diff --git a/lib/Slic3r/GCode.pm b/lib/Slic3r/GCode.pm
index 1180b76ff..4519d933a 100644
--- a/lib/Slic3r/GCode.pm
+++ b/lib/Slic3r/GCode.pm
@@ -6,6 +6,7 @@ use Slic3r::ExtrusionPath ':roles';
 use Slic3r::Geometry qw(scale unscale scaled_epsilon points_coincide PI X Y B);
 use Slic3r::Geometry::Clipper qw(union_ex);
 
+has 'config'             => (is => 'ro', required => 1);
 has 'multiple_extruders' => (is => 'ro', default => sub {0} );
 has 'layer_count'        => (is => 'ro', required => 1 );
 has 'layer'              => (is => 'rw');
@@ -15,6 +16,7 @@ has 'shift_y'            => (is => 'rw', default => sub {0} );
 has 'z'                  => (is => 'rw');
 has 'speed'              => (is => 'rw');
 
+has 'speeds'             => (is => 'lazy');  # mm/min
 has 'external_mp'        => (is => 'rw');
 has 'layer_mp'           => (is => 'rw');
 has 'new_object'         => (is => 'rw', default => sub {0});
@@ -35,15 +37,14 @@ has 'dec'                => (is => 'ro', default => sub { 3 } );
 has 'last_dir'           => (is => 'ro', default => sub { [0,0] });
 has 'dir_time'           => (is => 'ro', default => sub { [0,0] });
 
-# calculate speeds (mm/min)
-has 'speeds' => (
-    is      => 'ro',
-    default => sub {+{
-        map { $_ => 60 * $Slic3r::Config->get_value("${_}_speed") }
+sub _build_speeds {
+    my $self = shift;
+    return {
+        map { $_ => 60 * $self->config->get_value("${_}_speed") }
             qw(travel perimeter small_perimeter external_perimeter infill
                 solid_infill top_solid_infill support_material bridge gap_fill retract),
-    }},
-);
+    };
+}
 
 # assign speeds to roles
 my %role_speeds = (
@@ -81,17 +82,17 @@ sub change_layer {
     my ($layer) = @_;
     
     $self->layer($layer);
-    if ($Slic3r::Config->avoid_crossing_perimeters) {
+    if ($self->config->avoid_crossing_perimeters) {
         $self->layer_mp(Slic3r::GCode::MotionPlanner->new(
             islands => union_ex([ map @$_, @{$layer->slices} ], undef, 1),
         ));
     }
     
     my $gcode = "";
-    if ($Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/) {
+    if ($self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/) {
         $gcode .= sprintf "M73 P%s%s\n",
             int(99 * ($layer->id / ($self->layer_count - 1))),
-            ($Slic3r::Config->gcode_comments ? ' ; update progress' : '');
+            ($self->config->gcode_comments ? ' ; update progress' : '');
     }
     return $gcode;
 }
@@ -102,7 +103,7 @@ sub move_z {
     my ($z, $comment) = @_;
     
     $z *= &Slic3r::SCALING_FACTOR;
-    $z += $Slic3r::Config->z_offset;
+    $z += $self->config->z_offset;
     
     my $gcode = "";
     my $current_z = $self->z;
@@ -136,9 +137,9 @@ sub extrude_loop {
     # find the point of the loop that is closest to the current extruder position
     # or randomize if requested
     my $last_pos = $self->last_pos;
-    if ($Slic3r::Config->randomize_start && $loop->role == EXTR_ROLE_CONTOUR_INTERNAL_PERIMETER) {
-        $last_pos = Slic3r::Point->new(scale $Slic3r::Config->print_center->[X], scale $Slic3r::Config->bed_size->[Y]);
-        $last_pos->rotate(rand(2*PI), $Slic3r::Config->print_center);
+    if ($self->config->randomize_start && $loop->role == EXTR_ROLE_CONTOUR_INTERNAL_PERIMETER) {
+        $last_pos = Slic3r::Point->new(scale $self->config->print_center->[X], scale $self->config->bed_size->[Y]);
+        $last_pos->rotate(rand(2*PI), $self->config->print_center);
     }
     my $start_index = $loop->nearest_point_index_to($last_pos);
     
@@ -156,7 +157,7 @@ sub extrude_loop {
     $self->wipe_path($extrusion_path->polyline);
     
     # make a little move inwards before leaving loop
-    if ($loop->role == EXTR_ROLE_EXTERNAL_PERIMETER && $Slic3r::Config->perimeters > 1) {
+    if ($loop->role == EXTR_ROLE_EXTERNAL_PERIMETER && $self->config->perimeters > 1) {
         # detect angle between last and first segment
         # the side depends on the original winding order of the polygon (left for contours, right for holes)
         my @points = $was_clockwise ? (-2, 1) : (1, -2);
@@ -187,7 +188,7 @@ sub extrude_path {
     $path->simplify(&Slic3r::SCALED_RESOLUTION);
     
     # detect arcs
-    if ($Slic3r::Config->gcode_arcs && !$recursive) {
+    if ($self->config->gcode_arcs && !$recursive) {
         my $gcode = "";
         foreach my $arc_path ($path->detect_arcs) {
             $gcode .= $self->extrude_path($arc_path, $description, 1);
@@ -204,12 +205,12 @@ sub extrude_path {
     
     # adjust acceleration
     my $acceleration;
-    if ($Slic3r::Config->perimeter_acceleration && $path->is_perimeter) {
-        $acceleration = $Slic3r::Config->perimeter_acceleration;
-    } elsif ($Slic3r::Config->infill_acceleration && $path->is_fill) {
-        $acceleration = $Slic3r::Config->infill_acceleration;
-    } elsif ($Slic3r::Config->infill_acceleration && ($path->role == EXTR_ROLE_BRIDGE || $path->role == EXTR_ROLE_INTERNALBRIDGE)) {
-        $acceleration = $Slic3r::Config->bridge_acceleration;
+    if ($self->config->perimeter_acceleration && $path->is_perimeter) {
+        $acceleration = $self->config->perimeter_acceleration;
+    } elsif ($self->config->infill_acceleration && $path->is_fill) {
+        $acceleration = $self->config->infill_acceleration;
+    } elsif ($self->config->infill_acceleration && ($path->role == EXTR_ROLE_BRIDGE || $path->role == EXTR_ROLE_INTERNALBRIDGE)) {
+        $acceleration = $self->config->bridge_acceleration;
     }
     $gcode .= $self->set_acceleration($acceleration) if $acceleration;
     
@@ -251,19 +252,19 @@ sub extrude_path {
             if $self->extruder->wipe;
     }
     
-    if ($Slic3r::Config->cooling) {
+    if ($self->config->cooling) {
         my $path_time = $path_length / $self->speeds->{$self->last_speed} * 60;
         if ($self->layer->id == 0) {
-            $path_time = $Slic3r::Config->first_layer_speed =~ /^(\d+(?:\.\d+)?)%$/
+            $path_time = $self->config->first_layer_speed =~ /^(\d+(?:\.\d+)?)%$/
                 ? $path_time / ($1/100)
-                : $path_length / $Slic3r::Config->first_layer_speed * 60;
+                : $path_length / $self->config->first_layer_speed * 60;
         }
         $self->elapsed_time($self->elapsed_time + $path_time);
     }
     
     # reset acceleration
-    $gcode .= $self->set_acceleration($Slic3r::Config->default_acceleration)
-        if $acceleration && $Slic3r::Config->default_acceleration;
+    $gcode .= $self->set_acceleration($self->config->default_acceleration)
+        if $acceleration && $self->config->default_acceleration;
     
     return $gcode;
 }
@@ -282,13 +283,13 @@ sub travel_to {
     $travel->translate(-$self->shift_x, -$self->shift_y);
     
     if ($travel->length < scale $self->extruder->retract_before_travel
-        || ($Slic3r::Config->only_retract_when_crossing_perimeters && first { $_->encloses_line($travel, scaled_epsilon) } @{$self->layer->slices})
+        || ($self->config->only_retract_when_crossing_perimeters && first { $_->encloses_line($travel, scaled_epsilon) } @{$self->layer->slices})
         || ($role == EXTR_ROLE_SUPPORTMATERIAL && $self->layer->support_islands_enclose_line($travel))
         ) {
         $self->straight_once(0);
         $self->speed('travel');
         $gcode .= $self->G0($point, undef, 0, $comment || "");
-    } elsif (!$Slic3r::Config->avoid_crossing_perimeters || $self->straight_once) {
+    } elsif (!$self->config->avoid_crossing_perimeters || $self->straight_once) {
         $self->straight_once(0);
         $gcode .= $self->retract(travel_to => $point);
         $self->speed('travel');
@@ -322,7 +323,7 @@ sub _plan {
     my @travel = $mp->shortest_path($self->last_pos, $point)->lines;
     
     # if the path is not contained in a single island we need to retract
-    my $need_retract = !$Slic3r::Config->only_retract_when_crossing_perimeters;
+    my $need_retract = !$self->config->only_retract_when_crossing_perimeters;
     if (!$need_retract) {
         $need_retract = 1;
         foreach my $slice (@{$self->layer->slices}) {
@@ -370,7 +371,7 @@ sub retract {
         ? undef
         : [undef, $self->z + $self->extruder->retract_lift, 0, 'lift plate during travel'];
     
-    if (($Slic3r::Config->g0 || $Slic3r::Config->gcode_flavor eq 'mach3') && $params{travel_to}) {
+    if (($self->config->g0 || $self->config->gcode_flavor eq 'mach3') && $params{travel_to}) {
         $self->speed('travel');
         if ($lift) {
             # combine lift and retract
@@ -381,7 +382,7 @@ sub retract {
             my $travel = [$params{travel_to}, undef, $retract->[2], "travel and $comment"];
             $gcode .= $self->G0(@$travel);
         }
-    } elsif (($Slic3r::Config->g0 || $Slic3r::Config->gcode_flavor eq 'mach3') && defined $params{move_z}) {
+    } elsif (($self->config->g0 || $self->config->gcode_flavor eq 'mach3') && defined $params{move_z}) {
         # combine Z change and retraction
         $self->speed('travel');
         my $travel = [undef, $params{move_z}, $retract->[2], "change layer and $comment"];
@@ -417,7 +418,7 @@ sub retract {
     
     # reset extrusion distance during retracts
     # this makes sure we leave sufficient precision in the firmware
-    $gcode .= $self->reset_e if $Slic3r::Config->gcode_flavor !~ /^(?:mach3|makerbot)$/;
+    $gcode .= $self->reset_e if $self->config->gcode_flavor !~ /^(?:mach3|makerbot)$/;
     
     return $gcode;
 }
@@ -448,8 +449,8 @@ sub reset_e {
     my $self = shift;
     
     $self->extrusion_distance(0);
-    return sprintf "G92 %s0%s\n", $Slic3r::Config->extrusion_axis, ($Slic3r::Config->gcode_comments ? ' ; reset extrusion distance' : '')
-        if $Slic3r::Config->extrusion_axis && !$Slic3r::Config->use_relative_e_distances;
+    return sprintf "G92 %s0%s\n", $self->config->extrusion_axis, ($self->config->gcode_comments ? ' ; reset extrusion distance' : '')
+        if $self->config->extrusion_axis && !$self->config->use_relative_e_distances;
 }
 
 sub set_acceleration {
@@ -458,12 +459,12 @@ sub set_acceleration {
     return "" if !$acceleration;
     
     return sprintf "M204 S%s%s\n",
-        $acceleration, ($Slic3r::Config->gcode_comments ? ' ; adjust acceleration' : '');
+        $acceleration, ($self->config->gcode_comments ? ' ; adjust acceleration' : '');
 }
 
 sub G0 {
     my $self = shift;
-    return $self->G1(@_) if !($Slic3r::Config->g0 || $Slic3r::Config->gcode_flavor eq 'mach3');
+    return $self->G1(@_) if !($self->config->g0 || $self->config->gcode_flavor eq 'mach3');
     return $self->_G0_G1("G0", @_);
 }
 
@@ -533,9 +534,9 @@ sub _Gx {
             ? ($self->extruder->retract_speed_mm_min)
             : $self->speeds->{$self->speed} // $self->speed;
         if ($e && $self->layer && $self->layer->id == 0 && $comment !~ /retract/) {
-            $F = $Slic3r::Config->first_layer_speed =~ /^(\d+(?:\.\d+)?)%$/
+            $F = $self->config->first_layer_speed =~ /^(\d+(?:\.\d+)?)%$/
                 ? ($F * $1/100)
-                : $Slic3r::Config->first_layer_speed * 60;
+                : $self->config->first_layer_speed * 60;
         }
         $self->last_speed($self->speed);
         $self->last_f($F);
@@ -543,14 +544,14 @@ sub _Gx {
     $gcode .= sprintf " F%.${dec}f", $F if defined $F;
     
     # output extrusion distance
-    if ($e && $Slic3r::Config->extrusion_axis) {
-        $self->extrusion_distance(0) if $Slic3r::Config->use_relative_e_distances;
+    if ($e && $self->config->extrusion_axis) {
+        $self->extrusion_distance(0) if $self->config->use_relative_e_distances;
         $self->extrusion_distance($self->extrusion_distance + $e);
         $self->total_extrusion_length($self->total_extrusion_length + $e);
-        $gcode .= sprintf " %s%.5f", $Slic3r::Config->extrusion_axis, $self->extrusion_distance;
+        $gcode .= sprintf " %s%.5f", $self->config->extrusion_axis, $self->extrusion_distance;
     }
     
-    $gcode .= sprintf " ; %s", $comment if $comment && $Slic3r::Config->gcode_comments;
+    $gcode .= sprintf " ; %s", $comment if $comment && $self->config->gcode_comments;
     if ($append_bridge_off) {
         $gcode .= "\n;_BRIDGE_FAN_END";
     }
@@ -575,8 +576,8 @@ sub set_extruder {
     $gcode .= $self->retract(toolchange => 1) if defined $self->extruder;
     
     # append custom toolchange G-code
-    if (defined $self->extruder && $Slic3r::Config->toolchange_gcode) {
-        $gcode .= sprintf "%s\n", $Slic3r::Config->replace_options($Slic3r::Config->toolchange_gcode, {
+    if (defined $self->extruder && $self->config->toolchange_gcode) {
+        $gcode .= sprintf "%s\n", $self->config->replace_options($self->config->toolchange_gcode, {
             previous_extruder   => $self->extruder->id,
             next_extruder       => $extruder->id,
         });
@@ -585,11 +586,11 @@ sub set_extruder {
     # set the new extruder
     $self->extruder($extruder);
     my $toolchange_gcode = sprintf "%s%d%s\n", 
-        ($Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/ ? 'M108 T' : 'T'),
+        ($self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/ ? 'M108 T' : 'T'),
         $extruder->id,
-        ($Slic3r::Config->gcode_comments ? ' ; change extruder' : '');
+        ($self->config->gcode_comments ? ' ; change extruder' : '');
     
-    if ($Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/) {
+    if ($self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/) {
         $gcode .= $self->reset_e;
         $gcode .= $toolchange_gcode;
     } else {
@@ -607,18 +608,18 @@ sub set_fan {
     if ($self->last_fan_speed != $speed || $dont_save) {
         $self->last_fan_speed($speed) if !$dont_save;
         if ($speed == 0) {
-            my $code = $Slic3r::Config->gcode_flavor eq 'teacup'
+            my $code = $self->config->gcode_flavor eq 'teacup'
                 ? 'M106 S0'
-                : $Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/
+                : $self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/
                     ? 'M127'
                     : 'M107';
-            return sprintf "$code%s\n", ($Slic3r::Config->gcode_comments ? ' ; disable fan' : '');
+            return sprintf "$code%s\n", ($self->config->gcode_comments ? ' ; disable fan' : '');
         } else {
-            if ($Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/) {
-                return sprintf "M126%s\n", ($Slic3r::Config->gcode_comments ? ' ; enable fan' : '');
+            if ($self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/) {
+                return sprintf "M126%s\n", ($self->config->gcode_comments ? ' ; enable fan' : '');
             } else {
-                return sprintf "M106 %s%d%s\n", ($Slic3r::Config->gcode_flavor eq 'mach3' ? 'P' : 'S'),
-                    (255 * $speed / 100), ($Slic3r::Config->gcode_comments ? ' ; enable fan' : '');
+                return sprintf "M106 %s%d%s\n", ($self->config->gcode_flavor eq 'mach3' ? 'P' : 'S'),
+                    (255 * $speed / 100), ($self->config->gcode_comments ? ' ; enable fan' : '');
             }
         }
     }
@@ -629,17 +630,17 @@ sub set_temperature {
     my $self = shift;
     my ($temperature, $wait, $tool) = @_;
     
-    return "" if $wait && $Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/;
+    return "" if $wait && $self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/;
     
-    my ($code, $comment) = ($wait && $Slic3r::Config->gcode_flavor ne 'teacup')
+    my ($code, $comment) = ($wait && $self->config->gcode_flavor ne 'teacup')
         ? ('M109', 'wait for temperature to be reached')
         : ('M104', 'set temperature');
     my $gcode = sprintf "$code %s%d %s; $comment\n",
-        ($Slic3r::Config->gcode_flavor eq 'mach3' ? 'P' : 'S'), $temperature,
-        (defined $tool && ($self->multiple_extruders || $Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/)) ? "T$tool " : "";
+        ($self->config->gcode_flavor eq 'mach3' ? 'P' : 'S'), $temperature,
+        (defined $tool && ($self->multiple_extruders || $self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/)) ? "T$tool " : "";
     
     $gcode .= "M116 ; wait for temperature to be reached\n"
-        if $Slic3r::Config->gcode_flavor eq 'teacup' && $wait;
+        if $self->config->gcode_flavor eq 'teacup' && $wait;
     
     return $gcode;
 }
@@ -648,14 +649,14 @@ sub set_bed_temperature {
     my $self = shift;
     my ($temperature, $wait) = @_;
     
-    my ($code, $comment) = ($wait && $Slic3r::Config->gcode_flavor ne 'teacup')
-        ? (($Slic3r::Config->gcode_flavor =~ /^(?:makerbot|sailfish)$/ ? 'M109' : 'M190'), 'wait for bed temperature to be reached')
+    my ($code, $comment) = ($wait && $self->config->gcode_flavor ne 'teacup')
+        ? (($self->config->gcode_flavor =~ /^(?:makerbot|sailfish)$/ ? 'M109' : 'M190'), 'wait for bed temperature to be reached')
         : ('M140', 'set bed temperature');
     my $gcode = sprintf "$code %s%d ; $comment\n",
-        ($Slic3r::Config->gcode_flavor eq 'mach3' ? 'P' : 'S'), $temperature;
+        ($self->config->gcode_flavor eq 'mach3' ? 'P' : 'S'), $temperature;
     
     $gcode .= "M116 ; wait for bed temperature to be reached\n"
-        if $Slic3r::Config->gcode_flavor eq 'teacup' && $wait;
+        if $self->config->gcode_flavor eq 'teacup' && $wait;
     
     return $gcode;
 }
@@ -665,8 +666,8 @@ sub _limit_frequency {
     my $self = shift;
     my ($point) = @_;
     
-    return '' if $Slic3r::Config->vibration_limit == 0;
-    my $min_time = 1 / ($Slic3r::Config->vibration_limit * 60);  # in minutes
+    return '' if $self->config->vibration_limit == 0;
+    my $min_time = 1 / ($self->config->vibration_limit * 60);  # in minutes
     
     # calculate the move vector and move direction
     my $vector = Slic3r::Line->new($self->last_pos, $point)->vector;
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 9acbe2cf3..04fc20ed8 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -688,6 +688,7 @@ sub write_gcode {
     
     # set up our extruder object
     my $gcodegen = Slic3r::GCode->new(
+        config              => $self->config,
         multiple_extruders  => (@{$self->extruders} > 1),
         layer_count         => $self->layer_count,
     );
diff --git a/t/gcode.t b/t/gcode.t
index c41307d4f..61c940faf 100644
--- a/t/gcode.t
+++ b/t/gcode.t
@@ -11,8 +11,10 @@ use Slic3r;
 use Slic3r::Geometry qw(scale);
 
 {
-    local $Slic3r::Config = Slic3r::Config->new_from_defaults;
-    my $gcodegen = Slic3r::GCode->new(layer_count => 1);
+    my $gcodegen = Slic3r::GCode->new(
+        config      => Slic3r::Config->new_from_defaults,
+        layer_count => 1,
+    );
     $gcodegen->set_shift(10, 10);
     is_deeply $gcodegen->last_pos, [scale -10, scale -10], 'last_pos is shifted correctly';
 }