diff --git a/lib/Slic3r/Print/SupportMaterial.pm b/lib/Slic3r/Print/SupportMaterial.pm
index cc297a415..5c7324d65 100644
--- a/lib/Slic3r/Print/SupportMaterial.pm
+++ b/lib/Slic3r/Print/SupportMaterial.pm
@@ -1018,4 +1018,3 @@ sub contact_distance {
 }
 
 1;
-
diff --git a/src/test/libslic3r/test_support_material.cpp b/src/test/libslic3r/test_support_material.cpp
index 0222ffa07..0ecdb9f3b 100644
--- a/src/test/libslic3r/test_support_material.cpp
+++ b/src/test/libslic3r/test_support_material.cpp
@@ -1,5 +1,6 @@
 //#include <catch.hpp>
 #include <libslic3r/IO.hpp>
+#include <libslic3r/GCodeReader.hpp>
 #include "/home/ahmedsamir/Work/SamirSlic3r/Slic3r/build/external/Catch/include/catch.hpp"
 
 #include "libslic3r.h"
@@ -10,9 +11,10 @@
 using namespace std;
 using namespace Slic3r;
 
-void test_1_check(Print &print, bool &a, bool &b, bool &c, bool &d);
+void test_1_checks(Print &print, bool &a, bool &b, bool &c, bool &d);
+bool test_6_checks(Print &print);
 
-// Testing supports material member functions.
+// Testing 0.1: supports material member functions.
 TEST_CASE("", "")
 {
     // Create a mesh & modelObject.
@@ -44,6 +46,95 @@ TEST_CASE("", "")
 
 }
 
+// Test 1.
+SCENARIO("SupportMaterial: support_layers_z and contact_distance")
+{
+    GIVEN("A print object having one modelObject") {
+        // Create a mesh & modelObject.
+        TriangleMesh mesh = TriangleMesh::make_cube(20, 20, 20);
+
+        // Create modelObject.
+        Model model = Model();
+        ModelObject *object = model.add_object();
+        object->add_volume(mesh);
+        model.add_default_instances();
+
+        // Align to origin.
+        model.align_instances_to_origin();
+        // Create Print.
+        Print print = Print();
+        print.default_object_config.set_deserialize("support_material", "1");
+
+        WHEN("First layer height = 0.4") {
+            print.default_object_config.set_deserialize("layer_height", "0.2");
+            print.default_object_config.set_deserialize("first_layer_height", "0.4");
+
+            print.add_model_object(model.objects[0]);
+            print.objects.front()->_slice();
+            bool a, b, c, d;
+
+            test_1_checks(print, a, b, c, d);
+            THEN("First layer height is honored") {
+                REQUIRE(a == true);
+            }
+            THEN("No null or negative support layers") {
+                REQUIRE(b == true);
+            }
+            THEN("No layers thicker than nozzle diameter") {
+                REQUIRE(c == true);
+            }
+            THEN("Layers above top surfaces are spaced correctly") {
+                REQUIRE(d == true);
+            }
+        }
+        WHEN("Layer height = 0.2 and, first layer height = 0.3") {
+            print.default_object_config.set_deserialize("layer_height", "0.2");
+            print.default_object_config.set_deserialize("first_layer_height", "0.3");
+            print.add_model_object(model.objects[0]);
+            print.objects.front()->_slice();
+            bool a, b, c, d;
+
+            test_1_checks(print, a, b, c, d);
+            THEN("First layer height is honored") {
+                REQUIRE(a == true);
+            }
+            THEN("No null or negative support layers") {
+                REQUIRE(b == true);
+            }
+            THEN("No layers thicker than nozzle diameter") {
+                REQUIRE(c == true);
+            }
+            THEN("Layers above top surfaces are spaced correctly") {
+                REQUIRE(d == true);
+            }
+        }
+
+
+        WHEN("Layer height = nozzle_diameter[0]") {
+            print.default_object_config.set_deserialize("layer_height", "0.2");
+            print.default_object_config.set_deserialize("first_layer_height", "0.3");
+            print.add_model_object(model.objects[0]);
+            print.objects.front()->_slice();
+            bool a, b, c, d;
+
+            test_1_checks(print, a, b, c, d);
+            THEN("First layer height is honored") {
+                REQUIRE(a == true);
+            }
+            THEN("No null or negative support layers") {
+                REQUIRE(b == true);
+            }
+            THEN("No layers thicker than nozzle diameter") {
+                REQUIRE(c == true);
+            }
+            THEN("Layers above top surfaces are spaced correctly") {
+                REQUIRE(d == true);
+            }
+        }
+    }
+}
+
+// Test 8.
 TEST_CASE("SupportMaterial: forced support is generated", "")
 {
     // Create a mesh & modelObject.
@@ -71,7 +162,7 @@ TEST_CASE("SupportMaterial: forced support is generated", "")
     auto support_z = support->support_layers_z(contact_z, top_z, print.default_object_config.layer_height);
 
     bool check = true;
-    for (int i = 1; i < support_z.size(); i++) {
+    for (size_t i = 1; i < support_z.size(); i++) {
         if (support_z[i] - support_z[i - 1] <= 0)
             check = false;
     }
@@ -79,107 +170,67 @@ TEST_CASE("SupportMaterial: forced support is generated", "")
     REQUIRE(check == true);
 }
 
-SCENARIO("SupportMaterial: support_layers_z and contact_distance")
+// Test 6.
+SCENARIO("SupportMaterial: Checking bridge speed")
 {
-    GIVEN("A print object having one modelObject") {
+    GIVEN("Print object") {
         // Create a mesh & modelObject.
         TriangleMesh mesh = TriangleMesh::make_cube(20, 20, 20);
 
-        // Create modelObject.
         Model model = Model();
         ModelObject *object = model.add_object();
         object->add_volume(mesh);
         model.add_default_instances();
-
-        // Align to origin.
         model.align_instances_to_origin();
 
-        WHEN("First layer height = 0.4") {
-            // Create Print.
-            Print print = Print();
-            print.default_object_config.set_deserialize("support_material", "1");
-            print.default_object_config.set_deserialize("layer_height", "0.2");
-            print.default_object_config.set_deserialize("first_layer_height", "0.4");
+        Print print = Print();
+        print.config.brim_width = 0;
+        print.config.skirts = 0;
+        print.config.skirts = 0;
+        print.default_object_config.support_material = 1;
+        print.default_region_config.top_solid_layers = 0; // so that we don't have the internal bridge over infill.
+        print.default_region_config.bridge_speed = 99;
+        print.config.cooling = 0;
+        print.config.set_deserialize("first_layer_speed", "100%");
 
+        WHEN("support_material_contact_distance = 0.2") {
+            print.default_object_config.support_material_contact_distance = 0.2;
             print.add_model_object(model.objects[0]);
-            print.objects.front()->_slice();
-            bool a, b, c, d;
 
-            test_1_check(print, a, b, c, d);
-            THEN("First layer height is honored") {
-                REQUIRE(a == true);
-            }
-            THEN("No null or negative support layers") {
-                REQUIRE(b == true);
-            }
-            THEN("No layers thicker than nozzle diameter") {
-                REQUIRE(c == true);
-            }
-            THEN("Layers above top surfaces are spaced correctly") {
-                REQUIRE(d == true);
-            }
+            bool check = test_6_checks(print);
+            REQUIRE(check == true); // bridge speed is used.
+        }
+
+        WHEN("support_material_contact_distance = 0") {
+            print.default_object_config.support_material_contact_distance = 0;
+            print.add_model_object(model.objects[0]);
+
+            bool check = test_6_checks(print);
+            REQUIRE(check == true); // bridge speed is not used.
+        }
+
+        WHEN("support_material_contact_distance = 0.2 & raft_layers = 5") {
+            print.default_object_config.support_material_contact_distance = 0.2;
+            print.default_object_config.raft_layers = 5;
+            print.add_model_object(model.objects[0]);
+
+            bool check = test_6_checks(print);
+            REQUIRE(check == true); // bridge speed is used.
+        }
+
+        WHEN("support_material_contact_distance = 0 & raft_layers = 5") {
+            print.default_object_config.support_material_contact_distance = 0;
+            print.default_object_config.raft_layers = 5;
+            print.add_model_object(model.objects[0]);
+
+            bool check = test_6_checks(print);
+
+            REQUIRE(check == true); // bridge speed is not used.
         }
-//        WHEN("Layer height = 0.2 and, first layer height = 0.3") {
-//            print.default_object_config.set_deserialize("layer_height", "0.2");
-//            print.default_object_config.set_deserialize("first_layer_height", "0.3");
-//            print.add_model_object(model.objects[0]);
-//            print.objects.front()->_slice();
-//            bool a, b, c, d;
-//
-//            test_1_check(print, a, b, c, d);
-//            THEN("First layer height is honored") {
-//                REQUIRE(a == true);
-//            }
-//            THEN("No null or negative support layers") {
-//                REQUIRE(b == true);
-//            }
-//            THEN("No layers thicker than nozzle diameter") {
-//                REQUIRE(c == true);
-//            }
-//            THEN("Layers above top surfaces are spaced correctly") {
-//                REQUIRE(d == true);
-//            }
-//        }
-//
-//
-//        WHEN("Layer height = nozzle_diameter[0]") {
-//            print.default_object_config.set_deserialize("layer_height", "0.2");
-//            print.default_object_config.set_deserialize("first_layer_height", "0.3");
-//            print.add_model_object(model.objects[0]);
-//            print.objects.front()->_slice();
-//            bool a, b, c, d;
-//
-//            test_1_check(print, a, b, c, d);
-//            THEN("First layer height is honored") {
-//                REQUIRE(a == true);
-//            }
-//            THEN("No null or negative support layers") {
-//                REQUIRE(b == true);
-//            }
-//            THEN("No layers thicker than nozzle diameter") {
-//                REQUIRE(c == true);
-//            }
-//            THEN("Layers above top surfaces are spaced correctly") {
-//                REQUIRE(d == true);
-//            }
-//        }
     }
 }
 
-SCENARIO("SupportMaterial: Checking bridge speed") {
-    // Create a mesh & modelObject.
-    TriangleMesh mesh = TriangleMesh::make_cube(20, 20, 20);
-
-    Model model = Model();
-    ModelObject *object = model.add_object();
-    object->add_volume(mesh);
-    model.add_default_instances();
-    model.align_instances_to_origin();
-
-    Print print = Print();
-}
-
-void test_1_check(Print &print, bool &a, bool &b, bool &c, bool &d)
+void test_1_checks(Print &print, bool &a, bool &b, bool &c, bool &d)
 {
     vector<coordf_t> contact_z = {1.9};
     vector<coordf_t> top_z = {1.1};
@@ -188,9 +239,6 @@ void test_1_check(Print &print, bool &a, bool &b, bool &c, bool &d)
 
     vector<coordf_t>
         support_z = support->support_layers_z(contact_z, top_z, print.default_object_config.layer_height);
-for(auto el: support_z)
-    cout << el << endl;
-    cout << endl;
 
     a = (support_z[0] == print.default_object_config.first_layer_height.value);
 
@@ -227,3 +275,22 @@ for(auto el: support_z)
     }
     d = !wrong_top_spacing;
 }
+
+// TODO
+bool test_6_checks(Print &print)
+{
+    bool has_bridge_speed = true;
+
+    // Pre-Processing.
+    PrintObject *print_object = print.objects.front();
+    print_object->_infill();
+    SupportMaterial *support_material = print.objects.front()->_support_material();
+    support_material->generate(print_object);
+    // TODO but not needed in test 6 (make brims and make skirts).
+
+    // Exporting gcode.
+    // TODO validation found in Simple.pm
+
+
+    return has_bridge_speed;
+}
\ No newline at end of file
diff --git a/t/support.t b/t/support.t
index 61d1416fa..0a5a75337 100644
--- a/t/support.t
+++ b/t/support.t
@@ -1,4 +1,4 @@
-use Test::More tests => 12;
+use Test::More tests => 29;
 use strict;
 use warnings;
 
@@ -7,7 +7,7 @@ BEGIN {
     use lib "$FindBin::Bin/../lib";
     use local::lib "$FindBin::Bin/../local-lib";
 }
-use Data::Dumper;
+
 use List::Util qw(first);
 use Slic3r;
 use Slic3r::Geometry qw(epsilon scale PI);
@@ -31,7 +31,7 @@ use Slic3r::Test;
         );
         my $support_z = $support->support_layers_z(\@contact_z, \@top_z, $config->layer_height);
         my $expected_top_spacing = $support->contact_distance($config->layer_height, $config->nozzle_diameter->[0]);
-        diag(Dumper($support_z));
+        
         is $support_z->[0], $config->first_layer_height,
             'first layer height is honored';
         is scalar(grep { $support_z->[$_]-$support_z->[$_-1] <= 0 } 1..$#$support_z), 0,
@@ -64,281 +64,280 @@ use Slic3r::Test;
     $config->set('layer_height', $config->nozzle_diameter->[0]);
     $test->();
 }
-#
-#{
-#    my $config = Slic3r::Config->new_from_defaults;
-#    $config->set('raft_layers', 3);
-#    $config->set('brim_width',  0);
-#    $config->set('skirts', 0);
-#    $config->set('support_material_extruder', 2);
-#    $config->set('support_material_interface_extruder', 2);
-#    $config->set('layer_height', 0.4);
-#    $config->set('first_layer_height', 0.4);
-#    my $print = Slic3r::Test::init_print('overhang', config => $config);
-#    ok my $gcode = Slic3r::Test::gcode($print), 'no conflict between raft/support and brim';
-#
-#    my $tool = 0;
-#    Slic3r::GCode::Reader->new->parse($gcode, sub {
-#        my ($self, $cmd, $args, $info) = @_;
-#
-#        if ($cmd =~ /^T(\d+)/) {
-#            $tool = $1;
-#        } elsif ($info->{extruding}) {
-#            if ($self->Z <= ($config->raft_layers * $config->layer_height)) {
-#                fail 'not extruding raft with support material extruder'
-#                    if $tool != ($config->support_material_extruder-1);
-#            } else {
-#                fail 'support material exceeds raft layers'
-#                    if $tool == $config->support_material_extruder-1;
-#                # TODO: we should test that full support is generated when we use raft too
-#            }
-#        }
-#    });
-#}
-#
-#{
-#    my $config = Slic3r::Config->new_from_defaults;
-#    $config->set('skirts', 0);
-#    $config->set('raft_layers', 3);
-#    $config->set('support_material_pattern', 'honeycomb');
-#    $config->set('support_material_extrusion_width', 0.6);
-#    $config->set('first_layer_extrusion_width', '100%');
-#    $config->set('bridge_speed', 99);
-#    $config->set('cooling', 0);                 # prevent speed alteration
-#    $config->set('first_layer_speed', '100%');  # prevent speed alteration
-#    $config->set('start_gcode', '');            # prevent any unexpected Z move
-#    my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
-#
-#    my $layer_id = -1;  # so that first Z move sets this to 0
-#    my @raft = my @first_object_layer = ();
-#    my %first_object_layer_speeds = ();  # F => 1
-#    Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
-#        my ($self, $cmd, $args, $info) = @_;
-#        if ($info->{extruding} && $info->{dist_XY} > 0) {
-#            if ($layer_id <= $config->raft_layers) {
-#                # this is a raft layer or the first object layer
-#                my $line = Slic3r::Line->new_scale([ $self->X, $self->Y ], [ $info->{new_X}, $info->{new_Y} ]);
-#                my @path = @{$line->grow(scale($config->support_material_extrusion_width/2))};
-#                if ($layer_id < $config->raft_layers) {
-#                    # this is a raft layer
-#                    push @raft, @path;
-#                } else {
-#                    push @first_object_layer, @path;
-#                    $first_object_layer_speeds{ $args->{F} // $self->F } = 1;
-#                }
-#            }
-#        } elsif ($cmd eq 'G1' && $info->{dist_Z} > 0) {
-#            $layer_id++;
-#        }
-#    });
-#
-#    ok !@{diff(\@first_object_layer, \@raft)},
-#        'first object layer is completely supported by raft';
-#    is scalar(keys %first_object_layer_speeds), 1,
-#        'only one speed used in first object layer';
-#    ok +(keys %first_object_layer_speeds)[0] == $config->bridge_speed*60,
-#        'bridge speed used in first object layer';
-#}
-#
-#{
-#    my $config = Slic3r::Config->new_from_defaults;
-#    $config->set('layer_height', 0.2);
-#    $config->set('skirts', 0);
-#    $config->set('raft_layers', 5);
-#    $config->set('support_material_pattern', 'rectilinear');
-#    $config->set('support_material_extrusion_width', 0.4);
-#    $config->set('support_material_interface_extrusion_width', 0.6);
-#    $config->set('support_material_interface_layers', 2);
-#    $config->set('first_layer_extrusion_width', '100%');
-#    $config->set('bridge_speed', 99);
-#    $config->set('cooling', 0);                 # prevent speed alteration
-#    $config->set('first_layer_speed', '100%');  # prevent speed alteration
-#    $config->set('start_gcode', '');            # prevent any unexpected Z move
-#    my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
-#
-#    my $layer_id = -1;
-#    my $success = 1;
-#    Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
-#        my ($self, $cmd, $args, $info) = @_;
-#        if ($info->{extruding} && $info->{dist_XY} > 0) {
-#            # this is a raft layer
-#            if (($layer_id < $config->raft_layers) && ($layer_id > 0)) {
-#                my $width;
-#                my $support_layer_height = $config->nozzle_diameter->[0] * 0.75;
-#
-#                # support layer
-#                if ($config->raft_layers - $config->support_material_interface_layers > $layer_id) {
-#                    $width = $config->support_material_extrusion_width;
-#                }
-#                # interface layer
-#                else {
-#                    $width = $config->support_material_interface_extrusion_width;
-#                }
-#                my $expected_E_per_mm3 = 4 / (($config->filament_diameter->[0]**2) * PI);
-#                my $expected_mm3_per_mm = $width * $support_layer_height + ($support_layer_height**2) / 4.0 * (PI-4.0);
-#                my $expected_e_per_mm = $expected_E_per_mm3 * $expected_mm3_per_mm;
-#
-#                my $e_per_mm = ($info->{dist_E} / $info->{dist_XY});;
-#
-#                my $diff = abs($e_per_mm - $expected_e_per_mm);
-#
-#                if ($diff > 0.001) {
-#                    $success = 0;
-#                }
-#            }
-#        } elsif ($cmd eq 'G1' && $info->{dist_Z} > 0) {
-#            $layer_id++;
-#        }
-#    });
-#
-#    ok $success,
-#        'support material interface extrusion width is used for interfaces';
-#}
-#
-#{
-#    my $config = Slic3r::Config->new_from_defaults;
-#    $config->set('skirts', 0);
-#    $config->set('layer_height', 0.35);
-#    $config->set('first_layer_height', 0.3);
-#    $config->set('nozzle_diameter', [0.5]);
-#    $config->set('support_material_extruder', 2);
-#    $config->set('support_material_interface_extruder', 2);
-#
-#    my $test = sub {
-#        my ($raft_layers) = @_;
-#        $config->set('raft_layers', $raft_layers);
-#        my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
-#        my %raft_z = ();  # z => 1
-#        my $tool = undef;
-#        Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
-#            my ($self, $cmd, $args, $info) = @_;
-#
-#            if ($cmd =~ /^T(\d+)/) {
-#                $tool = $1;
-#            } elsif ($info->{extruding} && $info->{dist_XY} > 0) {
-#                if ($tool == $config->support_material_extruder-1) {
-#                    $raft_z{$self->Z} = 1;
-#                }
-#            }
-#        });
-#
-#        is scalar(keys %raft_z), $config->raft_layers, 'correct number of raft layers is generated';
-#    };
-#
-#    $test->(2);
-#    $test->(70);
-#
-#    $config->set('layer_height', 0.4);
-#    $config->set('first_layer_height', 0.35);
-#    $test->(3);
-#    $test->(70);
-#}
-#
-#{
-#    my $config = Slic3r::Config->new_from_defaults;
-#    $config->set('brim_width',  0);
-#    $config->set('skirts', 0);
-#    $config->set('support_material', 1);
-#    $config->set('top_solid_layers', 0); # so that we don't have the internal bridge over infill
-#    $config->set('bridge_speed', 99);
-#    $config->set('cooling', 0);
-#    $config->set('first_layer_speed', '100%');
-#
-#    my $test = sub {
-#        my $print = Slic3r::Test::init_print('overhang', config => $config);
-#
-#        my $has_bridge_speed = 0;
-#        Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
-#            my ($self, $cmd, $args, $info) = @_;
-#
-#            if ($info->{extruding}) {
-#                if (($args->{F} // $self->F) == $config->bridge_speed*60) {
-#                    $has_bridge_speed = 1;
-#                }
-#            }
-#        });
-#        return $has_bridge_speed;
-#    };
-#
-#    $config->set('support_material_contact_distance', 0.2);
-#    ok $test->(), 'bridge speed is used when support_material_contact_distance > 0';
-#
-#    $config->set('support_material_contact_distance', 0);
-#    ok !$test->(), 'bridge speed is not used when support_material_contact_distance == 0';
-#
-#    $config->set('raft_layers', 5);
-#    $config->set('support_material_contact_distance', 0.2);
-#    ok $test->(), 'bridge speed is used when raft_layers > 0 and support_material_contact_distance > 0';
-#
-#    $config->set('support_material_contact_distance', 0);
-#    ok !$test->(), 'bridge speed is not used when raft_layers > 0 and support_material_contact_distance == 0';
-#}
-#
-#{
-#    my $config = Slic3r::Config->new_from_defaults;
-#    $config->set('skirts', 0);
-#    $config->set('start_gcode', '');
-#    $config->set('raft_layers', 8);
-#    $config->set('nozzle_diameter', [0.4, 1]);
-#    $config->set('layer_height', 0.1);
-#    $config->set('first_layer_height', 0.8);
-#    $config->set('support_material_extruder', 2);
-#    $config->set('support_material_interface_extruder', 2);
-#    $config->set('support_material_contact_distance', 0);
-#    my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
-#    ok my $gcode = Slic3r::Test::gcode($print), 'first_layer_height is validated with support material extruder nozzle diameter when using raft layers';
-#
-#    my $tool = undef;
-#    my @z = (0);
-#    my %layer_heights_by_tool = ();  # tool => [ lh, lh... ]
-#    Slic3r::GCode::Reader->new->parse($gcode, sub {
-#        my ($self, $cmd, $args, $info) = @_;
-#
-#        if ($cmd =~ /^T(\d+)/) {
-#            $tool = $1;
-#        } elsif ($cmd eq 'G1' && exists $args->{Z} && $args->{Z} != $self->Z) {
-#            push @z, $args->{Z};
-#        } elsif ($info->{extruding} && $info->{dist_XY} > 0) {
-#            $layer_heights_by_tool{$tool} ||= [];
-#            push @{ $layer_heights_by_tool{$tool} }, $z[-1] - $z[-2];
-#        }
-#    });
-#
-#    ok !defined(first { $_ > $config->nozzle_diameter->[0] + epsilon }
-#        @{ $layer_heights_by_tool{$config->perimeter_extruder-1} }),
-#        'no object layer is thicker than nozzle diameter';
-#
-#    ok !defined(first { abs($_ - $config->layer_height) < epsilon }
-#        @{ $layer_heights_by_tool{$config->support_material_extruder-1} }),
-#        'no support material layer is as thin as object layers';
-#}
-#
-#{
-#    my $config = Slic3r::Config->new_from_defaults;
-#    $config->set('support_material_enforce_layers', 100);
-#    $config->set('support_material', 0);
-#    my @contact_z = my @top_z = ();
-#
-#    my $test = sub {
-#        my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
-#        my $flow = $print->print->objects->[0]->support_material_flow;
-#        my $support = Slic3r::Print::SupportMaterial->new(
-#            object_config       => $print->print->objects->[0]->config,
-#            print_config        => $print->print->config,
-#            flow                => $flow,
-#            interface_flow      => $flow,
-#            first_layer_flow    => $flow,
-#        );
-#        my $support_z = $support->support_layers_z(\@contact_z, \@top_z, $config->layer_height);
-#
-#        is scalar(grep { $support_z->[$_]-$support_z->[$_-1] <= 0 } 1..$#$support_z), 0,
-#            'forced support is generated';
-#
-#    };
-#    $config->set('layer_height', 0.2);
-#    $config->set('first_layer_height', 0.3);
-#    @contact_z = (1.9);
-#    @top_z = (1.1);
-#    $test->();
-#}
+
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('raft_layers', 3);
+    $config->set('brim_width',  0);
+    $config->set('skirts', 0);
+    $config->set('support_material_extruder', 2);
+    $config->set('support_material_interface_extruder', 2);
+    $config->set('layer_height', 0.4);
+    $config->set('first_layer_height', 0.4);
+    my $print = Slic3r::Test::init_print('overhang', config => $config);
+    ok my $gcode = Slic3r::Test::gcode($print), 'no conflict between raft/support and brim';
+    
+    my $tool = 0;
+    Slic3r::GCode::Reader->new->parse($gcode, sub {
+        my ($self, $cmd, $args, $info) = @_;
+        
+        if ($cmd =~ /^T(\d+)/) {
+            $tool = $1;
+        } elsif ($info->{extruding}) {
+            if ($self->Z <= ($config->raft_layers * $config->layer_height)) {
+                fail 'not extruding raft with support material extruder'
+                    if $tool != ($config->support_material_extruder-1);
+            } else {
+                fail 'support material exceeds raft layers'
+                    if $tool == $config->support_material_extruder-1;
+                # TODO: we should test that full support is generated when we use raft too
+            }
+        }
+    });
+}
+
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('skirts', 0);
+    $config->set('raft_layers', 3);
+    $config->set('support_material_pattern', 'honeycomb');
+    $config->set('support_material_extrusion_width', 0.6);
+    $config->set('first_layer_extrusion_width', '100%');
+    $config->set('bridge_speed', 99);
+    $config->set('cooling', 0);                 # prevent speed alteration
+    $config->set('first_layer_speed', '100%');  # prevent speed alteration
+    $config->set('start_gcode', '');            # prevent any unexpected Z move
+    my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
+    
+    my $layer_id = -1;  # so that first Z move sets this to 0
+    my @raft = my @first_object_layer = ();
+    my %first_object_layer_speeds = ();  # F => 1
+    Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
+        my ($self, $cmd, $args, $info) = @_;
+        if ($info->{extruding} && $info->{dist_XY} > 0) {
+            if ($layer_id <= $config->raft_layers) {
+                # this is a raft layer or the first object layer
+                my $line = Slic3r::Line->new_scale([ $self->X, $self->Y ], [ $info->{new_X}, $info->{new_Y} ]);
+                my @path = @{$line->grow(scale($config->support_material_extrusion_width/2))};
+                if ($layer_id < $config->raft_layers) {
+                    # this is a raft layer
+                    push @raft, @path;
+                } else {
+                    push @first_object_layer, @path;
+                    $first_object_layer_speeds{ $args->{F} // $self->F } = 1;
+                }
+            }
+        } elsif ($cmd eq 'G1' && $info->{dist_Z} > 0) {
+            $layer_id++;
+        }
+    });
+    
+    ok !@{diff(\@first_object_layer, \@raft)},
+        'first object layer is completely supported by raft';
+    is scalar(keys %first_object_layer_speeds), 1,
+        'only one speed used in first object layer';
+    ok +(keys %first_object_layer_speeds)[0] == $config->bridge_speed*60,
+        'bridge speed used in first object layer';
+}
+
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('layer_height', 0.2);
+    $config->set('skirts', 0);
+    $config->set('raft_layers', 5);
+    $config->set('support_material_pattern', 'rectilinear');
+    $config->set('support_material_extrusion_width', 0.4);
+    $config->set('support_material_interface_extrusion_width', 0.6);
+    $config->set('support_material_interface_layers', 2);
+    $config->set('first_layer_extrusion_width', '100%');
+    $config->set('bridge_speed', 99);
+    $config->set('cooling', 0);                 # prevent speed alteration
+    $config->set('first_layer_speed', '100%');  # prevent speed alteration
+    $config->set('start_gcode', '');            # prevent any unexpected Z move
+    my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
+
+    my $layer_id = -1;
+    my $success = 1;
+    Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
+        my ($self, $cmd, $args, $info) = @_;
+        if ($info->{extruding} && $info->{dist_XY} > 0) {
+            # this is a raft layer
+            if (($layer_id < $config->raft_layers) && ($layer_id > 0)) {
+                my $width;
+                my $support_layer_height = $config->nozzle_diameter->[0] * 0.75;
+
+                # support layer
+                if ($config->raft_layers - $config->support_material_interface_layers > $layer_id) {
+                    $width = $config->support_material_extrusion_width;
+                }
+                # interface layer
+                else {
+                    $width = $config->support_material_interface_extrusion_width;
+                }
+                my $expected_E_per_mm3 = 4 / (($config->filament_diameter->[0]**2) * PI);
+                my $expected_mm3_per_mm = $width * $support_layer_height + ($support_layer_height**2) / 4.0 * (PI-4.0);
+                my $expected_e_per_mm = $expected_E_per_mm3 * $expected_mm3_per_mm;
+                
+                my $e_per_mm = ($info->{dist_E} / $info->{dist_XY});;
+                
+                my $diff = abs($e_per_mm - $expected_e_per_mm);
+
+                if ($diff > 0.001) {
+                    $success = 0;
+                }
+            }
+        } elsif ($cmd eq 'G1' && $info->{dist_Z} > 0) {
+            $layer_id++;
+        }
+    });
+
+    ok $success,
+        'support material interface extrusion width is used for interfaces';
+}
+
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('skirts', 0);
+    $config->set('layer_height', 0.35);
+    $config->set('first_layer_height', 0.3);
+    $config->set('nozzle_diameter', [0.5]);
+    $config->set('support_material_extruder', 2);
+    $config->set('support_material_interface_extruder', 2);
+    
+    my $test = sub {
+        my ($raft_layers) = @_;
+        $config->set('raft_layers', $raft_layers);
+        my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
+        my %raft_z = ();  # z => 1
+        my $tool = undef;
+        Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
+            my ($self, $cmd, $args, $info) = @_;
+        
+            if ($cmd =~ /^T(\d+)/) {
+                $tool = $1;
+            } elsif ($info->{extruding} && $info->{dist_XY} > 0) {
+                if ($tool == $config->support_material_extruder-1) {
+                    $raft_z{$self->Z} = 1;
+                }
+            }
+        });
+    
+        is scalar(keys %raft_z), $config->raft_layers, 'correct number of raft layers is generated';
+    };
+    
+    $test->(2);
+    $test->(70);
+    
+    $config->set('layer_height', 0.4);
+    $config->set('first_layer_height', 0.35);
+    $test->(3);
+    $test->(70);
+}
+
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('brim_width',  0);
+    $config->set('skirts', 0);
+    $config->set('support_material', 1);
+    $config->set('top_solid_layers', 0); # so that we don't have the internal bridge over infill
+    $config->set('bridge_speed', 99);
+    $config->set('cooling', 0);
+    $config->set('first_layer_speed', '100%');
+    
+    my $test = sub {
+        my $print = Slic3r::Test::init_print('overhang', config => $config);
+    
+        my $has_bridge_speed = 0;
+        Slic3r::GCode::Reader->new->parse(Slic3r::Test::gcode($print), sub {
+            my ($self, $cmd, $args, $info) = @_;
+        
+            if ($info->{extruding}) {
+                if (($args->{F} // $self->F) == $config->bridge_speed*60) {
+                    $has_bridge_speed = 1;
+                }
+            }
+        });
+        return $has_bridge_speed;
+    };
+    
+    $config->set('support_material_contact_distance', 0.2);
+    ok $test->(), 'bridge speed is used when support_material_contact_distance > 0';
+    
+    $config->set('support_material_contact_distance', 0);
+    ok !$test->(), 'bridge speed is not used when support_material_contact_distance == 0';
+    
+    $config->set('raft_layers', 5);
+    $config->set('support_material_contact_distance', 0.2);
+    ok $test->(), 'bridge speed is used when raft_layers > 0 and support_material_contact_distance > 0';
+    
+    $config->set('support_material_contact_distance', 0);
+    ok !$test->(), 'bridge speed is not used when raft_layers > 0 and support_material_contact_distance == 0';
+}
+
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('skirts', 0);
+    $config->set('start_gcode', '');
+    $config->set('raft_layers', 8);
+    $config->set('nozzle_diameter', [0.4, 1]);
+    $config->set('layer_height', 0.1);
+    $config->set('first_layer_height', 0.8);
+    $config->set('support_material_extruder', 2);
+    $config->set('support_material_interface_extruder', 2);
+    $config->set('support_material_contact_distance', 0);
+    my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
+    ok my $gcode = Slic3r::Test::gcode($print), 'first_layer_height is validated with support material extruder nozzle diameter when using raft layers';
+    
+    my $tool = undef;
+    my @z = (0);
+    my %layer_heights_by_tool = ();  # tool => [ lh, lh... ]
+    Slic3r::GCode::Reader->new->parse($gcode, sub {
+        my ($self, $cmd, $args, $info) = @_;
+    
+        if ($cmd =~ /^T(\d+)/) {
+            $tool = $1;
+        } elsif ($cmd eq 'G1' && exists $args->{Z} && $args->{Z} != $self->Z) {
+            push @z, $args->{Z};
+        } elsif ($info->{extruding} && $info->{dist_XY} > 0) {
+            $layer_heights_by_tool{$tool} ||= [];
+            push @{ $layer_heights_by_tool{$tool} }, $z[-1] - $z[-2];
+        }
+    });
+    
+    ok !defined(first { $_ > $config->nozzle_diameter->[0] + epsilon }
+        @{ $layer_heights_by_tool{$config->perimeter_extruder-1} }),
+        'no object layer is thicker than nozzle diameter';
+    
+    ok !defined(first { abs($_ - $config->layer_height) < epsilon }
+        @{ $layer_heights_by_tool{$config->support_material_extruder-1} }),
+        'no support material layer is as thin as object layers';
+}
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('support_material_enforce_layers', 100);
+    $config->set('support_material', 0);
+    my @contact_z = my @top_z = ();
+    
+    my $test = sub {
+        my $print = Slic3r::Test::init_print('20mm_cube', config => $config);
+        my $flow = $print->print->objects->[0]->support_material_flow;
+        my $support = Slic3r::Print::SupportMaterial->new(
+            object_config       => $print->print->objects->[0]->config,
+            print_config        => $print->print->config,
+            flow                => $flow,
+            interface_flow      => $flow,
+            first_layer_flow    => $flow,
+        );
+        my $support_z = $support->support_layers_z(\@contact_z, \@top_z, $config->layer_height);
+        
+        is scalar(grep { $support_z->[$_]-$support_z->[$_-1] <= 0 } 1..$#$support_z), 0,
+            'forced support is generated';
+        
+    };
+    $config->set('layer_height', 0.2);
+    $config->set('first_layer_height', 0.3);
+    @contact_z = (1.9);
+    @top_z = (1.1);
+    $test->();
+}
 __END__
diff --git a/xs/src/libslic3r/SupportMaterial.cpp b/xs/src/libslic3r/SupportMaterial.cpp
index 598423265..62beb24f0 100644
--- a/xs/src/libslic3r/SupportMaterial.cpp
+++ b/xs/src/libslic3r/SupportMaterial.cpp
@@ -28,7 +28,7 @@ SupportMaterial::generate_toolpaths(PrintObject *object,
     params.circle = create_circle(params.circle_radius);
 
 #ifdef SLIC3R_DEBUG
-    printf("Generating patterns\n");
+    printf("Generating patterns.\n");
 #endif
 
     // Prepare fillers.
@@ -448,7 +448,7 @@ SupportMaterial::contact_area(PrintObject *object)
                 if (difference.empty()) continue;
 
                 // NOTE: this is not the full overhang as it misses the outermost half of the perimeter width!
-                append_polygons(tmp_overhang, difference);
+                append_to(tmp_overhang, difference);
 
                 // Let's define the required contact area by using a max gap of half the upper
                 // extrusion width and extending the area according to the configured margin.
@@ -473,7 +473,7 @@ SupportMaterial::contact_area(PrintObject *object)
                         );
                     }
                 }
-                append_polygons(tmp_contact, difference);
+                append_to(tmp_contact, difference);
             }
         }
         if (tmp_contact.empty())
@@ -666,22 +666,22 @@ SupportMaterial::generate_base_layers(vector<coordf_t> support_z,
             // (1 interface layer means we only have contact layer, so $interface->{$i+1} is empty).
             Polygons upper_contact;
             if (object_config->support_material_interface_layers.value <= 1) {
-                append_polygons(upper_contact, (i + 1 < support_z.size() ? contact[support_z[i + 1]] : contact[-1]));
+                append_to(upper_contact, (i + 1 < support_z.size() ? contact[support_z[i + 1]] : contact[-1]));
             }
 
             Polygons ps_1;
-            append_polygons(ps_1, base[i + 1]); // support regions on upper layer.
-            append_polygons(ps_1, interface[i + 1]); // interface regions on upper layer
-            append_polygons(ps_1, upper_contact); // contact regions on upper layer
+            append_to(ps_1, base[i + 1]); // support regions on upper layer.
+            append_to(ps_1, interface[i + 1]); // interface regions on upper layer
+            append_to(ps_1, upper_contact); // contact regions on upper layer
 
             Polygons ps_2;
             for (auto el : overlapping_z) {
                 if (top.count(el) > 0)
-                    append_polygons(ps_2, top[el]); // top slices on this layer.
+                    append_to(ps_2, top[el]); // top slices on this layer.
                 if (interface.count(el) > 0)
-                    append_polygons(ps_2, interface[el]); // interface regions on this layer.
+                    append_to(ps_2, interface[el]); // interface regions on this layer.
                 if (contact.count(el) > 0)
-                    append_polygons(ps_2, contact[el]); // contact regions on this layer.
+                    append_to(ps_2, contact[el]); // contact regions on this layer.
             }
 
             base[i] = diff(
@@ -725,15 +725,15 @@ SupportMaterial::generate_interface_layers(vector<coordf_t> support_z,
             // surfaces vertically before performing the diff, but this needs
             // investigation.
             Polygons ps_1;
-            append_polygons(ps_1, _contact); // clipped projection of the current contact regions.
-            append_polygons(ps_1, interface[i]); // interface regions already applied to this layer.
+            append_to(ps_1, _contact); // clipped projection of the current contact regions.
+            append_to(ps_1, interface[i]); // interface regions already applied to this layer.
 
             Polygons ps_2;
             for (auto el : overlapping_z) {
                 if (top.count(el) > 0)
-                    append_polygons(ps_2, top[el]); // top slices on this layer.
+                    append_to(ps_2, top[el]); // top slices on this layer.
                 if (contact.count(el) > 0)
-                    append_polygons(ps_2, contact[el]); // contact regions on this layer.
+                    append_to(ps_2, contact[el]); // contact regions on this layer.
             }
 
             _contact = interface[i] = diff(
@@ -792,7 +792,7 @@ SupportMaterial::generate_bottom_interface_layers(const vector<coordf_t> &suppor
                 );
 
                 // Add the new interface area to interface.
-                append_polygons(interface[layer_id], interface_area);
+                append_to(interface[layer_id], interface_area);
             }
 
             interface_layers++;
diff --git a/xs/src/libslic3r/SupportMaterial.hpp b/xs/src/libslic3r/SupportMaterial.hpp
index 4b1eda2f0..75668fa82 100644
--- a/xs/src/libslic3r/SupportMaterial.hpp
+++ b/xs/src/libslic3r/SupportMaterial.hpp
@@ -81,7 +81,7 @@ public:
     /// Generate support material for the given print object.
     void generate(PrintObject *object);
 
-    /// Generate the support layers z coordinates. (TODO Dicuss more).
+    /// Generate the support layers slicing z coordinates.
     vector<coordf_t> support_layers_z(vector<coordf_t> contact_z,
                                       vector<coordf_t> top_z,
                                       coordf_t max_object_layer_height);
@@ -140,7 +140,7 @@ private:
     // Get the maximum layer height given a print object.
     coordf_t get_max_layer_height(PrintObject *object);
 
-    // (Deprecated) use append_to instead TODO @Samir55.
+    // (Deprecated) use append_to instead
     void append_polygons(Polygons &dst, Polygons &src);
 
     // Return polygon vector given a vector of surfaces.