diff --git a/lib/Slic3r/GUI/OptionsGroup/Field.pm b/lib/Slic3r/GUI/OptionsGroup/Field.pm
index d2cf76ce69..920d4cec11 100644
--- a/lib/Slic3r/GUI/OptionsGroup/Field.pm
+++ b/lib/Slic3r/GUI/OptionsGroup/Field.pm
@@ -548,11 +548,16 @@ sub BUILD {
     EVT_TEXT($self->parent, $textctrl, sub {
         my $value = $textctrl->GetValue;
         if ($value =~ /^-?\d+(\.\d*)?$/) {
-            $self->set_value($value);
+            # Update the slider without re-updating the text field being modified.
+            $self->disable_change_event(1);
+            $self->slider->SetValue($value*$self->scale);
+            $self->disable_change_event(0);
+            
             $self->_on_change($self->option->opt_id);
         }
     });
     EVT_KILL_FOCUS($textctrl, sub {
+        $self->_update_textctrl;
         $self->_on_kill_focus($self->option->opt_id, @_);
     });
 }
@@ -573,7 +578,9 @@ sub get_value {
 
 sub _update_textctrl {
     my ($self) = @_;
-    $self->textctrl->SetLabel($self->get_value);
+    
+    $self->textctrl->ChangeValue($self->get_value);
+    $self->textctrl->SetInsertionPointEnd;
 }
 
 sub enable {
diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index f15c8911d1..59fa49659d 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -782,7 +782,7 @@ sub add_tin {
 
 sub load_file {
     my $self = shift;
-    my ($input_file) = @_;
+    my ($input_file, $obj_idx) = @_;
     
     $Slic3r::GUI::Settings->{recent}{skein_directory} = dirname($input_file);
     wxTheApp->save_settings;
@@ -807,7 +807,19 @@ sub load_file {
                 $model->convert_multipart_object;
             }
         }
-        @obj_idx = $self->load_model_objects(@{$model->objects});
+        
+        if (defined $obj_idx) {
+            return () if $obj_idx >= $model->objects_count;
+            @obj_idx = $self->load_model_objects($model->get_object($obj_idx));
+        } else {
+            @obj_idx = $self->load_model_objects(@{$model->objects});
+        }
+        
+        my $i = 0;
+        foreach my $obj_idx (@obj_idx) {
+            $self->{objects}[$obj_idx]->input_file($input_file);
+            $self->{objects}[$obj_idx]->input_file_obj_idx($i++);
+        }
         $self->statusbar->SetStatusText("Loaded " . basename($input_file));
     }
     
@@ -1677,13 +1689,14 @@ sub reload_from_disk {
     my ($obj_idx, $object) = $self->selected_object;
     return if !defined $obj_idx;
     
-    my $model_object = $self->{model}->objects->[$obj_idx];
-    return if !$model_object->input_file
-        || !-e $model_object->input_file;
+    return if !$object->input_file
+        || !-e $object->input_file;
     
-    my @new_obj_idx = $self->load_file($model_object->input_file);
+    # Only reload the selected object and not all objects from the input file.
+    my @new_obj_idx = $self->load_file($object->input_file, $object->input_file_obj_idx);
     return if !@new_obj_idx;
     
+    my $model_object = $self->{model}->objects->[$obj_idx];
     foreach my $new_obj_idx (@new_obj_idx) {
         my $o = $self->{model}->objects->[$new_obj_idx];
         $o->clear_instances;
@@ -1698,6 +1711,8 @@ sub reload_from_disk {
     
     $self->remove($obj_idx);
     
+    # TODO: refresh object list which contains wrong count and scale
+    
     # Trigger thumbnail generation again, because the remove() method altered
     # object indexes before background thumbnail generation called its completion
     # event, so the on_thumbnail_made callback is called with the wrong $obj_idx.
@@ -2252,6 +2267,8 @@ use List::Util qw(first);
 use Slic3r::Geometry qw(X Y Z MIN MAX deg2rad);
 
 has 'name'                  => (is => 'rw', required => 1);
+has 'input_file'            => (is => 'rw');
+has 'input_file_obj_idx'    => (is => 'rw');
 has 'thumbnail'             => (is => 'rw'); # ExPolygon::Collection in scaled model units with no transforms
 has 'transformed_thumbnail' => (is => 'rw');
 has 'instance_thumbnails'   => (is => 'ro', default => sub { [] });  # array of ExPolygon::Collection objects, each one representing the actual placed thumbnail of each instance in pixel units
diff --git a/package/osx/startup_script.sh b/package/osx/startup_script.sh
index b98fa5bdc4..4f665ac644 100644
--- a/package/osx/startup_script.sh
+++ b/package/osx/startup_script.sh
@@ -1,4 +1,4 @@
 #!/bin/bash
 
 DIR=$(dirname "$0")
-$DIR/perl-local -I$DIR/local-lib/lib/perl5 $DIR/slic3r.pl $@
+"$DIR/perl-local" -I"$DIR/local-lib/lib/perl5" "$DIR/slic3r.pl" $@
diff --git a/xs/Build.PL b/xs/Build.PL
index 87ba0c1ef6..619cc879fa 100644
--- a/xs/Build.PL
+++ b/xs/Build.PL
@@ -39,6 +39,19 @@ if ($^O eq 'darwin') {
     # that prevents this from happening, not needed with newer Boost versions.
     # See here for more details: https://svn.boost.org/trac/boost/ticket/7671
     push @cflags, qw(-DBOOST_THREAD_DONT_USE_CHRONO -DBOOST_NO_CXX11_RVALUE_REFERENCES -DBOOST_THREAD_USES_MOVE);
+    
+    # ExtUtils::CppGuess has a hard-coded -lstdc++, so we filter it out
+    {
+        no strict 'refs';
+        no warnings 'redefine';
+        my $func = "ExtUtils::CppGuess::_get_lflags";
+        my $orig = *$func{CODE};
+        *{$func} = sub {
+            my $lflags = $orig->(@_);
+            $lflags =~ s/\s*-lstdc\+\+//;
+            return $lflags;
+        };
+    }
 }
 if ($mswin) {
     # In case windows.h is included, we don't want the min / max macros to be active.
diff --git a/xs/MANIFEST b/xs/MANIFEST
index a2ffbba5a7..61a97afede 100644
--- a/xs/MANIFEST
+++ b/xs/MANIFEST
@@ -68,6 +68,8 @@ src/libslic3r/GCode/CoolingBuffer.cpp
 src/libslic3r/GCode/CoolingBuffer.hpp
 src/libslic3r/GCode/SpiralVase.cpp
 src/libslic3r/GCode/SpiralVase.hpp
+src/libslic3r/GCodeReader.cpp
+src/libslic3r/GCodeReader.hpp
 src/libslic3r/GCodeSender.cpp
 src/libslic3r/GCodeSender.hpp
 src/libslic3r/GCodeWriter.cpp
diff --git a/xs/src/clipper.hpp b/xs/src/clipper.hpp
index df1f8137d4..66876905c2 100755
--- a/xs/src/clipper.hpp
+++ b/xs/src/clipper.hpp
@@ -76,7 +76,7 @@ enum PolyFillType { pftEvenOdd, pftNonZero, pftPositive, pftNegative };
 #else
   typedef signed long long cInt;
   static cInt const loRange = 0x3FFFFFFF;
-  static cInt const hiRange = 0x3FFFFFFFFFFFFFFFLL;
+  constexpr cInt hiRange = 0x3FFFFFFFFFFFFFFFLL;
   typedef signed long long long64;     //used by Int128 class
   typedef unsigned long long ulong64;
 
diff --git a/xs/src/libslic3r/ClipperUtils.hpp b/xs/src/libslic3r/ClipperUtils.hpp
index 9e4e5e89ae..ddd551ca26 100644
--- a/xs/src/libslic3r/ClipperUtils.hpp
+++ b/xs/src/libslic3r/ClipperUtils.hpp
@@ -19,7 +19,8 @@ namespace Slic3r {
 // How about 2^17=131072?
 // By the way, is the scalling needed at all? Cura runs all the computation with a fixed point precision of 1um, while Slic3r scales to 1nm,
 // further scaling by 10e5 brings us to 
-#define CLIPPER_OFFSET_SCALE 100000.0
+constexpr float CLIPPER_OFFSET_SCALE = 100000.0;
+constexpr auto MAX_COORD = ClipperLib::hiRange / CLIPPER_OFFSET_SCALE;
 
 //-----------------------------------------------------------
 // legacy code from Clipper documentation
diff --git a/xs/src/libslic3r/ExPolygon.cpp b/xs/src/libslic3r/ExPolygon.cpp
index ec02acc356..93fbba4676 100644
--- a/xs/src/libslic3r/ExPolygon.cpp
+++ b/xs/src/libslic3r/ExPolygon.cpp
@@ -514,4 +514,12 @@ ExPolygon::dump_perl() const
     return ret.str();
 }
 
+std::ostream&
+operator <<(std::ostream &s, const ExPolygons &expolygons)
+{
+    for (const ExPolygon &e : expolygons)
+        s << e.dump_perl() << std::endl;
+    return s;
+}
+
 }
diff --git a/xs/src/libslic3r/ExPolygon.hpp b/xs/src/libslic3r/ExPolygon.hpp
index 63cc560cd9..404a4385e3 100644
--- a/xs/src/libslic3r/ExPolygon.hpp
+++ b/xs/src/libslic3r/ExPolygon.hpp
@@ -4,6 +4,7 @@
 #include "libslic3r.h"
 #include "Polygon.hpp"
 #include "Polyline.hpp"
+#include <ostream>
 #include <vector>
 
 namespace Slic3r {
@@ -62,6 +63,8 @@ operator+(ExPolygons src1, const ExPolygons &src2) {
     return src1;
 };
 
+std::ostream& operator <<(std::ostream &s, const ExPolygons &expolygons);
+
 }
 
 // start Boost
diff --git a/xs/src/libslic3r/Flow.hpp b/xs/src/libslic3r/Flow.hpp
index 2f041d03cd..fdfcac6950 100644
--- a/xs/src/libslic3r/Flow.hpp
+++ b/xs/src/libslic3r/Flow.hpp
@@ -7,8 +7,8 @@
 
 namespace Slic3r {
 
-#define BRIDGE_EXTRA_SPACING 0.05
-#define OVERLAP_FACTOR 1.0
+constexpr auto BRIDGE_EXTRA_SPACING = 0.05;
+constexpr auto OVERLAP_FACTOR = 1.0;
 
 enum FlowRole {
     frExternalPerimeter,
diff --git a/xs/src/libslic3r/GCode.cpp b/xs/src/libslic3r/GCode.cpp
index 39af871b27..f6ae8f75a4 100644
--- a/xs/src/libslic3r/GCode.cpp
+++ b/xs/src/libslic3r/GCode.cpp
@@ -453,8 +453,8 @@ GCode::extrude(ExtrusionLoop loop, std::string description, double speed)
             paths.front().polyline.points[0],
             paths.front().polyline.points[1]
         );
-        double distance = std::min(
-            scale_(EXTRUDER_CONFIG(nozzle_diameter)),
+        const double distance = std::min(
+            (double)scale_(EXTRUDER_CONFIG(nozzle_diameter)),
             first_segment.length()
         );
         Point point = first_segment.point_at(distance);
diff --git a/xs/src/libslic3r/GCodeReader.cpp b/xs/src/libslic3r/GCodeReader.cpp
index fcaaea9be8..1a0742864f 100644
--- a/xs/src/libslic3r/GCodeReader.cpp
+++ b/xs/src/libslic3r/GCodeReader.cpp
@@ -56,6 +56,9 @@ GCodeReader::parse(const std::string &gcode, callback_t callback)
             }
         }
         
+        if (gline.has('E') && this->_config.use_relative_e_distances)
+            this->E = 0;
+        
         if (callback) callback(*this, gline);
         
         // update coordinates
diff --git a/xs/src/libslic3r/GCodeSender.cpp b/xs/src/libslic3r/GCodeSender.cpp
index 5fc33d9c90..c1568790ec 100644
--- a/xs/src/libslic3r/GCodeSender.cpp
+++ b/xs/src/libslic3r/GCodeSender.cpp
@@ -26,10 +26,10 @@
 std::fstream fs;
 #endif
 
-#define KEEP_SENT 20
-
 namespace Slic3r {
 
+constexpr auto KEEP_SENT = 20;
+
 namespace asio = boost::asio;
 
 GCodeSender::GCodeSender()
diff --git a/xs/src/libslic3r/Geometry.cpp b/xs/src/libslic3r/Geometry.cpp
index 0cc9a575c3..b8584000fa 100644
--- a/xs/src/libslic3r/Geometry.cpp
+++ b/xs/src/libslic3r/Geometry.cpp
@@ -609,6 +609,13 @@ MedialAxis::process_edge_neighbors(const VD::edge_type* edge, ThickPolyline* pol
 bool
 MedialAxis::validate_edge(const VD::edge_type* edge)
 {
+    // prevent overflows and detect almost-infinite edges
+    if (std::abs(edge->vertex0()->x()) > (double)MAX_COORD
+     || std::abs(edge->vertex0()->y()) > (double)MAX_COORD
+     || std::abs(edge->vertex1()->x()) > (double)MAX_COORD
+     || std::abs(edge->vertex1()->y()) > (double)MAX_COORD)
+        return false;
+    
     // construct the line representing this edge of the Voronoi diagram
     const Line line(
         Point( edge->vertex0()->x(), edge->vertex0()->y() ),
diff --git a/xs/src/libslic3r/LayerRegion.cpp b/xs/src/libslic3r/LayerRegion.cpp
index b7d9058fe6..1baaa0bef5 100644
--- a/xs/src/libslic3r/LayerRegion.cpp
+++ b/xs/src/libslic3r/LayerRegion.cpp
@@ -231,12 +231,13 @@ LayerRegion::prepare_fill_surfaces()
     }
         
     // turn too small internal regions into solid regions according to the user setting
-    if (this->region()->config.fill_density.value > 0) {
+    const float &fill_density = this->region()->config.fill_density;
+    if (fill_density > 0 && fill_density < 100) {
         // scaling an area requires two calls!
-        double min_area = scale_(scale_(this->region()->config.solid_infill_below_area.value));
-        for (Surfaces::iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface) {
-            if (surface->surface_type == stInternal && surface->area() <= min_area)
-                surface->surface_type = stInternalSolid;
+        const double min_area = scale_(scale_(this->region()->config.solid_infill_below_area.value));
+        for (Surface &surface : this->fill_surfaces.surfaces) {
+            if (surface.surface_type == stInternal && surface.area() <= min_area)
+                surface.surface_type = stInternalSolid;
         }
     }
 }
diff --git a/xs/src/libslic3r/Model.cpp b/xs/src/libslic3r/Model.cpp
index ca9c0b2274..9182cf56b9 100644
--- a/xs/src/libslic3r/Model.cpp
+++ b/xs/src/libslic3r/Model.cpp
@@ -92,9 +92,8 @@ Model::delete_object(size_t idx)
 void
 Model::clear_objects()
 {
-    // int instead of size_t because it can be -1 when vector is empty
-    for (int i = this->objects.size()-1; i >= 0; --i)
-        this->delete_object(i);
+    while (!this->objects.empty())
+        this->delete_object(0);
 }
 
 void
@@ -467,9 +466,8 @@ ModelObject::delete_volume(size_t idx)
 void
 ModelObject::clear_volumes()
 {
-    // int instead of size_t because it can be -1 when vector is empty
-    for (int i = this->volumes.size()-1; i >= 0; --i)
-        this->delete_volume(i);
+    while (!this->volumes.empty())
+        this->delete_volume(0);
 }
 
 ModelInstance*
@@ -508,8 +506,8 @@ ModelObject::delete_last_instance()
 void
 ModelObject::clear_instances()
 {
-    for (size_t i = 0; i < this->instances.size(); ++i)
-        this->delete_instance(i);
+    while (!this->instances.empty())
+        this->delete_last_instance();
 }
 
 // this returns the bounding box of the *transformed* instances
diff --git a/xs/src/libslic3r/MotionPlanner.hpp b/xs/src/libslic3r/MotionPlanner.hpp
index 1fbdb4123f..80d61213ec 100644
--- a/xs/src/libslic3r/MotionPlanner.hpp
+++ b/xs/src/libslic3r/MotionPlanner.hpp
@@ -9,11 +9,11 @@
 #include <utility>
 #include <vector>
 
-#define MP_INNER_MARGIN scale_(1.0)
-#define MP_OUTER_MARGIN scale_(2.0)
-
 namespace Slic3r {
 
+constexpr coord_t MP_INNER_MARGIN = scale_(1.0);
+constexpr coord_t MP_OUTER_MARGIN = scale_(2.0);
+
 class MotionPlanner;
 
 class MotionPlannerEnv
diff --git a/xs/src/libslic3r/SupportMaterial.hpp b/xs/src/libslic3r/SupportMaterial.hpp
index edea226959..03703aa40f 100644
--- a/xs/src/libslic3r/SupportMaterial.hpp
+++ b/xs/src/libslic3r/SupportMaterial.hpp
@@ -4,7 +4,7 @@
 namespace Slic3r {
 
 // how much we extend support around the actual contact area
-#define SUPPORT_MATERIAL_MARGIN 1.5
+constexpr coordf_t SUPPORT_MATERIAL_MARGIN = 1.5;
 
 }
 
diff --git a/xs/src/libslic3r/libslic3r.h b/xs/src/libslic3r/libslic3r.h
index 6789d58ffc..50b4241de3 100644
--- a/xs/src/libslic3r/libslic3r.h
+++ b/xs/src/libslic3r/libslic3r.h
@@ -10,33 +10,6 @@
 #include <vector>
 #include <boost/thread.hpp>
 
-#define SLIC3R_VERSION "1.3.0-dev"
-
-//FIXME This epsilon value is used for many non-related purposes:
-// For a threshold of a squared Euclidean distance,
-// for a trheshold in a difference of radians,
-// for a threshold of a cross product of two non-normalized vectors etc.
-#define EPSILON 1e-4
-// Scaling factor for a conversion from coord_t to coordf_t: 10e-6
-// This scaling generates a following fixed point representation with for a 32bit integer:
-// 0..4294mm with 1nm resolution
-#define SCALING_FACTOR 0.000001
-// RESOLUTION, SCALED_RESOLUTION: Used as an error threshold for a Douglas-Peucker polyline simplification algorithm.
-#define RESOLUTION 0.0125
-#define SCALED_RESOLUTION (RESOLUTION / SCALING_FACTOR)
-#define PI 3.141592653589793238
-// When extruding a closed loop, the loop is interrupted and shortened a bit to reduce the seam.
-#define LOOP_CLIPPING_LENGTH_OVER_NOZZLE_DIAMETER 0.15
-// Maximum perimeter length for the loop to apply the small perimeter speed. 
-#define SMALL_PERIMETER_LENGTH (6.5 / SCALING_FACTOR) * 2 * PI
-#define INSET_OVERLAP_TOLERANCE 0.4
-#define EXTERNAL_INFILL_MARGIN 3
-#define scale_(val) ((val) / SCALING_FACTOR)
-#define unscale(val) ((val) * SCALING_FACTOR)
-#define SCALED_EPSILON scale_(EPSILON)
-typedef long coord_t;
-typedef double coordf_t;
-
 /* Implementation of CONFESS("foo"): */
 #ifdef _MSC_VER
 	#define CONFESS(...) confess_at(__FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
@@ -61,6 +34,35 @@ void confess_at(const char *file, int line, const char *func, const char *pat, .
 
 namespace Slic3r {
 
+constexpr auto SLIC3R_VERSION = "1.3.0-dev";
+
+typedef long coord_t;
+typedef double coordf_t;
+
+// Scaling factor for a conversion from coord_t to coordf_t: 10e-6
+// This scaling generates a following fixed point representation with for a 32bit integer:
+// 0..4294mm with 1nm resolution
+constexpr auto SCALING_FACTOR = 0.000001;
+inline constexpr coord_t  scale_(const coordf_t &val) { return val / SCALING_FACTOR; }
+inline constexpr coordf_t unscale(const coord_t &val) { return val * SCALING_FACTOR; }
+
+//FIXME This epsilon value is used for many non-related purposes:
+// For a threshold of a squared Euclidean distance,
+// for a trheshold in a difference of radians,
+// for a threshold of a cross product of two non-normalized vectors etc.
+constexpr auto EPSILON = 1e-4;
+constexpr auto SCALED_EPSILON = scale_(EPSILON);
+// RESOLUTION, SCALED_RESOLUTION: Used as an error threshold for a Douglas-Peucker polyline simplification algorithm.
+constexpr auto RESOLUTION = 0.0125;
+constexpr auto SCALED_RESOLUTION = scale_(RESOLUTION);
+constexpr auto PI = 3.141592653589793238;
+// When extruding a closed loop, the loop is interrupted and shortened a bit to reduce the seam.
+constexpr auto LOOP_CLIPPING_LENGTH_OVER_NOZZLE_DIAMETER = 0.15;
+// Maximum perimeter length for the loop to apply the small perimeter speed. 
+constexpr coord_t SMALL_PERIMETER_LENGTH = scale_(6.5) * 2 * PI;
+constexpr coordf_t INSET_OVERLAP_TOLERANCE = 0.4;
+constexpr coordf_t EXTERNAL_INFILL_MARGIN = 3;
+
 enum Axis { X=0, Y, Z };
 
 template <class T>