diff --git a/src/libslic3r/GCode/WipeTowerPrusaMM.cpp b/src/libslic3r/GCode/WipeTowerPrusaMM.cpp
index 5c24cd71c..db38a7462 100644
--- a/src/libslic3r/GCode/WipeTowerPrusaMM.cpp
+++ b/src/libslic3r/GCode/WipeTowerPrusaMM.cpp
@@ -505,8 +505,9 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::prime(
 		  .speed_override(100);
 
 	writer.set_initial_position(xy(0.f, 0.f))	// Always move to the starting position
-		.travel(cleaning_box.ld, 7200)
-		.set_extruder_trimpot(750); 			// Increase the extruder driver current to allow fast ramming.
+		.travel(cleaning_box.ld, 7200);
+	if (m_set_extruder_trimpot)
+		writer.set_extruder_trimpot(750); 			// Increase the extruder driver current to allow fast ramming.
 
     for (size_t idx_tool = 0; idx_tool < tools.size(); ++ idx_tool) {
         unsigned int tool = tools[idx_tool];
@@ -533,8 +534,9 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::prime(
                             // in the output gcode - we should not remember emitting them (we will output them twice in the worst case)
 
 	// Reset the extruder current to a normal value.
-	writer.set_extruder_trimpot(550)
-		  .feedrate(6000)
+	if (m_set_extruder_trimpot)
+		writer.set_extruder_trimpot(550);
+	writer.feedrate(6000)
 		  .flush_planner_queue()
 		  .reset_extruder()
 		  .append("; CP PRIMING END\n"
@@ -607,7 +609,8 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
     writer.set_initial_position(initial_position, m_wipe_tower_width, m_wipe_tower_depth, m_internal_rotation);
 
     // Increase the extruder driver current to allow fast ramming.
-    writer.set_extruder_trimpot(750);
+	if (m_set_extruder_trimpot)
+		writer.set_extruder_trimpot(550);
 
     // Ram the hot material out of the melt zone, retract the filament into the cooling tubes and let it cool.
     if (tool != (unsigned int)-1){ 			// This is not the last change.
@@ -635,8 +638,9 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
         }
     }
 
-    writer.set_extruder_trimpot(550)    // Reset the extruder current to a normal value.
-          .feedrate(6000)
+	if (m_set_extruder_trimpot)
+		writer.set_extruder_trimpot(550);    // Reset the extruder current to a normal value.
+    writer.feedrate(6000)
           .flush_planner_queue()
           .reset_extruder()
           .append("; CP TOOLCHANGE END\n"
@@ -916,12 +920,10 @@ void WipeTowerPrusaMM::toolchange_Load(
 		  .resume_preview();
 
 	// Reset the extruder current to the normal value.
-	writer.set_extruder_trimpot(550);
+	if (m_set_extruder_trimpot)
+		writer.set_extruder_trimpot(550);
 }
 
-
-
-
 // Wipe the newly loaded filament until the end of the assigned wipe area.
 void WipeTowerPrusaMM::toolchange_Wipe(
 	PrusaMultiMaterial::Writer &writer,
diff --git a/src/libslic3r/GCode/WipeTowerPrusaMM.hpp b/src/libslic3r/GCode/WipeTowerPrusaMM.hpp
index 06625d189..c0aeee3ae 100644
--- a/src/libslic3r/GCode/WipeTowerPrusaMM.hpp
+++ b/src/libslic3r/GCode/WipeTowerPrusaMM.hpp
@@ -44,7 +44,8 @@ public:
 	// width		-- width of wipe tower in mm ( default 60 mm - leave as it is )
 	// wipe_area	-- space available for one toolchange in mm
 	WipeTowerPrusaMM(float x, float y, float width, float rotation_angle, float cooling_tube_retraction,
-                     float cooling_tube_length, float parking_pos_retraction, float extra_loading_move, float bridging,
+                     float cooling_tube_length, float parking_pos_retraction, float extra_loading_move, 
+                     float bridging, bool set_extruder_trimpot,
                      const std::vector<std::vector<float>>& wiping_matrix, unsigned int initial_tool) :
     m_wipe_tower_pos(x, y),
 		m_wipe_tower_width(width),
@@ -57,6 +58,7 @@ public:
         m_parking_pos_retraction(parking_pos_retraction),
         m_extra_loading_move(extra_loading_move),
 		m_bridging(bridging),
+		m_set_extruder_trimpot(set_extruder_trimpot),
         m_current_tool(initial_tool),
         wipe_volumes(wiping_matrix)
         {}
@@ -212,6 +214,7 @@ private:
     float           m_parking_pos_retraction    = 0.f;
     float           m_extra_loading_move        = 0.f;
     float           m_bridging                  = 0.f;
+    bool            m_set_extruder_trimpot      = false;
     bool            m_adhesion                  = true;
 
 	float m_perimeter_width = 0.4 * Width_To_Nozzle_Ratio; // Width of an extrusion line, also a perimeter spacing for 100% infill.
diff --git a/src/libslic3r/Line.cpp b/src/libslic3r/Line.cpp
index 35cfa2b76..02f1cb7c2 100644
--- a/src/libslic3r/Line.cpp
+++ b/src/libslic3r/Line.cpp
@@ -34,23 +34,22 @@ bool Line::intersection_infinite(const Line &other, Point* point) const
     return true;
 }
 
-/* distance to the closest point of line */
-double Line::distance_to(const Point &point) const
+// Distance to the closest point of line.
+double Line::distance_to_squared(const Point &point, const Point &a, const Point &b)
 {
-    const Line   &line = *this;
-    const Vec2d   v  = (line.b - line.a).cast<double>();
-    const Vec2d   va = (point  - line.a).cast<double>();
+    const Vec2d   v  = (b - a).cast<double>();
+    const Vec2d   va = (point  - a).cast<double>();
     const double  l2 = v.squaredNorm();  // avoid a sqrt
     if (l2 == 0.0) 
-        // line.a == line.b case
-        return va.norm();
-    // Consider the line extending the segment, parameterized as line.a + t (line.b - line.a).
+        // a == b case
+        return va.squaredNorm();
+    // Consider the line extending the segment, parameterized as a + t (b - a).
     // We find projection of this point onto the line. 
-    // It falls where t = [(this-line.a) . (line.b-line.a)] / |line.b-line.a|^2
+    // It falls where t = [(this-a) . (b-a)] / |b-a|^2
     const double t = va.dot(v) / l2;
-    if (t < 0.0)      return va.norm();  // beyond the 'a' end of the segment
-    else if (t > 1.0) return (point - line.b).cast<double>().norm();  // beyond the 'b' end of the segment
-    return (t * v - va).norm();
+    if (t < 0.0)      return va.squaredNorm();  // beyond the 'a' end of the segment
+    else if (t > 1.0) return (point - b).cast<double>().squaredNorm();  // beyond the 'b' end of the segment
+    return (t * v - va).squaredNorm();
 }
 
 double Line::perp_distance_to(const Point &point) const
diff --git a/src/libslic3r/Line.hpp b/src/libslic3r/Line.hpp
index 36e02247c..559ca946a 100644
--- a/src/libslic3r/Line.hpp
+++ b/src/libslic3r/Line.hpp
@@ -31,7 +31,8 @@ public:
     Point  midpoint() const { return (this->a + this->b) / 2; }
     bool   intersection_infinite(const Line &other, Point* point) const;
     bool   operator==(const Line &rhs) const { return this->a == rhs.a && this->b == rhs.b; }
-    double distance_to(const Point &point) const;
+    double distance_to_squared(const Point &point) const { return distance_to_squared(point, this->a, this->b); }
+    double distance_to(const Point &point) const { return distance_to(point, this->a, this->b); }
     double perp_distance_to(const Point &point) const;
     bool   parallel_to(double angle) const;
     bool   parallel_to(const Line &line) const { return this->parallel_to(line.direction()); }
@@ -43,6 +44,9 @@ public:
     bool   intersection(const Line& line, Point* intersection) const;
     double ccw(const Point& point) const { return point.ccw(*this); }
 
+    static double distance_to_squared(const Point &point, const Point &a, const Point &b);
+    static double distance_to(const Point &point, const Point &a, const Point &b) { return sqrt(distance_to_squared(point, a, b)); }
+
     Point a;
     Point b;
 };
diff --git a/src/libslic3r/MultiPoint.cpp b/src/libslic3r/MultiPoint.cpp
index 93c63c4cf..795ee38c2 100644
--- a/src/libslic3r/MultiPoint.cpp
+++ b/src/libslic3r/MultiPoint.cpp
@@ -162,45 +162,51 @@ bool MultiPoint::first_intersection(const Line& line, Point* intersection) const
     return found;
 }
 
-//FIXME This is very inefficient in term of memory use.
-// The recursive algorithm shall run in place, not allocating temporary data in each recursion.
-Points
-MultiPoint::_douglas_peucker(const Points &points, const double tolerance)
+std::vector<Point> MultiPoint::_douglas_peucker(const std::vector<Point>& pts, const double tolerance)
 {
-    assert(points.size() >= 2);
-    Points results;
-    double dmax = 0;
-    size_t index = 0;
-    Line full(points.front(), points.back());
-    for (Points::const_iterator it = points.begin() + 1; it != points.end(); ++it) {
-        // we use shortest distance, not perpendicular distance
-        double d = full.distance_to(*it);
-        if (d > dmax) {
-            index = it - points.begin();
-            dmax = d;
+    std::vector<Point> result_pts;
+    if (! pts.empty()) {
+        const Point  *anchor      = &pts.front();
+        size_t        anchor_idx  = 0;
+        const Point  *floater     = &pts.back();
+        size_t        floater_idx = pts.size() - 1;
+        result_pts.reserve(pts.size());
+        result_pts.emplace_back(*anchor);
+        if (anchor_idx != floater_idx) {
+            assert(pts.size() > 1);
+            std::vector<size_t> dpStack;
+            dpStack.reserve(pts.size());
+            dpStack.emplace_back(floater_idx);
+            for (;;) {
+                double max_distSq   = 0.0;
+                size_t furthest_idx = anchor_idx;
+                // find point furthest from line seg created by (anchor, floater) and note it
+                for (size_t i = anchor_idx + 1; i < floater_idx; ++ i) {
+                    double dist = Line::distance_to_squared(pts[i], *anchor, *floater);
+                    if (dist > max_distSq) {
+                        max_distSq   = dist;
+                        furthest_idx = i;
+                    }
+                }
+                // remove point if less than tolerance
+                if (max_distSq <= tolerance) {
+                    result_pts.emplace_back(*floater);
+                    anchor_idx = floater_idx;
+                    anchor     = floater;
+                    assert(dpStack.back() == floater_idx);
+                    dpStack.pop_back();
+                    if (dpStack.empty())
+                        break;
+                    floater_idx = dpStack.back();
+                } else {
+                    floater_idx = furthest_idx;
+                    dpStack.emplace_back(floater_idx);
+                }
+                floater = &pts[floater_idx];
+            }
         }
     }
-    if (dmax >= tolerance) {
-        Points dp0;
-        dp0.reserve(index + 1);
-        dp0.insert(dp0.end(), points.begin(), points.begin() + index + 1);
-        // Recursive call.
-        Points dp1 = MultiPoint::_douglas_peucker(dp0, tolerance);
-        results.reserve(results.size() + dp1.size() - 1);
-        results.insert(results.end(), dp1.begin(), dp1.end() - 1);
-        
-        dp0.clear();
-        dp0.reserve(points.size() - index);
-        dp0.insert(dp0.end(), points.begin() + index, points.end());
-        // Recursive call.
-        dp1 = MultiPoint::_douglas_peucker(dp0, tolerance);
-        results.reserve(results.size() + dp1.size());
-        results.insert(results.end(), dp1.begin(), dp1.end());
-    } else {
-        results.push_back(points.front());
-        results.push_back(points.back());
-    }
-    return results;
+    return result_pts;
 }
 
 // Visivalingam simplification algorithm https://github.com/slic3r/Slic3r/pull/3825
diff --git a/src/libslic3r/Print.cpp b/src/libslic3r/Print.cpp
index 77cf9c0f6..e3382573c 100644
--- a/src/libslic3r/Print.cpp
+++ b/src/libslic3r/Print.cpp
@@ -213,6 +213,7 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
             || opt_key == "filament_cooling_final_speed"
             || opt_key == "filament_ramming_parameters"
             || opt_key == "gcode_flavor"
+            || opt_key == "high_current_on_filament_swap"
             || opt_key == "infill_first"
             || opt_key == "single_extruder_multi_material"
             || opt_key == "spiral_vase"
@@ -1768,7 +1769,8 @@ void Print::_make_wipe_tower()
         float(m_config.wipe_tower_width.value),
         float(m_config.wipe_tower_rotation_angle.value), float(m_config.cooling_tube_retraction.value),
         float(m_config.cooling_tube_length.value), float(m_config.parking_pos_retraction.value),
-        float(m_config.extra_loading_move.value), float(m_config.wipe_tower_bridging), wipe_volumes,
+        float(m_config.extra_loading_move.value), float(m_config.wipe_tower_bridging), 
+        m_config.high_current_on_filament_swap.value, wipe_volumes,
         m_wipe_tower_data.tool_ordering.first_extruder());
 
     //wipe_tower.set_retract();
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 8a564b6b5..f24d40fed 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -925,6 +925,15 @@ void PrintConfigDef::init_fff_params()
     def->mode = comExpert;
     def->default_value = new ConfigOptionEnum<GCodeFlavor>(gcfRepRap);
 
+    def = this->add("high_current_on_filament_swap", coBool);
+    def->label = L("High extruder current on filament swap");
+    def->tooltip = L("It may be beneficial to increase the extruder motor current during the filament exchange"
+                   " sequence to allow for rapid ramming feed rates and to overcome resistance when loading"
+                   " a filament with an ugly shaped tip.");
+    def->cli = "high-current-on-filament-swap!";
+    def->mode = comExpert;
+    def->default_value = new ConfigOptionBool(0);
+
     def = this->add("infill_acceleration", coFloat);
     def->label = L("Infill");
     def->tooltip = L("This is the acceleration your printer will use for infill. Set zero to disable "
diff --git a/src/libslic3r/PrintConfig.hpp b/src/libslic3r/PrintConfig.hpp
index 1949a8ac8..487e35bf2 100644
--- a/src/libslic3r/PrintConfig.hpp
+++ b/src/libslic3r/PrintConfig.hpp
@@ -627,6 +627,7 @@ public:
     ConfigOptionBool                variable_layer_height;
     ConfigOptionFloat               cooling_tube_retraction;
     ConfigOptionFloat               cooling_tube_length;
+    ConfigOptionBool                high_current_on_filament_swap;
     ConfigOptionFloat               parking_pos_retraction;
     ConfigOptionBool                remaining_times;
     ConfigOptionBool                silent_mode;
@@ -695,6 +696,7 @@ protected:
         OPT_PTR(variable_layer_height);
         OPT_PTR(cooling_tube_retraction);
         OPT_PTR(cooling_tube_length);
+        OPT_PTR(high_current_on_filament_swap);
         OPT_PTR(parking_pos_retraction);
         OPT_PTR(remaining_times);
         OPT_PTR(silent_mode);
diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index 772d930aa..fdf950ee5 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -385,11 +385,13 @@ void PrintObject::generate_support_material()
             this->_generate_support_material();
             m_print->throw_if_canceled();
         } else {
+#if 0
             // Printing without supports. Empty layer means some objects or object parts are levitating,
             // therefore they cannot be printed without supports.
             for (const Layer *layer : m_layers)
                 if (layer->empty())
                     throw std::runtime_error("Levitating objects cannot be printed without supports.");
+#endif
         }
         this->set_done(posSupportMaterial);
     }
diff --git a/src/slic3r/GUI/Preset.cpp b/src/slic3r/GUI/Preset.cpp
index 639f70cf7..90372ecd4 100644
--- a/src/slic3r/GUI/Preset.cpp
+++ b/src/slic3r/GUI/Preset.cpp
@@ -366,7 +366,8 @@ const std::vector<std::string>& Preset::printer_options()
             "host_type", "print_host", "printhost_apikey", "printhost_cafile",
             "single_extruder_multi_material", "start_gcode", "end_gcode", "before_layer_gcode", "layer_gcode", "toolchange_gcode",
             "between_objects_gcode", "printer_vendor", "printer_model", "printer_variant", "printer_notes", "cooling_tube_retraction",
-            "cooling_tube_length", "parking_pos_retraction", "extra_loading_move", "max_print_height", "default_print_profile", "inherits",
+            "cooling_tube_length", "high_current_on_filament_swap", "parking_pos_retraction", "extra_loading_move", "max_print_height", 
+            "default_print_profile", "inherits",
             "remaining_times", "silent_mode", "machine_max_acceleration_extruding", "machine_max_acceleration_retracting",
 			"machine_max_acceleration_x", "machine_max_acceleration_y", "machine_max_acceleration_z", "machine_max_acceleration_e",
         	"machine_max_feedrate_x", "machine_max_feedrate_y", "machine_max_feedrate_z", "machine_max_feedrate_e",
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 6372f7321..30d83d845 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -2041,6 +2041,7 @@ void TabPrinter::build_extruder_pages()
 		optgroup->append_single_option_line("cooling_tube_length");
 		optgroup->append_single_option_line("parking_pos_retraction");
         optgroup->append_single_option_line("extra_loading_move");
+        optgroup->append_single_option_line("high_current_on_filament_swap");
 		m_pages.insert(m_pages.end() - n_after_single_extruder_MM, page);
 		m_has_single_extruder_MM_page = true;
 	}