diff --git a/Build.PL b/Build.PL
index ead18f55e..80007abaa 100644
--- a/Build.PL
+++ b/Build.PL
@@ -28,6 +28,8 @@ my %prereqs = qw(
 );
 my %recommends = qw(
     Class::XSAccessor               0
+    LWP::UserAgent                  0
+    Net::Bonjour                    0
     XML::SAX::ExpatXS               0
 );
 
@@ -109,7 +111,9 @@ EOF
     my %modules = (%prereqs, %recommends);
     foreach my $module (sort keys %modules) {
         my $version = $modules{$module};
-        my @cmd = ($cpanm, @cpanm_args, "$module~$version");
+        my @cmd = ($cpanm, @cpanm_args);
+        push @cmd, '-f', if $module eq 'OpenGL';  # temporary workaround for upstream bug in test
+        push @cmd, "$module~$version";
         if ($module eq 'XML::SAX::ExpatXS' && $^O eq 'MSWin32') {
             my $mingw = 'C:\dev\CitrusPerl\mingw64';
             $mingw = 'C:\dev\CitrusPerl\mingw32' if !-d $mingw;
diff --git a/lib/Slic3r/Fill.pm b/lib/Slic3r/Fill.pm
index 504230933..1881d461b 100644
--- a/lib/Slic3r/Fill.pm
+++ b/lib/Slic3r/Fill.pm
@@ -187,7 +187,7 @@ sub make_fill {
         if ($surface->is_solid) {
             $density = 100;
             $filler = 'rectilinear';
-            if ($surface->is_external) {
+            if ($surface->is_external && !$is_bridge) {
                 $filler = $layerm->config->external_fill_pattern;
             }
         } else {
diff --git a/lib/Slic3r/Fill/3DHoneycomb.pm b/lib/Slic3r/Fill/3DHoneycomb.pm
index 256437707..3bf7e547f 100644
--- a/lib/Slic3r/Fill/3DHoneycomb.pm
+++ b/lib/Slic3r/Fill/3DHoneycomb.pm
@@ -19,12 +19,14 @@ sub fill_surface {
     
     my $distance = scale($self->spacing) / $params{density};
     
-    # align bounding box to a multiple of our honeycomb grid
+    # align bounding box to a multiple of our honeycomb grid module
+    # (a module is 2*$distance since one $distance half-module is 
+    # growing while the other $distance half-module is shrinking)
     {
         my $min = $bb->min_point;
         $min->translate(
-            -($bb->x_min % $distance),
-            -($bb->y_min % $distance),
+            -($bb->x_min % (2*$distance)),
+            -($bb->y_min % (2*$distance)),
         );
         $bb->merge_point($min);
     }
@@ -34,8 +36,8 @@ sub fill_surface {
         makeGrid(
             scale($self->z),
             $distance,
-            ceil($size->x / $distance),
-            ceil($size->y / $distance),  #//
+            ceil($size->x / $distance) + 1,
+            ceil($size->y / $distance) + 1,  #//
             (($self->layer_id / $surface->thickness_layers) % 2) + 1,
         );
     
diff --git a/lib/Slic3r/GCode.pm b/lib/Slic3r/GCode.pm
index 7adec0529..0a8f3951c 100644
--- a/lib/Slic3r/GCode.pm
+++ b/lib/Slic3r/GCode.pm
@@ -220,7 +220,7 @@ sub extrude_loop {
         $point->rotate($angle, $first_segment->a);
         
         # generate the travel move
-        $gcode .= $self->travel_to($point, $paths[-1]->role, "move inwards before travel");
+        $gcode .= $self->writer->travel_to_xy($self->point_to_gcode($point), "move inwards before travel");
     }
     
     return $gcode;
@@ -328,6 +328,7 @@ sub _extrude_path {
     return $gcode;
 }
 
+# This method accepts $point in print coordinates.
 sub travel_to {
     my ($self, $point, $role, $comment) = @_;
     
@@ -355,11 +356,11 @@ sub travel_to {
         || (defined $role && $role == EXTR_ROLE_SUPPORTMATERIAL && $self->layer->support_islands->contains_line($travel))
         ) {
         # Just perform a straight travel move without any retraction.
-        $gcode .= $self->writer->travel_to_xy($self->point_to_gcode($point), $comment);
+        $gcode .= $self->writer->travel_to_xy($self->point_to_gcode($point), $comment || '');
     } elsif ($self->config->avoid_crossing_perimeters && !$self->avoid_crossing_perimeters->disable_once) {
         # If avoid_crossing_perimeters is enabled and the disable_once flag is not set
         # we need to plan a multi-segment travel move inside the configuration space.
-        $gcode .= $self->avoid_crossing_perimeters->travel_to($self, $point, $comment);
+        $gcode .= $self->avoid_crossing_perimeters->travel_to($self, $point, $comment || '');
     } else {
         # If avoid_crossing_perimeters is disabled or the disable_once flag is set,
         # perform a straight move with a retraction.
@@ -473,7 +474,7 @@ sub pre_toolchange {
         $last_pos->translate(scale +$gcodegen->origin->x, scale +$gcodegen->origin->y);  #))
         my $standby_point = $last_pos->nearest_point($self->standby_points);
         $standby_point->translate(scale -$gcodegen->origin->x, scale -$gcodegen->origin->y);  #))
-        $gcode .= $gcodegen->travel_to($standby_point);
+        $gcode .= $gcodegen->travel_to($standby_point, undef, 'move to standby position');
     }
     
     if ($gcodegen->config->standby_temperature_delta != 0) {
diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index d089bbf29..e08e6362d 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -7,6 +7,7 @@ use File::Basename qw(basename);
 use FindBin;
 use Slic3r::GUI::AboutDialog;
 use Slic3r::GUI::BedShapeDialog;
+use Slic3r::GUI::BonjourBrowser;
 use Slic3r::GUI::ConfigWizard;
 use Slic3r::GUI::MainFrame;
 use Slic3r::GUI::Notifier;
@@ -27,6 +28,7 @@ use Slic3r::GUI::SimpleTab;
 use Slic3r::GUI::Tab;
 
 our $have_OpenGL = eval "use Slic3r::GUI::PreviewCanvas; 1";
+our $have_LWP    = eval "use LWP::UserAgent; 1";
 
 use Wx 0.9901 qw(:bitmap :dialog :icon :id :misc :systemsettings :toplevelwindow
     :filedialog);
@@ -228,7 +230,7 @@ sub have_version_check {
     my ($self) = @_;
     
     # return an explicit 0
-    return ($Slic3r::have_threads && $Slic3r::build && eval "use LWP::UserAgent; 1") || 0;
+    return ($Slic3r::have_threads && $Slic3r::build && $have_LWP) || 0;
 }
 
 sub check_version {
diff --git a/lib/Slic3r/GUI/BonjourBrowser.pm b/lib/Slic3r/GUI/BonjourBrowser.pm
new file mode 100644
index 000000000..281277768
--- /dev/null
+++ b/lib/Slic3r/GUI/BonjourBrowser.pm
@@ -0,0 +1,51 @@
+package Slic3r::GUI::BonjourBrowser;
+use strict;
+use warnings;
+use utf8;
+
+use Wx qw(:dialog :id :misc :sizer :choicebook wxTAB_TRAVERSAL);
+use Wx::Event qw(EVT_CLOSE);
+use base 'Wx::Dialog';
+
+sub new {
+    my $class = shift;
+    my ($parent) = @_;
+    my $self = $class->SUPER::new($parent, -1, "Device Browser", wxDefaultPosition, [350,700], wxDEFAULT_DIALOG_STYLE | wxRESIZE_BORDER);
+    
+    # look for devices
+    eval "use Net::Bonjour; 1";
+    my $res = Net::Bonjour->new('http');
+    $res->discover;
+    $self->{devices} = [ $res->entries ];
+    
+    # label
+    my $text = Wx::StaticText->new($self, -1, "Choose an OctoPrint device in your network:", wxDefaultPosition, wxDefaultSize);
+    
+    # selector
+    $self->{choice} = my $choice = Wx::Choice->new($self, -1, wxDefaultPosition, wxDefaultSize,
+        [ map $_->name, @{$self->{devices}} ]);
+    
+    my $main_sizer = Wx::BoxSizer->new(wxVERTICAL);
+    $main_sizer->Add($text, 1, wxEXPAND | wxALL, 10);
+    $main_sizer->Add($choice, 1, wxEXPAND | wxALL, 10);
+    $main_sizer->Add($self->CreateButtonSizer(wxOK | wxCANCEL), 0, wxEXPAND);
+    
+    $self->SetSizer($main_sizer);
+    $self->SetMinSize($self->GetSize);
+    $main_sizer->SetSizeHints($self);
+    
+    # needed to actually free memory
+    EVT_CLOSE($self, sub {
+        $self->EndModal(wxID_OK);
+        $self->Destroy;
+    });
+    
+    return $self;
+}
+
+sub GetValue {
+    my ($self) = @_;
+    return $self->{devices}[ $self->{choice}->GetSelection ]->address;
+}
+
+1;
diff --git a/lib/Slic3r/GUI/MainFrame.pm b/lib/Slic3r/GUI/MainFrame.pm
index 31b9ff0a3..4cd4db706 100644
--- a/lib/Slic3r/GUI/MainFrame.pm
+++ b/lib/Slic3r/GUI/MainFrame.pm
@@ -673,7 +673,11 @@ sub config {
 sub check_unsaved_changes {
     my $self = shift;
     
-    my @dirty = map $_->title, grep $_->is_dirty, values %{$self->{options_tabs}};
+    my @dirty = ();
+    foreach my $tab (values %{$self->{options_tabs}}) {
+        push @dirty, $tab->title if $tab->is_dirty;
+    }
+    
     if (@dirty) {
         my $titles = join ', ', @dirty;
         my $confirm = Wx::MessageDialog->new($self, "You have unsaved changes ($titles). Discard changes and continue anyway?",
diff --git a/lib/Slic3r/GUI/OptionsGroup.pm b/lib/Slic3r/GUI/OptionsGroup.pm
index 46d8aa678..d6a486828 100644
--- a/lib/Slic3r/GUI/OptionsGroup.pm
+++ b/lib/Slic3r/GUI/OptionsGroup.pm
@@ -83,7 +83,7 @@ sub append_line {
     # if we have a single option with no sidetext just add it directly to the grid sizer
     my @options = @{$line->get_options};
     $self->_options->{$_->opt_id} = $_ for @options;
-    if (@options == 1 && !$options[0]->sidetext) {
+    if (@options == 1 && !$options[0]->sidetext && !@{$line->get_extra_widgets}) {
         my $option = $options[0];
         my $field = $self->_build_field($option);
         $grid_sizer->Add($field, 0, ($option->full_width ? wxEXPAND : 0) | wxALIGN_CENTER_VERTICAL, 0);
@@ -114,9 +114,14 @@ sub append_line {
             $sizer->Add($sidetext, 0, wxLEFT | wxALIGN_CENTER_VERTICAL , 4);
         }
     }
+        
+    # add extra sizers if any
+    foreach my $extra_widget (@{$line->get_extra_widgets}) {
+        $sizer->Add($extra_widget->($self->parent), 0, wxLEFT | wxALIGN_CENTER_VERTICAL , 4);
+    }
 }
 
-sub append_single_option_line {
+sub create_single_option_line {
     my ($self, $option) = @_;
     
     my $line = Slic3r::GUI::OptionsGroup::Line->new(
@@ -125,11 +130,15 @@ sub append_single_option_line {
     );
     $option->label("");
     $line->append_option($option);
-    $self->append_line($line);
     
     return $line;
 }
 
+sub append_single_option_line {
+    my ($self, $option) = @_;
+    return $self->append_line($self->create_single_option_line($option));
+}
+
 sub _build_field {
     my $self = shift;
     my ($opt) = @_;
@@ -241,6 +250,7 @@ has 'label_tooltip' => (is => 'rw', default => sub { "" });
 has 'sizer'         => (is => 'rw');
 has 'widget'        => (is => 'rw');
 has '_options'      => (is => 'ro', default => sub { [] });
+has '_extra_widgets' => (is => 'ro', default => sub { [] });
 
 # this method accepts a Slic3r::GUI::OptionsGroup::Option object
 sub append_option {
@@ -248,11 +258,21 @@ sub append_option {
     push @{$self->_options}, $option;
 }
 
+sub append_widget {
+    my ($self, $widget) = @_;
+    push @{$self->_extra_widgets}, $widget;
+}
+
 sub get_options {
     my ($self) = @_;
     return [ @{$self->_options} ];
 }
 
+sub get_extra_widgets {
+    my ($self) = @_;
+    return [ @{$self->_extra_widgets} ];
+}
+
 
 package Slic3r::GUI::OptionsGroup::Option;
 use Moo;
@@ -320,7 +340,7 @@ sub get_option {
     );
 }
 
-sub append_single_option_line {
+sub create_single_option_line {
     my ($self, $opt_key, $opt_index) = @_;
     
     my $option;
@@ -329,7 +349,12 @@ sub append_single_option_line {
     } else {
         $option = $self->get_option($opt_key, $opt_index);
     }
-    return $self->SUPER::append_single_option_line($option);
+    return $self->SUPER::create_single_option_line($option);
+}
+
+sub append_single_option_line {
+    my ($self, $option, $opt_index) = @_;
+    return $self->append_line($self->create_single_option_line($option, $opt_index));
 }
 
 sub reload_config {
diff --git a/lib/Slic3r/GUI/OptionsGroup/Field.pm b/lib/Slic3r/GUI/OptionsGroup/Field.pm
index fcf97eb3f..13b86cdfc 100644
--- a/lib/Slic3r/GUI/OptionsGroup/Field.pm
+++ b/lib/Slic3r/GUI/OptionsGroup/Field.pm
@@ -347,6 +347,7 @@ sub BUILD {
     $self->wxSizer($sizer);
     
     my $field_size = Wx::Size->new(40, -1);
+    
     $self->x_textctrl(Wx::TextCtrl->new($self->parent, -1, $self->option->default->[X], wxDefaultPosition, $field_size));
     $self->y_textctrl(Wx::TextCtrl->new($self->parent, -1, $self->option->default->[Y], wxDefaultPosition, $field_size));
     
diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index 42b875036..2517cd893 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -48,6 +48,7 @@ sub new {
     my $self = $class->SUPER::new($parent, -1, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL);
     $self->{config} = Slic3r::Config->new_from_defaults(qw(
         bed_shape complete_objects extruder_clearance_radius skirts skirt_distance brim_width
+        octoprint_host octoprint_apikey
     ));
     $self->{model} = Slic3r::Model->new;
     $self->{print} = Slic3r::Print->new;
@@ -88,16 +89,7 @@ sub new {
     };
     my $on_instance_moved = sub {
         my ($obj_idx, $instance_idx) = @_;
-        
         $self->update;
-        
-        $self->pause_background_process;
-        my $invalidated = $self->{print}->objects->[$obj_idx]->reload_model_instances();
-        if ($invalidated) {
-            $self->schedule_background_process;
-        } else {
-            $self->resume_background_process;
-        }
     };
     
     # Initialize 2D preview canvas
@@ -181,9 +173,11 @@ sub new {
     
     # right pane buttons
     $self->{btn_export_gcode} = Wx::Button->new($self, -1, "Export G-code…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
+    $self->{btn_send_gcode} = Wx::Button->new($self, -1, "Send to printer", wxDefaultPosition, [-1, 30], wxBU_LEFT);
     $self->{btn_export_stl} = Wx::Button->new($self, -1, "Export STL…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
     #$self->{btn_export_gcode}->SetFont($Slic3r::GUI::small_font);
     #$self->{btn_export_stl}->SetFont($Slic3r::GUI::small_font);
+    $self->{btn_send_gcode}->Hide;
     
     if ($Slic3r::GUI::have_button_icons) {
         my %icons = qw(
@@ -192,6 +186,7 @@ sub new {
             reset           cross.png
             arrange         bricks.png
             export_gcode    cog_go.png
+            send_gcode      arrow_up.png
             export_stl      brick_go.png
             
             increase        add.png
@@ -213,7 +208,11 @@ sub new {
         $self->export_gcode;
         Slic3r::thread_cleanup();
     });
-    #EVT_BUTTON($self, $self->{btn_export_stl}, \&export_stl);
+    EVT_BUTTON($self, $self->{btn_send_gcode}, sub {
+        $self->{send_gcode_file} = $self->export_gcode(Wx::StandardPaths::Get->GetTempDir());
+        Slic3r::thread_cleanup();
+    });
+    EVT_BUTTON($self, $self->{btn_export_stl}, \&export_stl);
     
     if ($self->{htoolbar}) {
         EVT_TOOL($self, TB_ADD, sub { $self->add; });
@@ -355,6 +354,7 @@ sub new {
         my $buttons_sizer = Wx::BoxSizer->new(wxHORIZONTAL);
         $buttons_sizer->AddStretchSpacer(1);
         $buttons_sizer->Add($self->{btn_export_stl}, 0, wxALIGN_RIGHT, 0);
+        $buttons_sizer->Add($self->{btn_send_gcode}, 0, wxALIGN_RIGHT, 0);
         $buttons_sizer->Add($self->{btn_export_gcode}, 0, wxALIGN_RIGHT, 0);
         
         my $right_sizer = Wx::BoxSizer->new(wxVERTICAL);
@@ -555,7 +555,6 @@ sub remove {
     
     $self->select_object(undef);
     $self->update;
-    
     $self->schedule_background_process;
 }
 
@@ -666,10 +665,10 @@ sub rotate {
     $model_object->update_bounding_box;
     # update print and start background processing
     $self->{print}->add_model_object($model_object, $obj_idx);
-    $self->schedule_background_process;
     
     $self->selection_changed;  # refresh info (size etc.)
     $self->update;
+    $self->schedule_background_process;
 }
 
 sub flip {
@@ -694,11 +693,10 @@ sub flip {
     # update print and start background processing
     $self->stop_background_process;
     $self->{print}->add_model_object($model_object, $obj_idx);
-    $self->schedule_background_process;
     
     $self->selection_changed;  # refresh info (size etc.)
     $self->update;
-    $self->refresh_canvases;
+    $self->schedule_background_process;
 }
 
 sub changescale {
@@ -749,11 +747,10 @@ sub changescale {
     # update print and start background processing
     $self->stop_background_process;
     $self->{print}->add_model_object($model_object, $obj_idx);
-    $self->schedule_background_process;
     
     $self->selection_changed(1);  # refresh info (size, volume etc.)
     $self->update;
-    $self->refresh_canvases;
+    $self->schedule_background_process;
 }
 
 sub arrange {
@@ -769,17 +766,6 @@ sub arrange {
     # when parts don't fit in print bed
     
     $self->update(1);
-    
-    my $invalidated = 0;
-    foreach my $object (@{$self->{print}->objects}) {
-        $invalidated = 1 if $object->reload_model_instances;
-    }
-    if ($invalidated) {
-        $self->schedule_background_process;
-    } else {
-        $self->resume_background_process;
-    }
-    $self->refresh_canvases;
 }
 
 sub split_object {
@@ -788,19 +774,22 @@ sub split_object {
     my ($obj_idx, $current_object)  = $self->selected_object;
     
     # we clone model object because split_object() adds the split volumes
-    # into the same model object, thus causing duplicated when we call load_model_objects()
-    my $current_model_object        = $self->{model}->clone->objects->[$obj_idx];
+    # into the same model object, thus causing duplicates when we call load_model_objects()
+    my $new_model = $self->{model}->clone;  # store this before calling get_object()
+    my $current_model_object = $new_model->get_object($obj_idx);
     
-    if (@{$current_model_object->volumes} > 1) {
+    if ($current_model_object->volumes_count > 1) {
         Slic3r::GUI::warning_catcher($self)->("The selected object can't be split because it contains more than one volume/material.");
         return;
     }
     
-    $self->stop_background_process;
+    $self->pause_background_process;
     
     my @model_objects = @{$current_model_object->split_object};
     if (@model_objects == 1) {
+        $self->resume_background_process;
         Slic3r::GUI::warning_catcher($self)->("The selected object couldn't be split because it contains only one part.");
+        $self->resume_background_process;
         return;
     }
     
@@ -944,7 +933,7 @@ sub resume_background_process {
 }
 
 sub export_gcode {
-    my $self = shift;
+    my ($self, $output_file) = @_;
     
     return if !@{$self->{objects}};
     
@@ -976,14 +965,14 @@ sub export_gcode {
     }
     
     # select output file
-    $self->{export_gcode_output_file} = $main::opt{output};
-    {
-        my $default_output_file = $self->{print}->expanded_output_filepath($self->{export_gcode_output_file});
+    if ($output_file) {
+        $self->{export_gcode_output_file} = $self->{print}->expanded_output_filepath($output_file);
+    } else {
+        my $default_output_file = $self->{print}->expanded_output_filepath($main::opt{output});
         my $dlg = Wx::FileDialog->new($self, 'Save G-code file as:', wxTheApp->output_path(dirname($default_output_file)),
             basename($default_output_file), &Slic3r::GUI::FILE_WILDCARDS->{gcode}, wxFD_SAVE);
         if ($dlg->ShowModal != wxID_OK) {
             $dlg->Destroy;
-            $self->{export_gcode_output_file} = undef;
             return;
         }
         $Slic3r::GUI::Settings->{_}{last_output_path} = dirname($dlg->GetPath);
@@ -1011,6 +1000,8 @@ sub export_gcode {
         my $result = !Slic3r::GUI::catch_error($self);
         $self->on_export_completed($result);
     }
+    
+    return $self->{export_gcode_output_file};
 }
 
 # This gets called only if we have threads.
@@ -1072,14 +1063,52 @@ sub on_export_completed {
     $self->{export_thread} = undef;
     
     my $message;
+    my $send_gcode = 0;
     if ($result) {
-        $message = "G-code file exported to " . $self->{export_gcode_output_file};
+        if ($self->{send_gcode_file}) {
+            $message = "Sending G-code file to the OctoPrint server...";
+            $send_gcode = 1;
+        } else {
+            $message = "G-code file exported to " . $self->{export_gcode_output_file};
+        }
     } else {
         $message = "Export failed";
     }
     $self->{export_gcode_output_file} = undef;
     $self->statusbar->SetStatusText($message);
     wxTheApp->notify($message);
+    
+    $self->send_gcode if $send_gcode;
+    $self->{send_gcode_file} = undef;
+}
+
+sub send_gcode {
+    my ($self) = @_;
+    
+    $self->statusbar->StartBusy;
+    
+    my $ua = LWP::UserAgent->new;
+    $ua->timeout(10);
+    
+    my $res = $ua->post(
+        "http://" . $self->{config}->octoprint_host . "/api/files/local",
+        Content_Type => 'form-data',
+        'X-Api-Key' => $self->{config}->octoprint_apikey,
+        Content => [
+            # OctoPrint doesn't like Windows paths
+            file => [ $self->{send_gcode_file}, basename($self->{send_gcode_file}) ],
+        ],
+    );
+    
+    $self->statusbar->StopBusy;
+    
+    if ($res->is_success) {
+        $self->statusbar->SetStatusText("G-code file successfully uploaded to the OctoPrint server");
+    } else {
+        my $message = "Error while uploading to the OctoPrint server: " . $res->status_line;
+        Slic3r::GUI::show_error($self, $message);
+        $self->statusbar->SetStatusText($message);
+    }
 }
 
 sub export_stl {
@@ -1159,7 +1188,6 @@ sub on_thumbnail_made {
     my ($obj_idx) = @_;
     
     $self->{objects}[$obj_idx]->transform_thumbnail($self->{model}, $obj_idx);
-    $self->update;
     $self->refresh_canvases;
 }
 
@@ -1172,9 +1200,23 @@ sub update {
         $self->{model}->center_instances_around_point($self->bed_centerf);
     }
     
+    $self->pause_background_process;
+    my $invalidated = $self->{print}->reload_model_instances();
+    if ($invalidated) {
+        $self->schedule_background_process;
+    } else {
+        $self->resume_background_process;
+    }
+    
     $self->refresh_canvases;
 }
 
+sub on_model_instances_changed {
+    my ($self) = @_;
+    
+    
+}
+
 sub on_extruders_change {
     my ($self, $num_extruders) = @_;
     
@@ -1208,6 +1250,13 @@ sub on_config_change {
             $self->{canvas}->update_bed_size;
             $self->{canvas3D}->update_bed_size if $self->{canvas3D};
             $self->update;
+        } elsif ($opt_key eq 'octoprint_host') {
+            if ($config->get('octoprint_host')) {
+                $self->{btn_send_gcode}->Show;
+            } else {
+                $self->{btn_send_gcode}->Hide;
+            }
+            $self->Layout;
         }
     }
     
@@ -1313,7 +1362,7 @@ sub object_list_changed {
     my $have_objects = @{$self->{objects}} ? 1 : 0;
     my $method = $have_objects ? 'Enable' : 'Disable';
     $self->{"btn_$_"}->$method
-        for grep $self->{"btn_$_"}, qw(reset arrange export_gcode export_stl);
+        for grep $self->{"btn_$_"}, qw(reset arrange export_gcode export_stl send_gcode);
     
     if ($self->{htoolbar}) {
         $self->{htoolbar}->EnableTool($_, $have_objects)
diff --git a/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm b/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
index fb4b0291c..255a1685a 100644
--- a/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
+++ b/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
@@ -224,13 +224,7 @@ sub on_btn_load {
         }
     }
     
-    $self->reload_tree;
-    if ($self->{canvas}) {
-        $self->{canvas}->reset_objects;
-        $self->{canvas}->load_object($self->{model_object});
-        $self->{canvas}->set_bounding_box($self->{model_object}->bounding_box);
-        $self->{canvas}->Render;
-    }
+    $self->_parts_changed;
 }
 
 sub on_btn_delete {
@@ -250,9 +244,17 @@ sub on_btn_delete {
         $self->{parts_changed} = 1;
     }
     
+    $self->_parts_changed;
+}
+
+sub _parts_changed {
+    my ($self) = @_;
+    
     $self->reload_tree;
     if ($self->{canvas}) {
+        $self->{canvas}->reset_objects;
         $self->{canvas}->load_object($self->{model_object});
+        $self->{canvas}->zoom_to_volumes;
         $self->{canvas}->Render;
     }
 }
diff --git a/lib/Slic3r/GUI/Preferences.pm b/lib/Slic3r/GUI/Preferences.pm
index aab037ce7..74846cfc9 100644
--- a/lib/Slic3r/GUI/Preferences.pm
+++ b/lib/Slic3r/GUI/Preferences.pm
@@ -5,7 +5,7 @@ use base 'Wx::Dialog';
 
 sub new {
     my ($class, $parent) = @_;
-    my $self = $class->SUPER::new($parent, -1, "Preferences", wxDefaultPosition, [500,200]);
+    my $self = $class->SUPER::new($parent, -1, "Preferences", wxDefaultPosition, wxDefaultSize);
     $self->{values} = {};
     
     my $optgroup;
@@ -16,7 +16,7 @@ sub new {
             my ($opt_id) = @_;
             $self->{values}{$opt_id} = $optgroup->get_value($opt_id);
         },
-        label_width => 100,
+        label_width => 200,
     );
     $optgroup->append_single_option_line(Slic3r::GUI::OptionsGroup::Option->new(
         opt_id      => 'mode',
@@ -26,6 +26,7 @@ sub new {
         labels      => ['Simple','Expert'],
         values      => ['simple','expert'],
         default     => $Slic3r::GUI::Settings->{_}{mode},
+        width       => 100,
     ));
     $optgroup->append_single_option_line(Slic3r::GUI::OptionsGroup::Option->new(
         opt_id      => 'version_check',
diff --git a/lib/Slic3r/GUI/PreviewCanvas.pm b/lib/Slic3r/GUI/PreviewCanvas.pm
index d9e418345..f48240392 100644
--- a/lib/Slic3r/GUI/PreviewCanvas.pm
+++ b/lib/Slic3r/GUI/PreviewCanvas.pm
@@ -151,9 +151,6 @@ sub mouse_event {
             }
         }
     } elsif ($e->Dragging && $e->LeftIsDown && defined($self->_drag_volume_idx)) {
-        # get volume being dragged
-        my $volume = $self->volumes->[$self->_drag_volume_idx];
-        
         # get new position at the same Z of the initial click point
         my $mouse_ray = $self->mouse_ray($e->GetX, $e->GetY);
         my $cur_pos = $mouse_ray->intersect_plane($self->_drag_start_pos->z);
@@ -161,8 +158,14 @@ sub mouse_event {
         # calculate the translation vector
         my $vector = $self->_drag_start_pos->vector_to($cur_pos);
         
+        # get volume being dragged
+        my $volume = $self->volumes->[$self->_drag_volume_idx];
+        
+        # get all volumes belonging to the same group but only having the same instance_idx
+        my @volumes = grep $_->group_id == $volume->group_id && $_->instance_idx == $volume->instance_idx, @{$self->volumes};
+        
         # apply new temporary volume origin and ignore Z
-        $volume->origin->translate($vector->x, $vector->y, 0); #,,
+        $_->origin->translate($vector->x, $vector->y, 0) for @volumes; #,,
         $self->_drag_start_pos($cur_pos);
         $self->_dragged(1);
         $self->Refresh;
@@ -346,6 +349,7 @@ sub load_object {
     # sort volumes: non-modifiers first
     my @volumes = sort { ($a->modifier // 0) <=> ($b->modifier // 0) } @{$object->volumes};
     my @volumes_idx = ();
+    my $group_id = $#{$self->volumes} + 1;
     foreach my $volume (@volumes) {
         my @instance_idxs = $all_instances ? (0..$#{$object->instances}) : (0);
         foreach my $instance_idx (@instance_idxs) {
@@ -363,6 +367,7 @@ sub load_object {
             my $color = [ @{COLORS->[ $color_idx % scalar(@{&COLORS}) ]} ];
             push @$color, $volume->modifier ? 0.5 : 1;
             push @{$self->volumes}, my $v = Slic3r::GUI::PreviewCanvas::Volume->new(
+                group_id        => $group_id,
                 instance_idx    => $instance_idx,
                 mesh            => $mesh,
                 color           => $color,
@@ -888,6 +893,7 @@ use Moo;
 
 has 'mesh'          => (is => 'ro', required => 1);
 has 'color'         => (is => 'ro', required => 1);
+has 'group_id'      => (is => 'ro', required => 1);
 has 'instance_idx'  => (is => 'ro', default => sub { 0 });
 has 'origin'        => (is => 'rw', default => sub { Slic3r::Pointf3->new(0,0,0) });
 has 'verts'         => (is => 'rw');
diff --git a/lib/Slic3r/GUI/Tab.pm b/lib/Slic3r/GUI/Tab.pm
index 398aecac2..6aac1c862 100644
--- a/lib/Slic3r/GUI/Tab.pm
+++ b/lib/Slic3r/GUI/Tab.pm
@@ -923,6 +923,7 @@ sub build {
     $self->init_config_options(qw(
         bed_shape z_offset
         gcode_flavor use_relative_e_distances
+        octoprint_host octoprint_apikey
         use_firmware_retraction pressure_advance vibration_limit
         start_gcode end_gcode layer_gcode toolchange_gcode
         nozzle_diameter extruder_offset
@@ -996,6 +997,45 @@ sub build {
                 }
             });
         }
+        {
+            my $optgroup = $page->new_optgroup('OctoPrint upload');
+            
+            # append a button to the Host line
+            my $octoprint_host_widget = sub {
+                my ($parent) = @_;
+                
+                my $btn = Wx::Button->new($parent, -1, "Browse…", wxDefaultPosition, wxDefaultSize, wxBU_LEFT);
+                $btn->SetFont($Slic3r::GUI::small_font);
+                if ($Slic3r::GUI::have_button_icons) {
+                    $btn->SetBitmap(Wx::Bitmap->new("$Slic3r::var/zoom.png", wxBITMAP_TYPE_PNG));
+                }
+                
+                if (!eval "use Net::Bonjour; 1") {
+                    $btn->Disable;
+                }
+        
+                my $sizer = Wx::BoxSizer->new(wxHORIZONTAL);
+                $sizer->Add($btn);
+        
+                EVT_BUTTON($self, $btn, sub {
+                    my $dlg = Slic3r::GUI::BonjourBrowser->new($self);
+                    if ($dlg->ShowModal == wxID_OK) {
+                        my $value = $dlg->GetValue;
+                        $self->{config}->set('octoprint_host', $value);
+                        $self->update_dirty;
+                        $self->_on_value_change('octoprint_host', $value);
+                        $self->reload_config;
+                    }
+                });
+                
+                return $sizer;
+            };
+            
+            my $host_line = $optgroup->create_single_option_line('octoprint_host');
+            $host_line->append_widget($octoprint_host_widget);
+            $optgroup->append_line($host_line);
+            $optgroup->append_single_option_line('octoprint_apikey');
+        }
         {
             my $optgroup = $page->new_optgroup('Advanced');
             $optgroup->append_single_option_line('use_firmware_retraction');
@@ -1129,6 +1169,8 @@ sub _update {
     
     my $config = $self->{config};
     
+    $self->get_field('octoprint_apikey')->toggle($config->get('octoprint_host'));
+    
     my $have_multiple_extruders = $self->{extruders_count} > 1;
     $self->get_field('toolchange_gcode')->toggle($have_multiple_extruders);
     
@@ -1319,8 +1361,8 @@ sub config {
         }
         
         # apply preset values on top of defaults
+        my $config = Slic3r::Config->new_from_defaults(@$keys);
         my $external_config = Slic3r::Config->load($self->file);
-        my $config = Slic3r::Config->new;
         $config->set($_, $external_config->get($_))
             for grep $external_config->has($_), @$keys;
         
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 69df1c900..b68e191a5 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -219,7 +219,7 @@ sub make_skirt {
     # $skirt_height_z in this case is the highest possible skirt height for safety.
     my $skirt_height_z = -1;
     foreach my $object (@{$self->objects}) {
-        my $skirt_height = ($self->config->skirt_height == -1)
+        my $skirt_height = ($self->config->skirt_height == -1 || $self->config->ooze_prevention)
             ? scalar(@{$object->layers})
             : min($self->config->skirt_height, scalar(@{$object->layers}));
         
diff --git a/lib/Slic3r/Print/GCode.pm b/lib/Slic3r/Print/GCode.pm
index dae9eb3a7..a40a64e28 100644
--- a/lib/Slic3r/Print/GCode.pm
+++ b/lib/Slic3r/Print/GCode.pm
@@ -147,15 +147,26 @@ sub export {
             my $outer_skirt = convex_hull(\@skirt_points);
             my @skirts = ();
             foreach my $extruder_id (@{$self->print->extruders}) {
+                my $extruder_offset = $self->config->get_at('extruder_offset', $extruder_id);
                 push @skirts, my $s = $outer_skirt->clone;
-                $s->translate(map scale($_), @{$self->config->get_at('extruder_offset', $extruder_id)});
+                $s->translate(-scale($extruder_offset->x), -scale($extruder_offset->y));  #)
             }
             my $convex_hull = convex_hull([ map @$_, @skirts ]);
             
             $gcodegen->ooze_prevention->enable(1);
             $gcodegen->ooze_prevention->standby_points(
-                [ map $_->clone, map @$_, map $_->subdivide(scale 10), @{offset([$convex_hull], scale 3)} ]
+                [ map @{$_->equally_spaced_points(scale 10)}, @{offset([$convex_hull], scale 3)} ]
             );
+            
+            if (0) {
+                require "Slic3r/SVG.pm";
+                Slic3r::SVG::output(
+                    "ooze_prevention.svg",
+                    polygons        => [$outer_skirt],
+                    red_polygons    => \@skirts,
+                    points          => $gcodegen->ooze_prevention->standby_points,
+                );
+            }
         }
     }
     
diff --git a/lib/Slic3r/Print/SupportMaterial.pm b/lib/Slic3r/Print/SupportMaterial.pm
index a738c1dd8..7e23a75c7 100644
--- a/lib/Slic3r/Print/SupportMaterial.pm
+++ b/lib/Slic3r/Print/SupportMaterial.pm
@@ -442,23 +442,25 @@ sub generate_bottom_interface_layers {
             my $z = $support_z->[$layer_id];
             next unless $z > $top_z;
             
-            # get the support material area that should be considered interface
-            my $interface_area = intersection(
-                $base->{$layer_id},
-                $this,
-            );
+            if ($base->{$layer_id}) {
+                # get the support material area that should be considered interface
+                my $interface_area = intersection(
+                    $base->{$layer_id},
+                    $this,
+                );
             
-            # discard too small areas
-            $interface_area = [ grep abs($_->area) >= $area_threshold, @$interface_area ];
+                # discard too small areas
+                $interface_area = [ grep abs($_->area) >= $area_threshold, @$interface_area ];
             
-            # subtract new interface area from base
-            $base->{$layer_id} = diff(
-                $base->{$layer_id},
-                $interface_area,
-            );
+                # subtract new interface area from base
+                $base->{$layer_id} = diff(
+                    $base->{$layer_id},
+                    $interface_area,
+                );
             
-            # add new interface area to interface
-            push @{$interface->{$layer_id}}, @$interface_area;
+                # add new interface area to interface
+                push @{$interface->{$layer_id}}, @$interface_area;
+            }
             
             $interface_layers++;
             last if $interface_layers == $self->object_config->support_material_interface_layers;
diff --git a/t/multi.t b/t/multi.t
index 5431370dd..96703bed2 100644
--- a/t/multi.t
+++ b/t/multi.t
@@ -17,23 +17,25 @@ use Slic3r::Test;
     my $config = Slic3r::Config->new_from_defaults;
     $config->set('raft_layers', 2);
     $config->set('infill_extruder', 2);
-    $config->set('support_material_extruder', 3);
+    $config->set('solid_infill_extruder', 3);
+    $config->set('support_material_extruder', 4);
     $config->set('ooze_prevention', 1);
-    $config->set('extruder_offset', [ [0,0], [20,0], [0,20] ]);
-    $config->set('temperature', [200, 180, 170]);
-    $config->set('first_layer_temperature', [206, 186, 166]);
+    $config->set('extruder_offset', [ [0,0], [20,0], [0,20], [20,20] ]);
+    $config->set('temperature', [200, 180, 170, 160]);
+    $config->set('first_layer_temperature', [206, 186, 166, 156]);
     $config->set('toolchange_gcode', ';toolchange');  # test that it doesn't crash when this is supplied
     
     my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
     
     my $tool = undef;
-    my @tool_temp = (0,0,0);
+    my @tool_temp = (0,0,0,0);
     my @toolchange_points = ();
     my @extrusion_points = ();
     Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
         my ($self, $cmd, $args, $info) = @_;
         
         if ($cmd =~ /^T(\d+)/) {
+            # ignore initial toolchange
             if (defined $tool) {
                 my $expected_temp = $self->Z == ($config->get_value('first_layer_height') + $config->z_offset)
                     ? $config->first_layer_temperature->[$tool]
@@ -41,8 +43,8 @@ use Slic3r::Test;
                 die 'standby temperature was not set before toolchange'
                     if $tool_temp[$tool] != $expected_temp + $config->standby_temperature_delta;
                 
-                # ignore initial toolchange
-                push @toolchange_points, Slic3r::Point->new_scale($self->X, $self->Y);
+                push @toolchange_points, my $point = Slic3r::Point->new_scale($self->X, $self->Y);
+                $point->translate(map +scale($_), @{ $config->extruder_offset->[$tool] });
             }
             $tool = $1;
         } elsif ($cmd eq 'M104' || $cmd eq 'M109') {
@@ -54,11 +56,30 @@ use Slic3r::Test;
             $tool_temp[$t] = $args->{S};
         } elsif ($cmd eq 'G1' && $info->{extruding} && $info->{dist_XY} > 0) {
             push @extrusion_points, my $point = Slic3r::Point->new_scale($args->{X}, $args->{Y});
-            $point->translate(map scale($_), @{ $config->extruder_offset->[$tool] });
+            $point->translate(map +scale($_), @{ $config->extruder_offset->[$tool] });
         }
     });
     my $convex_hull = convex_hull(\@extrusion_points);
-    ok !(defined first { $convex_hull->contains_point($_) } @toolchange_points), 'all toolchanges happen outside skirt';
+    
+    my @t = ();
+    foreach my $point (@toolchange_points) {
+        foreach my $offset (@{$config->extruder_offset}) {
+            push @t, my $p = $point->clone;
+            $p->translate(map +scale($_), @$offset);
+        }
+    }
+    ok !(defined first { $convex_hull->contains_point($_) } @t), 'all nozzles are outside skirt at toolchange';
+    
+    if (0) {
+        require "Slic3r/SVG.pm";
+        Slic3r::SVG::output(
+            "ooze_prevention.svg",
+            no_arrows   => 1,
+            polygons    => [$convex_hull],
+            points      => \@toolchange_points,
+            red_points  => \@t,
+        );
+    }
     
     # offset the skirt by the maximum displacement between extruders plus a safety extra margin
     my $delta = scale(20 * sqrt(2) + 1);
diff --git a/var/zoom.png b/var/zoom.png
new file mode 100755
index 000000000..908612e39
Binary files /dev/null and b/var/zoom.png differ
diff --git a/xs/src/libslic3r/Model.cpp b/xs/src/libslic3r/Model.cpp
index 06919cedd..40926eb93 100644
--- a/xs/src/libslic3r/Model.cpp
+++ b/xs/src/libslic3r/Model.cpp
@@ -13,7 +13,7 @@ Model::Model(const Model &other)
     // copy objects
     this->objects.reserve(other.objects.size());
     for (ModelObjectPtrs::const_iterator i = other.objects.begin(); i != other.objects.end(); ++i)
-        this->add_object(**i);
+        this->add_object(**i, true);
 }
 
 Model& Model::operator= (Model other)
@@ -618,6 +618,7 @@ ModelObject::split(ModelObjectPtrs* new_objects)
         new_volume->material_id(volume->material_id());
         
         new_objects->push_back(new_object);
+        delete *mesh;
     }
     
     return;
diff --git a/xs/src/libslic3r/Print.cpp b/xs/src/libslic3r/Print.cpp
index b40430fec..b87d1c8cf 100644
--- a/xs/src/libslic3r/Print.cpp
+++ b/xs/src/libslic3r/Print.cpp
@@ -116,6 +116,16 @@ Print::reload_object(size_t idx)
     }
 }
 
+bool
+Print::reload_model_instances()
+{
+    bool invalidated = false;
+    FOREACH_OBJECT(this, object) {
+        if ((*object)->reload_model_instances()) invalidated = true;
+    }
+    return invalidated;
+}
+
 void
 Print::clear_regions()
 {
diff --git a/xs/src/libslic3r/Print.hpp b/xs/src/libslic3r/Print.hpp
index 0e7334eaf..aa67e1c6d 100644
--- a/xs/src/libslic3r/Print.hpp
+++ b/xs/src/libslic3r/Print.hpp
@@ -174,6 +174,7 @@ class Print
     PrintObject* get_object(size_t idx);
     void delete_object(size_t idx);
     void reload_object(size_t idx);
+    bool reload_model_instances();
 
     // methods for handling regions
     PrintRegion* get_region(size_t idx);
diff --git a/xs/src/libslic3r/PrintConfig.cpp b/xs/src/libslic3r/PrintConfig.cpp
index 4565ba5af..2ca83c15e 100644
--- a/xs/src/libslic3r/PrintConfig.cpp
+++ b/xs/src/libslic3r/PrintConfig.cpp
@@ -498,6 +498,16 @@ PrintConfigDef::build_def() {
     Options["nozzle_diameter"].sidetext = "mm";
     Options["nozzle_diameter"].cli = "nozzle-diameter=f@";
 
+    Options["octoprint_apikey"].type = coString;
+    Options["octoprint_apikey"].label = "API Key";
+    Options["octoprint_apikey"].tooltip = "Slic3r can upload G-code files to OctoPrint. This field should contain the API Key required for authentication.";
+    Options["octoprint_apikey"].cli = "octoprint-apikey=s";
+
+    Options["octoprint_host"].type = coString;
+    Options["octoprint_host"].label = "Host or IP";
+    Options["octoprint_host"].tooltip = "Slic3r can upload G-code files to OctoPrint. This field should contain the hostname or IP address of the OctoPrint instance.";
+    Options["octoprint_host"].cli = "octoprint-host=s";
+
     Options["only_retract_when_crossing_perimeters"].type = coBool;
     Options["only_retract_when_crossing_perimeters"].label = "Only retract when crossing perimeters";
     Options["only_retract_when_crossing_perimeters"].tooltip = "Disables retraction when the travel path does not exceed the upper layer's perimeters (and thus any ooze will be probably invisible).";
diff --git a/xs/src/libslic3r/PrintConfig.hpp b/xs/src/libslic3r/PrintConfig.hpp
index 48235c7d1..b647acfb8 100644
--- a/xs/src/libslic3r/PrintConfig.hpp
+++ b/xs/src/libslic3r/PrintConfig.hpp
@@ -582,7 +582,27 @@ class PrintConfig : public GCodeConfig
     };
 };
 
-class FullPrintConfig : public PrintObjectConfig, public PrintRegionConfig, public PrintConfig
+class HostConfig : public virtual StaticPrintConfig
+{
+    public:
+    ConfigOptionString              octoprint_host;
+    ConfigOptionString              octoprint_apikey;
+    
+    HostConfig() : StaticPrintConfig() {
+        this->octoprint_host.value                              = "";
+        this->octoprint_apikey.value                            = "";
+    };
+    
+    ConfigOption* option(const t_config_option_key opt_key, bool create = false) {
+        if (opt_key == "octoprint_host")                        return &this->octoprint_host;
+        if (opt_key == "octoprint_apikey")                      return &this->octoprint_apikey;
+        
+        return NULL;
+    };
+};
+
+class FullPrintConfig
+    : public PrintObjectConfig, public PrintRegionConfig, public PrintConfig, public HostConfig
 {
     public:
     ConfigOption* option(const t_config_option_key opt_key, bool create = false) {
@@ -590,6 +610,7 @@ class FullPrintConfig : public PrintObjectConfig, public PrintRegionConfig, publ
         if ((opt = PrintObjectConfig::option(opt_key, create)) != NULL) return opt;
         if ((opt = PrintRegionConfig::option(opt_key, create)) != NULL) return opt;
         if ((opt = PrintConfig::option(opt_key, create)) != NULL) return opt;
+        if ((opt = HostConfig::option(opt_key, create)) != NULL) return opt;
         return NULL;
     };
 };
diff --git a/xs/src/libslic3r/libslic3r.h b/xs/src/libslic3r/libslic3r.h
index 42bfa6164..4a02ac2cd 100644
--- a/xs/src/libslic3r/libslic3r.h
+++ b/xs/src/libslic3r/libslic3r.h
@@ -6,7 +6,7 @@
 #include <iostream>
 #include <sstream>
 
-#define SLIC3R_VERSION "1.2.2"
+#define SLIC3R_VERSION "1.2.4"
 
 #define EPSILON 1e-4
 #define SCALING_FACTOR 0.000001
diff --git a/xs/src/perlglue.hpp b/xs/src/perlglue.hpp
index 833eee6f3..84c9a7ae9 100644
--- a/xs/src/perlglue.hpp
+++ b/xs/src/perlglue.hpp
@@ -42,9 +42,9 @@ template <class T>
 class Ref {
     T* val;
 public:
-    Ref() {}
+    Ref() : val(NULL) {}
     Ref(T* t) : val(t) {}
-    operator T*() const {return val; }
+    operator T*() const { return val; }
     static const char* CLASS() { return ClassTraits<T>::name_ref; }
 };
   
@@ -52,10 +52,10 @@ template <class T>
 class Clone {
     T* val;
 public:
-    Clone() : val() {}
+    Clone() : val(NULL) {}
     Clone(T* t) : val(new T(*t)) {}
     Clone(const T& t) : val(new T(t)) {}
-    operator T*() const {return val; }
+    operator T*() const { return val; }
     static const char* CLASS() { return ClassTraits<T>::name; }
 };
 };
diff --git a/xs/xsp/Print.xsp b/xs/xsp/Print.xsp
index c3c9a97c5..fb0d17721 100644
--- a/xs/xsp/Print.xsp
+++ b/xs/xsp/Print.xsp
@@ -143,6 +143,7 @@ _constant()
     Ref<PrintObject> get_object(int idx);
     void delete_object(int idx);
     void reload_object(int idx);
+    bool reload_model_instances();
     size_t object_count()
         %code%{ RETVAL = THIS->objects.size(); %};