(), medoids.end(), i) != medoids.end())
+                    continue;
+
+                for (int j = 0; j < 2; ++j) {
+                    std::vector<int> new_medoids = medoids;
+                    new_medoids[j] = i;
+                    std::vector<int> new_labels = assign_label(new_medoids);
+                    int new_cost = calc_cost(new_labels, new_medoids);
+
+                    if (new_cost < cost)
+                    {
+                        labels = new_labels;
+                        cost = new_cost;
+                        medoids = new_medoids;
+                    }
+                }
+            }
+
+
+            if (cost < best_cost)
+            {
+                best_cost = cost;
+                best_labels = labels;
+                best_medoids = medoids;
+            }
+            count += 1;
+
+            if (T.time_machine_end() > timeout_ms)
+                break;
+        }
+
+        this->m_filament_labels = best_labels;
+    }
+
+    std::vector<int> KMediods::assign_label(const std::vector<int>& medoids) const
+    {
+        std::vector<int>labels(m_filament_num);
+        struct Comp {
+            bool operator()(const std::pair<int, int>& a, const std::pair<int, int>& b) {
+                return a.second > b.second;
+            }
+        };
+        std::priority_queue<std::pair<int, int>, std::vector<std::pair<int, int>>,Comp>min_heap;
+
+        for (int i = 0; i < m_filament_num; ++i) {
+            int distancec_to_0 = m_distance_matrix[i][medoids[0]];
+            int distancec_to_1 = m_distance_matrix[i][medoids[1]];
+            min_heap.push({ i,distancec_to_0 - distancec_to_1 });
+        }
+        std::set<int> group_0, group_1;
+        while (!min_heap.empty()) {
+            auto top = min_heap.top();
+            min_heap.pop();
+            if (group_0.size() < m_max_group_size[0] && (top.second <= 0 || group_1.size() >= m_max_group_size[1]))
+                group_0.insert(top.first);
+            else
+                group_1.insert(top.first);
+
+        }
+        for (auto& item : group_0)
+            labels[item] = 0;
+        for (auto& item : group_1)
+            labels[item] = 1;
+
+        return labels;
+    }
+
+    int KMediods::calc_cost(const std::vector<int>& labels, const std::vector<int>& medoids) const
+    {
+        int total_cost = 0;
+        for (int i = 0; i < m_filament_num; ++i)
+            total_cost += m_distance_matrix[i][medoids[labels[i]]];
+        return total_cost;
+    }
+
+    std::vector<int> KMediods::initialize(INIT_TYPE type) const
+    {
+        auto hash_func = [](int n1, int n2) {
+            return n1 * 100 + n2;
+        };
+        srand(time(nullptr));
+        std::vector<int>ret;
+        if (type == INIT_TYPE::Farthest) {
+            //get the farthest items
+            int target_i=0,target_j=0,target_val=std::numeric_limits<int>::min();
+            for(int i=0;i<m_distance_matrix.size();++i){
+                for(int j=0;j<m_distance_matrix[0].size();++j){
+                    if(i!=j &&m_distance_matrix[i][j]>target_val){
+                        target_val=m_distance_matrix[i][j];
+                        target_i=i;
+                        target_j=j;
+                    }
+                }
+            }
+            ret.emplace_back(std::min(target_i, target_j));
+            ret.emplace_back(std::max(target_i, target_j));
+        }
+        else if (type == INIT_TYPE::Random) {
+            while (true) {
+                std::vector<int>medoids;
+                while (medoids.size() < 2)
+                {
+                    int candidate = rand() % m_filament_num;
+                    if (std::find(medoids.begin(), medoids.end(), candidate) == medoids.end())
+                        medoids.push_back(candidate);
+                }
+                std::sort(medoids.begin(), medoids.end());
+
+                if (m_medoids_set.find(hash_func(medoids[0], medoids[1])) != m_medoids_set.end() && m_medoids_set.size() != (m_filament_num * (m_filament_num - 1) / 2))
+                    continue;
+                else {
+                    ret = medoids;
+                    break;
+                }
+            }
+        }
+        m_medoids_set.insert(hash_func(ret[0],ret[1]));
+        return ret;
+    }
+}
+
+
diff --git a/src/libslic3r/FilamentGroup.hpp b/src/libslic3r/FilamentGroup.hpp
new file mode 100644
index 000000000..3d14094d5
--- /dev/null
+++ b/src/libslic3r/FilamentGroup.hpp
@@ -0,0 +1,90 @@
+#ifndef FILAMENT_GROUP_HPP
+#define FILAMENT_GROUP_HPP
+
+#include<chrono>
+
+namespace Slic3r
+{
+    using FlushMatrix = std::vector<std::vector<float>>;
+
+    struct FlushTimeMachine
+    {
+    private:
+        std::chrono::high_resolution_clock::time_point start;
+
+    public:
+        void time_machine_start()
+        {
+            start = std::chrono::high_resolution_clock::now();
+        }
+
+        int time_machine_end()
+        {
+            auto end = std::chrono::high_resolution_clock::now();
+            auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
+            return duration.count();
+        }
+    };
+
+
+    class FilamentGroup
+    {
+    public:
+        FilamentGroup(const std::vector<FlushMatrix>& flush_matrix, const int filament_num, const std::vector<int>& max_group_size) :
+            m_flush_matrix{ flush_matrix },
+            m_filament_num{ filament_num },
+            m_max_group_size{ max_group_size }
+        {}
+
+        int calc_filament_group(const std::vector<std::vector<unsigned int>>& layer_filaments);
+        int calc_filament_group_by_enum(const std::vector<std::vector<unsigned int>>& layer_filaments);
+        int calc_filament_group_by_pam(const std::vector<std::vector<unsigned int>>& layer_filaments, int timeout_ms = 300);
+
+        std::vector<int> get_filament_map() const {return m_filament_labels;}
+
+    private:
+        std::vector<FlushMatrix>m_flush_matrix;
+        int m_filament_num;
+        std::vector<int>m_max_group_size;
+        std::vector<unsigned int>m_used_filaments;
+    public:
+        std::optional<std::function<bool(int, std::vector<int>&)>> get_custom_seq;
+    private:
+        std::vector<int>m_filament_labels;
+        std::vector<std::vector<unsigned int>>m_filament_orders;
+
+    };
+
+    class KMediods
+    {
+        enum INIT_TYPE
+        {
+            Random = 0,
+            Farthest
+        };
+    public:
+        KMediods(const std::vector<std::vector<float>>& distance_matrix, const int filament_num, const std::vector<int>& max_group_size) :
+            m_distance_matrix{ distance_matrix },
+            m_filament_num{ filament_num },
+            m_max_group_size{ max_group_size } {}
+
+        void fit(int timeout_ms = 300);
+        std::vector<int>get_filament_labels()const {
+            return m_filament_labels;
+        }
+
+    private:
+        std::vector<int>initialize(INIT_TYPE type)const;
+        std::vector<int>assign_label(const std::vector<int>& medoids)const;
+        int calc_cost(const std::vector<int>& labels, const std::vector<int>& medoids)const;
+    private:
+        std::vector<std::vector<float>>m_distance_matrix;
+        int m_filament_num;
+        std::vector<int>m_max_group_size;
+        std::vector<int>m_used_filaments;
+        mutable std::set<int>m_medoids_set;
+    private:
+        std::vector<int>m_filament_labels;
+    };
+}
+#endif // !FILAMENT_GROUP_HPP
diff --git a/src/libslic3r/GCode/ToolOrdering.cpp b/src/libslic3r/GCode/ToolOrdering.cpp
index ea8885491..6beaabe85 100644
--- a/src/libslic3r/GCode/ToolOrdering.cpp
+++ b/src/libslic3r/GCode/ToolOrdering.cpp
@@ -3,7 +3,6 @@
 #include "Layer.hpp"
 #include "ClipperUtils.hpp"
 #include "ParameterUtils.hpp"
-
 // #define SLIC3R_DEBUG
 
 // Make assert active if SLIC3R_DEBUG
@@ -94,7 +93,7 @@ static std::vector<unsigned int> solve_extruder_order(const std::vector<std::vec
 
 std::vector<unsigned int> get_extruders_order(const std::vector<std::vector<float>> &wipe_volumes, std::vector<unsigned int> all_extruders, std::optional<unsigned int>start_extruder_id, float* cost = nullptr)
 {
-    if (all_extruders.size() == 1) {
+    if (all_extruders.size() <= 1) {
         if (cost)
             *cost = 0;
         return all_extruders;
@@ -104,7 +103,7 @@ std::vector<unsigned int> get_extruders_order(const std::vector<std::vector<floa
 #ifdef USE_DP_OPTIMIZE
     return solve_extruder_order(wipe_volumes, all_extruders, start_extruder_id, cost);
 #else
-if (all_extruders.size() > 1) {
+    if (all_extruders.size() > 1) {
         int begin_index = 0;
         auto iter = std::find(all_extruders.begin(), all_extruders.end(), start_extruder_id);
         if (iter != all_extruders.end()) {
@@ -137,6 +136,75 @@ if (all_extruders.size() > 1) {
 #endif // OPTIMIZE
 }
 
+int reorder_filaments_for_minimum_flush_volume(const std::vector<unsigned int>&filament_lists,
+                                               const std::vector<int>&filament_maps,
+                                               const std::vector<std::vector<unsigned int>>& layer_filaments,
+                                               const std::vector<FlushMatrix>& flush_matrix,
+                                               std::optional<std::function<bool(int,std::vector<int>&)>> get_custom_seq,
+                                               std::vector<std::vector<unsigned int>>* filament_sequences)
+{
+    int cost = 0;
+
+    if (filament_sequences) {
+        filament_sequences->clear();
+        filament_sequences->resize(layer_filaments.size());
+    }
+
+    std::vector<std::set<int>>groups(2);
+    for (int i = 0; i < filament_maps.size(); ++i) {
+        if (filament_maps[i] == 0)
+            groups[0].insert(filament_lists[i]);
+        if (filament_maps[i] == 1)
+            groups[1].insert(filament_lists[i]);
+    }
+
+    for (size_t idx = 0; idx < groups.size();++idx) {
+        std::optional<unsigned int>current_extruder_id;
+        int layer = 0;
+        for (const auto& lf : layer_filaments) {
+
+            std::vector<int>custom_filament_seq;
+            if (get_custom_seq && (*get_custom_seq)(layer, custom_filament_seq) && !custom_filament_seq.empty()) {
+                std::vector<unsigned int> unsign_custom_extruder_seq;
+                for (int extruder : custom_filament_seq) {
+                    unsigned int unsign_extruder = static_cast<unsigned int>(extruder) - 1;
+                    auto it = std::find(lf.begin(), lf.end(), unsign_extruder);
+                    if (it != lf.end()) {
+                        unsign_custom_extruder_seq.emplace_back(unsign_extruder);
+                    }
+                }
+                assert(lf.size() == unsign_custom_extruder_seq.size());
+                if (filament_sequences)
+                    (*filament_sequences)[layer] = unsign_custom_extruder_seq;
+
+                current_extruder_id = unsign_custom_extruder_seq.back();
+                continue;
+            }
+
+            std::vector<unsigned>filament_used_in_group;
+            for (const auto& filament : lf) {
+                if (groups[idx].find(filament) != groups[idx].end())
+                    filament_used_in_group.emplace_back(filament);
+            }
+            float tmp_cost = 0;
+            auto sequence = get_extruders_order(flush_matrix[idx], filament_used_in_group, current_extruder_id, &tmp_cost);
+
+            assert(sequence.size()==filament_used_in_group.size());
+
+            if (filament_sequences)
+                (*filament_sequences)[layer].insert((*filament_sequences)[layer].end(), sequence.begin(), sequence.end());
+
+            if (!sequence.empty())
+                current_extruder_id = sequence.back();
+            cost += tmp_cost;
+            layer += 1;
+        }
+    }
+
+    return cost;
+}
+
+
 
 // Returns true in case that extruder a comes before b (b does not have to be present). False otherwise.
 bool LayerTools::is_extruder_order(unsigned int a, unsigned int b) const
@@ -869,8 +937,6 @@ std::set<std::pair<std::vector<unsigned int>, std::vector<unsigned int>>> genera
     return unique_combinations;
 }
 
-using FlushMatrix = std::vector<std::vector<float>>;
-
 float get_flush_volume(const std::vector<int> &filament_maps, const std::vector<unsigned int> &extruders, const std::vector<FlushMatrix> &matrix, size_t nozzle_nums)
 {
     std::vector<std::vector<unsigned int>> nozzle_filaments;
@@ -914,14 +980,6 @@ std::vector<int> ToolOrdering::get_recommended_filament_maps()
         nozzle_flush_mtx.emplace_back(wipe_volumes);
     }
 
-    auto extruders_to_hash_key = [](const std::vector<unsigned int> &extruders, std::optional<unsigned int> initial_extruder_id) -> uint32_t {
-        uint32_t hash_key = 0;
-        // high 16 bit define initial extruder ,low 16 bit define extruder set
-        if (initial_extruder_id) hash_key |= (1 << (16 + *initial_extruder_id));
-        for (auto item : extruders) hash_key |= (1 << item);
-        return hash_key;
-    };
-
     std::vector<LayerPrintSequence> other_layers_seqs;
     const ConfigOptionInts *        other_layers_print_sequence_op      = print_config->option<ConfigOptionInts>("other_layers_print_sequence");
     const ConfigOptionInt *         other_layers_print_sequence_nums_op = print_config->option<ConfigOptionInt>("other_layers_print_sequence_nums");
@@ -943,106 +1001,34 @@ std::vector<int> ToolOrdering::get_recommended_filament_maps()
         return false;
     };
 
-    std::set<unsigned int> extruders;
-    for (int i = 0; i < m_layer_tools.size(); ++i) {
-        LayerTools &lt = m_layer_tools[i];
-        for (unsigned int extruder : lt.extruders)
-            extruders.insert(extruder);
-    }
 
-    auto extruder_group = generate_combinations(std::vector<unsigned int>(extruders.begin(), extruders.end()));
 
-    std::vector<int> recommended_filament_maps;
-    float min_flush_volume = std::numeric_limits<float>::max();
-    for (auto iter = extruder_group.begin(); iter != extruder_group.end(); ++iter) {
-        std::vector<int> filament_maps;
-        filament_maps.resize(number_of_extruders);
-        for (unsigned int e : iter->first) {
-            filament_maps[e] = 0;
-        }
-        for (unsigned int e : iter->second) {
-            filament_maps[e] = 1;
-        }
-
-        std::optional<unsigned int>              current_extruder_id;
-        std::vector<std::optional<unsigned int>> nozzle_to_cur_filaments;
-        nozzle_to_cur_filaments.resize(nozzle_nums);
-
-        float flush_volume_cost = 0;
-        for (int i = 0; i < m_layer_tools.size(); ++i) {
-            LayerTools &lt = m_layer_tools[i];
-            if (lt.extruders.empty())
-                continue;
-
-            std::vector<int> custom_extruder_seq;
-            if (get_custom_seq(i, custom_extruder_seq) && !custom_extruder_seq.empty()) {
-                std::vector<unsigned int> unsign_custom_extruder_seq;
-                for (int extruder : custom_extruder_seq) {
-                    unsigned int unsign_extruder = static_cast<unsigned int>(extruder) - 1;
-                    auto         it              = std::find(lt.extruders.begin(), lt.extruders.end(), unsign_extruder);
-                    if (it != lt.extruders.end()) {
-                        unsign_custom_extruder_seq.emplace_back(unsign_extruder);
-                        nozzle_to_cur_filaments[filament_maps[unsign_extruder]] = unsign_extruder;
-                    }
-                }
-                assert(lt.extruders.size() == unsign_custom_extruder_seq.size());
-                lt.extruders        = unsign_custom_extruder_seq;
-                current_extruder_id = lt.extruders.back();
-                flush_volume_cost += get_flush_volume(filament_maps, lt.extruders, nozzle_flush_mtx, nozzle_nums);
-                continue;
-            }
-
-            // The algorithm complexity is O(n2*2^n)
-            if (i != 0) {
-                std::vector<std::vector<unsigned int>> nozzle_filaments;
-                nozzle_filaments.resize(nozzle_nums);
-
-                for (unsigned int filament_id : lt.extruders) {
-                    nozzle_filaments[filament_maps[filament_id]].emplace_back(filament_id);
-                }
-
-                for (size_t nozzle_id = 0; nozzle_id < nozzle_nums; ++nozzle_id) {
-                    auto hash_key = extruders_to_hash_key(nozzle_filaments[nozzle_id], nozzle_to_cur_filaments[nozzle_id]);
-                    auto iter     = m_tool_order_cache.find(hash_key);
-                    // todo : the cache with flush cost
-                    //if (iter == m_tool_order_cache.end()) {
-                        float f_cost = 0;
-                        nozzle_filaments[nozzle_id] = get_extruders_order(nozzle_flush_mtx[nozzle_id], nozzle_filaments[nozzle_id], nozzle_to_cur_filaments[nozzle_id], &f_cost);
-                        std::vector<uint8_t> hash_val;
-                        hash_val.reserve(nozzle_filaments[nozzle_id].size());
-                        for (auto item : nozzle_filaments[nozzle_id])
-                            hash_val.emplace_back(static_cast<uint8_t>(item));
-                        m_tool_order_cache[hash_key] = hash_val;
-                        flush_volume_cost += f_cost;
-                    //} else {
-                    //    std::vector<unsigned int> extruder_order;
-                    //    extruder_order.reserve(iter->second.size());
-                    //    for (auto item : iter->second)
-                    //        extruder_order.emplace_back(static_cast<unsigned int>(item));
-                    //    nozzle_filaments[nozzle_id] = std::move(extruder_order);
-                    //}
-                    nozzle_to_cur_filaments[nozzle_id] = nozzle_filaments[nozzle_id].back();
-                }
-
-                lt.extruders.clear();
-                for (size_t nozzle_id = 0; nozzle_id < nozzle_nums; ++nozzle_id) {
-                    lt.extruders.insert(lt.extruders.end(), nozzle_filaments[nozzle_id].begin(), nozzle_filaments[nozzle_id].end());
-                }
-            }
-            current_extruder_id = lt.extruders.back();
-        }
-
-        if (flush_volume_cost == 0) {
-            recommended_filament_maps = filament_maps;
-            break;
-        }
-
-        if (flush_volume_cost < min_flush_volume) {
-            min_flush_volume = flush_volume_cost;
-            recommended_filament_maps = filament_maps;
+    std::vector<unsigned int>used_filaments;
+    std::vector<std::vector<unsigned int>>layer_filaments;
+    for (auto& lt : m_layer_tools) {
+        layer_filaments.emplace_back(lt.extruders);
+        for (auto& extruder : lt.extruders) {
+            if (std::find(used_filaments.begin(), used_filaments.end(), extruder) == used_filaments.end())
+                used_filaments.emplace_back(extruder);
         }
     }
-    return recommended_filament_maps;
+    std::sort(used_filaments.begin(), used_filaments.end());
+
+    FilamentGroup fg(
+        nozzle_flush_mtx,
+        used_filaments.size(),
+        { 16,16 }
+    );
+    fg.get_custom_seq = get_custom_seq;
+    fg.calc_filament_group(layer_filaments);
+
+    std::vector<int>ret(number_of_extruders);
+    auto filament_map = fg.get_filament_map();
+    for (size_t idx = 0; idx < filament_map.size(); ++idx) {
+        if (filament_map[idx])
+            ret[used_filaments[idx]] = 1;
+    }
+    return ret;
 }
 
 // for print by object
@@ -1192,119 +1178,6 @@ void ToolOrdering::reorder_extruders_for_minimum_flush_volume()
         print_config = &(m_print_object_ptr->print()->config());
     }
 
-    if (!print_config || m_layer_tools.empty())
-        return;
-
-    size_t nozzle_nums = print_config->nozzle_diameter.values.size();
-    if (nozzle_nums > 1 && print_config->option<ConfigOptionEnum<FilamentMapMode>>("filament_map_mode")->value == FilamentMapMode::fmmAuto) {
-        std::vector<int> filament_maps = m_print->get_filament_maps();
-
-        if (print_config->print_sequence != PrintSequence::ByObject) {
-            filament_maps = get_recommended_filament_maps();
-            if (filament_maps.empty()) // multi-extruder and one-color
-                return;
-
-            std::transform(filament_maps.begin(), filament_maps.end(), filament_maps.begin(), [](int value) { return value + 1; });
-            m_print->update_filament_maps_to_config(filament_maps);
-        }
-
-        std::transform(filament_maps.begin(), filament_maps.end(), filament_maps.begin(), [](int value) { return value - 1; });
-        reorder_extruders_for_minimum_flush_volume_multi_extruder(filament_maps);
-        return;
-    }
-
-    // Get wiping matrix to get number of extruders and convert vector<double> to vector<float>:
-    std::vector<float> flush_matrix(cast<float>(print_config->flush_volumes_matrix.values));
-    const unsigned int number_of_extruders = (unsigned int) (sqrt(flush_matrix.size()) + EPSILON);
-    // Extract purging volumes for each extruder pair:
-    std::vector<std::vector<float>> wipe_volumes;
-    for (unsigned int i = 0; i < number_of_extruders; ++i)
-        wipe_volumes.push_back(std::vector<float>(flush_matrix.begin() + i * number_of_extruders, flush_matrix.begin() + (i + 1) * number_of_extruders));
-
-    auto extruders_to_hash_key = [](const std::vector<unsigned int>& extruders, std::optional<unsigned int>initial_extruder_id)->uint32_t {
-        uint32_t hash_key = 0;
-        // high 16 bit define initial extruder ,low 16 bit define extruder set
-        if (initial_extruder_id)
-            hash_key |= (1 << (16 + *initial_extruder_id));
-        for (auto item : extruders)
-            hash_key |= (1 << item);
-        return hash_key;
-    };
-
-    std::vector<LayerPrintSequence> other_layers_seqs;
-    const ConfigOptionInts *other_layers_print_sequence_op = print_config->option<ConfigOptionInts>("other_layers_print_sequence");
-    const ConfigOptionInt *other_layers_print_sequence_nums_op = print_config->option<ConfigOptionInt>("other_layers_print_sequence_nums");
-    if (other_layers_print_sequence_op && other_layers_print_sequence_nums_op) {
-        const std::vector<int> &print_sequence = other_layers_print_sequence_op->values;
-        int sequence_nums = other_layers_print_sequence_nums_op->value;
-        other_layers_seqs = get_other_layers_print_sequence(sequence_nums, print_sequence);
-    }
-
-    // other_layers_seq: the layer_idx and extruder_idx are base on 1
-    auto get_custom_seq = [&other_layers_seqs](int layer_idx, std::vector<int>& out_seq) -> bool {
-        for (size_t idx = other_layers_seqs.size() - 1; idx != size_t(-1); --idx) {
-            const auto &other_layers_seq = other_layers_seqs[idx];
-            if (layer_idx + 1 >= other_layers_seq.first.first && layer_idx + 1 <= other_layers_seq.first.second) {
-                out_seq = other_layers_seq.second;
-                return true;
-            }
-        }
-        return false;
-    };
-
-    std::optional<unsigned int>current_extruder_id;
-    for (int i = 0; i < m_layer_tools.size(); ++i) {
-        LayerTools& lt = m_layer_tools[i];
-        if (lt.extruders.empty())
-            continue;
-
-        std::vector<int> custom_extruder_seq;
-        if (get_custom_seq(i, custom_extruder_seq) && !custom_extruder_seq.empty()) {
-            std::vector<unsigned int> unsign_custom_extruder_seq;
-            for (int extruder : custom_extruder_seq) {
-                unsigned int unsign_extruder = static_cast<unsigned int>(extruder) - 1;
-                auto it = std::find(lt.extruders.begin(), lt.extruders.end(), unsign_extruder);
-                if (it != lt.extruders.end()) {
-                    unsign_custom_extruder_seq.emplace_back(unsign_extruder);
-                }
-            }
-            assert(lt.extruders.size() == unsign_custom_extruder_seq.size());
-            lt.extruders = unsign_custom_extruder_seq;
-            current_extruder_id = lt.extruders.back();
-            continue;
-        }
-
-        // The algorithm complexity is O(n2*2^n)
-        if (i != 0) {
-            auto hash_key = extruders_to_hash_key(lt.extruders, current_extruder_id);
-            auto iter = m_tool_order_cache.find(hash_key);
-            if (iter == m_tool_order_cache.end()) {
-                lt.extruders = get_extruders_order(wipe_volumes, lt.extruders, current_extruder_id);
-                std::vector<uint8_t> hash_val;
-                hash_val.reserve(lt.extruders.size());
-                for (auto item : lt.extruders)
-                    hash_val.emplace_back(static_cast<uint8_t>(item));
-                m_tool_order_cache[hash_key] = hash_val;
-            }
-            else {
-                std::vector<unsigned int>extruder_order;
-                extruder_order.reserve(iter->second.size());
-                for (auto item : iter->second)
-                    extruder_order.emplace_back(static_cast<unsigned int>(item));
-                lt.extruders = std::move(extruder_order);
-            }
-        }
-        current_extruder_id = lt.extruders.back();
-    }
-}
-
-void ToolOrdering::reorder_extruders_for_minimum_flush_volume_multi_extruder(const std::vector<int>& filament_maps)
-{
-    const PrintConfig *print_config = m_print_config_ptr;
-    if (!print_config && m_print_object_ptr) {
-        print_config = &(m_print_object_ptr->print()->config());
-    }
-
     if (!print_config || m_layer_tools.empty())
         return;
 
@@ -1321,14 +1194,27 @@ void ToolOrdering::reorder_extruders_for_minimum_flush_volume_multi_extruder(con
 
         nozzle_flush_mtx.emplace_back(wipe_volumes);
     }
+    
+    std::vector<int>filament_maps(number_of_extruders, 0);
+    if (nozzle_nums > 1) {
+        filament_maps = m_print->get_filament_maps();
+        if (print_config->print_sequence != PrintSequence::ByObject) {
+            filament_maps = get_recommended_filament_maps();
+            if (filament_maps.empty())
+                return;
+            std::transform(filament_maps.begin(), filament_maps.end(), filament_maps.begin(), [](int value) { return value + 1; });
+            m_print->update_filament_maps_to_config(filament_maps);
+        }
+        std::transform(filament_maps.begin(), filament_maps.end(), filament_maps.begin(), [](int value) { return value - 1; });
+    }
 
-    auto extruders_to_hash_key = [](const std::vector<unsigned int> &extruders, std::optional<unsigned int> initial_extruder_id) -> uint32_t {
-        uint32_t hash_key = 0;
-        // high 16 bit define initial extruder ,low 16 bit define extruder set
-        if (initial_extruder_id) hash_key |= (1 << (16 + *initial_extruder_id));
-        for (auto item : extruders) hash_key |= (1 << item);
-        return hash_key;
-    };
+    std::vector<std::vector<unsigned int>>filament_sequences;
+    std::vector<unsigned int>filament_lists(number_of_extruders);
+    std::iota(filament_lists.begin(),filament_lists.end(),0);
+    std::vector<std::vector<unsigned int>>layer_filaments;
+    for (auto& lt : m_layer_tools) {
+        layer_filaments.emplace_back(lt.extruders);
+    }
 
     std::vector<LayerPrintSequence> other_layers_seqs;
     const ConfigOptionInts *        other_layers_print_sequence_op      = print_config->option<ConfigOptionInts>("other_layers_print_sequence");
@@ -1349,74 +1235,20 @@ void ToolOrdering::reorder_extruders_for_minimum_flush_volume_multi_extruder(con
             }
         }
         return false;
-    };
+        };
 
-    std::optional<unsigned int> current_extruder_id;
+    reorder_filaments_for_minimum_flush_volume(
+        filament_lists,
+        filament_maps,
+        layer_filaments,
+        nozzle_flush_mtx,
+        get_custom_seq,
+        &filament_sequences
+    );
 
-    std::vector<std::optional<unsigned int>> nozzle_to_cur_filaments;
-    nozzle_to_cur_filaments.resize(nozzle_nums);
-
-    for (int i = 0; i < m_layer_tools.size(); ++i) {
-        LayerTools &lt = m_layer_tools[i];
-        if (lt.extruders.empty())
-            continue;
-
-        std::vector<int> custom_extruder_seq;
-        if (get_custom_seq(i, custom_extruder_seq) && !custom_extruder_seq.empty()) {
-            std::vector<unsigned int> unsign_custom_extruder_seq;
-            for (int extruder : custom_extruder_seq) {
-                unsigned int unsign_extruder = static_cast<unsigned int>(extruder) - 1;
-                auto         it              = std::find(lt.extruders.begin(), lt.extruders.end(), unsign_extruder);
-                if (it != lt.extruders.end()) {
-                    unsign_custom_extruder_seq.emplace_back(unsign_extruder);
-                    nozzle_to_cur_filaments[filament_maps[unsign_extruder]] = unsign_extruder;
-                }
-            }
-            assert(lt.extruders.size() == unsign_custom_extruder_seq.size());
-            lt.extruders        = unsign_custom_extruder_seq;
-            current_extruder_id = lt.extruders.back();
-            continue;
-        }
-
-        // The algorithm complexity is O(n2*2^n)
-        if (i != 0) {
-            std::vector<std::vector<unsigned int>> nozzle_filaments;
-            nozzle_filaments.resize(nozzle_nums);
-
-            for (unsigned int filament_id : lt.extruders) {
-                nozzle_filaments[filament_maps[filament_id]].emplace_back(filament_id);
-            }
-
-            for (size_t nozzle_id = 0; nozzle_id < nozzle_nums; ++nozzle_id)
-            {
-                auto hash_key = extruders_to_hash_key(nozzle_filaments[nozzle_id], nozzle_to_cur_filaments[nozzle_id]);
-                auto iter     = m_tool_order_cache.find(hash_key);
-                if (iter == m_tool_order_cache.end()) {
-                    nozzle_filaments[nozzle_id] = get_extruders_order(nozzle_flush_mtx[nozzle_id], nozzle_filaments[nozzle_id],  nozzle_to_cur_filaments[nozzle_id]);
-                    std::vector<uint8_t> hash_val;
-                    hash_val.reserve(nozzle_filaments[nozzle_id].size());
-                    for (auto item : nozzle_filaments[nozzle_id])
-                        hash_val.emplace_back(static_cast<uint8_t>(item));
-                    m_tool_order_cache[hash_key] = hash_val;
-                } else {
-                    std::vector<unsigned int> extruder_order;
-                    extruder_order.reserve(iter->second.size());
-                    for (auto item : iter->second)
-                        extruder_order.emplace_back(static_cast<unsigned int>(item));
-                    nozzle_filaments[nozzle_id] = std::move(extruder_order);
-                }
-                nozzle_to_cur_filaments[nozzle_id] = nozzle_filaments[nozzle_id].back();
-            }
-
-            lt.extruders.clear();
-            for (size_t nozzle_id = 0; nozzle_id < nozzle_nums; ++nozzle_id) {
-                lt.extruders.insert(lt.extruders.end(), nozzle_filaments[nozzle_id].begin(), nozzle_filaments[nozzle_id].end());
-            }
-        }
-        current_extruder_id = lt.extruders.back();
-    }
+    for (size_t i = 0; i < filament_sequences.size(); ++i)
+        m_layer_tools[i].extruders = std::move(filament_sequences[i]);
 }
-
 // Layers are marked for infinite skirt aka draft shield. Not all the layers have to be printed.
 void ToolOrdering::mark_skirt_layers(const PrintConfig &config, coordf_t max_layer_height)
 {
diff --git a/src/libslic3r/GCode/ToolOrdering.hpp b/src/libslic3r/GCode/ToolOrdering.hpp
index bde425797..f6552d92a 100644
--- a/src/libslic3r/GCode/ToolOrdering.hpp
+++ b/src/libslic3r/GCode/ToolOrdering.hpp
@@ -8,6 +8,9 @@
 #include <utility>
 
 #include <boost/container/small_vector.hpp>
+#include "FilamentGroup.hpp"
+#include "ExtrusionEntity.hpp"
+#include "PrintConfig.hpp"
 
 namespace Slic3r {
 
@@ -17,6 +20,13 @@ class LayerTools;
 namespace CustomGCode { struct Item; }
 class PrintRegion;
 
+
+int reorder_filaments_for_minimum_flush_volume(const std::vector<unsigned int>& filament_lists,
+    const std::vector<int>& filament_maps,
+    const std::vector<std::vector<unsigned int>>& layer_filaments,
+    const std::vector<FlushMatrix>& flush_matrix,
+    std::optional<std::function<bool(int, std::vector<int>&)>> get_custom_seq,
+    std::vector<std::vector<unsigned int>>* filament_sequences);
 // Object of this class holds information about whether an extrusion is printed immediately
 // after a toolchange (as part of infill/perimeter wiping) or not. One extrusion can be a part
 // of several copies - this has to be taken into account.
@@ -200,7 +210,6 @@ private:
     void 				collect_extruder_statistics(bool prime_multi_material);
     std::vector<int>    get_recommended_filament_maps();
     void                reorder_extruders_for_minimum_flush_volume();
-    void                reorder_extruders_for_minimum_flush_volume_multi_extruder(const std::vector<int> &filament_maps);
 
     // BBS
     std::vector<unsigned int> generate_first_layer_tool_order(const Print& print);