diff --git a/Build.PL b/Build.PL
index 951180135..1e2299632 100644
--- a/Build.PL
+++ b/Build.PL
@@ -9,7 +9,7 @@ my $build = Module::Build->new(
     requires        => {
         'File::Basename'            => '0',
         'Getopt::Long'              => '0',
-        'Math::Clipper'             => '1.02',
+        'Math::Clipper'             => '1.03',
         'Math::ConvexHull'          => '1.0.4',
         'Math::Geometry::Voronoi'   => '1.3',
         'Math::PlanePath'           => '53',
diff --git a/README.markdown b/README.markdown
index 794e97517..1c33decba 100644
--- a/README.markdown
+++ b/README.markdown
@@ -25,7 +25,8 @@ Slic3r current key features are:
 * easy configuration/calibration;
 * read binary and ASCII STL files;
 * powerful command line interface;
-* easy GUI
+* easy GUI;
+* multithreaded;
 * multiple infill patterns, with customizable density and angle;
 * retraction;
 * skirt;
diff --git a/lib/Slic3r.pm b/lib/Slic3r.pm
index deb894fdc..087a9d0da 100644
--- a/lib/Slic3r.pm
+++ b/lib/Slic3r.pm
@@ -36,6 +36,8 @@ use Slic3r::Surface;
 use Slic3r::TriangleMesh;
 use Slic3r::TriangleMesh::IntersectionLine;
 
+our $threads            = 4;
+
 # output options
 our $output_filename_format = '[input_filename_base].gcode';
 
diff --git a/lib/Slic3r/Fill.pm b/lib/Slic3r/Fill.pm
index b27891668..63c3174a6 100644
--- a/lib/Slic3r/Fill.pm
+++ b/lib/Slic3r/Fill.pm
@@ -121,6 +121,7 @@ sub make_fill {
         map [ $_->contour->[0], $_ ], @surfaces,
     ])};
     
+    my @fills = ();
     SURFACE: foreach my $surface (@surfaces) {
         my $filler          = $Slic3r::fill_pattern;
         my $density         = $Slic3r::fill_density;
@@ -150,7 +151,7 @@ sub make_fill {
         my $params = shift @paths;
         
         # save into layer
-        push @{ $layer->fills }, Slic3r::ExtrusionPath::Collection->new(
+        push @fills, Slic3r::ExtrusionPath::Collection->new(
             paths => [
                 map Slic3r::ExtrusionPath->new(
                     polyline => Slic3r::Polyline->new(@$_),
@@ -163,7 +164,7 @@ sub make_fill {
     }
     
     # add thin fill regions
-    push @{ $layer->fills }, Slic3r::ExtrusionPath::Collection->new(
+    push @fills, Slic3r::ExtrusionPath::Collection->new(
         paths => [
             map {
                 $_->isa('Slic3r::Polygon')
@@ -172,6 +173,8 @@ sub make_fill {
             } @{$layer->thin_fills},
         ],
     ) if @{$layer->thin_fills};
+    
+    return @fills;
 }
 
 1;
diff --git a/lib/Slic3r/Skein.pm b/lib/Slic3r/Skein.pm
index 15da408e6..f8ad0a199 100644
--- a/lib/Slic3r/Skein.pm
+++ b/lib/Slic3r/Skein.pm
@@ -1,6 +1,7 @@
 package Slic3r::Skein;
 use Moo;
 
+use Config;
 use File::Basename qw(basename fileparse);
 use Slic3r::Geometry qw(PI);
 use Time::HiRes qw(gettimeofday tv_interval);
@@ -84,7 +85,31 @@ sub go {
     $self->status_cb->(80, "Infilling layers...");
     {
         my $fill_maker = Slic3r::Fill->new('print' => $print);
-        $fill_maker->make_fill($_) for @{$print->layers};
+        
+        if ($Config{useithreads} && $Slic3r::threads > 1 && eval "use threads; use Thread::Queue; 1") {
+            my $q = Thread::Queue->new;
+            $q->enqueue(0..($print->layer_count-1), (map undef, 1..$Slic3r::threads));
+            
+            my $thread_cb = sub {
+                $Slic3r::Geometry::Clipper::clipper = Math::Clipper->new;
+                my $fills = {};
+                while (defined (my $layer_id = $q->dequeue)) {
+                    $fills->{$layer_id} = [ $fill_maker->make_fill($print->layers->[$layer_id]) ];
+                }
+                return $fills;
+            };
+            
+            foreach my $th (map threads->create($thread_cb), 1..$Slic3r::threads) {
+                my $fills = $th->join;
+                foreach my $layer_id (keys %$fills) {
+                    @{$print->layers->[$layer_id]->fills} = @{$fills->{$layer_id}};
+                }
+            }
+        } else {
+            foreach my $layer (@{$print->layers}) {
+                @{$layer->fills} = $fill_maker->make_fill($layer);
+            }
+        }
     }
     
     # output everything to a GCODE file
diff --git a/slic3r.pl b/slic3r.pl
index d9b6ccc05..9cd944201 100755
--- a/slic3r.pl
+++ b/slic3r.pl
@@ -25,6 +25,7 @@ my %cli_options = ();
         'save=s'                => \$opt{save},
         'load=s@'               => \$opt{load},
         'ignore-nonexistent-config' => \$opt{ignore_nonexistent_config},
+        'threads|j=i'           => \$Slic3r::threads,
     );
     foreach my $opt_key (keys %$Slic3r::Config::Options) {
         my $opt = $Slic3r::Config::Options->{$opt_key};