Enhance GCode handling for Z-axis movements (#10803)

* Enhance GCode handling for Z-axis movements

- Updated `travel_to_z` method to include a `force` parameter, allowing forced Z movements.
- Modified GCode generation logic to ensure Z position is restored after unknown last positions.
- Enforce z restoreation after tool changer

* Improve filament_multitool_ramming logic

* fix indent

src/libslic3r/GCode.cpp

@@ -769,7 +769,7 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
                 gcodegen.m_wipe.reset_path();                                           // We don't want wiping on the ramming lines.
             toolchange_gcode_str = gcodegen.set_extruder(new_extruder_id, tcr.print_z); // TODO: toolchange_z vs print_z
             if (gcodegen.config().enable_prime_tower) {
-            deretraction_str += gcodegen.writer().travel_to_z(z, "restore layer Z");
+                deretraction_str += gcodegen.writer().travel_to_z(z, "Force restore layer Z", true);
                 Vec3d position{gcodegen.writer().get_position()};
                 position.z() = z;
                 gcodegen.writer().set_position(position);
@@ -5210,10 +5210,11 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
         auto target_z = get_sloped_z(sloped->slope_begin.z_ratio);
         slope_need_z_travel = m_writer.will_move_z(target_z);
     }
-    // go to first point of extrusion path
+    // Move to first point of extrusion path
-    //BBS: path.first_point is 2D point. But in lazy raise case, lift z is done in travel_to function.
+    // path is 2D. But in slope lift case, lift z is done in travel_to function.
     // Add m_need_change_layer_lift_z when change_layer in case of no lift if m_last_pos is equal to path.first_point() by chance
     if (!m_last_pos_defined || m_last_pos != path.first_point() || m_need_change_layer_lift_z || slope_need_z_travel) {
+        const bool _last_pos_undefined = !m_last_pos_defined;
         gcode += this->travel_to(
             path.first_point(),
             path.role(),
@@ -5221,7 +5222,12 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
             sloped == nullptr ? DBL_MAX : get_sloped_z(sloped->slope_begin.z_ratio)
         );
         m_need_change_layer_lift_z = false;
+        // Orca: force restore Z after unknown last pos
+        if (_last_pos_undefined && !slope_need_z_travel) {
+            gcode += this->writer().travel_to_z(m_last_layer_z, "force restore Z after unknown last pos", true);
         }
+    }
+
 
     // if needed, write the gcode_label_objects_end then gcode_label_objects_start
     // should be already done by travel_to, but just in case
@@ -6612,6 +6618,8 @@ std::string GCode::set_extruder(unsigned int extruder_id, double print_z, bool b
     if (m_config.enable_pressure_advance.get_at(extruder_id)) {
         gcode += m_writer.set_pressure_advance(m_config.pressure_advance.get_at(extruder_id));
     }
+    //Orca: tool changer or IDEX's firmware may change Z position, so we set it to unknown/undefined
+    m_last_pos_defined = false;
 
     return gcode;
 }

src/libslic3r/GCode/WipeTower2.cpp

@@ -1350,7 +1350,7 @@ void WipeTower2::set_extruder(size_t idx, const PrintConfig& config)
         // We will use the same variables internally, but the correspondence to the configuration options will be different.
         float vol  = config.filament_multitool_ramming_volume.get_at(idx);
         float flow = config.filament_multitool_ramming_flow.get_at(idx);
-        m_filpar[idx].multitool_ramming = config.filament_multitool_ramming.get_at(idx);
+        m_filpar[idx].multitool_ramming = config.filament_multitool_ramming.get_at(idx) && vol > 0.f && flow > 0.f;
         m_filpar[idx].ramming_line_width_multiplicator = 2.;
         m_filpar[idx].ramming_step_multiplicator = 1.;
 
@@ -1360,7 +1360,7 @@ void WipeTower2::set_extruder(size_t idx, const PrintConfig& config)
         // ramming_speed vector that would respect both the volume and flow (because of 
         // rounding issues with small volumes and high flow).
         m_filpar[idx].ramming_speed.push_back(flow);
-        m_filpar[idx].multitool_ramming_time = vol/flow;
+        m_filpar[idx].multitool_ramming_time = flow > 0.f ? vol/flow : 0.f;
     }
 
     m_used_filament_length.resize(std::max(m_used_filament_length.size(), idx + 1)); // makes sure that the vector is big enough so we don't have to check later

src/libslic3r/GCodeWriter.cpp

@@ -633,12 +633,12 @@ std::string GCodeWriter::travel_to_xyz(const Vec3d &point, const std::string &co
     return out_string;
 }
 
-std::string GCodeWriter::travel_to_z(double z, const std::string &comment)
+std::string GCodeWriter::travel_to_z(double z, const std::string &comment, bool force)
 {
     /*  If target Z is lower than current Z but higher than nominal Z
         we don't perform the move but we only adjust the nominal Z by
         reducing the lift amount that will be used for unlift. */
-    if (!this->will_move_z(z)) {
+    if (!force && !this->will_move_z(z)) {
         double nominal_z = m_pos(2) - m_lifted;
         m_lifted -= (z - nominal_z);
         if (std::abs(m_lifted) < EPSILON)

src/libslic3r/GCodeWriter.hpp

@@ -72,7 +72,7 @@ public:
     double      get_current_speed() const { return m_current_speed;}
     std::string travel_to_xy(const Vec2d &point, const std::string &comment = std::string());
     std::string travel_to_xyz(const Vec3d &point, const std::string &comment = std::string(), bool force_z = false);
-    std::string travel_to_z(double z, const std::string &comment = std::string());
+    std::string travel_to_z(double z, const std::string &comment = std::string(), bool force = false);
     bool        will_move_z(double z) const;
     std::string extrude_to_xy(const Vec2d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false);
     //BBS: generate G2 or G3 extrude which moves by arc

src/slic3r/GUI/Tab.cpp

@@ -3809,6 +3809,10 @@ void TabFilament::toggle_options()
                         "filament_unloading_speed_start", "filament_unloading_speed", "filament_toolchange_delay", "filament_cooling_moves",
                         "filament_cooling_initial_speed", "filament_cooling_final_speed"})
             toggle_option(el, !is_BBL_printer);
+
+        bool multitool_ramming = m_config->opt_bool("filament_multitool_ramming", 0);
+        toggle_option("filament_multitool_ramming_volume", multitool_ramming);
+        toggle_option("filament_multitool_ramming_flow", multitool_ramming);
     }
 }