diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index 32645e338..49b5a62a0 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -102,10 +102,13 @@ sub new {
         }
     });
     
-    # Initialize 3D preview canvas
+    # Initialize 3D preview and toolpaths preview
     if ($Slic3r::GUI::have_OpenGL) {
         $self->{canvas3D} = Slic3r::GUI::Plater::3D->new($self->{preview_notebook}, $self->{objects}, $self->{model}, $self->{config});
         $self->{preview_notebook}->AddPage($self->{canvas3D}, '3D');
+        
+        $self->{toolpaths2D} = Slic3r::GUI::Plater::2DToolpaths->new($self->{preview_notebook}, $self->{print});
+        $self->{preview_notebook}->AddPage($self->{toolpaths2D}, 'Preview');
     }
     
     # toolbar for object manipulation
@@ -169,11 +172,8 @@ sub new {
     # right pane buttons
     $self->{btn_export_gcode} = Wx::Button->new($self, -1, "Export G-code…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
     $self->{btn_export_stl} = Wx::Button->new($self, -1, "Export STL…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
-    $self->{btn_toolpaths_preview} = Wx::Button->new($self, -1, "Toolpaths preview…", wxDefaultPosition, [-1, 30], wxBU_LEFT);
     $self->{btn_export_gcode}->SetFont($Slic3r::GUI::small_font);
     $self->{btn_export_stl}->SetFont($Slic3r::GUI::small_font);
-    $self->{btn_toolpaths_preview}->SetFont($Slic3r::GUI::small_font);
-    $self->{btn_toolpaths_preview}->Disable;
     
     if ($Slic3r::GUI::have_button_icons) {
         my %icons = qw(
@@ -183,7 +183,6 @@ sub new {
             arrange         bricks.png
             export_gcode    cog_go.png
             export_stl      brick_go.png
-            toolpaths_preview joystick.png
             
             increase        add.png
             decrease        delete.png
@@ -205,7 +204,6 @@ sub new {
         Slic3r::thread_cleanup();
     });
     EVT_BUTTON($self, $self->{btn_export_stl}, \&export_stl);
-    EVT_BUTTON($self, $self->{btn_toolpaths_preview}, \&toolpaths_preview);
     
     if ($self->{htoolbar}) {
         EVT_TOOL($self, TB_ADD, sub { $self->add; });
@@ -346,7 +344,6 @@ sub new {
         my $right_buttons_sizer = Wx::BoxSizer->new(wxVERTICAL);
         $right_buttons_sizer->Add($presets, 0, wxEXPAND, 0) if defined $presets;
         $right_buttons_sizer->Add($self->{btn_export_gcode}, 0, wxEXPAND | wxTOP, 8);
-        $right_buttons_sizer->Add($self->{btn_toolpaths_preview}, 0, wxEXPAND | wxTOP, 2);
         $right_buttons_sizer->Add($self->{btn_export_stl}, 0, wxEXPAND | wxTOP, 2);
         
         my $right_top_sizer = Wx::BoxSizer->new(wxHORIZONTAL);
@@ -809,7 +806,7 @@ sub schedule_background_process {
     
     if (defined $self->{apply_config_timer}) {
         $self->{apply_config_timer}->Start(PROCESS_DELAY, 1);  # 1 = one shot
-        $self->{btn_toolpaths_preview}->Disable;
+        $self->{toolpaths2D}->reload_print;
     }
 }
 
@@ -885,7 +882,7 @@ sub stop_background_process {
     $self->statusbar->SetCancelCallback(undef);
     $self->statusbar->StopBusy;
     $self->statusbar->SetStatusText("");
-    $self->{btn_toolpaths_preview}->Disable;
+    $self->{toolpaths2D}->reload_print;
     
     if ($self->{process_thread}) {
         Slic3r::debugf "Killing background process.\n";
@@ -1004,7 +1001,7 @@ sub on_process_completed {
     $self->{process_thread} = undef;
     
     return if !$result;
-    $self->{btn_toolpaths_preview}->Enable;
+    $self->{toolpaths2D}->reload_print;
     
     # if we have an export filename, start a new thread for exporting G-code
     if ($self->{export_gcode_output_file}) {
@@ -1281,19 +1278,6 @@ sub object_settings_dialog {
     }
 }
 
-sub toolpaths_preview {
-    my ($self) = @_;
-    
-    # TODO: we should check whether steps are done in $print rather then checking the thread
-    if ($self->{process_thread}) {
-        Slic3r::GUI::show_error($self, "Unable to show preview while toolpaths are being generated.");
-        return;
-    }
-    
-    my $dlg = Slic3r::GUI::Plater::2DToolpaths::Dialog->new($self, $self->{print});
-	$dlg->ShowModal;
-}
-
 sub object_list_changed {
     my $self = shift;
     
diff --git a/lib/Slic3r/GUI/Plater/2DToolpaths.pm b/lib/Slic3r/GUI/Plater/2DToolpaths.pm
index 8e48a7290..c69562c1d 100644
--- a/lib/Slic3r/GUI/Plater/2DToolpaths.pm
+++ b/lib/Slic3r/GUI/Plater/2DToolpaths.pm
@@ -3,11 +3,12 @@ use strict;
 use warnings;
 use utf8;
 
-use List::Util qw();
-use Slic3r::Geometry qw();
+use Slic3r::Print::State ':steps';
 use Wx qw(:misc :sizer :slider :statictext);
 use Wx::Event qw(EVT_SLIDER EVT_KEY_DOWN);
-use base 'Wx::Panel';
+use base qw(Wx::Panel Class::Accessor);
+
+__PACKAGE__->mk_accessors(qw(print enabled));
 
 sub new {
     my $class = shift;
@@ -15,17 +16,13 @@ sub new {
     
     my $self = $class->SUPER::new($parent, -1, wxDefaultPosition);
     
-    # init print
-    $self->{print} = $print;
-    $self->reload_print;
-    
     # init GUI elements
     my $canvas = $self->{canvas} = Slic3r::GUI::Plater::2DToolpaths::Canvas->new($self, $print);
     my $slider = $self->{slider} = Wx::Slider->new(
         $self, -1,
         0,                              # default
         0,                              # min
-        scalar(@{$self->{layers_z}})-1,    # max
+        0,                              # max
         wxDefaultPosition,
         wxDefaultSize,
         wxVERTICAL | wxSL_INVERSE,
@@ -43,7 +40,8 @@ sub new {
     $sizer->Add($vsizer, 0, wxTOP | wxBOTTOM | wxEXPAND, 5);
     
     EVT_SLIDER($self, $slider, sub {
-        $self->set_z($self->{layers_z}[$slider->GetValue]);
+        $self->set_z($self->{layers_z}[$slider->GetValue])
+            if $self->enabled;
     });
     EVT_KEY_DOWN($canvas, sub {
         my ($s, $event) = @_;
@@ -62,7 +60,9 @@ sub new {
     $self->SetMinSize($self->GetSize);
     $sizer->SetSizeHints($self);
     
-    $self->set_z($self->{layers_z}[0]);
+    # init print
+    $self->{print} = $print;
+    $self->reload_print;
     
     return $self;
 }
@@ -70,6 +70,18 @@ sub new {
 sub reload_print {
     my ($self) = @_;
     
+    # we require that there's at least one object and the posSlice step
+    # is performed on all of them (this ensures that _shifted_copies was
+    # populated and we know the number of layers)
+    if (!$self->print->object_step_done(STEP_SLICE)) {
+        $self->enabled(0);
+        $self->{slider}->Hide;
+        $self->{canvas}->Refresh;  # clears canvas
+        return;
+    }
+    
+    $self->{canvas}->bb($self->print->total_bounding_box);
+    
     my %z = ();  # z => 1
     foreach my $object (@{$self->{print}->objects}) {
         foreach my $layer (@{$object->layers}, @{$object->support_layers}) {
@@ -77,11 +89,16 @@ sub reload_print {
         }
     }
     $self->{layers_z} = [ sort { $a <=> $b } keys %z ];
+    ###$self->{slider}->SetMax(scalar(@{$self->{layers_z}})-1);
+    $self->enabled(1);
+    $self->set_z($self->{layers_z}[0]) if @{$self->{layers_z}};
+    $self->{slider}->Show;
 }
 
 sub set_z {
     my ($self, $z) = @_;
     
+    return if !$self->enabled;
     $self->{z_label}->SetLabel(sprintf '%.2f', $z);
     $self->{canvas}->set_z($z);
 }
@@ -89,14 +106,15 @@ sub set_z {
 
 package Slic3r::GUI::Plater::2DToolpaths::Canvas;
 
-use Wx::Event qw(EVT_PAINT EVT_SIZE EVT_ERASE_BACKGROUND EVT_IDLE EVT_MOUSEWHEEL EVT_MOUSE_EVENTS);
+use Wx::Event qw(EVT_PAINT EVT_SIZE EVT_ERASE_BACKGROUND EVT_MOUSEWHEEL EVT_MOUSE_EVENTS);
 use OpenGL qw(:glconstants :glfunctions :glufunctions);
 use base qw(Wx::GLCanvas Class::Accessor);
 use Wx::GLCanvas qw(:all);
 use List::Util qw(min first);
 use Slic3r::Geometry qw(scale unscale epsilon);
+use Slic3r::Print::State ':steps';
 
-__PACKAGE__->mk_accessors(qw(print z layers color init dirty bb));
+__PACKAGE__->mk_accessors(qw(print z layers color init bb));
 
 # make OpenGL::Array thread-safe
 {
@@ -109,15 +127,12 @@ sub new {
     
     my $self = $class->SUPER::new($parent);
     $self->print($print);
-    $self->bb($self->print->total_bounding_box);
     
     EVT_PAINT($self, sub {
         my $dc = Wx::PaintDC->new($self);
         $self->Render($dc);
     });
-    EVT_SIZE($self, sub { $self->dirty(1) });
-    EVT_IDLE($self, sub {
-        return unless $self->dirty;
+    EVT_SIZE($self, sub {
         return if !$self->IsShownOnScreen;
         $self->Resize( $self->GetSizeWH );
         $self->Refresh;
@@ -152,7 +167,7 @@ sub set_z {
     
     $self->z($z);
     $self->layers([ @layers ]);
-    $self->dirty(1);
+    $self->Refresh;
 }
 
 sub Render {
@@ -164,6 +179,15 @@ sub Render {
     $self->SetCurrent($context);
     $self->InitGL;
     
+    glClearColor(1, 1, 1, 0);
+    glClear(GL_COLOR_BUFFER_BIT);
+    
+    if (!$self->GetParent->enabled || !$self->layers) {
+        glFlush();
+        $self->SwapBuffers;
+        return;
+    }
+    
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     my $bb = $self->bb;
@@ -184,9 +208,6 @@ sub Render {
     glMatrixMode(GL_MODELVIEW);
     glLoadIdentity();
     
-    glClearColor(1, 1, 1, 0);
-    glClear(GL_COLOR_BUFFER_BIT);
-    
     my $skirt_drawn = 0;
     my $brim_drawn = 0;
     foreach my $layer (@{$self->layers}) {
@@ -194,29 +215,37 @@ sub Render {
         my $print_z = $layer->print_z;
         
         # draw brim
-        if ($layer->id == 0 && !$brim_drawn) {
+        if ($self->print->step_done(STEP_BRIM) && $layer->id == 0 && !$brim_drawn) {
             $self->color([0, 0, 0]);
             $self->_draw(undef, $print_z, $_) for @{$self->print->brim};
             $brim_drawn = 1;
         }
-        if (($self->print->config->skirt_height == -1 || $self->print->config->skirt_height >= $layer->id) && !$skirt_drawn) {
+        if ($self->print->step_done(STEP_SKIRT)
+            && ($self->print->config->skirt_height == -1 || $self->print->config->skirt_height > $layer->id)
+            && !$skirt_drawn) {
             $self->color([0, 0, 0]);
             $self->_draw(undef, $print_z, $_) for @{$self->print->skirt};
             $skirt_drawn = 1;
         }
         
         foreach my $layerm (@{$layer->regions}) {
-            $self->color([0.7, 0, 0]);
-            $self->_draw($object, $print_z, $_) for @{$layerm->perimeters};
+            if ($object->step_done(STEP_PERIMETERS)) {
+                $self->color([0.7, 0, 0]);
+                $self->_draw($object, $print_z, $_) for @{$layerm->perimeters};
+            }
             
-            $self->color([0, 0, 0.7]);
-            $self->_draw($object, $print_z, $_) for map @$_, @{$layerm->fills};
+            if ($object->step_done(STEP_INFILL)) {
+                $self->color([0, 0, 0.7]);
+                $self->_draw($object, $print_z, $_) for map @$_, @{$layerm->fills};
+            }
         }
         
-        if ($layer->isa('Slic3r::Layer::Support')) {
-            $self->color([0, 0, 0]);
-            $self->_draw($object, $print_z, $_) for @{$layer->support_fills};
-            $self->_draw($object, $print_z, $_) for @{$layer->support_interface_fills};
+        if ($object->step_done(STEP_SUPPORTMATERIAL)) {
+            if ($layer->isa('Slic3r::Layer::Support')) {
+                $self->color([0, 0, 0]);
+                $self->_draw($object, $print_z, $_) for @{$layer->support_fills};
+                $self->_draw($object, $print_z, $_) for @{$layer->support_interface_fills};
+            }
         }
     }
     
@@ -299,8 +328,7 @@ sub Resize {
     my ($self, $x, $y) = @_;
  
     return unless $self->GetContext;
-    $self->dirty(0);
- 
+    
     $self->SetCurrent($self->GetContext);
     glViewport(0, 0, $x, $y);
 }
diff --git a/xs/src/libslic3r/Print.cpp b/xs/src/libslic3r/Print.cpp
index d0175ebac..3339162c7 100644
--- a/xs/src/libslic3r/Print.cpp
+++ b/xs/src/libslic3r/Print.cpp
@@ -290,6 +290,19 @@ Print::invalidate_all_steps()
     return invalidated;
 }
 
+// returns true if an object step is done on all objects
+// and there's at least one object
+bool
+Print::step_done(PrintObjectStep step) const
+{
+    if (this->objects.empty()) return false;
+    FOREACH_OBJECT(this, object) {
+        if (!(*object)->state.is_done(step))
+            return false;
+    }
+    return true;
+}
+
 // returns 0-based indices of used extruders
 std::set<size_t>
 Print::extruders() const
diff --git a/xs/src/libslic3r/Print.hpp b/xs/src/libslic3r/Print.hpp
index 0c4d7c24f..574a9b6d2 100644
--- a/xs/src/libslic3r/Print.hpp
+++ b/xs/src/libslic3r/Print.hpp
@@ -178,6 +178,7 @@ class Print
     bool invalidate_state_by_config_options(const std::vector<t_config_option_key> &opt_keys);
     bool invalidate_step(PrintStep step);
     bool invalidate_all_steps();
+    bool step_done(PrintObjectStep step) const;
     
     void add_model_object(ModelObject* model_object, int idx = -1);
     bool apply_config(DynamicPrintConfig config);
diff --git a/xs/xsp/Print.xsp b/xs/xsp/Print.xsp
index 556e87396..6369524e1 100644
--- a/xs/xsp/Print.xsp
+++ b/xs/xsp/Print.xsp
@@ -156,6 +156,8 @@ _constant()
     bool invalidate_all_steps();
     bool step_done(PrintStep step)
         %code%{ RETVAL = THIS->state.is_done(step); %};
+    bool object_step_done(PrintObjectStep step)
+        %code%{ RETVAL = THIS->step_done(step); %};
     void set_step_done(PrintStep step)
         %code%{ THIS->state.set_done(step); %};
     void set_step_started(PrintStep step)