Merge branch 'master' into time_estimate

15 files changed, 896 insertions, 464 deletions

diff --git a/xs/src/libslic3r/GCode.cpp b/xs/src/libslic3r/GCode.cpp
index 94634f4e4..1c1eeee6f 100644
--- a/xs/src/libslic3r/GCode.cpp
+++ b/xs/src/libslic3r/GCode.cpp
@@ -167,6 +167,18 @@ std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::T
 {
     std::string gcode;
 
+    // Toolchangeresult.gcode assumes the wipe tower corner is at the origin
+    // We want to rotate and shift all extrusions (gcode postprocessing) and starting and ending position
+    float alpha = m_wipe_tower_rotation/180.f * M_PI;
+    WipeTower::xy start_pos = tcr.start_pos;
+    WipeTower::xy end_pos = tcr.end_pos;
+    start_pos.rotate(alpha);
+    start_pos.translate(m_wipe_tower_pos);
+    end_pos.rotate(alpha);
+    end_pos.translate(m_wipe_tower_pos);
+    std::string tcr_rotated_gcode = rotate_wipe_tower_moves(tcr.gcode, tcr.start_pos, m_wipe_tower_pos, alpha);
+    
+
     // Disable linear advance for the wipe tower operations.
     gcode += "M900 K0\n";
     // Move over the wipe tower.
@@ -174,14 +186,14 @@ std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::T
     gcode += gcodegen.retract(true);
     gcodegen.m_avoid_crossing_perimeters.use_external_mp_once = true;
     gcode += gcodegen.travel_to(
-        wipe_tower_point_to_object_point(gcodegen, tcr.start_pos),
+        wipe_tower_point_to_object_point(gcodegen, start_pos),
         erMixed,
         "Travel to a Wipe Tower");
     gcode += gcodegen.unretract();
 
     // Let the tool change be executed by the wipe tower class.
     // Inform the G-code writer about the changes done behind its back.
-    gcode += tcr.gcode;
+    gcode += tcr_rotated_gcode;
     // Let the m_writer know the current extruder_id, but ignore the generated G-code.
 	if (new_extruder_id >= 0 && gcodegen.writer().need_toolchange(new_extruder_id))
         gcodegen.writer().toolchange(new_extruder_id);
@@ -195,18 +207,18 @@ std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::T
         check_add_eol(gcode);
     }
     // A phony move to the end position at the wipe tower.
-    gcodegen.writer().travel_to_xy(Pointf(tcr.end_pos.x, tcr.end_pos.y));
-    gcodegen.set_last_pos(wipe_tower_point_to_object_point(gcodegen, tcr.end_pos));
+    gcodegen.writer().travel_to_xy(Pointf(end_pos.x, end_pos.y));
+    gcodegen.set_last_pos(wipe_tower_point_to_object_point(gcodegen, end_pos));
 
     // Prepare a future wipe.
     gcodegen.m_wipe.path.points.clear();
     if (new_extruder_id >= 0) {
         // Start the wipe at the current position.
-        gcodegen.m_wipe.path.points.emplace_back(wipe_tower_point_to_object_point(gcodegen, tcr.end_pos));
+        gcodegen.m_wipe.path.points.emplace_back(wipe_tower_point_to_object_point(gcodegen, end_pos));
         // Wipe end point: Wipe direction away from the closer tower edge to the further tower edge.
         gcodegen.m_wipe.path.points.emplace_back(wipe_tower_point_to_object_point(gcodegen, 
-            WipeTower::xy((std::abs(m_left - tcr.end_pos.x) < std::abs(m_right - tcr.end_pos.x)) ? m_right : m_left,
-            tcr.end_pos.y)));
+            WipeTower::xy((std::abs(m_left - end_pos.x) < std::abs(m_right - end_pos.x)) ? m_right : m_left,
+            end_pos.y)));
     }
 
     // Let the planner know we are traveling between objects.
@@ -214,6 +226,57 @@ std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::T
     return gcode;
 }
 
+// This function postprocesses gcode_original, rotates and moves all G1 extrusions and returns resulting gcode
+// Starting position has to be supplied explicitely (otherwise it would fail in case first G1 command only contained one coordinate)
+std::string WipeTowerIntegration::rotate_wipe_tower_moves(const std::string& gcode_original, const WipeTower::xy& start_pos, const WipeTower::xy& translation, float angle) const
+{
+    std::istringstream gcode_str(gcode_original);
+    std::string gcode_out;
+    std::string line;
+    WipeTower::xy pos = start_pos;
+    WipeTower::xy transformed_pos;
+    WipeTower::xy old_pos(-1000.1f, -1000.1f);
+
+    while (gcode_str) {
+        std::getline(gcode_str, line);  // we read the gcode line by line
+        if (line.find("G1 ") == 0) {
+            std::ostringstream line_out;
+            std::istringstream line_str(line);
+            line_str >> std::noskipws;  // don't skip whitespace
+            char ch = 0;
+            while (line_str >> ch) {
+                if (ch == 'X')
+                    line_str >> pos.x;
+                else
+                    if (ch == 'Y')
+                        line_str >> pos.y;
+                    else
+                        line_out << ch;
+            }
+
+            transformed_pos = pos;
+            transformed_pos.rotate(angle);
+            transformed_pos.translate(translation);
+
+            if (transformed_pos != old_pos) {
+                line = line_out.str();
+                char buf[2048] = "G1";
+                if (transformed_pos.x != old_pos.x)
+                    sprintf(buf + strlen(buf), " X%.3f", transformed_pos.x);
+                if (transformed_pos.y != old_pos.y)
+                    sprintf(buf + strlen(buf), " Y%.3f", transformed_pos.y);
+
+                line.replace(line.find("G1 "), 3, buf);
+                old_pos = transformed_pos;
+            }
+        }
+        gcode_out += line + "\n";
+    }
+    return gcode_out;
+}
+
+
+
 std::string WipeTowerIntegration::prime(GCode &gcodegen)
 {
     assert(m_layer_idx == 0);
@@ -608,15 +671,18 @@ void GCode::_do_export(Print &print, FILE *file, GCodePreviewData *preview_data)
             if ((initial_extruder_id = tool_ordering.first_extruder()) != (unsigned int)-1)
                 break;
         }
-    }
-    else {
+    } else {
 		// Find tool ordering for all the objects at once, and the initial extruder ID.
         // If the tool ordering has been pre-calculated by Print class for wipe tower already, reuse it.
 		tool_ordering = print.m_tool_ordering.empty() ?
             ToolOrdering(print, initial_extruder_id) :
             print.m_tool_ordering;
-		initial_extruder_id = tool_ordering.first_extruder();
         has_wipe_tower = print.has_wipe_tower() && tool_ordering.has_wipe_tower();
+        initial_extruder_id = (has_wipe_tower && ! print.config.single_extruder_multi_material_priming) ? 
+            // The priming towers will be skipped.
+            tool_ordering.all_extruders().back() :
+            // Don't skip the priming towers. 
+            tool_ordering.first_extruder();
     }
     if (initial_extruder_id == (unsigned int)-1) {
         // Nothing to print!
@@ -644,6 +710,7 @@ void GCode::_do_export(Print &print, FILE *file, GCodePreviewData *preview_data)
     m_placeholder_parser.set("current_object_idx", 0);
     // For the start / end G-code to do the priming and final filament pull in case there is no wipe tower provided.
     m_placeholder_parser.set("has_wipe_tower", has_wipe_tower);
+    m_placeholder_parser.set("has_single_extruder_multi_material_priming", has_wipe_tower && print.config.single_extruder_multi_material_priming);
     std::string start_gcode = this->placeholder_parser_process("start_gcode", print.config.start_gcode.value, initial_extruder_id);
     
     // Set bed temperature if the start G-code does not contain any bed temp control G-codes.
@@ -724,8 +791,11 @@ void GCode::_do_export(Print &print, FILE *file, GCodePreviewData *preview_data)
         }
     }
     
-    // Set initial extruder only after custom start G-code.
-    _write(file, this->set_extruder(initial_extruder_id));
+    if (! (has_wipe_tower && print.config.single_extruder_multi_material_priming)) {
+        // Set initial extruder only after custom start G-code.
+        // Ugly hack: Do not set the initial extruder if the extruder is primed using the MMU priming towers at the edge of the print bed.
+        _write(file, this->set_extruder(initial_extruder_id));
+    }
 
     // Do all objects for each layer.
     if (print.config.complete_objects.value) {
@@ -803,27 +873,29 @@ void GCode::_do_export(Print &print, FILE *file, GCodePreviewData *preview_data)
         if (has_wipe_tower && ! layers_to_print.empty()) {
             m_wipe_tower.reset(new WipeTowerIntegration(print.config, *print.m_wipe_tower_priming.get(), print.m_wipe_tower_tool_changes, *print.m_wipe_tower_final_purge.get()));
             _write(file, m_writer.travel_to_z(first_layer_height + m_config.z_offset.value, "Move to the first layer height"));
-		    _write(file, m_wipe_tower->prime(*this));
-            // Verify, whether the print overaps the priming extrusions.
-            BoundingBoxf bbox_print(get_print_extrusions_extents(print));
-            coordf_t twolayers_printz = ((layers_to_print.size() == 1) ? layers_to_print.front() : layers_to_print[1]).first + EPSILON;
-            for (const PrintObject *print_object : printable_objects)
-                bbox_print.merge(get_print_object_extrusions_extents(*print_object, twolayers_printz));
-            bbox_print.merge(get_wipe_tower_extrusions_extents(print, twolayers_printz));
-            BoundingBoxf bbox_prime(get_wipe_tower_priming_extrusions_extents(print));
-            bbox_prime.offset(0.5f);
-            // Beep for 500ms, tone 800Hz. Yet better, play some Morse.
-            _write(file, this->retract());
-            _write(file, "M300 S800 P500\n");
-            if (bbox_prime.overlap(bbox_print)) {
-                // Wait for the user to remove the priming extrusions, otherwise they would
-                // get covered by the print.
-                _write(file, "M1 Remove priming towers and click button.\n");
-            }
-            else {
-                // Just wait for a bit to let the user check, that the priming succeeded.
-                //TODO Add a message explaining what the printer is waiting for. This needs a firmware fix.
-                _write(file, "M1 S10\n");
+            if (print.config.single_extruder_multi_material_priming) {
+    		    _write(file, m_wipe_tower->prime(*this));
+                // Verify, whether the print overaps the priming extrusions.
+                BoundingBoxf bbox_print(get_print_extrusions_extents(print));
+                coordf_t twolayers_printz = ((layers_to_print.size() == 1) ? layers_to_print.front() : layers_to_print[1]).first + EPSILON;
+                for (const PrintObject *print_object : printable_objects)
+                    bbox_print.merge(get_print_object_extrusions_extents(*print_object, twolayers_printz));
+                bbox_print.merge(get_wipe_tower_extrusions_extents(print, twolayers_printz));
+                BoundingBoxf bbox_prime(get_wipe_tower_priming_extrusions_extents(print));
+                bbox_prime.offset(0.5f);
+                // Beep for 500ms, tone 800Hz. Yet better, play some Morse.
+                _write(file, this->retract());
+                _write(file, "M300 S800 P500\n");
+                if (bbox_prime.overlap(bbox_print)) {
+                    // Wait for the user to remove the priming extrusions, otherwise they would
+                    // get covered by the print.
+                    _write(file, "M1 Remove priming towers and click button.\n");
+                }
+                else {
+                    // Just wait for a bit to let the user check, that the priming succeeded.
+                    //TODO Add a message explaining what the printer is waiting for. This needs a firmware fix.
+                    _write(file, "M1 S10\n");
+                }
             }
         }
         // Extrude the layers.
@@ -1003,9 +1075,10 @@ void GCode::print_machine_envelope(FILE *file, Print &print)
             int(print.config.machine_max_feedrate_y.values.front() + 0.5),
             int(print.config.machine_max_feedrate_z.values.front() + 0.5),
             int(print.config.machine_max_feedrate_e.values.front() + 0.5));
-        fprintf(file, "M204 S%d T%d ; sets acceleration (S) and retract acceleration (T), mm/sec^2\n",
+        fprintf(file, "M204 P%d R%d T%d ; sets acceleration (P, T) and retract acceleration (R), mm/sec^2\n",
             int(print.config.machine_max_acceleration_extruding.values.front() + 0.5),
-            int(print.config.machine_max_acceleration_retracting.values.front() + 0.5));
+            int(print.config.machine_max_acceleration_retracting.values.front() + 0.5),
+            int(print.config.machine_max_acceleration_extruding.values.front() + 0.5));
         fprintf(file, "M205 X%.2lf Y%.2lf Z%.2lf E%.2lf ; sets the jerk limits, mm/sec\n",
             print.config.machine_max_jerk_x.values.front(),
             print.config.machine_max_jerk_y.values.front(),
diff --git a/xs/src/libslic3r/GCode.hpp b/xs/src/libslic3r/GCode.hpp
index 8b40385e6..4953c39fe 100644
--- a/xs/src/libslic3r/GCode.hpp
+++ b/xs/src/libslic3r/GCode.hpp
@@ -83,8 +83,10 @@ public:
         const WipeTower::ToolChangeResult                           &priming,
         const std::vector<std::vector<WipeTower::ToolChangeResult>> &tool_changes,
         const WipeTower::ToolChangeResult                           &final_purge) :
-        m_left(float(print_config.wipe_tower_x.value)),
-        m_right(float(print_config.wipe_tower_x.value + print_config.wipe_tower_width.value)),
+        m_left(/*float(print_config.wipe_tower_x.value)*/ 0.f),
+        m_right(float(/*print_config.wipe_tower_x.value +*/ print_config.wipe_tower_width.value)),
+        m_wipe_tower_pos(float(print_config.wipe_tower_x.value), float(print_config.wipe_tower_y.value)),
+        m_wipe_tower_rotation(float(print_config.wipe_tower_rotation_angle)),
         m_priming(priming),
         m_tool_changes(tool_changes),
         m_final_purge(final_purge),
@@ -101,9 +103,14 @@ private:
     WipeTowerIntegration& operator=(const WipeTowerIntegration&);
     std::string append_tcr(GCode &gcodegen, const WipeTower::ToolChangeResult &tcr, int new_extruder_id) const;
 
+    // Postprocesses gcode: rotates and moves all G1 extrusions and returns result
+    std::string rotate_wipe_tower_moves(const std::string& gcode_original, const WipeTower::xy& start_pos, const WipeTower::xy& translation, float angle) const;
+
     // Left / right edges of the wipe tower, for the planning of wipe moves.
     const float                                                  m_left;
     const float                                                  m_right;
+    const WipeTower::xy                                          m_wipe_tower_pos;
+    const float                                                  m_wipe_tower_rotation;
     // Reference to cached values at the Printer class.
     const WipeTower::ToolChangeResult                           &m_priming;
     const std::vector<std::vector<WipeTower::ToolChangeResult>> &m_tool_changes;
@@ -112,6 +119,7 @@ private:
     int                                                          m_layer_idx;
     int                                                          m_tool_change_idx;
     bool                                                         m_brim_done;
+    bool                                                         i_have_brim = false;
 };
 
 class GCode {
diff --git a/xs/src/libslic3r/GCode/PrintExtents.cpp b/xs/src/libslic3r/GCode/PrintExtents.cpp
index 3c3f0f8d5..37b79f343 100644
--- a/xs/src/libslic3r/GCode/PrintExtents.cpp
+++ b/xs/src/libslic3r/GCode/PrintExtents.cpp
@@ -134,6 +134,11 @@ BoundingBoxf get_print_object_extrusions_extents(const PrintObject &print_object
 // The projection does not contain the priming regions.
 BoundingBoxf get_wipe_tower_extrusions_extents(const Print &print, const coordf_t max_print_z)
 {
+    // Wipe tower extrusions are saved as if the tower was at the origin with no rotation
+    // We need to get position and angle of the wipe tower to transform them to actual position.
+    Pointf wipe_tower_pos(print.config.wipe_tower_x.value, print.config.wipe_tower_y.value);
+    float wipe_tower_angle = print.config.wipe_tower_rotation_angle.value;
+
     BoundingBoxf bbox;
     for (const std::vector<WipeTower::ToolChangeResult> &tool_changes : print.m_wipe_tower_tool_changes) {
         if (! tool_changes.empty() && tool_changes.front().print_z > max_print_z)
@@ -144,6 +149,11 @@ BoundingBoxf get_wipe_tower_extrusions_extents(const Print &print, const coordf_
                 if (e.width > 0) {
                     Pointf  p1((&e - 1)->pos.x, (&e - 1)->pos.y);
                     Pointf  p2(e.pos.x, e.pos.y);
+                    p1.rotate(wipe_tower_angle);
+                    p1.translate(wipe_tower_pos);
+                    p2.rotate(wipe_tower_angle);
+                    p2.translate(wipe_tower_pos);
+
                     bbox.merge(p1);
                     coordf_t radius = 0.5 * e.width;
                     bbox.min.x = std::min(bbox.min.x, std::min(p1.x, p2.x) - radius);
diff --git a/xs/src/libslic3r/GCode/WipeTower.hpp b/xs/src/libslic3r/GCode/WipeTower.hpp
index 36cebeb84..9bf350328 100644
--- a/xs/src/libslic3r/GCode/WipeTower.hpp
+++ b/xs/src/libslic3r/GCode/WipeTower.hpp
@@ -25,18 +25,30 @@ public:
 		bool operator==(const xy &rhs) const { return x == rhs.x && y == rhs.y; }
 		bool operator!=(const xy &rhs) const { return x != rhs.x || y != rhs.y; }
 		
-		// Rotate the point around given point about given angle (in degrees)
-		// shifts the result so that point of rotation is in the middle of the tower
-		xy rotate(const xy& origin, float width, float depth, float angle) const {
+		// Rotate the point around center of the wipe tower about given angle (in degrees)
+		xy rotate(float width, float depth, float angle) const {
 			xy out(0,0);
 			float temp_x = x - width / 2.f;
 			float temp_y = y - depth / 2.f;
 			angle *= M_PI/180.;
-			out.x += (temp_x - origin.x) * cos(angle)  -  (temp_y - origin.y) * sin(angle);
-			out.y += (temp_x - origin.x) * sin(angle)  +  (temp_y - origin.y) * cos(angle);
-			return out + origin;
+			out.x += temp_x * cos(angle)  -  temp_y * sin(angle) + width / 2.f;
+			out.y += temp_x * sin(angle)  +  temp_y * cos(angle) + depth / 2.f;
+
+			return out;
 		}
-		
+        
+        // Rotate the point around origin about given angle in degrees
+        void rotate(float angle) {
+            float temp_x = x * cos(angle)  -  y * sin(angle);
+			y = x * sin(angle)  +  y * cos(angle);
+            x = temp_x;
+		}
+
+        void translate(const xy& vect) {
+            x += vect.x;
+            y += vect.y;
+        }
+
 		float x;
 		float y;
 	};
@@ -104,6 +116,9 @@ public:
 		// This is useful not only for the print time estimation, but also for the control of layer cooling.
 		float  				    elapsed_time;
 
+        // Is this a priming extrusion? (If so, the wipe tower rotation & translation will not be applied later)
+        bool                    priming;
+
 		// Sum the total length of the extrusion.
 		float total_extrusion_length_in_plane() {
 			float e_length = 0.f;
diff --git a/xs/src/libslic3r/GCode/WipeTowerPrusaMM.cpp b/xs/src/libslic3r/GCode/WipeTowerPrusaMM.cpp
index f466fc4f6..3d0dba07a 100644
--- a/xs/src/libslic3r/GCode/WipeTowerPrusaMM.cpp
+++ b/xs/src/libslic3r/GCode/WipeTowerPrusaMM.cpp
@@ -5,7 +5,7 @@ TODO LIST
 
 1. cooling moves - DONE
 2. account for perimeter and finish_layer extrusions and subtract it from last wipe - DONE
-3. priming extrusions (last wipe must clear the color)
+3. priming extrusions (last wipe must clear the color) - DONE
 4. Peter's wipe tower - layer's are not exactly square
 5. Peter's wipe tower - variable width for higher levels
 6. Peter's wipe tower - make sure it is not too sparse (apply max_bridge_distance and make last wipe longer)
@@ -17,7 +17,6 @@ TODO LIST
 
 #include <assert.h>
 #include <math.h>
-#include <fstream>
 #include <iostream>
 #include <vector>
 #include <numeric>
@@ -68,8 +67,11 @@ public:
             return *this;
     }
 
-	Writer& 			 set_initial_position(const WipeTower::xy &pos) { 
-		m_start_pos = WipeTower::xy(pos,0.f,m_y_shift).rotate(m_wipe_tower_pos, m_wipe_tower_width, m_wipe_tower_depth, m_angle_deg);
+	Writer& 			 set_initial_position(const WipeTower::xy &pos, float width = 0.f, float depth = 0.f, float internal_angle = 0.f) {
+        m_wipe_tower_width = width;
+        m_wipe_tower_depth = depth;
+        m_internal_angle = internal_angle;
+		m_start_pos = WipeTower::xy(pos,0.f,m_y_shift).rotate(m_wipe_tower_width, m_wipe_tower_depth, m_internal_angle);
 		m_current_pos = pos;
 		return *this;
 	}
@@ -81,9 +83,6 @@ public:
 
 	Writer& 			 set_extrusion_flow(float flow)
 		{ m_extrusion_flow = flow; return *this; }
-		
-	Writer&				 set_rotation(WipeTower::xy& pos, float width, float depth, float angle)
-		{ m_wipe_tower_pos = pos; m_wipe_tower_width = width; m_wipe_tower_depth=depth; m_angle_deg = angle; return (*this); }
 
 	Writer&				 set_y_shift(float shift) {
         m_current_pos.y -= shift-m_y_shift;
@@ -110,7 +109,7 @@ public:
 	float                y()     const { return m_current_pos.y; }
 	const WipeTower::xy& pos()   const { return m_current_pos; }
 	const WipeTower::xy	 start_pos_rotated() const { return m_start_pos; }
-	const WipeTower::xy  pos_rotated() const { return WipeTower::xy(m_current_pos,0.f,m_y_shift).rotate(m_wipe_tower_pos, m_wipe_tower_width, m_wipe_tower_depth, m_angle_deg); }
+	const WipeTower::xy  pos_rotated() const { return WipeTower::xy(m_current_pos, 0.f, m_y_shift).rotate(m_wipe_tower_width, m_wipe_tower_depth, m_internal_angle); }
 	float 				 elapsed_time() const { return m_elapsed_time; }
 
 	// Extrude with an explicitely provided amount of extrusion.
@@ -125,9 +124,9 @@ public:
 		double len = sqrt(dx*dx+dy*dy);
 
 
-		// For rotated wipe tower, transform position to printer coordinates
-		WipeTower::xy rotated_current_pos(WipeTower::xy(m_current_pos,0.f,m_y_shift).rotate(m_wipe_tower_pos, m_wipe_tower_width, m_wipe_tower_depth, m_angle_deg)); // this is where we are
-		WipeTower::xy rot(WipeTower::xy(x,y+m_y_shift).rotate(m_wipe_tower_pos, m_wipe_tower_width, m_wipe_tower_depth, m_angle_deg));                               // this is where we want to go
+		// Now do the "internal rotation" with respect to the wipe tower center
+		WipeTower::xy rotated_current_pos(WipeTower::xy(m_current_pos,0.f,m_y_shift).rotate(m_wipe_tower_width, m_wipe_tower_depth, m_internal_angle)); // this is where we are
+		WipeTower::xy rot(WipeTower::xy(x,y+m_y_shift).rotate(m_wipe_tower_width, m_wipe_tower_depth, m_internal_angle));                               // this is where we want to go
 
 		if (! m_preview_suppressed && e > 0.f && len > 0.) {
 			// Width of a squished extrusion, corrected for the roundings of the squished extrusions.
@@ -147,6 +146,7 @@ public:
 		if (std::abs(rot.y - rotated_current_pos.y) > EPSILON)
 			m_gcode += set_format_Y(rot.y);
 
+
 		if (e != 0.f)
 			m_gcode += set_format_E(e);
 
@@ -397,9 +397,8 @@ private:
 	std::string   m_gcode;
 	std::vector<WipeTower::Extrusion> m_extrusions;
 	float         m_elapsed_time;
-	float   	  m_angle_deg = 0.f;
+	float   	  m_internal_angle = 0.f;
 	float		  m_y_shift = 0.f;
-	WipeTower::xy m_wipe_tower_pos;
 	float 		  m_wipe_tower_width = 0.f;
 	float		  m_wipe_tower_depth = 0.f;
 	float		  m_last_fan_speed = 0.f;
@@ -539,6 +538,7 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::prime(
 	m_print_brim = true;
 
 	ToolChangeResult result;
+    result.priming      = true;
 	result.print_z 	  	= this->m_z_pos;
 	result.layer_height = this->m_layer_height;
 	result.gcode   	  	= writer.gcode();
@@ -575,7 +575,7 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
 	}
 
 	box_coordinates cleaning_box(
-		m_wipe_tower_pos + xy(m_perimeter_width / 2.f, m_perimeter_width / 2.f),
+		xy(m_perimeter_width / 2.f, m_perimeter_width / 2.f),
 		m_wipe_tower_width - m_perimeter_width,
 		(tool != (unsigned int)(-1) ? /*m_layer_info->depth*/wipe_area+m_depth_traversed-0.5*m_perimeter_width
                                     : m_wipe_tower_depth-m_perimeter_width));
@@ -584,7 +584,6 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
 	writer.set_extrusion_flow(m_extrusion_flow)
 		.set_z(m_z_pos)
 		.set_initial_tool(m_current_tool)
-		.set_rotation(m_wipe_tower_pos, m_wipe_tower_width, m_wipe_tower_depth, m_wipe_tower_rotation_angle)
 		.set_y_shift(m_y_shift + (tool!=(unsigned int)(-1) && (m_current_shape == SHAPE_REVERSED && !m_peters_wipe_tower) ? m_layer_info->depth - m_layer_info->toolchanges_depth(): 0.f))
 		.append(";--------------------\n"
 				"; CP TOOLCHANGE START\n")
@@ -594,7 +593,7 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
 		.speed_override(100);
 
 	xy initial_position = cleaning_box.ld + WipeTower::xy(0.f,m_depth_traversed);
-    writer.set_initial_position(initial_position);
+    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);
@@ -616,11 +615,11 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
     if (last_change_in_layer) {// draw perimeter line
         writer.set_y_shift(m_y_shift);
         if (m_peters_wipe_tower)
-            writer.rectangle(m_wipe_tower_pos,m_layer_info->depth + 3*m_perimeter_width,m_wipe_tower_depth);
+            writer.rectangle(WipeTower::xy(0.f, 0.f),m_layer_info->depth + 3*m_perimeter_width,m_wipe_tower_depth);
         else {
-            writer.rectangle(m_wipe_tower_pos,m_wipe_tower_width, m_layer_info->depth + m_perimeter_width);
+            writer.rectangle(WipeTower::xy(0.f, 0.f),m_wipe_tower_width, m_layer_info->depth + m_perimeter_width);
             if (layer_finished()) { // no finish_layer will be called, we must wipe the nozzle
-                writer.travel(m_wipe_tower_pos.x + (writer.x()> (m_wipe_tower_pos.x + m_wipe_tower_width) / 2.f ? 0.f : m_wipe_tower_width), writer.y());
+                writer.travel(writer.x()> m_wipe_tower_width / 2.f ? 0.f : m_wipe_tower_width, writer.y());
             }
         }
     }
@@ -634,6 +633,7 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
                   "\n\n");
 
 	ToolChangeResult result;
+    result.priming      = false;
 	result.print_z 	  	= this->m_z_pos;
 	result.layer_height = this->m_layer_height;
 	result.gcode   	  	= writer.gcode();
@@ -647,7 +647,7 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::tool_change(unsigned int tool, boo
 WipeTower::ToolChangeResult WipeTowerPrusaMM::toolchange_Brim(bool sideOnly, float y_offset)
 {
 	const box_coordinates wipeTower_box(
-		m_wipe_tower_pos,
+		WipeTower::xy(0.f, 0.f),
 		m_wipe_tower_width,
 		m_wipe_tower_depth);
 
@@ -655,12 +655,11 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::toolchange_Brim(bool sideOnly, flo
 	writer.set_extrusion_flow(m_extrusion_flow * 1.1f)
 		  .set_z(m_z_pos) // Let the writer know the current Z position as a base for Z-hop.
 		  .set_initial_tool(m_current_tool)
-  		  .set_rotation(m_wipe_tower_pos, m_wipe_tower_width, m_wipe_tower_depth, m_wipe_tower_rotation_angle)
 		  .append(";-------------------------------------\n"
 				  "; CP WIPE TOWER FIRST LAYER BRIM START\n");
 
 	xy initial_position = wipeTower_box.lu - xy(m_perimeter_width * 6.f, 0);
-	writer.set_initial_position(initial_position);
+	writer.set_initial_position(initial_position, m_wipe_tower_width, m_wipe_tower_depth, m_internal_rotation);
 
     writer.extrude_explicit(wipeTower_box.ld - xy(m_perimeter_width * 6.f, 0), // Prime the extruder left of the wipe tower.
         1.5f * m_extrusion_flow * (wipeTower_box.lu.y - wipeTower_box.ld.y), 2400);
@@ -685,6 +684,7 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::toolchange_Brim(bool sideOnly, flo
     m_print_brim = false;  // Mark the brim as extruded
 
 	ToolChangeResult result;
+    result.priming      = false;
 	result.print_z 	  	= this->m_z_pos;
 	result.layer_height = this->m_layer_height;
 	result.gcode   	  	= writer.gcode();
@@ -724,7 +724,7 @@ void WipeTowerPrusaMM::toolchange_Unload(
     if (m_layer_info > m_plan.begin() && m_layer_info < m_plan.end() && (m_layer_info-1!=m_plan.begin() || !m_adhesion )) {
 
         // this is y of the center of previous sparse infill border
-        float sparse_beginning_y = m_wipe_tower_pos.y;
+        float sparse_beginning_y = 0.f;
         if (m_current_shape == SHAPE_REVERSED)
             sparse_beginning_y += ((m_layer_info-1)->depth - (m_layer_info-1)->toolchanges_depth())
                                       - ((m_layer_info)->depth-(m_layer_info)->toolchanges_depth()) ;
@@ -742,7 +742,7 @@ void WipeTowerPrusaMM::toolchange_Unload(
         for (const auto& tch : m_layer_info->tool_changes) {  // let's find this toolchange
             if (tch.old_tool == m_current_tool) {
                 sum_of_depths += tch.ramming_depth;
-                float ramming_end_y = m_wipe_tower_pos.y + sum_of_depths;
+                float ramming_end_y = sum_of_depths;
                 ramming_end_y -= (y_step/m_extra_spacing-m_perimeter_width) / 2.f;   // center of final ramming line
 
                 // debugging:
@@ -950,7 +950,7 @@ void WipeTowerPrusaMM::toolchange_Wipe(
     if (m_layer_info != m_plan.end() && m_current_tool != m_layer_info->tool_changes.back().new_tool) {
         m_left_to_right = !m_left_to_right;
         writer.travel(writer.x(), writer.y() - dy)
-        .travel(m_wipe_tower_pos.x + (m_left_to_right ? m_wipe_tower_width : 0.f), writer.y());
+        .travel(m_left_to_right ? m_wipe_tower_width : 0.f, writer.y());
     }
 
 	writer.set_extrusion_flow(m_extrusion_flow); // Reset the extrusion flow.
@@ -969,7 +969,6 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::finish_layer()
 	writer.set_extrusion_flow(m_extrusion_flow)
 		.set_z(m_z_pos)
 		.set_initial_tool(m_current_tool)
-		.set_rotation(m_wipe_tower_pos, m_wipe_tower_width, m_wipe_tower_depth, m_wipe_tower_rotation_angle)
 		.set_y_shift(m_y_shift - (m_current_shape == SHAPE_REVERSED && !m_peters_wipe_tower ? m_layer_info->toolchanges_depth() : 0.f))
 		.append(";--------------------\n"
 				"; CP EMPTY GRID START\n")
@@ -978,14 +977,12 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::finish_layer()
 	// Slow down on the 1st layer.
 	float speed_factor = m_is_first_layer ? 0.5f : 1.f;
 	float current_depth = m_layer_info->depth - m_layer_info->toolchanges_depth();
-	box_coordinates fill_box(m_wipe_tower_pos + xy(m_perimeter_width, m_depth_traversed + m_perimeter_width),
+	box_coordinates fill_box(xy(m_perimeter_width, m_depth_traversed + m_perimeter_width),
 							 m_wipe_tower_width - 2 * m_perimeter_width, current_depth-m_perimeter_width);
 
-    if (m_left_to_right) // so there is never a diagonal travel
-        writer.set_initial_position(fill_box.ru);
-    else
-        writer.set_initial_position(fill_box.lu);
 
+    writer.set_initial_position((m_left_to_right ? fill_box.ru : fill_box.lu), // so there is never a diagonal travel
+                                 m_wipe_tower_width, m_wipe_tower_depth, m_internal_rotation);
 
 	box_coordinates box = fill_box;
     for (int i=0;i<2;++i) {
@@ -1044,6 +1041,7 @@ WipeTower::ToolChangeResult WipeTowerPrusaMM::finish_layer()
     m_depth_traversed = m_wipe_tower_depth-m_perimeter_width;
 
 	ToolChangeResult result;
+    result.priming      = false;
 	result.print_z 	  	= this->m_z_pos;
 	result.layer_height = this->m_layer_height;
 	result.gcode   	  	= writer.gcode();
@@ -1165,9 +1163,9 @@ void WipeTowerPrusaMM::generate(std::vector<std::vector<WipeTower::ToolChangeRes
 	{
 		set_layer(layer.z,layer.height,0,layer.z == m_plan.front().z,layer.z == m_plan.back().z);
 		if (m_peters_wipe_tower)
-			m_wipe_tower_rotation_angle += 90.f;
+			m_internal_rotation += 90.f;
 		else
-            m_wipe_tower_rotation_angle += 180.f;
+            m_internal_rotation += 180.f;
 
 		if (!m_peters_wipe_tower && m_layer_info->depth < m_wipe_tower_depth - m_perimeter_width)
 			m_y_shift = (m_wipe_tower_depth-m_layer_info->depth-m_perimeter_width)/2.f;
@@ -1188,7 +1186,7 @@ void WipeTowerPrusaMM::generate(std::vector<std::vector<WipeTower::ToolChangeRes
 					last_toolchange.gcode += buf;
 				}
                 last_toolchange.gcode += finish_layer_toolchange.gcode;
-                last_toolchange.extrusions.insert(last_toolchange.extrusions.end(),finish_layer_toolchange.extrusions.begin(),finish_layer_toolchange.extrusions.end());
+                last_toolchange.extrusions.insert(last_toolchange.extrusions.end(), finish_layer_toolchange.extrusions.begin(), finish_layer_toolchange.extrusions.end());
                 last_toolchange.end_pos = finish_layer_toolchange.end_pos;
             }
             else
diff --git a/xs/src/libslic3r/GCode/WipeTowerPrusaMM.hpp b/xs/src/libslic3r/GCode/WipeTowerPrusaMM.hpp
index 1ae4616d8..e1529bcf4 100644
--- a/xs/src/libslic3r/GCode/WipeTowerPrusaMM.hpp
+++ b/xs/src/libslic3r/GCode/WipeTowerPrusaMM.hpp
@@ -102,6 +102,8 @@ public:
 	// Iterates through prepared m_plan, generates ToolChangeResults and appends them to "result"
 	void generate(std::vector<std::vector<WipeTower::ToolChangeResult>> &result);
 
+    float get_depth() const { return m_wipe_tower_depth; }
+
 
 
 	// Switch to a next layer.
@@ -189,6 +191,7 @@ private:
 	float  m_wipe_tower_width; 			// Width of the wipe tower.
 	float  m_wipe_tower_depth 	= 0.f; 	// Depth of the wipe tower
 	float  m_wipe_tower_rotation_angle = 0.f; // Wipe tower rotation angle in degrees (with respect to x axis)
+    float  m_internal_rotation  = 0.f;
 	float  m_y_shift			= 0.f;  // y shift passed to writer
 	float  m_z_pos 				= 0.f;  // Current Z position.
 	float  m_layer_height 		= 0.f; 	// Current layer height.
diff --git a/xs/src/libslic3r/GCodeTimeEstimator.cpp b/xs/src/libslic3r/GCodeTimeEstimator.cpp
index 909cdc26c..877695f39 100644
--- a/xs/src/libslic3r/GCodeTimeEstimator.cpp
+++ b/xs/src/libslic3r/GCodeTimeEstimator.cpp
@@ -1185,11 +1185,25 @@ namespace Slic3r {
     {
         PROFILE_FUNC();
         float value;
-        if (line.has_value('S', value))
+        if (line.has_value('S', value)) {
+            // Legacy acceleration format. This format is used by the legacy Marlin, MK2 or MK3 firmware,
+            // and it is also generated by Slic3r to control acceleration per extrusion type
+            // (there is a separate acceleration settings in Slicer for perimeter, first layer etc).
             set_acceleration(value);
-
-        if (line.has_value('T', value))
-            set_retract_acceleration(value);
+            if (line.has_value('T', value))
+                set_retract_acceleration(value);
+        } else {
+            // New acceleration format, compatible with the upstream Marlin.
+            if (line.has_value('P', value))
+                set_acceleration(value);
+            if (line.has_value('R', value))
+                set_retract_acceleration(value);
+            if (line.has_value('T', value)) {
+                // Interpret the T value as the travel acceleration in the new Marlin format.
+                //FIXME Prusa3D firmware currently does not support travel acceleration value independent from the extruding acceleration value.
+                // set_travel_acceleration(value);
+            }
+        }
     }
 
     void GCodeTimeEstimator::_processM205(const GCodeReader::GCodeLine& line)
diff --git a/xs/src/libslic3r/Model.cpp b/xs/src/libslic3r/Model.cpp
index d6f1f05c9..bceeea258 100644
--- a/xs/src/libslic3r/Model.cpp
+++ b/xs/src/libslic3r/Model.cpp
@@ -7,11 +7,6 @@
 #include "Format/STL.hpp"
 #include "Format/3mf.hpp"
 
-#include <numeric>
-#include <libnest2d.h>
-#include <ClipperUtils.hpp>
-#include "slic3r/GUI/GUI.hpp"
-
 #include <float.h>
 
 #include <boost/algorithm/string/predicate.hpp>
@@ -304,369 +299,36 @@ static bool _arrange(const Pointfs &sizes, coordf_t dist, const BoundingBoxf* bb
     return result;
 }
 
-namespace arr {
-
-using namespace libnest2d;
-
-std::string toString(const Model& model, bool holes = true) {
-    std::stringstream  ss;
-
-    ss << "{\n";
-
-    for(auto objptr : model.objects) {
-        if(!objptr) continue;
-
-        auto rmesh = objptr->raw_mesh();
-
-        for(auto objinst : objptr->instances) {
-            if(!objinst) continue;
-
-            Slic3r::TriangleMesh tmpmesh = rmesh;
-            tmpmesh.scale(objinst->scaling_factor);
-            objinst->transform_mesh(&tmpmesh);
-            ExPolygons expolys = tmpmesh.horizontal_projection();
-            for(auto& expoly_complex : expolys) {
-
-                auto tmp = expoly_complex.simplify(1.0/SCALING_FACTOR);
-                if(tmp.empty()) continue;
-                auto expoly = tmp.front();
-                expoly.contour.make_clockwise();
-                for(auto& h : expoly.holes) h.make_counter_clockwise();
-
-                ss << "\t{\n";
-                ss << "\t\t{\n";
-
-                for(auto v : expoly.contour.points) ss << "\t\t\t{"
-                                                    << v.x << ", "
-                                                    << v.y << "},\n";
-                {
-                    auto v = expoly.contour.points.front();
-                    ss << "\t\t\t{" << v.x << ", " << v.y << "},\n";
-                }
-                ss << "\t\t},\n";
-
-                // Holes:
-                ss << "\t\t{\n";
-                if(holes) for(auto h : expoly.holes) {
-                    ss << "\t\t\t{\n";
-                    for(auto v : h.points) ss << "\t\t\t\t{"
-                                           << v.x << ", "
-                                           << v.y << "},\n";
-                    {
-                        auto v = h.points.front();
-                        ss << "\t\t\t\t{" << v.x << ", " << v.y << "},\n";
-                    }
-                    ss << "\t\t\t},\n";
-                }
-                ss << "\t\t},\n";
-
-                ss << "\t},\n";
-            }
-        }
-    }
-
-    ss << "}\n";
-
-    return ss.str();
-}
-
-void toSVG(SVG& svg, const Model& model) {
-    for(auto objptr : model.objects) {
-        if(!objptr) continue;
-
-        auto rmesh = objptr->raw_mesh();
-
-        for(auto objinst : objptr->instances) {
-            if(!objinst) continue;
-
-            Slic3r::TriangleMesh tmpmesh = rmesh;
-            tmpmesh.scale(objinst->scaling_factor);
-            objinst->transform_mesh(&tmpmesh);
-            ExPolygons expolys = tmpmesh.horizontal_projection();
-            svg.draw(expolys);
-        }
-    }
-}
-
-// A container which stores a pointer to the 3D object and its projected
-// 2D shape from top view.
-using ShapeData2D =
-    std::vector<std::pair<Slic3r::ModelInstance*, Item>>;
-
-ShapeData2D projectModelFromTop(const Slic3r::Model &model) {
-    ShapeData2D ret;
-
-    auto s = std::accumulate(model.objects.begin(), model.objects.end(), 0,
-                    [](size_t s, ModelObject* o){
-        return s + o->instances.size();
-    });
-
-    ret.reserve(s);
-
-    for(auto objptr : model.objects) {
-        if(objptr) {
-
-            auto rmesh = objptr->raw_mesh();
-
-            for(auto objinst : objptr->instances) {
-                if(objinst) {
-                    Slic3r::TriangleMesh tmpmesh = rmesh;
-                    ClipperLib::PolygonImpl pn;
-
-                    tmpmesh.scale(objinst->scaling_factor);
-
-                    // TODO export the exact 2D projection
-                    auto p = tmpmesh.convex_hull();
-
-                    p.make_clockwise();
-                    p.append(p.first_point());
-                    pn.Contour = Slic3rMultiPoint_to_ClipperPath( p );
-
-                    // Efficient conversion to item.
-                    Item item(std::move(pn));
-
-                    // Invalid geometries would throw exceptions when arranging
-                    if(item.vertexCount() > 3) {
-                        item.rotation(objinst->rotation);
-                        item.translation( {
-                            ClipperLib::cInt(objinst->offset.x/SCALING_FACTOR),
-                            ClipperLib::cInt(objinst->offset.y/SCALING_FACTOR)
-                        });
-                        ret.emplace_back(objinst, item);
-                    }
-                }
-            }
-        }
-    }
-
-    return ret;
-}
-
-/**
- * \brief Arranges the model objects on the screen.
- *
- * The arrangement considers multiple bins (aka. print beds) for placing all
- * the items provided in the model argument. If the items don't fit on one
- * print bed, the remaining will be placed onto newly created print beds.
- * The first_bin_only parameter, if set to true, disables this behaviour and
- * makes sure that only one print bed is filled and the remaining items will be
- * untouched. When set to false, the items which could not fit onto the
- * print bed will be placed next to the print bed so the user should see a
- * pile of items on the print bed and some other piles outside the print
- * area that can be dragged later onto the print bed as a group.
- *
- * \param model The model object with the 3D content.
- * \param dist The minimum distance which is allowed for any pair of items
- * on the print bed  in any direction.
- * \param bb The bounding box of the print bed. It corresponds to the 'bin'
- * for bin packing.
- * \param first_bin_only This parameter controls whether to place the
- * remaining items which do not fit onto the print area next to the print
- * bed or leave them untouched (let the user arrange them by hand or remove
- * them).
- */
-bool arrange(Model &model, coordf_t dist, const Slic3r::BoundingBoxf* bb,
-             bool first_bin_only,
-             std::function<void(unsigned)> progressind)
-{
-    using ArrangeResult = _IndexedPackGroup<PolygonImpl>;
-
-    bool ret = true;
-
-    // Create the arranger config
-    auto min_obj_distance = static_cast<Coord>(dist/SCALING_FACTOR);
-
-    // Get the 2D projected shapes with their 3D model instance pointers
-    auto shapemap = arr::projectModelFromTop(model);
-
-    bool hasbin = bb != nullptr && bb->defined;
-    double area_max = 0;
-
-    // Copy the references for the shapes only as the arranger expects a
-    // sequence of objects convertible to Item or ClipperPolygon
-    std::vector<std::reference_wrapper<Item>> shapes;
-    shapes.reserve(shapemap.size());
-    std::for_each(shapemap.begin(), shapemap.end(),
-                  [&shapes, min_obj_distance, &area_max, hasbin]
-                  (ShapeData2D::value_type& it)
-    {
-        shapes.push_back(std::ref(it.second));
-    });
-
-    Box bin;
-
-    if(hasbin) {
-        // Scale up the bounding box to clipper scale.
-        BoundingBoxf bbb = *bb;
-        bbb.scale(1.0/SCALING_FACTOR);
-
-        bin = Box({
-                    static_cast<libnest2d::Coord>(bbb.min.x),
-                    static_cast<libnest2d::Coord>(bbb.min.y)
-                },
-                {
-                    static_cast<libnest2d::Coord>(bbb.max.x),
-                    static_cast<libnest2d::Coord>(bbb.max.y)
-                });
-    }
-
-    // Will use the DJD selection heuristic with the BottomLeft placement
-    // strategy
-    using Arranger = Arranger<NfpPlacer, FirstFitSelection>;
-    using PConf = Arranger::PlacementConfig;
-    using SConf = Arranger::SelectionConfig;
-
-    PConf pcfg;     // Placement configuration
-    SConf scfg;     // Selection configuration
-
-    // Align the arranged pile into the center of the bin
-    pcfg.alignment = PConf::Alignment::CENTER;
-
-    // Start placing the items from the center of the print bed
-    pcfg.starting_point = PConf::Alignment::CENTER;
-
-    // TODO cannot use rotations until multiple objects of same geometry can
-    // handle different rotations
-    // arranger.useMinimumBoundigBoxRotation();
-    pcfg.rotations = { 0.0 };
-
-    // Magic: we will specify what is the goal of arrangement... In this case
-    // we override the default object function to make the larger items go into
-    // the center of the pile and smaller items orbit it so the resulting pile
-    // has a circle-like shape. This is good for the print bed's heat profile.
-    // We alse sacrafice a bit of pack efficiency for this to work. As a side
-    // effect, the arrange procedure is a lot faster (we do not need to
-    // calculate the convex hulls)
-    pcfg.object_function = [bin, hasbin](
-            NfpPlacer::Pile pile,   // The currently arranged pile
-            double /*area*/,        // Sum area of items (not needed)
-            double norm,            // A norming factor for physical dimensions
-            double penality)        // Min penality in case of bad arrangement
-    {
-        auto bb = ShapeLike::boundingBox(pile);
-
-        // We get the current item that's being evaluated.
-        auto& sh = pile.back();
-
-        // We retrieve the reference point of this item
-        auto rv = Nfp::referenceVertex(sh);
-
-        // We get the distance of the reference point from the center of the
-        // heat bed
-        auto c = bin.center();
-        auto d = PointLike::distance(rv, c);
-
-        // The score will be the normalized distance which will be minimized,
-        // effectively creating a circle shaped pile of items
-        double score = double(d)/norm;
-
-        // If it does not fit into the print bed we will beat it
-        // with a large penality. If we would not do this, there would be only
-        // one big pile that doesn't care whether it fits onto the print bed.
-        if(hasbin && !NfpPlacer::wouldFit(bb, bin)) score = 2*penality - score;
-
-        return score;
-    };
-
-    // Create the arranger object
-    Arranger arranger(bin, min_obj_distance, pcfg, scfg);
-
-    // Set the progress indicator for the arranger.
-    arranger.progressIndicator(progressind);
-
-    // Arrange and return the items with their respective indices within the
-    // input sequence.
-    auto result = arranger.arrangeIndexed(shapes.begin(), shapes.end());
-
-    auto applyResult = [&shapemap](ArrangeResult::value_type& group,
-            Coord batch_offset)
-    {
-        for(auto& r : group) {
-            auto idx = r.first;     // get the original item index
-            Item& item = r.second;  // get the item itself
-
-            // Get the model instance from the shapemap using the index
-            ModelInstance *inst_ptr = shapemap[idx].first;
-
-            // Get the tranformation data from the item object and scale it
-            // appropriately
-            auto off = item.translation();
-            Radians rot = item.rotation();
-            Pointf foff(off.X*SCALING_FACTOR + batch_offset,
-                        off.Y*SCALING_FACTOR);
-
-            // write the tranformation data into the model instance
-            inst_ptr->rotation = rot;
-            inst_ptr->offset = foff;
-        }
-    };
-
-    if(first_bin_only) {
-        applyResult(result.front(), 0);
-    } else {
-
-        const auto STRIDE_PADDING = 1.2;
-
-        Coord stride = static_cast<Coord>(STRIDE_PADDING*
-                                          bin.width()*SCALING_FACTOR);
-        Coord batch_offset = 0;
-
-        for(auto& group : result) {
-            applyResult(group, batch_offset);
-
-            // Only the first pack group can be placed onto the print bed. The
-            // other objects which could not fit will be placed next to the
-            // print bed
-            batch_offset += stride;
-        }
-    }
-
-    for(auto objptr : model.objects) objptr->invalidate_bounding_box();
-
-    return ret && result.size() == 1;
-}
-}
-
 /*  arrange objects preserving their instance count
     but altering their instance positions */
-bool Model::arrange_objects(coordf_t dist, const BoundingBoxf* bb,
-                            std::function<void(unsigned)> progressind)
-{
-    bool ret = false;
-    if(bb != nullptr && bb->defined) {
-        // Despite the new arrange is able to run without a specified bin,
-        // the perl testsuit still fails for this case. For now the safest
-        // thing to do is to use the new arrange only when a proper bin is
-        // specified.
-        ret = arr::arrange(*this, dist, bb, false, progressind);
-    } else {
-        // get the (transformed) size of each instance so that we take
-        // into account their different transformations when packing
-        Pointfs instance_sizes;
-        Pointfs instance_centers;
-        for (const ModelObject *o : this->objects)
-            for (size_t i = 0; i < o->instances.size(); ++ i) {
-                // an accurate snug bounding box around the transformed mesh.
-                BoundingBoxf3 bbox(o->instance_bounding_box(i, true));
-                instance_sizes.push_back(bbox.size());
-                instance_centers.push_back(bbox.center());
-            }
+bool Model::arrange_objects(coordf_t dist, const BoundingBoxf* bb)
+{
+    // get the (transformed) size of each instance so that we take
+    // into account their different transformations when packing
+    Pointfs instance_sizes;
+    Pointfs instance_centers;
+    for (const ModelObject *o : this->objects)
+        for (size_t i = 0; i < o->instances.size(); ++ i) {
+            // an accurate snug bounding box around the transformed mesh.
+            BoundingBoxf3 bbox(o->instance_bounding_box(i, true));
+            instance_sizes.push_back(bbox.size());
+            instance_centers.push_back(bbox.center());
+        }
 
-        Pointfs positions;
-        if (! _arrange(instance_sizes, dist, bb, positions))
-            return false;
+    Pointfs positions;
+    if (! _arrange(instance_sizes, dist, bb, positions))
+        return false;
 
-        size_t idx = 0;
-        for (ModelObject *o : this->objects) {
-            for (ModelInstance *i : o->instances) {
-                i->offset = positions[idx] - instance_centers[idx];
-                ++ idx;
-            }
-            o->invalidate_bounding_box();
+    size_t idx = 0;
+    for (ModelObject *o : this->objects) {
+        for (ModelInstance *i : o->instances) {
+            i->offset = positions[idx] - instance_centers[idx];
+            ++ idx;
         }
+        o->invalidate_bounding_box();
     }
 
-    return ret;
+    return true;
 }
 
 // Duplicate the entire model preserving instance relative positions.
@@ -1109,9 +771,23 @@ void ModelObject::scale(const Pointf3 &versor)
 
 void ModelObject::rotate(float angle, const Axis &axis)
 {
+    float min_z = FLT_MAX;
     for (ModelVolume *v : this->volumes)
+    {
         v->mesh.rotate(angle, axis);
-    this->origin_translation = Pointf3(0,0,0);
+        min_z = std::min(min_z, v->mesh.stl.stats.min.z);
+    }
+
+    if (min_z != 0.0f)
+    {
+        // translate the object so that its minimum z lays on the bed
+        for (ModelVolume *v : this->volumes)
+        {
+            v->mesh.translate(0.0f, 0.0f, -min_z);
+        }
+    }
+
+    this->origin_translation = Pointf3(0, 0, 0);
     this->invalidate_bounding_box();
 }
 
diff --git a/xs/src/libslic3r/Model.hpp b/xs/src/libslic3r/Model.hpp
index f5e97fb6a..4c650f0de 100644
--- a/xs/src/libslic3r/Model.hpp
+++ b/xs/src/libslic3r/Model.hpp
@@ -290,8 +290,7 @@ public:
     void center_instances_around_point(const Pointf &point);
     void translate(coordf_t x, coordf_t y, coordf_t z) { for (ModelObject *o : this->objects) o->translate(x, y, z); }
     TriangleMesh mesh() const;
-    bool arrange_objects(coordf_t dist, const BoundingBoxf* bb = NULL,
-                         std::function<void(unsigned)> progressind = [](unsigned){});
+    bool arrange_objects(coordf_t dist, const BoundingBoxf* bb = NULL);
     // Croaks if the duplicated objects do not fit the print bed.
     void duplicate(size_t copies_num, coordf_t dist, const BoundingBoxf* bb = NULL);
     void duplicate_objects(size_t copies_num, coordf_t dist, const BoundingBoxf* bb = NULL);
diff --git a/xs/src/libslic3r/ModelArrange.hpp b/xs/src/libslic3r/ModelArrange.hpp
new file mode 100644
index 000000000..f2d399ac6
--- /dev/null
+++ b/xs/src/libslic3r/ModelArrange.hpp
@@ -0,0 +1,597 @@
+#ifndef MODELARRANGE_HPP
+#define MODELARRANGE_HPP
+
+#include "Model.hpp"
+#include "SVG.hpp"
+#include <libnest2d.h>
+
+#include <numeric>
+#include <ClipperUtils.hpp>
+
+#include <boost/geometry/index/rtree.hpp>
+
+namespace Slic3r {
+namespace arr {
+
+using namespace libnest2d;
+
+std::string toString(const Model& model, bool holes = true) {
+    std::stringstream  ss;
+
+    ss << "{\n";
+
+    for(auto objptr : model.objects) {
+        if(!objptr) continue;
+
+        auto rmesh = objptr->raw_mesh();
+
+        for(auto objinst : objptr->instances) {
+            if(!objinst) continue;
+
+            Slic3r::TriangleMesh tmpmesh = rmesh;
+            tmpmesh.scale(objinst->scaling_factor);
+            objinst->transform_mesh(&tmpmesh);
+            ExPolygons expolys = tmpmesh.horizontal_projection();
+            for(auto& expoly_complex : expolys) {
+
+                auto tmp = expoly_complex.simplify(1.0/SCALING_FACTOR);
+                if(tmp.empty()) continue;
+                auto expoly = tmp.front();
+                expoly.contour.make_clockwise();
+                for(auto& h : expoly.holes) h.make_counter_clockwise();
+
+                ss << "\t{\n";
+                ss << "\t\t{\n";
+
+                for(auto v : expoly.contour.points) ss << "\t\t\t{"
+                                                    << v.x << ", "
+                                                    << v.y << "},\n";
+                {
+                    auto v = expoly.contour.points.front();
+                    ss << "\t\t\t{" << v.x << ", " << v.y << "},\n";
+                }
+                ss << "\t\t},\n";
+
+                // Holes:
+                ss << "\t\t{\n";
+                if(holes) for(auto h : expoly.holes) {
+                    ss << "\t\t\t{\n";
+                    for(auto v : h.points) ss << "\t\t\t\t{"
+                                           << v.x << ", "
+                                           << v.y << "},\n";
+                    {
+                        auto v = h.points.front();
+                        ss << "\t\t\t\t{" << v.x << ", " << v.y << "},\n";
+                    }
+                    ss << "\t\t\t},\n";
+                }
+                ss << "\t\t},\n";
+
+                ss << "\t},\n";
+            }
+        }
+    }
+
+    ss << "}\n";
+
+    return ss.str();
+}
+
+void toSVG(SVG& svg, const Model& model) {
+    for(auto objptr : model.objects) {
+        if(!objptr) continue;
+
+        auto rmesh = objptr->raw_mesh();
+
+        for(auto objinst : objptr->instances) {
+            if(!objinst) continue;
+
+            Slic3r::TriangleMesh tmpmesh = rmesh;
+            tmpmesh.scale(objinst->scaling_factor);
+            objinst->transform_mesh(&tmpmesh);
+            ExPolygons expolys = tmpmesh.horizontal_projection();
+            svg.draw(expolys);
+        }
+    }
+}
+
+namespace bgi = boost::geometry::index;
+
+using SpatElement = std::pair<Box, unsigned>;
+using SpatIndex = bgi::rtree< SpatElement, bgi::rstar<16, 4> >;
+
+std::tuple<double /*score*/, Box /*farthest point from bin center*/>
+objfunc(const PointImpl& bincenter,
+        double /*bin_area*/,
+        ShapeLike::Shapes<PolygonImpl>& pile,   // The currently arranged pile
+        double /*pile_area*/,
+        const Item &item,
+        double norm,            // A norming factor for physical dimensions
+        std::vector<double>& areacache, // pile item areas will be cached
+        // a spatial index to quickly get neighbors of the candidate item
+        SpatIndex& spatindex
+        )
+{
+    using pl = PointLike;
+    using sl = ShapeLike;
+
+    static const double BIG_ITEM_TRESHOLD = 0.2;
+    static const double ROUNDNESS_RATIO = 0.5;
+    static const double DENSITY_RATIO = 1.0 - ROUNDNESS_RATIO;
+
+    // We will treat big items (compared to the print bed) differently
+    auto normarea = [norm](double area) { return std::sqrt(area)/norm; };
+
+    // If a new bin has been created:
+    if(pile.size() < areacache.size()) {
+        areacache.clear();
+        spatindex.clear();
+    }
+
+    // We must fill the caches:
+    int idx = 0;
+    for(auto& p : pile) {
+        if(idx == areacache.size()) {
+            areacache.emplace_back(sl::area(p));
+            if(normarea(areacache[idx]) > BIG_ITEM_TRESHOLD)
+                spatindex.insert({sl::boundingBox(p), idx});
+        }
+
+        idx++;
+    }
+
+    // Candidate item bounding box
+    auto ibb = item.boundingBox();
+
+    // Calculate the full bounding box of the pile with the candidate item
+    pile.emplace_back(item.transformedShape());
+    auto fullbb = ShapeLike::boundingBox(pile);
+    pile.pop_back();
+
+    // The bounding box of the big items (they will accumulate in the center
+    // of the pile
+    Box bigbb;
+    if(spatindex.empty()) bigbb = fullbb;
+    else {
+        auto boostbb = spatindex.bounds();
+        boost::geometry::convert(boostbb, bigbb);
+    }
+
+    // The size indicator of the candidate item. This is not the area,
+    // but almost...
+    double item_normarea = normarea(item.area());
+
+    // Will hold the resulting score
+    double score = 0;
+
+    if(item_normarea > BIG_ITEM_TRESHOLD) {
+        // This branch is for the bigger items..
+        // Here we will use the closest point of the item bounding box to
+        // the already arranged pile. So not the bb center nor the a choosen
+        // corner but whichever is the closest to the center. This will
+        // prevent some unwanted strange arrangements.
+
+        auto minc = ibb.minCorner(); // bottom left corner
+        auto maxc = ibb.maxCorner(); // top right corner
+
+        // top left and bottom right corners
+        auto top_left = PointImpl{getX(minc), getY(maxc)};
+        auto bottom_right = PointImpl{getX(maxc), getY(minc)};
+
+        // Now the distance of the gravity center will be calculated to the
+        // five anchor points and the smallest will be chosen.
+        std::array<double, 5> dists;
+        auto cc = fullbb.center(); // The gravity center
+        dists[0] = pl::distance(minc, cc);
+        dists[1] = pl::distance(maxc, cc);
+        dists[2] = pl::distance(ibb.center(), cc);
+        dists[3] = pl::distance(top_left, cc);
+        dists[4] = pl::distance(bottom_right, cc);
+
+        // The smalles distance from the arranged pile center:
+        auto dist = *(std::min_element(dists.begin(), dists.end())) / norm;
+
+        // Density is the pack density: how big is the arranged pile
+        auto density = std::sqrt(fullbb.width()*fullbb.height()) / norm;
+
+        // Prepare a variable for the alignment score.
+        // This will indicate: how well is the candidate item aligned with
+        // its neighbors. We will check the aligment with all neighbors and
+        // return the score for the best alignment. So it is enough for the
+        // candidate to be aligned with only one item.
+        auto alignment_score = std::numeric_limits<double>::max();
+
+        auto& trsh =  item.transformedShape();
+
+        auto querybb = item.boundingBox();
+
+        // Query the spatial index for the neigbours
+        std::vector<SpatElement> result;
+        spatindex.query(bgi::intersects(querybb), std::back_inserter(result));
+
+        for(auto& e : result) { // now get the score for the best alignment
+            auto idx = e.second;
+            auto& p = pile[idx];
+            auto parea = areacache[idx];
+            auto bb = sl::boundingBox(sl::Shapes<PolygonImpl>{p, trsh});
+            auto bbarea = bb.area();
+            auto ascore = 1.0 - (item.area() + parea)/bbarea;
+
+            if(ascore < alignment_score) alignment_score = ascore;
+        }
+
+        // The final mix of the score is the balance between the distance
+        // from the full pile center, the pack density and the
+        // alignment with the neigbours
+        auto C = 0.33;
+        score = C * dist +  C * density + C * alignment_score;
+
+    } else if( item_normarea < BIG_ITEM_TRESHOLD && spatindex.empty()) {
+        // If there are no big items, only small, we should consider the
+        // density here as well to not get silly results
+        auto bindist = pl::distance(ibb.center(), bincenter) / norm;
+        auto density = std::sqrt(fullbb.width()*fullbb.height()) / norm;
+        score = ROUNDNESS_RATIO * bindist + DENSITY_RATIO * density;
+    } else {
+        // Here there are the small items that should be placed around the
+        // already processed bigger items.
+        // No need to play around with the anchor points, the center will be
+        // just fine for small items
+        score = pl::distance(ibb.center(), bigbb.center()) / norm;
+    }
+
+    return std::make_tuple(score, fullbb);
+}
+
+template<class PConf>
+void fillConfig(PConf& pcfg) {
+
+    // Align the arranged pile into the center of the bin
+    pcfg.alignment = PConf::Alignment::CENTER;
+
+    // Start placing the items from the center of the print bed
+    pcfg.starting_point = PConf::Alignment::CENTER;
+
+    // TODO cannot use rotations until multiple objects of same geometry can
+    // handle different rotations
+    // arranger.useMinimumBoundigBoxRotation();
+    pcfg.rotations = { 0.0 };
+
+    // The accuracy of optimization.
+    // Goes from 0.0 to 1.0 and scales performance as well
+    pcfg.accuracy = 0.6f;
+}
+
+template<class TBin>
+class AutoArranger {};
+
+template<class TBin>
+class _ArrBase {
+protected:
+    using Placer = strategies::_NofitPolyPlacer<PolygonImpl, TBin>;
+    using Selector = FirstFitSelection;
+    using Packer = Arranger<Placer, Selector>;
+    using PConfig = typename Packer::PlacementConfig;
+    using Distance = TCoord<PointImpl>;
+    using Pile = ShapeLike::Shapes<PolygonImpl>;
+
+    Packer pck_;
+    PConfig pconf_; // Placement configuration
+    double bin_area_;
+    std::vector<double> areacache_;
+    SpatIndex rtree_;
+public:
+
+    _ArrBase(const TBin& bin, Distance dist,
+             std::function<void(unsigned)> progressind):
+       pck_(bin, dist), bin_area_(ShapeLike::area<PolygonImpl>(bin))
+    {
+        fillConfig(pconf_);
+        pck_.progressIndicator(progressind);
+    }
+
+    template<class...Args> inline IndexedPackGroup operator()(Args&&...args) {
+        areacache_.clear();
+        return pck_.arrangeIndexed(std::forward<Args>(args)...);
+    }
+};
+
+template<>
+class AutoArranger<Box>: public _ArrBase<Box> {
+public:
+
+    AutoArranger(const Box& bin, Distance dist,
+                 std::function<void(unsigned)> progressind):
+        _ArrBase<Box>(bin, dist, progressind)
+    {
+        pconf_.object_function = [this, bin] (
+                    Pile& pile,
+                    const Item &item,
+                    double pile_area,
+                    double norm,
+                    double /*penality*/) {
+
+            auto result = objfunc(bin.center(), bin_area_, pile,
+                                  pile_area, item, norm, areacache_, rtree_);
+            double score = std::get<0>(result);
+            auto& fullbb = std::get<1>(result);
+
+            auto wdiff = fullbb.width() - bin.width();
+            auto hdiff = fullbb.height() - bin.height();
+            if(wdiff > 0) score += std::pow(wdiff, 2) / norm;
+            if(hdiff > 0) score += std::pow(hdiff, 2) / norm;
+
+            return score;
+        };
+
+        pck_.configure(pconf_);
+    }
+};
+
+template<>
+class AutoArranger<PolygonImpl>: public _ArrBase<PolygonImpl> {
+public:
+    AutoArranger(const PolygonImpl& bin, Distance dist,
+                 std::function<void(unsigned)> progressind):
+        _ArrBase<PolygonImpl>(bin, dist, progressind)
+    {
+        pconf_.object_function = [this, &bin] (
+                    Pile& pile,
+                    const Item &item,
+                    double pile_area,
+                    double norm,
+                    double /*penality*/) {
+
+            auto binbb = ShapeLike::boundingBox(bin);
+            auto result = objfunc(binbb.center(), bin_area_, pile,
+                                  pile_area, item, norm, areacache_, rtree_);
+            double score = std::get<0>(result);
+
+            pile.emplace_back(item.transformedShape());
+            auto chull = ShapeLike::convexHull(pile);
+            pile.pop_back();
+
+            // If it does not fit into the print bed we will beat it with a
+            // large penality. If we would not do this, there would be only one
+            // big pile that doesn't care whether it fits onto the print bed.
+            if(!Placer::wouldFit(chull, bin)) score += norm;
+
+            return score;
+        };
+
+        pck_.configure(pconf_);
+    }
+};
+
+template<> // Specialization with no bin
+class AutoArranger<bool>: public _ArrBase<Box> {
+public:
+
+    AutoArranger(Distance dist, std::function<void(unsigned)> progressind):
+        _ArrBase<Box>(Box(0, 0), dist, progressind)
+    {
+        this->pconf_.object_function = [this] (
+                    Pile& pile,
+                    const Item &item,
+                    double pile_area,
+                    double norm,
+                    double /*penality*/) {
+
+            auto result = objfunc({0, 0}, 0, pile, pile_area,
+                                  item, norm, areacache_, rtree_);
+            return std::get<0>(result);
+        };
+
+        this->pck_.configure(pconf_);
+    }
+};
+
+// A container which stores a pointer to the 3D object and its projected
+// 2D shape from top view.
+using ShapeData2D =
+    std::vector<std::pair<Slic3r::ModelInstance*, Item>>;
+
+ShapeData2D projectModelFromTop(const Slic3r::Model &model) {
+    ShapeData2D ret;
+
+    auto s = std::accumulate(model.objects.begin(), model.objects.end(), 0,
+                    [](size_t s, ModelObject* o){
+        return s + o->instances.size();
+    });
+
+    ret.reserve(s);
+
+    for(auto objptr : model.objects) {
+        if(objptr) {
+
+            auto rmesh = objptr->raw_mesh();
+
+            for(auto objinst : objptr->instances) {
+                if(objinst) {
+                    Slic3r::TriangleMesh tmpmesh = rmesh;
+                    ClipperLib::PolygonImpl pn;
+
+                    tmpmesh.scale(objinst->scaling_factor);
+
+                    // TODO export the exact 2D projection
+                    auto p = tmpmesh.convex_hull();
+
+                    p.make_clockwise();
+                    p.append(p.first_point());
+                    pn.Contour = Slic3rMultiPoint_to_ClipperPath( p );
+
+                    // Efficient conversion to item.
+                    Item item(std::move(pn));
+
+                    // Invalid geometries would throw exceptions when arranging
+                    if(item.vertexCount() > 3) {
+                        item.rotation(objinst->rotation);
+                        item.translation( {
+                            ClipperLib::cInt(objinst->offset.x/SCALING_FACTOR),
+                            ClipperLib::cInt(objinst->offset.y/SCALING_FACTOR)
+                        });
+                        ret.emplace_back(objinst, item);
+                    }
+                }
+            }
+        }
+    }
+
+    return ret;
+}
+
+enum BedShapeHint {
+    BOX,
+    CIRCLE,
+    IRREGULAR,
+    WHO_KNOWS
+};
+
+BedShapeHint bedShape(const Slic3r::Polyline& /*bed*/) {
+    // Determine the bed shape by hand
+    return BOX;
+}
+
+void applyResult(
+        IndexedPackGroup::value_type& group,
+        Coord batch_offset,
+        ShapeData2D& shapemap)
+{
+    for(auto& r : group) {
+        auto idx = r.first;     // get the original item index
+        Item& item = r.second;  // get the item itself
+
+        // Get the model instance from the shapemap using the index
+        ModelInstance *inst_ptr = shapemap[idx].first;
+
+        // Get the tranformation data from the item object and scale it
+        // appropriately
+        auto off = item.translation();
+        Radians rot = item.rotation();
+        Pointf foff(off.X*SCALING_FACTOR + batch_offset,
+                    off.Y*SCALING_FACTOR);
+
+        // write the tranformation data into the model instance
+        inst_ptr->rotation = rot;
+        inst_ptr->offset = foff;
+    }
+}
+
+
+/**
+ * \brief Arranges the model objects on the screen.
+ *
+ * The arrangement considers multiple bins (aka. print beds) for placing all
+ * the items provided in the model argument. If the items don't fit on one
+ * print bed, the remaining will be placed onto newly created print beds.
+ * The first_bin_only parameter, if set to true, disables this behaviour and
+ * makes sure that only one print bed is filled and the remaining items will be
+ * untouched. When set to false, the items which could not fit onto the
+ * print bed will be placed next to the print bed so the user should see a
+ * pile of items on the print bed and some other piles outside the print
+ * area that can be dragged later onto the print bed as a group.
+ *
+ * \param model The model object with the 3D content.
+ * \param dist The minimum distance which is allowed for any pair of items
+ * on the print bed  in any direction.
+ * \param bb The bounding box of the print bed. It corresponds to the 'bin'
+ * for bin packing.
+ * \param first_bin_only This parameter controls whether to place the
+ * remaining items which do not fit onto the print area next to the print
+ * bed or leave them untouched (let the user arrange them by hand or remove
+ * them).
+ */
+bool arrange(Model &model, coordf_t min_obj_distance,
+             const Slic3r::Polyline& bed,
+             BedShapeHint bedhint,
+             bool first_bin_only,
+             std::function<void(unsigned)> progressind)
+{
+    using ArrangeResult = _IndexedPackGroup<PolygonImpl>;
+
+    bool ret = true;
+
+    // Get the 2D projected shapes with their 3D model instance pointers
+    auto shapemap = arr::projectModelFromTop(model);
+
+    // Copy the references for the shapes only as the arranger expects a
+    // sequence of objects convertible to Item or ClipperPolygon
+    std::vector<std::reference_wrapper<Item>> shapes;
+    shapes.reserve(shapemap.size());
+    std::for_each(shapemap.begin(), shapemap.end(),
+                  [&shapes] (ShapeData2D::value_type& it)
+    {
+        shapes.push_back(std::ref(it.second));
+    });
+
+    IndexedPackGroup result;
+    BoundingBox bbb(bed.points);
+
+    auto binbb = Box({
+                         static_cast<libnest2d::Coord>(bbb.min.x),
+                         static_cast<libnest2d::Coord>(bbb.min.y)
+                     },
+                     {
+                         static_cast<libnest2d::Coord>(bbb.max.x),
+                         static_cast<libnest2d::Coord>(bbb.max.y)
+                     });
+
+    switch(bedhint) {
+    case BOX: {
+
+        // Create the arranger for the box shaped bed
+        AutoArranger<Box> arrange(binbb, min_obj_distance, progressind);
+
+        // Arrange and return the items with their respective indices within the
+        // input sequence.
+        result = arrange(shapes.begin(), shapes.end());
+        break;
+    }
+    case CIRCLE:
+        break;
+    case IRREGULAR:
+    case WHO_KNOWS: {
+        using P = libnest2d::PolygonImpl;
+
+        auto ctour = Slic3rMultiPoint_to_ClipperPath(bed);
+        P irrbed = ShapeLike::create<PolygonImpl>(std::move(ctour));
+
+//        std::cout << ShapeLike::toString(irrbed) << std::endl;
+
+        AutoArranger<P> arrange(irrbed, min_obj_distance, progressind);
+
+        // Arrange and return the items with their respective indices within the
+        // input sequence.
+        result = arrange(shapes.begin(), shapes.end());
+        break;
+    }
+    };
+
+    if(first_bin_only) {
+        applyResult(result.front(), 0, shapemap);
+    } else {
+
+        const auto STRIDE_PADDING = 1.2;
+
+        Coord stride = static_cast<Coord>(STRIDE_PADDING*
+                                          binbb.width()*SCALING_FACTOR);
+        Coord batch_offset = 0;
+
+        for(auto& group : result) {
+            applyResult(group, batch_offset, shapemap);
+
+            // Only the first pack group can be placed onto the print bed. The
+            // other objects which could not fit will be placed next to the
+            // print bed
+            batch_offset += stride;
+        }
+    }
+
+    for(auto objptr : model.objects) objptr->invalidate_bounding_box();
+
+    return ret && result.size() == 1;
+}
+
+}
+}
+#endif // MODELARRANGE_HPP
diff --git a/xs/src/libslic3r/Print.cpp b/xs/src/libslic3r/Print.cpp
index e08ae1fc4..ab5d13950 100644
--- a/xs/src/libslic3r/Print.cpp
+++ b/xs/src/libslic3r/Print.cpp
@@ -155,6 +155,7 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
         "retract_restart_extra",
         "retract_restart_extra_toolchange",
         "retract_speed",
+        "single_extruder_multi_material_priming",
         "slowdown_below_layer_time",
         "standby_temperature_delta",
         "start_gcode",
@@ -166,7 +167,10 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
         "use_relative_e_distances",
         "use_volumetric_e",
         "variable_layer_height",
-        "wipe"
+        "wipe",
+        "wipe_tower_x",
+        "wipe_tower_y",
+        "wipe_tower_rotation_angle"
     };
 
     std::vector<PrintStep> steps;
@@ -175,7 +179,12 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
 
     // Always invalidate the wipe tower. This is probably necessary because of the wipe_into_infill / wipe_into_objects
     // features - nearly anything can influence what should (and could) be wiped into.
-    steps.emplace_back(psWipeTower);
+    // Only these three parameters don't invalidate the wipe tower (they only affect the gcode export):
+    for (const t_config_option_key &opt_key : opt_keys)
+        if (opt_key != "wipe_tower_x" && opt_key != "wipe_tower_y" && opt_key != "wipe_tower_rotation_angle") {
+            steps.emplace_back(psWipeTower);
+            break;
+        }
 
     for (const t_config_option_key &opt_key : opt_keys) {
         if (steps_ignore.find(opt_key) != steps_ignore.end()) {
@@ -204,6 +213,7 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
             || opt_key == "filament_unloading_speed"
             || opt_key == "filament_toolchange_delay"
             || opt_key == "filament_cooling_moves"
+            || opt_key == "filament_minimal_purge_on_wipe_tower"
             || opt_key == "filament_cooling_initial_speed"
             || opt_key == "filament_cooling_final_speed"
             || opt_key == "filament_ramming_parameters"
@@ -212,10 +222,7 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
             || opt_key == "spiral_vase"
             || opt_key == "temperature"
             || opt_key == "wipe_tower"
-            || opt_key == "wipe_tower_x"
-            || opt_key == "wipe_tower_y"
             || opt_key == "wipe_tower_width"
-            || opt_key == "wipe_tower_rotation_angle"
             || opt_key == "wipe_tower_bridging"
             || opt_key == "wiping_volumes_matrix"
             || opt_key == "parking_pos_retraction"
@@ -1051,6 +1058,8 @@ void Print::_make_wipe_tower()
     if (! this->has_wipe_tower())
         return;
 
+    m_wipe_tower_depth = 0.f;
+
     // Get wiping matrix to get number of extruders and convert vector<double> to vector<float>:
     std::vector<float> wiping_matrix((this->config.wiping_volumes_matrix.values).begin(),(this->config.wiping_volumes_matrix.values).end());
     // Extract purging volumes for each extruder pair:
@@ -1144,12 +1153,19 @@ void Print::_make_wipe_tower()
             wipe_tower.plan_toolchange(layer_tools.print_z, layer_tools.wipe_tower_layer_height, current_extruder_id, current_extruder_id,false);
             for (const auto extruder_id : layer_tools.extruders) {
                 if ((first_layer && extruder_id == m_tool_ordering.all_extruders().back()) || extruder_id != current_extruder_id) {
-                    float volume_to_wipe = wipe_volumes[current_extruder_id][extruder_id];    // total volume to wipe after this toolchange
+                    float volume_to_wipe = wipe_volumes[current_extruder_id][extruder_id];             // total volume to wipe after this toolchange
+                    // Not all of that can be used for infill purging:
+                    volume_to_wipe -= config.filament_minimal_purge_on_wipe_tower.get_at(extruder_id);
 
                     // try to assign some infills/objects for the wiping:
-                    volume_to_wipe = layer_tools.wiping_extrusions().mark_wiping_extrusions(*this, current_extruder_id, extruder_id, wipe_volumes[current_extruder_id][extruder_id]);
+                    volume_to_wipe = layer_tools.wiping_extrusions().mark_wiping_extrusions(*this, current_extruder_id, extruder_id, volume_to_wipe);
 
-                    wipe_tower.plan_toolchange(layer_tools.print_z, layer_tools.wipe_tower_layer_height, current_extruder_id, extruder_id, first_layer && extruder_id == m_tool_ordering.all_extruders().back(), volume_to_wipe);
+                    // add back the minimal amount toforce on the wipe tower:
+                    volume_to_wipe += config.filament_minimal_purge_on_wipe_tower.get_at(extruder_id);
+
+                    // request a toolchange at the wipe tower with at least volume_to_wipe purging amount
+                    wipe_tower.plan_toolchange(layer_tools.print_z, layer_tools.wipe_tower_layer_height, current_extruder_id, extruder_id,
+                                               first_layer && extruder_id == m_tool_ordering.all_extruders().back(), volume_to_wipe);
                     current_extruder_id = extruder_id;
                 }
             }
@@ -1162,7 +1178,8 @@ void Print::_make_wipe_tower()
     // Generate the wipe tower layers.
     m_wipe_tower_tool_changes.reserve(m_tool_ordering.layer_tools().size());
     wipe_tower.generate(m_wipe_tower_tool_changes);
-    
+    m_wipe_tower_depth = wipe_tower.get_depth();
+
     // Unload the current filament over the purge tower.
     coordf_t layer_height = this->objects.front()->config.layer_height.value;
     if (m_tool_ordering.back().wipe_tower_partitions > 0) {
@@ -1183,10 +1200,6 @@ void Print::_make_wipe_tower()
 		wipe_tower.tool_change((unsigned int)-1, false));
 }
 
-
-
-
-
 std::string Print::output_filename()
 {
     this->placeholder_parser.update_timestamp();
@@ -1225,7 +1238,6 @@ void Print::set_status(int percent, const std::string &message)
     printf("Print::status %d => %s\n", percent, message.c_str());
 }
 
-
 // Returns extruder this eec should be printed with, according to PrintRegion config
 int Print::get_extruder(const ExtrusionEntityCollection& fill, const PrintRegion &region)
 {
@@ -1233,5 +1245,4 @@ int Print::get_extruder(const ExtrusionEntityCollection& fill, const PrintRegion
                                     std::max<int>(region.config.perimeter_extruder.value - 1, 0);
 }
 
-
 }
diff --git a/xs/src/libslic3r/Print.hpp b/xs/src/libslic3r/Print.hpp
index bcd61ea02..e3430ad0e 100644
--- a/xs/src/libslic3r/Print.hpp
+++ b/xs/src/libslic3r/Print.hpp
@@ -273,6 +273,7 @@ public:
     
     void add_model_object(ModelObject* model_object, int idx = -1);
     bool apply_config(DynamicPrintConfig config);
+    float get_wipe_tower_depth() const { return m_wipe_tower_depth; }
     bool has_infinite_skirt() const;
     bool has_skirt() const;
     // Returns an empty string if valid, otherwise returns an error message.
@@ -326,6 +327,9 @@ private:
     bool invalidate_state_by_config_options(const std::vector<t_config_option_key> &opt_keys);
     PrintRegionConfig _region_config_from_model_volume(const ModelVolume &volume);
 
+    // Depth of the wipe tower to pass to GLCanvas3D for exact bounding box:
+    float m_wipe_tower_depth = 0.f;
+
     // Has the calculation been canceled?
     tbb::atomic<bool>   m_canceled;
 };
diff --git a/xs/src/libslic3r/PrintConfig.cpp b/xs/src/libslic3r/PrintConfig.cpp
index 01d0a7380..1035951eb 100644
--- a/xs/src/libslic3r/PrintConfig.cpp
+++ b/xs/src/libslic3r/PrintConfig.cpp
@@ -504,15 +504,27 @@ PrintConfigDef::PrintConfigDef()
     def = this->add("filament_cooling_initial_speed", coFloats);
     def->label = L("Speed of the first cooling move");
     def->tooltip = L("Cooling moves are gradually accelerating beginning at this speed. ");
-    def->cli = "filament-cooling-initial-speed=i@";
+    def->cli = "filament-cooling-initial-speed=f@";
     def->sidetext = L("mm/s");
     def->min = 0;
     def->default_value = new ConfigOptionFloats { 2.2f };
 
+    def = this->add("filament_minimal_purge_on_wipe_tower", coFloats);
+    def->label = L("Minimal purge on wipe tower");
+    def->tooltip = L("After a toolchange, certain amount of filament is used for purging. This "
+                     "can end up on the wipe tower, infill or sacrificial object. If there was "
+                     "enough infill etc. available, this could result in bad quality at the beginning "
+                     "of purging. This is a minimum that must be wiped on the wipe tower before "
+                     "Slic3r considers moving elsewhere. ");
+    def->cli = "filament-minimal-purge-on-wipe-tower=f@";
+    def->sidetext = L("mm³");
+    def->min = 0;
+    def->default_value = new ConfigOptionFloats { 5.f };
+
     def = this->add("filament_cooling_final_speed", coFloats);
     def->label = L("Speed of the last cooling move");
     def->tooltip = L("Cooling moves are gradually accelerating towards this speed. ");
-    def->cli = "filament-cooling-final-speed=i@";
+    def->cli = "filament-cooling-final-speed=f@";
     def->sidetext = L("mm/s");
     def->min = 0;
     def->default_value = new ConfigOptionFloats { 3.4f };
@@ -1639,6 +1651,12 @@ PrintConfigDef::PrintConfigDef()
     def->cli = "single-extruder-multi-material!";
 	def->default_value = new ConfigOptionBool(false);
 
+    def = this->add("single_extruder_multi_material_priming", coBool);
+    def->label = L("Prime all printing extruders");
+    def->tooltip = L("If enabled, all printing extruders will be primed at the front edge of the print bed at the start of the print.");
+    def->cli = "single-extruder-multi-material-priming!";
+    def->default_value = new ConfigOptionBool(true);
+
     def = this->add("support_material", coBool);
     def->label = L("Generate support material");
     def->category = L("Support material");
diff --git a/xs/src/libslic3r/PrintConfig.hpp b/xs/src/libslic3r/PrintConfig.hpp
index 0a5f70f78..602f1f0aa 100644
--- a/xs/src/libslic3r/PrintConfig.hpp
+++ b/xs/src/libslic3r/PrintConfig.hpp
@@ -534,6 +534,7 @@ public:
     ConfigOptionFloats              filament_unload_time;
     ConfigOptionInts                filament_cooling_moves;
     ConfigOptionFloats              filament_cooling_initial_speed;
+    ConfigOptionFloats              filament_minimal_purge_on_wipe_tower;
     ConfigOptionFloats              filament_cooling_final_speed;
     ConfigOptionStrings             filament_ramming_parameters;
     ConfigOptionBool                gcode_comments;
@@ -555,6 +556,7 @@ public:
     ConfigOptionString              start_gcode;
     ConfigOptionStrings             start_filament_gcode;
     ConfigOptionBool                single_extruder_multi_material;
+    ConfigOptionBool                single_extruder_multi_material_priming;
     ConfigOptionString              toolchange_gcode;
     ConfigOptionFloat               travel_speed;
     ConfigOptionBool                use_firmware_retraction;
@@ -597,6 +599,7 @@ protected:
         OPT_PTR(filament_toolchange_delay);
         OPT_PTR(filament_cooling_moves);
         OPT_PTR(filament_cooling_initial_speed);
+        OPT_PTR(filament_minimal_purge_on_wipe_tower);
         OPT_PTR(filament_cooling_final_speed);
         OPT_PTR(filament_ramming_parameters);
         OPT_PTR(gcode_comments);
@@ -616,6 +619,7 @@ protected:
         OPT_PTR(retract_restart_extra_toolchange);
         OPT_PTR(retract_speed);
         OPT_PTR(single_extruder_multi_material);
+        OPT_PTR(single_extruder_multi_material_priming);
         OPT_PTR(start_gcode);
         OPT_PTR(start_filament_gcode);
         OPT_PTR(toolchange_gcode);
diff --git a/xs/src/libslic3r/PrintObject.cpp b/xs/src/libslic3r/PrintObject.cpp
index 47495dad8..7150ead59 100644
--- a/xs/src/libslic3r/PrintObject.cpp
+++ b/xs/src/libslic3r/PrintObject.cpp
@@ -75,6 +75,7 @@ bool PrintObject::delete_last_copy()
 
 bool PrintObject::set_copies(const Points &points)
 {
+    bool copies_num_changed = this->_copies.size() != points.size();
     this->_copies = points;
     
     // order copies with a nearest neighbor search and translate them by _copies_shift
@@ -93,7 +94,8 @@ bool PrintObject::set_copies(const Points &points)
     
     bool invalidated = this->_print->invalidate_step(psSkirt);
     invalidated |= this->_print->invalidate_step(psBrim);
-    invalidated |= this->_print->invalidate_step(psWipeTower);
+    if (copies_num_changed)
+        invalidated |= this->_print->invalidate_step(psWipeTower);
     return invalidated;
 }