diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index 887d35320..380120a1d 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -21,6 +21,7 @@ use constant MI_QUICK_SLICE   => &Wx::NewId;
 use constant MI_REPEAT_QUICK  => &Wx::NewId;
 use constant MI_QUICK_SAVE_AS => &Wx::NewId;
 use constant MI_SLICE_SVG     => &Wx::NewId;
+use constant MI_COMBINE_STLS  => &Wx::NewId;
 
 use constant MI_PLATER_EXPORT_GCODE => &Wx::NewId;
 use constant MI_PLATER_EXPORT_STL   => &Wx::NewId;
@@ -90,6 +91,8 @@ sub OnInit {
         $fileMenu->AppendSeparator();
         $fileMenu->Append(MI_SLICE_SVG, "Slice to SV&G…\tCtrl+G", 'Slice file to SVG');
         $fileMenu->AppendSeparator();
+        $fileMenu->Append(MI_COMBINE_STLS, "Combine multi-material STL files…", 'Combine multiple STL files into a single multi-material AMF file');
+        $fileMenu->AppendSeparator();
         $fileMenu->Append(wxID_EXIT, "&Quit", 'Quit Slic3r');
         EVT_MENU($frame, MI_LOAD_CONF, sub { $self->{skeinpanel}->load_config_file });
         EVT_MENU($frame, MI_EXPORT_CONF, sub { $self->{skeinpanel}->export_config });
@@ -99,6 +102,7 @@ sub OnInit {
         EVT_MENU($frame, MI_QUICK_SAVE_AS, sub { $self->{skeinpanel}->do_slice(save_as => 1);
                                                  $repeat->Enable(defined $Slic3r::GUI::SkeinPanel::last_input_file) });
         EVT_MENU($frame, MI_SLICE_SVG, sub { $self->{skeinpanel}->do_slice(save_as => 1, export_svg => 1) });
+        EVT_MENU($frame, MI_COMBINE_STLS, sub { $self->{skeinpanel}->combine_stls });
         EVT_MENU($frame, wxID_EXIT, sub {$_[0]->Close(0)});
     }
     
diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index e68b72778..1c9f910a2 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -502,7 +502,7 @@ sub export_gcode {
     {
         $self->{output_file} = $print->expanded_output_filepath($self->{output_file}, $self->{objects}[0]->input_file);
         my $dlg = Wx::FileDialog->new($self, 'Save G-code file as:', dirname($self->{output_file}),
-            basename($self->{output_file}), $Slic3r::GUI::SkeinPanel::gcode_wildcard, wxFD_SAVE);
+            basename($self->{output_file}), &Slic3r::GUI::SkeinPanel::FILE_WILDCARDS->{gcode}, wxFD_SAVE);
         if ($dlg->ShowModal != wxID_OK) {
             $dlg->Destroy;
             return;
@@ -654,7 +654,7 @@ sub _get_export_file {
         $output_file = $self->_init_print->expanded_output_filepath($output_file, $self->{objects}[0]->input_file);
         $output_file =~ s/\.gcode$/$suffix/i;
         my $dlg = Wx::FileDialog->new($self, "Save $format file as:", dirname($output_file),
-            basename($output_file), $Slic3r::GUI::SkeinPanel::model_wildcard, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
+            basename($output_file), &Slic3r::GUI::SkeinPanel::MODEL_WILDCARD, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
         if ($dlg->ShowModal != wxID_OK) {
             $dlg->Destroy;
             return undef;
diff --git a/lib/Slic3r/GUI/SkeinPanel.pm b/lib/Slic3r/GUI/SkeinPanel.pm
index 6712b52f3..8cdc8d7b2 100644
--- a/lib/Slic3r/GUI/SkeinPanel.pm
+++ b/lib/Slic3r/GUI/SkeinPanel.pm
@@ -13,6 +13,16 @@ our $last_input_file;
 our $last_output_file;
 our $last_config;
 
+use constant FILE_WILDCARDS => {
+    stl     => 'STL files (*.stl)|*.stl;*.STL',
+    obj     => 'OBJ files (*.obj)|*.obj;*.OBJ',
+    amf     => 'AMF files (*.amf)|*.amf;*.AMF;*.xml;*.XML',
+    ini     => 'INI files *.ini|*.ini;*.INI',
+    gcode   => 'G-code files *.gcode|*.gcode;*.GCODE|G-code files *.g|*.g;*.G',
+    svg     => 'SVG files *.svg|*.svg;*.SVG',
+};
+use constant MODEL_WILDCARD => join '|', @{&FILE_WILDCARDS}{qw(stl obj amf)};
+
 sub new {
     my $class = shift;
     my ($parent) = @_;
@@ -41,11 +51,6 @@ sub new {
     return $self;
 }
 
-our $model_wildcard = "STL files (*.stl)|*.stl;*.STL|OBJ files (*.obj)|*.obj;*.OBJ|AMF files (*.amf)|*.amf;*.AMF;*.xml;*.XML";
-our $ini_wildcard = "INI files *.ini|*.ini;*.INI";
-our $gcode_wildcard = "G-code files *.gcode|*.gcode;*.GCODE|G-code files *.g|*.g;*.G";
-our $svg_wildcard = "SVG files *.svg|*.svg;*.SVG";
-
 sub do_slice {
     my $self = shift;
     my %params = @_;
@@ -70,7 +75,7 @@ sub do_slice {
 
         my $input_file;
         if (!$params{reslice}) {
-            my $dialog = Wx::FileDialog->new($self, 'Choose a file to slice (STL/OBJ/AMF):', $dir, "", $model_wildcard, wxFD_OPEN | wxFD_FILE_MUST_EXIST);
+            my $dialog = Wx::FileDialog->new($self, 'Choose a file to slice (STL/OBJ/AMF):', $dir, "", MODEL_WILDCARD, wxFD_OPEN | wxFD_FILE_MUST_EXIST);
             if ($dialog->ShowModal != wxID_OK) {
                 $dialog->Destroy;
                 return;
@@ -107,7 +112,7 @@ sub do_slice {
             $output_file = $print->expanded_output_filepath($output_file);
             $output_file =~ s/\.gcode$/.svg/i if $params{export_svg};
             my $dlg = Wx::FileDialog->new($self, 'Save ' . ($params{export_svg} ? 'SVG' : 'G-code') . ' file as:', dirname($output_file),
-                basename($output_file), $params{export_svg} ? $svg_wildcard : $gcode_wildcard, wxFD_SAVE);
+                basename($output_file), $params{export_svg} ? FILE_WILDCARDS->{svg} : FILE_WILDCARDS->{gcode}, wxFD_SAVE);
             if ($dlg->ShowModal != wxID_OK) {
                 $dlg->Destroy;
                 return;
@@ -172,7 +177,7 @@ sub export_config {
     my $dir = $last_config ? dirname($last_config) : $Slic3r::GUI::Settings->{recent}{config_directory} || $Slic3r::GUI::Settings->{recent}{skein_directory} || '';
     my $filename = $last_config ? basename($last_config) : "config.ini";
     my $dlg = Wx::FileDialog->new($self, 'Save configuration as:', $dir, $filename, 
-        $ini_wildcard, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
+        FILE_WILDCARDS->{ini}, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
     if ($dlg->ShowModal == wxID_OK) {
         my $file = $dlg->GetPath;
         $Slic3r::GUI::Settings->{recent}{config_directory} = dirname($file);
@@ -191,7 +196,7 @@ sub load_config_file {
         return unless $self->check_unsaved_changes;
         my $dir = $last_config ? dirname($last_config) : $Slic3r::GUI::Settings->{recent}{config_directory} || $Slic3r::GUI::Settings->{recent}{skein_directory} || '';
         my $dlg = Wx::FileDialog->new($self, 'Select configuration to load:', $dir, "config.ini", 
-                $ini_wildcard, wxFD_OPEN | wxFD_FILE_MUST_EXIST);
+                FILE_WILDCARDS->{ini}, wxFD_OPEN | wxFD_FILE_MUST_EXIST);
         return unless $dlg->ShowModal == wxID_OK;
         ($file) = $dlg->GetPaths;
         $dlg->Destroy;
@@ -221,6 +226,58 @@ sub config_wizard {
     }
 }
 
+sub combine_stls {
+    my $self = shift;
+    
+    # get input files
+    my @input_files = ();
+    my $dir = $Slic3r::GUI::Settings->{recent}{skein_directory} || '';
+    {
+        my $dlg_message = 'Choose one or more files to combine (STL/OBJ)';
+        while (1) {
+            my $dialog = Wx::FileDialog->new($self, "$dlg_message:", $dir, "", MODEL_WILDCARD, 
+                wxFD_OPEN | wxFD_MULTIPLE | wxFD_FILE_MUST_EXIST);
+            if ($dialog->ShowModal != wxID_OK) {
+                $dialog->Destroy;
+                last;
+            }
+            push @input_files, $dialog->GetPaths;
+            $dialog->Destroy;
+            $dlg_message .= " or hit Cancel if you have finished";
+            $dir = dirname($input_files[0]);
+        }
+        return if !@input_files;
+    }
+    
+    # get output file
+    my $output_file = $input_files[0];
+    {
+        $output_file =~ s/\.(?:stl|obj)$/.amf.xml/i;
+        my $dlg = Wx::FileDialog->new($self, 'Save multi-material AMF file as:', dirname($output_file),
+            basename($output_file), FILE_WILDCARDS->{amf}, wxFD_SAVE);
+        if ($dlg->ShowModal != wxID_OK) {
+            $dlg->Destroy;
+            return;
+        }
+        $output_file = $dlg->GetPath;
+    }
+    
+    my @models = map Slic3r::Model->read_from_file($_), @input_files;
+    my $new_model = Slic3r::Model->new;
+    my $new_object = $new_model->add_object;
+    for my $m (0 .. $#models) {
+        my $model = $models[$m];
+        $new_model->set_material($m, { Name => basename($input_files[$m]) });
+        $new_object->add_volume(
+            material_id => $m,
+            facets      => $model->objects->[0]->volumes->[0]->facets,
+            vertices    => $model->objects->[0]->vertices,
+        );
+    }
+    
+    Slic3r::Format::AMF->write_file($output_file, $new_model);
+}
+
 =head2 config
 
 This method collects all config values from the tabs and merges them into a single config object.
diff --git a/lib/Slic3r/Model.pm b/lib/Slic3r/Model.pm
index 0914ea1c6..1e2a6b2ba 100644
--- a/lib/Slic3r/Model.pm
+++ b/lib/Slic3r/Model.pm
@@ -77,8 +77,20 @@ has 'instances' => (is => 'rw');
 
 sub add_volume {
     my $self = shift;
+    my %args = @_;
     
-    my $volume = Slic3r::Model::Volume->new(object => $self, @_);
+    if (my $vertices = delete $args{vertices}) {
+        my $v_offset = @{$self->vertices};
+        push @{$self->vertices}, @$vertices;
+        
+        @{$args{facets}} = map {
+            my $f = [@$_];
+            $f->[$_] += $v_offset for -3..-1;
+            $f;
+        } @{$args{facets}};
+    }
+    
+    my $volume = Slic3r::Model::Volume->new(object => $self, %args);
     push @{$self->volumes}, $volume;
     return $volume;
 }
diff --git a/utils/stl-to-amf.pl b/utils/stl-to-amf.pl
index e6fc1fa8d..e1adec7ce 100755
--- a/utils/stl-to-amf.pl
+++ b/utils/stl-to-amf.pl
@@ -35,19 +35,11 @@ my %opt = ();
         my $new_object = $new_model->add_object;
         for my $m (0 .. $#models) {
             my $model = $models[$m];
-            my $v_offset = @{$new_object->vertices};
-            push @{$new_object->vertices}, @{$model->objects->[0]->vertices};
-            my @new_facets = map {
-                my $f = [@$_];
-                $f->[$_] += $v_offset for -3..-1;
-                $f;
-            } @{ $model->objects->[0]->volumes->[0]->facets };
-            
-            my $material_id = scalar keys %{$new_model->materials};
-            $new_model->set_material($material_id, { Name => basename($ARGV[$m]) });
+            $new_model->set_material($m, { Name => basename($ARGV[$m]) });
             $new_object->add_volume(
-                material_id => $material_id,
-                facets      => [@new_facets],
+                material_id => $m,
+                facets      => $model->objects->[0]->volumes->[0]->facets,
+                vertices    => $model->objects->[0]->vertices,
             );
         }
     } else {