diff --git a/README.markdown b/README.markdown
index daaafff56..ad65a7561 100644
--- a/README.markdown
+++ b/README.markdown
@@ -31,17 +31,18 @@ Slic3r current features are:
 * generate multiple perimeters (skins);
 * generate rectilinear fill (100% solid for external surfaces or with customizable less density for inner surfaces);
 * retraction;
-* skirt;
+* skirt (with rounded corners);
 * use relative or absolute extrusion commands;
 * center print around bed center point;
+* multiple solid layers near horizontal external surfaces;
 * use different speed for bottom layer.
 
 Roadmap includes the following goals:
 
 * output some statistics;
 * allow the user to customize initial and final GCODE commands;
-* option for filling multiple solid layers near external surfaces;
 * support material for internal perimeters;
+* travel path optimization;
 * ability to infill in the direction of bridges;
 * input object transform (scale, rotate, multiply);
 * cool;
diff --git a/lib/Slic3r.pm b/lib/Slic3r.pm
index 8ddb90085..3185c24d8 100644
--- a/lib/Slic3r.pm
+++ b/lib/Slic3r.pm
@@ -42,6 +42,7 @@ our $flow_width;
 
 # print options
 our $perimeter_offsets  = 3;
+our $solid_layers       = 3;
 our $fill_density       = 0.4;  # 1 = 100%
 our $temperature        = 195;
 
@@ -51,7 +52,7 @@ our $retract_restart_extra  = 0;    # mm
 our $retract_speed          = 40;   # mm/sec
 
 # skirt options
-our $skirts             = 3;
+our $skirts             = 1;
 our $skirt_distance     = 6;    # mm
 
 1;
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 160a3785f..dc9f7ac73 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -1,6 +1,9 @@
 package Slic3r::Print;
 use Moo;
 
+use Math::Clipper ':all';
+use XXX;
+
 use constant PI => 4 * atan2(1, 1);
 use constant X => 0;
 use constant Y => 1;
@@ -49,6 +52,76 @@ sub layer {
     return $self->layers->[$layer_id];
 }
 
+sub discover_horizontal_shells {
+    my $self = shift;
+    
+    Slic3r::debugf "==> DISCOVERING HORIZONTAL SHELLS\n";
+    
+    my $clipper = Math::Clipper->new;
+    
+    for (my $i = 0; $i < $self->layer_count; $i++) {
+        my $layer = $self->layers->[$i];
+        foreach my $type (qw(top bottom)) {
+            # find surfaces of current type for current layer
+            my @surfaces = grep $_->surface_type eq $type, @{$layer->surfaces} or next;
+            Slic3r::debugf "Layer %d has %d surfaces of type '%s'\n",
+                $i, scalar(@surfaces), $type;
+            
+            for (my $n = $type eq 'top' ? $i-1 : $i+1; 
+                    abs($n - $i) <= $Slic3r::solid_layers-1; 
+                    $type eq 'top' ? $n-- : $n++) {
+                
+                next if $n < 0 || $n >= $self->layer_count;
+                Slic3r::debugf "  looking for neighbors on layer %d...\n", $n;
+                
+                my $neighbor_polygons = [ map $_->p, grep $_->surface_type eq 'internal', @{$self->layers->[$n]->surfaces} ];
+                # find intersection between @surfaces and current layer's surfaces
+                $clipper->add_subject_polygons([ map $_->p, @surfaces ]);
+                $clipper->add_clip_polygons($neighbor_polygons);
+                
+                # intersections have contours and holes
+                my $intersections = $clipper->ex_execute(CT_INTERSECTION, PFT_NONZERO, PFT_NONZERO);
+                $clipper->clear;
+                next if @$intersections == 0;
+                Slic3r::debugf "    %d intersections found\n", scalar @$intersections;
+                
+                # subtract intersections from layer surfaces to get resulting inner surfaces
+                $clipper->add_subject_polygons($neighbor_polygons);
+                $clipper->add_clip_polygons([ map { $_->{outer}, @{$_->{holes}} } @$intersections ]);
+                my $internal_polygons = $clipper->ex_execute(CT_DIFFERENCE, PFT_NONZERO, PFT_NONZERO);
+                $clipper->clear;
+                
+                # Note: due to floating point math we're going to get some very small
+                # polygons as $internal_polygons; they should be discarded, but a reliable
+                # way to detect them is needed, and they seem to be harmless so we keep them for now
+                
+                # assign resulting inner surfaces to layer
+                $self->layers->[$n]->surfaces([]);
+                foreach my $p (@$internal_polygons) {
+                    push @{$self->layers->[$n]->surfaces}, Slic3r::Surface->new(
+                        surface_type => 'internal',
+                        contour => Slic3r::Polyline::Closed->cast($p->{outer}),
+                        holes   => [
+                            map Slic3r::Polyline::Closed->cast($_), @{$p->{holes}}
+                        ],
+                    );
+                }
+                
+                # assign new internal-solid surfaces to layer
+                foreach my $p (@$intersections) {
+                    push @{$self->layers->[$n]->surfaces}, Slic3r::Surface->new(
+                        surface_type => 'internal-solid',
+                        contour => Slic3r::Polyline::Closed->cast($p->{outer}),
+                        holes   => [
+                            map Slic3r::Polyline::Closed->cast($_), @{$p->{holes}}
+                        ],
+                    );
+                }
+            }
+        }
+    }
+}
+
 sub extrude_perimeters {
     my $self = shift;
     
diff --git a/lib/Slic3r/STL.pm b/lib/Slic3r/STL.pm
index 590b0bb02..b6ce3f607 100644
--- a/lib/Slic3r/STL.pm
+++ b/lib/Slic3r/STL.pm
@@ -67,6 +67,9 @@ sub parse_file {
         $layer->merge_contiguous_surfaces;
     }
     
+    # detect which surfaces are near external layers
+    $print->discover_horizontal_shells;
+        
     return $print;
 }
 
diff --git a/lib/Slic3r/SVG.pm b/lib/Slic3r/SVG.pm
index b7c7e5199..67a4f9141 100644
--- a/lib/Slic3r/SVG.pm
+++ b/lib/Slic3r/SVG.pm
@@ -8,7 +8,7 @@ use constant X => 0;
 use constant Y => 1;
 
 sub factor {
-    return $Slic3r::resolution * 10;
+    return $Slic3r::resolution * 100;
 }
 
 sub svg {
@@ -24,6 +24,7 @@ sub output_polygons {
     my $g = $svg->group(
         style => {
             'stroke-width' => 2,
+            'stroke' => 'black',
         },
     );
     foreach my $polygon (@$polygons) {
diff --git a/lib/Slic3r/Surface.pm b/lib/Slic3r/Surface.pm
index 925c40fed..7e99f3f24 100644
--- a/lib/Slic3r/Surface.pm
+++ b/lib/Slic3r/Surface.pm
@@ -16,11 +16,9 @@ has 'holes' => (
     default => sub { [] },
 );
 
-# TODO: to allow for multiple solid skins to be filled near external
-# surfaces, a new type should be defined: internal-solid
 has 'surface_type' => (
     is      => 'rw',
-    #isa     => enum([qw(internal bottom top)]),
+    #isa     => enum([qw(internal internal-solid bottom top)]),
 );
 
 sub add_hole {
@@ -78,6 +76,11 @@ sub clipper_polygon {
     };
 }
 
+sub p {
+    my $self = shift;
+    return ($self->contour->p, map $_->p, @{$self->holes});
+}
+
 sub lines {
     my $self = shift;
     return @{ $self->contour->lines }, map @{ $_->lines }, @{ $self->holes };
diff --git a/slic3r.pl b/slic3r.pl
index 8a816e592..65b25b655 100755
--- a/slic3r.pl
+++ b/slic3r.pl
@@ -39,6 +39,7 @@ GetOptions(
     
     # print options
     'perimeters=i'          => \$Slic3r::perimeter_offsets,
+    'solid-layers=i'        => \$Slic3r::solid_layers,
     'fill-density=f'        => \$Slic3r::fill_density,
     'temperature=i'         => \$Slic3r::temperature,
     
@@ -75,6 +76,10 @@ GetOptions(
     die "Invalid value for --perimeters\n"
         if $Slic3r::perimeter_offsets < 1;
     
+    # --solid-layers
+    die "Invalid value for --solid-layers\n"
+        if $Slic3r::solid_layers < 1;
+    
     # --print-center
     die "Invalid value for --print-center\n"
         if !ref $Slic3r::print_center 
@@ -143,6 +148,8 @@ Usage: slic3r.pl [ OPTIONS ] file.stl
   Print options:
     --perimeters        Number of perimeters/horizontal skins (range: 1+, 
                         default: $Slic3r::perimeter_offsets)
+    --solid-layers      Number of solid layers to do for top/bottom surfaces
+                        (range: 1+, default: $Slic3r::solid_layers)
     --fill-density      Infill density (range: 0-1, default: $Slic3r::fill_density)
     --temperature       Extrusion temperature (default: $Slic3r::temperature)