From 138501872426ae1fc7023478dd1deba96d936ecf Mon Sep 17 00:00:00 2001
From: bubnikv <bubnikv@gmail.com>
Date: Thu, 3 Aug 2017 17:31:31 +0200
Subject: Unicode handling: Removed the Perl dependencies on Encode,
 Encode::Locale and Unicode::Normalize. Added dependency on boost::locale.
 Added encode_path, decode_path, normalize_utf8 functions to Slic3r.xs

Slic3r.xs has been made mostly utf8 safe by using the boost::nowide library,
thanks to @alexrj for the idea.

Simplified the encode_path / decode_path stuff:
wxWidgets are unicode already, so there is no need to decode_path() from it.
Perl / win32 interfacing is non-unicode, so decode_path() is executed
on ARGV just at the beginning of the perl scripts.
---
 Build.PL                              |   3 -
 lib/Slic3r.pm                         |  43 --
 lib/Slic3r/GUI.pm                     |   5 +-
 lib/Slic3r/GUI/BedShapeDialog.pm      |   2 +-
 lib/Slic3r/GUI/MainFrame.pm           |  20 +-
 lib/Slic3r/GUI/Plater.pm              |  14 +-
 lib/Slic3r/GUI/Tab.pm                 |   7 +-
 lib/Slic3r/Print.pm                   |  18 +-
 slic3r.pl                             |  14 +-
 utils/amf-to-stl.pl                   |   7 +-
 utils/dump-stl.pl                     |   4 +-
 utils/split_stl.pl                    |   4 +-
 utils/stl-to-amf.pl                   |   4 +-
 xs/Build.PL                           |   8 +-
 xs/MANIFEST                           |  12 +-
 xs/src/admesh/connect.c               | 988 ----------------------------------
 xs/src/admesh/connect.cpp             | 988 ++++++++++++++++++++++++++++++++++
 xs/src/admesh/normals.c               | 333 ------------
 xs/src/admesh/normals.cpp             | 325 +++++++++++
 xs/src/admesh/shared.c                | 262 ---------
 xs/src/admesh/shared.cpp              | 264 +++++++++
 xs/src/admesh/stl.h                   |   8 -
 xs/src/admesh/stl_io.c                | 420 ---------------
 xs/src/admesh/stl_io.cpp              | 421 +++++++++++++++
 xs/src/admesh/stlinit.c               | 426 ---------------
 xs/src/admesh/stlinit.cpp             | 428 +++++++++++++++
 xs/src/admesh/util.c                  | 573 --------------------
 xs/src/admesh/util.cpp                | 573 ++++++++++++++++++++
 xs/src/libslic3r/Format/AMF.cpp       |   6 +-
 xs/src/libslic3r/Format/PRUS.cpp      |  11 +-
 xs/src/libslic3r/Format/objparser.cpp |   8 +-
 xs/src/libslic3r/GCode.cpp            |  32 +-
 xs/src/libslic3r/GCode.hpp            |   4 +-
 xs/src/libslic3r/Model.cpp            |   3 +-
 xs/src/libslic3r/SVG.cpp              |   6 +-
 xs/src/libslic3r/Utils.hpp            |   4 +
 xs/src/libslic3r/utils.cpp            |  64 ++-
 xs/xsp/GCode.xsp                      |  12 +-
 xs/xsp/XS.xsp                         |  18 +
 39 files changed, 3196 insertions(+), 3146 deletions(-)
 delete mode 100644 xs/src/admesh/connect.c
 create mode 100644 xs/src/admesh/connect.cpp
 delete mode 100644 xs/src/admesh/normals.c
 create mode 100644 xs/src/admesh/normals.cpp
 delete mode 100644 xs/src/admesh/shared.c
 create mode 100644 xs/src/admesh/shared.cpp
 delete mode 100644 xs/src/admesh/stl_io.c
 create mode 100644 xs/src/admesh/stl_io.cpp
 delete mode 100644 xs/src/admesh/stlinit.c
 create mode 100644 xs/src/admesh/stlinit.cpp
 delete mode 100644 xs/src/admesh/util.c
 create mode 100644 xs/src/admesh/util.cpp

diff --git a/Build.PL b/Build.PL
index 196544846..0f340a585 100644
--- a/Build.PL
+++ b/Build.PL
@@ -8,8 +8,6 @@ use File::Spec;
 
 my %prereqs = qw(
     Devel::CheckLib                 0
-    Encode                          0
-    Encode::Locale                  1.05
     ExtUtils::MakeMaker             6.80
     ExtUtils::ParseXS               3.22
     File::Basename                  0
@@ -24,7 +22,6 @@ my %prereqs = qw(
     IO::Scalar                      0
     threads                         1.96
     Time::HiRes                     0
-    Unicode::Normalize              0
 );
 my %recommends = qw(
     Class::XSAccessor               0
diff --git a/lib/Slic3r.pm b/lib/Slic3r.pm
index bdd326140..17b783269 100644
--- a/lib/Slic3r.pm
+++ b/lib/Slic3r.pm
@@ -75,20 +75,10 @@ use Slic3r::Print::Simple;
 use Slic3r::Surface;
 our $build = eval "use Slic3r::Build; 1";
 use Thread::Semaphore;
-use Encode::Locale 1.05;
-use Encode;
-use Unicode::Normalize;
 
 # Scaling between the float and integer coordinates.
 # Floats are in mm.
 use constant SCALING_FACTOR         => 0.000001;
-use constant LOOP_CLIPPING_LENGTH_OVER_NOZZLE_DIAMETER => 0.15;
-
-# Following constants are used by the infill algorithms and integration tests.
-# Resolution to simplify perimeters to. These constants are now used in C++ code only. Better to publish them to Perl from the C++ code.
-# use constant RESOLUTION             => 0.0125;
-# use constant SCALED_RESOLUTION      => RESOLUTION / SCALING_FACTOR;
-use constant INFILL_OVERLAP_OVER_SPACING  => 0.3;
 
 # Keep track of threads we created. Perl worker threads shall not create further threads.
 my @threads = ();
@@ -211,39 +201,6 @@ sub resume_all_threads {
     $pause_sema->up;
 }
 
-# Convert a Unicode path to a file system locale.
-# The encoding is (from Encode::Locale POD):
-# Alias       | Windows | Mac OS X     | POSIX
-# locale_fs   | ANSI    | UTF-8        | nl_langinfo
-# where nl_langinfo is en-US.UTF-8 on a modern Linux as well.
-# So this conversion seems to make the most sense on Windows.
-sub encode_path {
-    my ($path) = @_;
-
-    # UTF8 encoding is not unique. Normalize the UTF8 string to make the file names unique.
-    # Unicode::Normalize::NFC() returns the Normalization Form C (formed by canonical decomposition followed by canonical composition).
-    $path = Unicode::Normalize::NFC($path);
-    $path = Encode::encode(locale_fs => $path);
-    
-    return $path;
-}
-
-# Convert a path coded by a file system locale to Unicode.
-sub decode_path {
-    my ($path) = @_;
-    
-    $path = Encode::decode(locale_fs => $path)
-        unless Encode::is_utf8($path);
-
-    # The filesystem might force a normalization form (like HFS+ does) so 
-    # if we rely on the filename being comparable after the open() + readdir()
-    # roundtrip (like when creating and then selecting a preset), we need to 
-    # restore our normalization form.
-    $path = Unicode::Normalize::NFC($path);
-    
-    return $path;
-}
-
 # Open a file by converting $filename to local file system locales.
 sub open {
     my ($fh, $mode, $filename) = @_;
diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index ccf0e9c9b..cf2729c92 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -101,7 +101,7 @@ sub OnInit {
     # Unix: ~/.Slic3r
     # Windows: "C:\Users\username\AppData\Roaming\Slic3r" or "C:\Documents and Settings\username\Application Data\Slic3r"
     # Mac: "~/Library/Application Support/Slic3r"
-    $datadir ||= Slic3r::decode_path(Wx::StandardPaths::Get->GetUserDataDir);
+    $datadir ||= Wx::StandardPaths::Get->GetUserDataDir;
     my $enc_datadir = Slic3r::encode_path($datadir);
     Slic3r::debugf "Data directory: %s\n", $datadir;
     
@@ -370,9 +370,8 @@ sub open_model {
         $dialog->Destroy;
         return;
     }
-    my @input_files = map Slic3r::decode_path($_), $dialog->GetPaths;
+    my @input_files = $dialog->GetPaths;
     $dialog->Destroy;
-    
     return @input_files;
 }
 
diff --git a/lib/Slic3r/GUI/BedShapeDialog.pm b/lib/Slic3r/GUI/BedShapeDialog.pm
index d71ceddba..70c8e0256 100644
--- a/lib/Slic3r/GUI/BedShapeDialog.pm
+++ b/lib/Slic3r/GUI/BedShapeDialog.pm
@@ -286,7 +286,7 @@ sub _load_stl {
         $dialog->Destroy;
         return;
     }
-    my $input_file = Slic3r::decode_path($dialog->GetPaths);
+    my $input_file = $dialog->GetPaths;
     $dialog->Destroy;
     
     my $model = Slic3r::Model->read_from_file($input_file);
diff --git a/lib/Slic3r/GUI/MainFrame.pm b/lib/Slic3r/GUI/MainFrame.pm
index f075b4b28..e15868fb6 100644
--- a/lib/Slic3r/GUI/MainFrame.pm
+++ b/lib/Slic3r/GUI/MainFrame.pm
@@ -368,7 +368,7 @@ sub quick_slice {
                 $dialog->Destroy;
                 return;
             }
-            $input_file = Slic3r::decode_path($dialog->GetPaths);
+            $input_file = $dialog->GetPaths;
             $dialog->Destroy;
             $qs_last_input_file = $input_file unless $params{export_svg};
         } else {
@@ -428,7 +428,7 @@ sub quick_slice {
                 $dlg->Destroy;
                 return;
             }
-            $output_file = Slic3r::decode_path($dlg->GetPath);
+            $output_file = $dlg->GetPath;
             $qs_last_output_file = $output_file unless $params{export_svg};
             $Slic3r::GUI::Settings->{_}{last_output_path} = dirname($output_file);
             wxTheApp->save_settings;
@@ -482,7 +482,7 @@ sub repair_stl {
             $dialog->Destroy;
             return;
         }
-        $input_file = Slic3r::decode_path($dialog->GetPaths);
+        $input_file = $dialog->GetPaths;
         $dialog->Destroy;
     }
     
@@ -495,14 +495,14 @@ sub repair_stl {
             $dlg->Destroy;
             return undef;
         }
-        $output_file = Slic3r::decode_path($dlg->GetPath);
+        $output_file = $dlg->GetPath;
         $dlg->Destroy;
     }
     
     my $tmesh = Slic3r::TriangleMesh->new;
-    $tmesh->ReadSTLFile(Slic3r::encode_path($input_file));
+    $tmesh->ReadSTLFile($input_file);
     $tmesh->repair;
-    $tmesh->WriteOBJFile(Slic3r::encode_path($output_file));
+    $tmesh->WriteOBJFile($output_file);
     Slic3r::GUI::show_info($self, "Your file was repaired.", "Repair");
 }
 
@@ -529,7 +529,7 @@ sub export_config {
     my $dlg = Wx::FileDialog->new($self, 'Save configuration as:', $dir, $filename, 
         &Slic3r::GUI::FILE_WILDCARDS->{ini}, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
     if ($dlg->ShowModal == wxID_OK) {
-        my $file = Slic3r::decode_path($dlg->GetPath);
+        my $file = $dlg->GetPath;
         $Slic3r::GUI::Settings->{recent}{config_directory} = dirname($file);
         wxTheApp->save_settings;
         $last_config = $file;
@@ -548,7 +548,7 @@ sub load_config_file {
         my $dlg = Wx::FileDialog->new($self, 'Select configuration to load:', $dir, "config.ini", 
                 'INI files (*.ini, *.gcode)|*.ini;*.INI;*.gcode;*.g', wxFD_OPEN | wxFD_FILE_MUST_EXIST);
         return unless $dlg->ShowModal == wxID_OK;
-        $file = Slic3r::decode_path($dlg->GetPaths);
+        $file = $dlg->GetPaths;
         $dlg->Destroy;
     }
     for my $tab (values %{$self->{options_tabs}}) {
@@ -574,7 +574,7 @@ sub export_configbundle {
     my $dlg = Wx::FileDialog->new($self, 'Save presets bundle as:', $dir, $filename, 
         &Slic3r::GUI::FILE_WILDCARDS->{ini}, wxFD_SAVE | wxFD_OVERWRITE_PROMPT);
     if ($dlg->ShowModal == wxID_OK) {
-        my $file = Slic3r::decode_path($dlg->GetPath);
+        my $file = $dlg->GetPath;
         $Slic3r::GUI::Settings->{recent}{config_directory} = dirname($file);
         wxTheApp->save_settings;
         
@@ -604,7 +604,7 @@ sub load_configbundle {
         my $dlg = Wx::FileDialog->new($self, 'Select configuration to load:', $dir, "config.ini", 
                 &Slic3r::GUI::FILE_WILDCARDS->{ini}, wxFD_OPEN | wxFD_FILE_MUST_EXIST);
         return unless $dlg->ShowModal == wxID_OK;
-        $file = Slic3r::decode_path($dlg->GetPaths);
+        $file = $dlg->GetPaths;
         $dlg->Destroy;
     }
     
diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index c473688c2..91dca96b9 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -1408,7 +1408,7 @@ sub export_gcode {
             $dlg->Destroy;
             return;
         }
-        my $path = Slic3r::decode_path($dlg->GetPath);
+        my $path = $dlg->GetPath;
         $Slic3r::GUI::Settings->{_}{last_output_path} = dirname($path);
         wxTheApp->save_settings;
         $self->{export_gcode_output_file} = $path;
@@ -1574,7 +1574,7 @@ sub send_gcode {
     my $ua = LWP::UserAgent->new;
     $ua->timeout(180);
     
-    my $path = Slic3r::encode_path($self->{send_gcode_file});
+    my $enc_path = Slic3r::encode_path($self->{send_gcode_file});
     my $res = $ua->post(
         "http://" . $self->{config}->octoprint_host . "/api/files/local",
         Content_Type => 'form-data',
@@ -1582,7 +1582,7 @@ sub send_gcode {
         Content => [
             # OctoPrint doesn't like Windows paths so we use basename()
             # Also, since we need to read from filesystem we process it through encode_path()
-            file => [ $path, basename($path) ],
+            file => [ $enc_path, basename($enc_path) ],
         ],
     );
     
@@ -1603,7 +1603,7 @@ sub export_stl {
     return if !@{$self->{objects}};
         
     my $output_file = $self->_get_export_file('STL') or return;
-    $self->{model}->store_stl(Slic3r::encode_path($output_file), 1);
+    $self->{model}->store_stl($output_file, 1);
     $self->statusbar->SetStatusText("STL file exported to $output_file");
 }
 
@@ -1644,7 +1644,7 @@ sub export_object_stl {
     my $model_object = $self->{model}->objects->[$obj_idx];
         
     my $output_file = $self->_get_export_file('STL') or return;
-    $model_object->mesh->write_binary(Slic3r::encode_path($output_file));
+    $model_object->mesh->write_binary($output_file);
     $self->statusbar->SetStatusText("STL file exported to $output_file");
 }
 
@@ -1654,7 +1654,7 @@ sub export_amf {
     return if !@{$self->{objects}};
         
     my $output_file = $self->_get_export_file('AMF') or return;
-    $self->{model}->store_amf(Slic3r::encode_path($output_file));
+    $self->{model}->store_amf($output_file);
     $self->statusbar->SetStatusText("AMF file exported to $output_file");
 }
 
@@ -1674,7 +1674,7 @@ sub _get_export_file {
             $dlg->Destroy;
             return undef;
         }
-        $output_file = Slic3r::decode_path($dlg->GetPath);
+        $output_file = $dlg->GetPath;
         $dlg->Destroy;
     }
     return $output_file;
diff --git a/lib/Slic3r/GUI/Tab.pm b/lib/Slic3r/GUI/Tab.pm
index 08b44ef1e..33b7a7752 100644
--- a/lib/Slic3r/GUI/Tab.pm
+++ b/lib/Slic3r/GUI/Tab.pm
@@ -112,8 +112,9 @@ sub new {
         my $res = Wx::MessageDialog->new($self, "Are you sure you want to delete the selected preset?", 'Delete Preset', wxYES_NO | wxNO_DEFAULT | wxICON_QUESTION)->ShowModal;
         return unless $res == wxID_YES;
         # Delete the file.
-        my $path = Slic3r::encode_path($self->{presets}[$i]->file);
-        if (-e $path && ! unlink $path) {
+        my $path = $self->{presets}[$i]->file;
+        my $enc_path = Slic3r::encode_path($path);
+        if (-e $enc_path && ! unlink $enc_path) {
             # Cannot delete the file, therefore the item will not be removed from the selection.
             Slic3r::GUI::show_error($self, "Cannot delete file $path : $!");
             return;
@@ -255,7 +256,7 @@ sub select_preset {
 sub select_preset_by_name {
     my ($self, $name) = @_;
     
-    $name = Unicode::Normalize::NFC($name);
+    $name = Slic3r::normalize_utf8_nfc($name);
     $self->select_preset(first { $self->{presets}[$_]->name eq $name } 0 .. $#{$self->{presets}});
 }
 
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 0c0bc4b0e..3db1b0b43 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -75,21 +75,9 @@ sub export_gcode {
     # output everything to a G-code file
     my $output_file = $self->output_filepath($params{output_file} // '');
     $self->status_cb->(90, "Exporting G-code" . ($output_file ? " to $output_file" : ""));
-    
-    {
-        # open output gcode file if we weren't supplied a file-handle
-        my $tempfile = "$output_file.tmp";
-        my $gcode    = Slic3r::GCode->new();
-        my $result   = $gcode->do_export($self, Slic3r::encode_path($tempfile));
-        die $result . "\n" if ($result ne '');
-        my $i;
-        for ($i = 0; $i < 5; $i += 1)  {
-            last if (rename Slic3r::encode_path($tempfile), Slic3r::encode_path($output_file));
-            # Wait for 1/4 seconds and try to rename once again.
-            select(undef, undef, undef, 0.25);
-        }
-        Slic3r::debugf "Failed to remove the output G-code file from $tempfile to $output_file. Is $tempfile locked?\n" if ($i == 5);
-    }
+
+    die "G-code export to " . $output_file . " failed\n" 
+        if ! Slic3r::GCode->new->do_export($self, $output_file);
     
     # run post-processing scripts
     if (@{$self->config->post_process}) {
diff --git a/slic3r.pl b/slic3r.pl
index 26a7f51d3..1d3807a6c 100755
--- a/slic3r.pl
+++ b/slic3r.pl
@@ -18,6 +18,9 @@ use Time::HiRes qw(gettimeofday tv_interval);
 $|++;
 binmode STDOUT, ':utf8';
 
+# Convert all parameters from the local code page to utf8 on Windows.
+@ARGV = map Slic3r::decode_path($_), @ARGV if $^O eq 'MSWin32';
+
 our %opt = ();
 my %cli_options = ();
 {
@@ -65,7 +68,6 @@ my %cli_options = ();
 my @external_configs = ();
 if ($opt{load}) {
     foreach my $configfile (@{$opt{load}}) {
-        $configfile = Slic3r::decode_path($configfile);
         if (-e $configfile) {
             push @external_configs, Slic3r::Config->load($configfile);
         } elsif (-e "$FindBin::Bin/$configfile") {
@@ -102,7 +104,7 @@ my $gui;
 if ((!@ARGV || $opt{gui}) && !$opt{save} && eval "require Slic3r::GUI; 1") {
     {
         no warnings 'once';
-        $Slic3r::GUI::datadir       = Slic3r::decode_path($opt{datadir} // '');
+        $Slic3r::GUI::datadir       = $opt{datadir} // '';
         $Slic3r::GUI::no_controller = $opt{no_controller};
         $Slic3r::GUI::no_plater     = $opt{no_plater};
         $Slic3r::GUI::autosave      = $opt{autosave};
@@ -111,7 +113,7 @@ if ((!@ARGV || $opt{gui}) && !$opt{save} && eval "require Slic3r::GUI; 1") {
     setlocale(LC_NUMERIC, 'C');
     $gui->{mainframe}->load_config_file($_) for @{$opt{load}};
     $gui->{mainframe}->load_config($cli_config);
-    my @input_files = map Slic3r::decode_path($_), @ARGV;
+    my @input_files = @ARGV;
     $gui->{mainframe}{plater}->load_files(\@input_files) unless $opt{no_plater};
     $gui->MainLoop;
     exit;
@@ -123,7 +125,6 @@ if (@ARGV) {  # slicing from command line
     
     if ($opt{repair}) {
         foreach my $file (@ARGV) {
-            $file = Slic3r::decode_path($file);
             die "Repair is currently supported only on STL files\n"
                 if $file !~ /\.[sS][tT][lL]$/;
             
@@ -139,7 +140,6 @@ if (@ARGV) {  # slicing from command line
     
     if ($opt{cut}) {
         foreach my $file (@ARGV) {
-            $file = Slic3r::decode_path($file);
             my $model = Slic3r::Model->read_from_file($file);
             my $mesh = $model->mesh;
             $mesh->translate(0, 0, -$mesh->bounding_box->z_min);
@@ -158,7 +158,6 @@ if (@ARGV) {  # slicing from command line
     
     if ($opt{split}) {
         foreach my $file (@ARGV) {
-            $file = Slic3r::decode_path($file);
             my $model = Slic3r::Model->read_from_file($file);
             my $mesh = $model->mesh;
             $mesh->repair;
@@ -167,14 +166,13 @@ if (@ARGV) {  # slicing from command line
             foreach my $new_mesh (@{$mesh->split}) {
                 my $output_file = sprintf '%s_%02d.stl', $file, ++$part_count;
                 printf "Writing to %s\n", basename($output_file);
-                $new_mesh->write_binary(Slic3r::encode_path($output_file));
+                $new_mesh->write_binary($output_file);
             }
         }
         exit;
     }
     
     while (my $input_file = shift @ARGV) {
-        $input_file = Slic3r::decode_path($input_file);
         my $model;
         if ($opt{merge}) {
             my @models = map Slic3r::Model->read_from_file($_), $input_file, (splice @ARGV, 0);
diff --git a/utils/amf-to-stl.pl b/utils/amf-to-stl.pl
index f49af94eb..2648ba25d 100755
--- a/utils/amf-to-stl.pl
+++ b/utils/amf-to-stl.pl
@@ -14,6 +14,9 @@ use Getopt::Long qw(:config no_auto_abbrev);
 use Slic3r;
 $|++;
 
+# Convert all parameters from the local code page to utf8 on Windows.
+@ARGV = map Slic3r::decode_path($_), @ARGV if $^O eq 'MSWin32';
+
 my %opt = ();
 {
     my %options = (
@@ -25,12 +28,12 @@ my %opt = ();
 }
 
 {
-    my $model = Slic3r::Model->load_amf(Slic3r::encode_path($ARGV[0]));
+    my $model = Slic3r::Model->load_amf($ARGV[0]);
     my $output_file = $ARGV[0];
     $output_file =~ s/\.[aA][mM][fF](?:\.[xX][mM][lL])?$/\.stl/;
     
     printf "Writing to %s\n", basename($output_file);
-    $model->store_stl(Slic3r::encode_path($output_file), binary => !$opt{ascii});
+    $model->store_stl($output_file, binary => !$opt{ascii});
 }
 
 
diff --git a/utils/dump-stl.pl b/utils/dump-stl.pl
index 12746feab..0f459ffb1 100644
--- a/utils/dump-stl.pl
+++ b/utils/dump-stl.pl
@@ -18,7 +18,7 @@ $|++;
 $ARGV[0] or usage(1);
 
 if (-e $ARGV[0]) {
-    my $model = Slic3r::Model->load_stl(Slic3r::encode_path($ARGV[0]), basename($ARGV[0]));
+    my $model = Slic3r::Model->load_stl($ARGV[0], basename($ARGV[0]));
     $model->objects->[0]->add_instance(offset => Slic3r::Pointf->new(0,0));
     my $mesh = $model->mesh;
     $mesh->repair;
@@ -27,7 +27,7 @@ if (-e $ARGV[0]) {
     exit 0;
 } elsif ((my $model = Slic3r::Test::model($ARGV[0]))) {
     $ARGV[1] or die "Missing writeable destination as second argument\n";
-    $model->store_stl(Slic3r::encode_path($ARGV[1]), 1);
+    $model->store_stl($ARGV[1], 1);
     printf "Model $ARGV[0] written to $ARGV[1]\n";
     exit 0;
 } else {
diff --git a/utils/split_stl.pl b/utils/split_stl.pl
index ac890fc3e..fffc57665 100755
--- a/utils/split_stl.pl
+++ b/utils/split_stl.pl
@@ -25,7 +25,7 @@ my %opt = ();
 }
 
 {
-    my $model = Slic3r::Model->load_stl(Slic3r::encode_path($ARGV[0]), basename($ARGV[0]));
+    my $model = Slic3r::Model->load_stl($ARGV[0], basename($ARGV[0]));
     my $basename = $ARGV[0];
     $basename =~ s/\.[sS][tT][lL]$//;
     
@@ -43,7 +43,7 @@ my %opt = ();
         
         my $output_file = sprintf '%s_%02d.stl', $basename, ++$part_count;
         printf "Writing to %s\n", basename($output_file);
-        $new_model->store_stl(Slic3r::encode_path($output_file), !$opt{ascii});
+        $new_model->store_stl($output_file, !$opt{ascii});
     }
 }
 
diff --git a/utils/stl-to-amf.pl b/utils/stl-to-amf.pl
index d32e799aa..f0d537b04 100755
--- a/utils/stl-to-amf.pl
+++ b/utils/stl-to-amf.pl
@@ -25,7 +25,7 @@ my %opt = ();
 }
 
 {
-    my @models = map Slic3r::Model->load_stl(Slic3r::encode_path($_), basename($_)), @ARGV;
+    my @models = map Slic3r::Model->load_stl($_, basename($_)), @ARGV;
     my $output_file = $ARGV[0];
     $output_file =~ s/\.[sS][tT][lL]$/.amf.xml/;
     
@@ -53,7 +53,7 @@ my %opt = ();
     }
     
     printf "Writing to %s\n", basename($output_file);
-    $new_model->store_amf(Slic3r::encode_path($output_file));
+    $new_model->store_amf($output_file);
 }
 
 
diff --git a/xs/Build.PL b/xs/Build.PL
index ff91114f0..7f2a03926 100644
--- a/xs/Build.PL
+++ b/xs/Build.PL
@@ -129,11 +129,11 @@ if (defined $ENV{BOOST_LIBRARYDIR}) {
 
 # In order to generate the -l switches we need to know how Boost libraries are named
 my $have_boost = 0;
-my @boost_libraries = qw(system thread filesystem log);  # we need these
+my @boost_libraries = qw(system thread filesystem locale log);  # we need these
 
 if (!$ENV{SLIC3R_STATIC}) {
     # Dynamic linking of boost libraries.
-    push @cflags, qw(-DBOOST_LOG_DYN_LINK);
+    push @cflags, qw(-DBOOST_LOG_DYN_LINK -DBOOST_LOCALE_DYN_LINK);
     if (! $mswin) {
         # Check without explicit lib path (works on Linux and OSX).
         $have_boost = 1
@@ -193,10 +193,10 @@ path through the BOOST_DIR environment variable:
 Or you may specify BOOST_INCLUDEDIR and BOOST_LIBRARYDIR separatly, which
 is handy, if you have built Boost libraries with mutliple settings.
 
-Following boost libraries are needed by Slic3r Prusa Edition: system, filesystem, thread, log.
+Following boost libraries are needed by Slic3r Prusa Edition: system, filesystem, thread, locale, log.
 
 On Debian, you need to run
-sudo apt-get install libboost-thread-dev libboost-system-dev libboost-filesystem-dev libboost-log-dev
+sudo apt-get install libboost-thread-dev libboost-system-dev libboost-filesystem-dev libboost-locale-dev libboost-log-dev
 
 EOF
 
diff --git a/xs/MANIFEST b/xs/MANIFEST
index 028556906..9148b3e08 100644
--- a/xs/MANIFEST
+++ b/xs/MANIFEST
@@ -1,13 +1,13 @@
 Build.PL
 lib/Slic3r/XS.pm
 MANIFEST			This list of files
-src/admesh/connect.c
-src/admesh/normals.c
-src/admesh/shared.c
+src/admesh/connect.cpp
+src/admesh/normals.cpp
+src/admesh/shared.cpp
 src/admesh/stl.h
-src/admesh/stl_io.c
-src/admesh/stlinit.c
-src/admesh/util.c
+src/admesh/stl_io.cpp
+src/admesh/stlinit.cpp
+src/admesh/util.cpp
 src/boost/nowide/args.hpp
 src/boost/nowide/cenv.hpp
 src/boost/nowide/config.hpp
diff --git a/xs/src/admesh/connect.c b/xs/src/admesh/connect.c
deleted file mode 100644
index e9129d007..000000000
--- a/xs/src/admesh/connect.c
+++ /dev/null
@@ -1,988 +0,0 @@
-/*  ADMesh -- process triangulated solid meshes
- *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
- *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
-
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
-
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *  Questions, comments, suggestions, etc to
- *           https://github.com/admesh/admesh/issues
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <math.h>
-
-#include "stl.h"
-
-
-static void stl_match_neighbors_exact(stl_file *stl,
-                                      stl_hash_edge *edge_a, stl_hash_edge *edge_b);
-static void stl_match_neighbors_nearby(stl_file *stl,
-                                       stl_hash_edge *edge_a, stl_hash_edge *edge_b);
-static void stl_record_neighbors(stl_file *stl,
-                                 stl_hash_edge *edge_a, stl_hash_edge *edge_b);
-static void stl_initialize_facet_check_exact(stl_file *stl);
-static void stl_initialize_facet_check_nearby(stl_file *stl);
-static void stl_load_edge_exact(stl_file *stl, stl_hash_edge *edge,
-                                stl_vertex *a, stl_vertex *b);
-static int stl_load_edge_nearby(stl_file *stl, stl_hash_edge *edge,
-                                stl_vertex *a, stl_vertex *b, float tolerance);
-static void insert_hash_edge(stl_file *stl, stl_hash_edge edge,
-                             void (*match_neighbors)(stl_file *stl,
-                                 stl_hash_edge *edge_a, stl_hash_edge *edge_b));
-static int stl_get_hash_for_edge(int M, stl_hash_edge *edge);
-static int stl_compare_function(stl_hash_edge *edge_a, stl_hash_edge *edge_b);
-static void stl_free_edges(stl_file *stl);
-static void stl_remove_facet(stl_file *stl, int facet_number);
-static void stl_change_vertices(stl_file *stl, int facet_num, int vnot,
-                                stl_vertex new_vertex);
-static void stl_which_vertices_to_change(stl_file *stl, stl_hash_edge *edge_a,
-    stl_hash_edge *edge_b, int *facet1, int *vertex1,
-    int *facet2, int *vertex2,
-    stl_vertex *new_vertex1, stl_vertex *new_vertex2);
-static void stl_remove_degenerate(stl_file *stl, int facet);
-extern int stl_check_normal_vector(stl_file *stl,
-                                   int facet_num, int normal_fix_flag);
-static void stl_update_connects_remove_1(stl_file *stl, int facet_num);
-
-
-void
-stl_check_facets_exact(stl_file *stl) {
-  /* This function builds the neighbors list.  No modifications are made
-   *  to any of the facets.  The edges are said to match only if all six
-   *  floats of the first edge matches all six floats of the second edge.
-   */
-
-  stl_hash_edge  edge;
-  stl_facet      facet;
-  int            i;
-  int            j;
-
-  if (stl->error) return;
-
-  stl->stats.connected_edges = 0;
-  stl->stats.connected_facets_1_edge = 0;
-  stl->stats.connected_facets_2_edge = 0;
-  stl->stats.connected_facets_3_edge = 0;
-
-  stl_initialize_facet_check_exact(stl);
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    facet = stl->facet_start[i];
-    // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
-    // When using a memcmp on raw floats, those numbers report to be different.
-    // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
-    {
-      uint32_t *f = (uint32_t*)&facet;
-      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
-        if (*f == 0x80000000)
-            // Negative zero, switch to positive zero.
-            *f = 0;
-    }
-
-    /* If any two of the three vertices are found to be exactally the same, call them degenerate and remove the facet. */
-    if(   !memcmp(&facet.vertex[0], &facet.vertex[1],
-                  sizeof(stl_vertex))
-          || !memcmp(&facet.vertex[1], &facet.vertex[2],
-                     sizeof(stl_vertex))
-          || !memcmp(&facet.vertex[0], &facet.vertex[2],
-                     sizeof(stl_vertex))) {
-      stl->stats.degenerate_facets += 1;
-      stl_remove_facet(stl, i);
-      i--;
-      continue;
-
-    }
-    for(j = 0; j < 3; j++) {
-      edge.facet_number = i;
-      edge.which_edge = j;
-      stl_load_edge_exact(stl, &edge, &facet.vertex[j],
-                          &facet.vertex[(j + 1) % 3]);
-
-      insert_hash_edge(stl, edge, stl_match_neighbors_exact);
-    }
-  }
-  stl_free_edges(stl);
-
-#if 0
-  printf("Number of faces: %d, number of manifold edges: %d, number of connected edges: %d, number of unconnected edges: %d\r\n", 
-    stl->stats.number_of_facets, stl->stats.number_of_facets * 3, 
-    stl->stats.connected_edges, stl->stats.number_of_facets * 3 - stl->stats.connected_edges);
-#endif
-}
-
-static void
-stl_load_edge_exact(stl_file *stl, stl_hash_edge *edge,
-                    stl_vertex *a, stl_vertex *b) {
-
-  if (stl->error) return;
-
-  {
-    float diff_x = ABS(a->x - b->x);
-    float diff_y = ABS(a->y - b->y);
-    float diff_z = ABS(a->z - b->z);
-    float max_diff = STL_MAX(diff_x, diff_y);
-    max_diff = STL_MAX(diff_z, max_diff);
-    stl->stats.shortest_edge = STL_MIN(max_diff, stl->stats.shortest_edge);
-  }
-
-  // Ensure identical vertex ordering of equal edges.
-  // This method is numerically robust.
-  if ((a->x != b->x) ? 
-        (a->x < b->x) : 
-        ((a->y != b->y) ? 
-            (a->y < b->y) : 
-            (a->z < b->z))) {
-    memcpy(&edge->key[0], a, sizeof(stl_vertex));
-    memcpy(&edge->key[3], b, sizeof(stl_vertex));
-  } else {
-    memcpy(&edge->key[0], b, sizeof(stl_vertex));
-    memcpy(&edge->key[3], a, sizeof(stl_vertex));
-    edge->which_edge += 3; /* this edge is loaded backwards */
-  }
-}
-
-static void
-stl_initialize_facet_check_exact(stl_file *stl) {
-  int i;
-
-  if (stl->error) return;
-
-  stl->stats.malloced = 0;
-  stl->stats.freed = 0;
-  stl->stats.collisions = 0;
-
-
-  stl->M = 81397;
-
-  for(i = 0; i < stl->stats.number_of_facets ; i++) {
-    /* initialize neighbors list to -1 to mark unconnected edges */
-    stl->neighbors_start[i].neighbor[0] = -1;
-    stl->neighbors_start[i].neighbor[1] = -1;
-    stl->neighbors_start[i].neighbor[2] = -1;
-  }
-
-  stl->heads = (stl_hash_edge**)calloc(stl->M, sizeof(*stl->heads));
-  if(stl->heads == NULL) perror("stl_initialize_facet_check_exact");
-
-  stl->tail = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
-  if(stl->tail == NULL) perror("stl_initialize_facet_check_exact");
-
-  stl->tail->next = stl->tail;
-
-  for(i = 0; i < stl->M; i++) {
-    stl->heads[i] = stl->tail;
-  }
-}
-
-static void
-insert_hash_edge(stl_file *stl, stl_hash_edge edge,
-                 void (*match_neighbors)(stl_file *stl,
-                     stl_hash_edge *edge_a, stl_hash_edge *edge_b)) {
-  stl_hash_edge *link;
-  stl_hash_edge *new_edge;
-  stl_hash_edge *temp;
-  int            chain_number;
-
-  if (stl->error) return;
-
-  chain_number = stl_get_hash_for_edge(stl->M, &edge);
-
-  link = stl->heads[chain_number];
-
-  if(link == stl->tail) {
-    /* This list doesn't have any edges currently in it.  Add this one. */
-    new_edge = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
-    if(new_edge == NULL) perror("insert_hash_edge");
-    stl->stats.malloced++;
-    *new_edge = edge;
-    new_edge->next = stl->tail;
-    stl->heads[chain_number] = new_edge;
-    return;
-  } else  if(!stl_compare_function(&edge, link)) {
-    /* This is a match.  Record result in neighbors list. */
-    match_neighbors(stl, &edge, link);
-    /* Delete the matched edge from the list. */
-    stl->heads[chain_number] = link->next;
-    free(link);
-    stl->stats.freed++;
-    return;
-  } else {
-    /* Continue through the rest of the list */
-    for(;;) {
-      if(link->next == stl->tail) {
-        /* This is the last item in the list. Insert a new edge. */
-        new_edge = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
-        if(new_edge == NULL) perror("insert_hash_edge");
-        stl->stats.malloced++;
-        *new_edge = edge;
-        new_edge->next = stl->tail;
-        link->next = new_edge;
-        stl->stats.collisions++;
-        return;
-      } else  if(!stl_compare_function(&edge, link->next)) {
-        /* This is a match.  Record result in neighbors list. */
-        match_neighbors(stl, &edge, link->next);
-
-        /* Delete the matched edge from the list. */
-        temp = link->next;
-        link->next = link->next->next;
-        free(temp);
-        stl->stats.freed++;
-        return;
-      } else {
-        /* This is not a match.  Go to the next link */
-        link = link->next;
-        stl->stats.collisions++;
-      }
-    }
-  }
-}
-
-
-static int
-stl_get_hash_for_edge(int M, stl_hash_edge *edge) {
-  return ((edge->key[0] / 23 + edge->key[1] / 19 + edge->key[2] / 17
-           + edge->key[3] /13  + edge->key[4] / 11 + edge->key[5] / 7 ) % M);
-}
-
-static int
-stl_compare_function(stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
-  if(edge_a->facet_number == edge_b->facet_number) {
-    return 1;			/* Don't match edges of the same facet */
-  } else {
-    return memcmp(edge_a, edge_b, SIZEOF_EDGE_SORT);
-  }
-}
-
-void
-stl_check_facets_nearby(stl_file *stl, float tolerance) {
-  stl_hash_edge  edge[3];
-  stl_facet      facet;
-  int            i;
-  int            j;
-
-  if (stl->error) return;
-
-  if(   (stl->stats.connected_facets_1_edge == stl->stats.number_of_facets)
-        && (stl->stats.connected_facets_2_edge == stl->stats.number_of_facets)
-        && (stl->stats.connected_facets_3_edge == stl->stats.number_of_facets)) {
-    /* No need to check any further.  All facets are connected */
-    return;
-  }
-
-  stl_initialize_facet_check_nearby(stl);
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    facet = stl->facet_start[i];
-    // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
-    // When using a memcmp on raw floats, those numbers report to be different.
-    // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
-    {
-      uint32_t *f = (uint32_t*)&facet;
-      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
-        if (*f == 0x80000000)
-            // Negative zero, switch to positive zero.
-            *f = 0;
-    }
-    for(j = 0; j < 3; j++) {
-      if(stl->neighbors_start[i].neighbor[j] == -1) {
-        edge[j].facet_number = i;
-        edge[j].which_edge = j;
-        if(stl_load_edge_nearby(stl, &edge[j], &facet.vertex[j],
-                                &facet.vertex[(j + 1) % 3],
-                                tolerance)) {
-          /* only insert edges that have different keys */
-          insert_hash_edge(stl, edge[j], stl_match_neighbors_nearby);
-        }
-      }
-    }
-  }
-
-  stl_free_edges(stl);
-}
-
-static int
-stl_load_edge_nearby(stl_file *stl, stl_hash_edge *edge,
-                     stl_vertex *a, stl_vertex *b, float tolerance) {
-  // Index of a grid cell spaced by tolerance.
-  uint32_t vertex1[3] = {
-    (uint32_t)((a->x - stl->stats.min.x) / tolerance),
-    (uint32_t)((a->y - stl->stats.min.y) / tolerance),
-    (uint32_t)((a->z - stl->stats.min.z) / tolerance)
-  };
-  uint32_t vertex2[3] = {
-    (uint32_t)((b->x - stl->stats.min.x) / tolerance),
-    (uint32_t)((b->y - stl->stats.min.y) / tolerance),
-    (uint32_t)((b->z - stl->stats.min.z) / tolerance)
-  };
-
-  if(   (vertex1[0] == vertex2[0])
-        && (vertex1[1] == vertex2[1])
-        && (vertex1[2] == vertex2[2])) {
-    /* Both vertices hash to the same value */
-    return 0;
-  }
-
-  // Ensure identical vertex ordering of edges, which vertices land into equal grid cells.
-  // This method is numerically robust.
-  if ((vertex1[0] != vertex2[0]) ? 
-        (vertex1[0] < vertex2[0]) : 
-        ((vertex1[1] != vertex2[1]) ? 
-            (vertex1[1] < vertex2[1]) : 
-            (vertex1[2] < vertex2[2]))) {
-    memcpy(&edge->key[0], vertex1, sizeof(stl_vertex));
-    memcpy(&edge->key[3], vertex2, sizeof(stl_vertex));
-  } else {
-    memcpy(&edge->key[0], vertex2, sizeof(stl_vertex));
-    memcpy(&edge->key[3], vertex1, sizeof(stl_vertex));
-    edge->which_edge += 3; /* this edge is loaded backwards */
-  }
-  return 1;
-}
-
-static void
-stl_free_edges(stl_file *stl) {
-  int i;
-  stl_hash_edge *temp;
-
-  if (stl->error) return;
-
-  if(stl->stats.malloced != stl->stats.freed) {
-    for(i = 0; i < stl->M; i++) {
-      for(temp = stl->heads[i]; stl->heads[i] != stl->tail;
-          temp = stl->heads[i]) {
-        stl->heads[i] = stl->heads[i]->next;
-        free(temp);
-        stl->stats.freed++;
-      }
-    }
-  }
-  free(stl->heads);
-  free(stl->tail);
-}
-
-static void
-stl_initialize_facet_check_nearby(stl_file *stl) {
-  int i;
-
-  if (stl->error) return;
-
-  stl->stats.malloced = 0;
-  stl->stats.freed = 0;
-  stl->stats.collisions = 0;
-
-  /*  tolerance = STL_MAX(stl->stats.shortest_edge, tolerance);*/
-  /*  tolerance = STL_MAX((stl->stats.bounding_diameter / 500000.0), tolerance);*/
-  /*  tolerance *= 0.5;*/
-
-  stl->M = 81397;
-
-  stl->heads = (stl_hash_edge**)calloc(stl->M, sizeof(*stl->heads));
-  if(stl->heads == NULL) perror("stl_initialize_facet_check_nearby");
-
-  stl->tail = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
-  if(stl->tail == NULL) perror("stl_initialize_facet_check_nearby");
-
-  stl->tail->next = stl->tail;
-
-  for(i = 0; i < stl->M; i++) {
-    stl->heads[i] = stl->tail;
-  }
-}
-
-
-
-static void
-stl_record_neighbors(stl_file *stl,
-                     stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
-  int i;
-  int j;
-
-  if (stl->error) return;
-
-  /* Facet a's neighbor is facet b */
-  stl->neighbors_start[edge_a->facet_number].neighbor[edge_a->which_edge % 3] =
-    edge_b->facet_number;	/* sets the .neighbor part */
-
-  stl->neighbors_start[edge_a->facet_number].
-  which_vertex_not[edge_a->which_edge % 3] =
-    (edge_b->which_edge + 2) % 3; /* sets the .which_vertex_not part */
-
-  /* Facet b's neighbor is facet a */
-  stl->neighbors_start[edge_b->facet_number].neighbor[edge_b->which_edge % 3] =
-    edge_a->facet_number;	/* sets the .neighbor part */
-
-  stl->neighbors_start[edge_b->facet_number].
-  which_vertex_not[edge_b->which_edge % 3] =
-    (edge_a->which_edge + 2) % 3; /* sets the .which_vertex_not part */
-
-  if(   ((edge_a->which_edge < 3) && (edge_b->which_edge < 3))
-        || ((edge_a->which_edge > 2) && (edge_b->which_edge > 2))) {
-    /* these facets are oriented in opposite directions.  */
-    /*  their normals are probably messed up. */
-    stl->neighbors_start[edge_a->facet_number].
-    which_vertex_not[edge_a->which_edge % 3] += 3;
-    stl->neighbors_start[edge_b->facet_number].
-    which_vertex_not[edge_b->which_edge % 3] += 3;
-  }
-
-
-  /* Count successful connects */
-  /* Total connects */
-  stl->stats.connected_edges += 2;
-  /* Count individual connects */
-  i = ((stl->neighbors_start[edge_a->facet_number].neighbor[0] == -1) +
-       (stl->neighbors_start[edge_a->facet_number].neighbor[1] == -1) +
-       (stl->neighbors_start[edge_a->facet_number].neighbor[2] == -1));
-  j = ((stl->neighbors_start[edge_b->facet_number].neighbor[0] == -1) +
-       (stl->neighbors_start[edge_b->facet_number].neighbor[1] == -1) +
-       (stl->neighbors_start[edge_b->facet_number].neighbor[2] == -1));
-  if(i == 2) {
-    stl->stats.connected_facets_1_edge +=1;
-  } else if(i == 1) {
-    stl->stats.connected_facets_2_edge +=1;
-  } else {
-    stl->stats.connected_facets_3_edge +=1;
-  }
-  if(j == 2) {
-    stl->stats.connected_facets_1_edge +=1;
-  } else if(j == 1) {
-    stl->stats.connected_facets_2_edge +=1;
-  } else {
-    stl->stats.connected_facets_3_edge +=1;
-  }
-}
-
-static void
-stl_match_neighbors_exact(stl_file *stl,
-                          stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
-  if (stl->error) return;
-  stl_record_neighbors(stl, edge_a, edge_b);
-}
-
-static void
-stl_match_neighbors_nearby(stl_file *stl,
-                           stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
-  int facet1;
-  int facet2;
-  int vertex1;
-  int vertex2;
-  int vnot1;
-  int vnot2;
-  stl_vertex new_vertex1;
-  stl_vertex new_vertex2;
-
-  if (stl->error) return;
-
-  stl_record_neighbors(stl, edge_a, edge_b);
-  stl_which_vertices_to_change(stl, edge_a, edge_b, &facet1, &vertex1,
-                               &facet2, &vertex2, &new_vertex1, &new_vertex2);
-  if(facet1 != -1) {
-    if(facet1 == edge_a->facet_number) {
-      vnot1 = (edge_a->which_edge + 2) % 3;
-    } else {
-      vnot1 = (edge_b->which_edge + 2) % 3;
-    }
-    if(((vnot1 + 2) % 3) == vertex1) {
-      vnot1 += 3;
-    }
-    stl_change_vertices(stl, facet1, vnot1, new_vertex1);
-  }
-  if(facet2 != -1) {
-    if(facet2 == edge_a->facet_number) {
-      vnot2 = (edge_a->which_edge + 2) % 3;
-    } else {
-      vnot2 = (edge_b->which_edge + 2) % 3;
-    }
-    if(((vnot2 + 2) % 3) == vertex2) {
-      vnot2 += 3;
-    }
-    stl_change_vertices(stl, facet2, vnot2, new_vertex2);
-  }
-  stl->stats.edges_fixed += 2;
-}
-
-
-static void
-stl_change_vertices(stl_file *stl, int facet_num, int vnot,
-                    stl_vertex new_vertex) {
-  int first_facet;
-  int direction;
-  int next_edge;
-  int pivot_vertex;
-
-  if (stl->error) return;
-
-  first_facet = facet_num;
-  direction = 0;
-
-  for(;;) {
-    if(vnot > 2) {
-      if(direction == 0) {
-        pivot_vertex = (vnot + 2) % 3;
-        next_edge = pivot_vertex;
-        direction = 1;
-      } else {
-        pivot_vertex = (vnot + 1) % 3;
-        next_edge = vnot % 3;
-        direction = 0;
-      }
-    } else {
-      if(direction == 0) {
-        pivot_vertex = (vnot + 1) % 3;
-        next_edge = vnot;
-      } else {
-        pivot_vertex = (vnot + 2) % 3;
-        next_edge = pivot_vertex;
-      }
-    }
-#if 0
-    if (stl->facet_start[facet_num].vertex[pivot_vertex].x == new_vertex.x &&
-        stl->facet_start[facet_num].vertex[pivot_vertex].y == new_vertex.y &&
-        stl->facet_start[facet_num].vertex[pivot_vertex].z == new_vertex.z)
-      printf("Changing vertex %f,%f,%f: Same !!!\r\n", 
-        new_vertex.x, new_vertex.y, new_vertex.z);
-    else {
-      if (stl->facet_start[facet_num].vertex[pivot_vertex].x != new_vertex.x)
-        printf("Changing coordinate x, vertex %e (0x%08x) to %e(0x%08x)\r\n", 
-          stl->facet_start[facet_num].vertex[pivot_vertex].x,
-          *reinterpret_cast<const int*>(&stl->facet_start[facet_num].vertex[pivot_vertex].x),
-          new_vertex.x,
-          *reinterpret_cast<const int*>(&new_vertex.x));
-      if (stl->facet_start[facet_num].vertex[pivot_vertex].y != new_vertex.y)
-        printf("Changing coordinate x, vertex %e (0x%08x) to %e(0x%08x)\r\n", 
-          stl->facet_start[facet_num].vertex[pivot_vertex].y,
-          *reinterpret_cast<const int*>(&stl->facet_start[facet_num].vertex[pivot_vertex].y),
-          new_vertex.y,
-          *reinterpret_cast<const int*>(&new_vertex.y));
-      if (stl->facet_start[facet_num].vertex[pivot_vertex].z != new_vertex.z)
-        printf("Changing coordinate x, vertex %e (0x%08x) to %e(0x%08x)\r\n", 
-          stl->facet_start[facet_num].vertex[pivot_vertex].z,
-          *reinterpret_cast<const int*>(&stl->facet_start[facet_num].vertex[pivot_vertex].z),
-          new_vertex.z,
-          *reinterpret_cast<const int*>(&new_vertex.z));
-    }
-#endif
-    stl->facet_start[facet_num].vertex[pivot_vertex] = new_vertex;
-    vnot = stl->neighbors_start[facet_num].which_vertex_not[next_edge];
-    facet_num = stl->neighbors_start[facet_num].neighbor[next_edge];
-
-    if(facet_num == -1) {
-      break;
-    }
-
-    if(facet_num == first_facet) {
-      /* back to the beginning */
-      printf("\
-Back to the first facet changing vertices: probably a mobius part.\n\
-Try using a smaller tolerance or don't do a nearby check\n");
-      return;
-    }
-  }
-}
-
-
-static void
-stl_which_vertices_to_change(stl_file *stl, stl_hash_edge *edge_a,
-                             stl_hash_edge *edge_b, int *facet1, int *vertex1,
-                             int *facet2, int *vertex2,
-                             stl_vertex *new_vertex1, stl_vertex *new_vertex2) {
-  int v1a;			/* pair 1, facet a */
-  int v1b;			/* pair 1, facet b */
-  int v2a;			/* pair 2, facet a */
-  int v2b;			/* pair 2, facet b */
-
-  /* Find first pair */
-  if(edge_a->which_edge < 3) {
-    v1a = edge_a->which_edge;
-    v2a = (edge_a->which_edge + 1) % 3;
-  } else {
-    v2a = edge_a->which_edge % 3;
-    v1a = (edge_a->which_edge + 1) % 3;
-  }
-  if(edge_b->which_edge < 3) {
-    v1b = edge_b->which_edge;
-    v2b = (edge_b->which_edge + 1) % 3;
-  } else {
-    v2b = edge_b->which_edge % 3;
-    v1b = (edge_b->which_edge + 1) % 3;
-  }
-
-  /* Of the first pair, which vertex, if any, should be changed */
-  if(!memcmp(&stl->facet_start[edge_a->facet_number].vertex[v1a],
-             &stl->facet_start[edge_b->facet_number].vertex[v1b],
-             sizeof(stl_vertex))) {
-    /* These facets are already equal.  No need to change. */
-    *facet1 = -1;
-  } else {
-    if(   (stl->neighbors_start[edge_a->facet_number].neighbor[v1a] == -1)
-          && (stl->neighbors_start[edge_a->facet_number].
-              neighbor[(v1a + 2) % 3] == -1)) {
-      /* This vertex has no neighbors.  This is a good one to change */
-      *facet1 = edge_a->facet_number;
-      *vertex1 = v1a;
-      *new_vertex1 = stl->facet_start[edge_b->facet_number].vertex[v1b];
-    } else {
-      *facet1 = edge_b->facet_number;
-      *vertex1 = v1b;
-      *new_vertex1 = stl->facet_start[edge_a->facet_number].vertex[v1a];
-    }
-  }
-
-  /* Of the second pair, which vertex, if any, should be changed */
-  if(!memcmp(&stl->facet_start[edge_a->facet_number].vertex[v2a],
-             &stl->facet_start[edge_b->facet_number].vertex[v2b],
-             sizeof(stl_vertex))) {
-    /* These facets are already equal.  No need to change. */
-    *facet2 = -1;
-  } else {
-    if(   (stl->neighbors_start[edge_a->facet_number].neighbor[v2a] == -1)
-          && (stl->neighbors_start[edge_a->facet_number].
-              neighbor[(v2a + 2) % 3] == -1)) {
-      /* This vertex has no neighbors.  This is a good one to change */
-      *facet2 = edge_a->facet_number;
-      *vertex2 = v2a;
-      *new_vertex2 = stl->facet_start[edge_b->facet_number].vertex[v2b];
-    } else {
-      *facet2 = edge_b->facet_number;
-      *vertex2 = v2b;
-      *new_vertex2 = stl->facet_start[edge_a->facet_number].vertex[v2a];
-    }
-  }
-}
-
-static void
-stl_remove_facet(stl_file *stl, int facet_number) {
-  int neighbor[3];
-  int vnot[3];
-  int i;
-  int j;
-
-  if (stl->error) return;
-
-  stl->stats.facets_removed += 1;
-  /* Update list of connected edges */
-  j = ((stl->neighbors_start[facet_number].neighbor[0] == -1) +
-       (stl->neighbors_start[facet_number].neighbor[1] == -1) +
-       (stl->neighbors_start[facet_number].neighbor[2] == -1));
-  if(j == 2) {
-    stl->stats.connected_facets_1_edge -= 1;
-  } else if(j == 1) {
-    stl->stats.connected_facets_2_edge -= 1;
-    stl->stats.connected_facets_1_edge -= 1;
-  } else if(j == 0) {
-    stl->stats.connected_facets_3_edge -= 1;
-    stl->stats.connected_facets_2_edge -= 1;
-    stl->stats.connected_facets_1_edge -= 1;
-  }
-
-  stl->facet_start[facet_number] =
-    stl->facet_start[stl->stats.number_of_facets - 1];
-  /* I could reallocate at this point, but it is not really necessary. */
-  stl->neighbors_start[facet_number] =
-    stl->neighbors_start[stl->stats.number_of_facets - 1];
-  stl->stats.number_of_facets -= 1;
-
-  for(i = 0; i < 3; i++) {
-    neighbor[i] = stl->neighbors_start[facet_number].neighbor[i];
-    vnot[i] = stl->neighbors_start[facet_number].which_vertex_not[i];
-  }
-
-  for(i = 0; i < 3; i++) {
-    if(neighbor[i] != -1) {
-      if(stl->neighbors_start[neighbor[i]].neighbor[(vnot[i] + 1)% 3] !=
-          stl->stats.number_of_facets) {
-        printf("\
-in stl_remove_facet: neighbor = %d numfacets = %d this is wrong\n",
-               stl->neighbors_start[neighbor[i]].neighbor[(vnot[i] + 1)% 3],
-               stl->stats.number_of_facets);
-        return;
-      }
-      stl->neighbors_start[neighbor[i]].neighbor[(vnot[i] + 1)% 3]
-        = facet_number;
-    }
-  }
-}
-
-void
-stl_remove_unconnected_facets(stl_file *stl) {
-  /* A couple of things need to be done here.  One is to remove any */
-  /* completely unconnected facets (0 edges connected) since these are */
-  /* useless and could be completely wrong.   The second thing that needs to */
-  /* be done is to remove any degenerate facets that were created during */
-  /* stl_check_facets_nearby(). */
-
-  int i;
-
-  if (stl->error) return;
-
-  /* remove degenerate facets */
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    if(   !memcmp(&stl->facet_start[i].vertex[0],
-                  &stl->facet_start[i].vertex[1], sizeof(stl_vertex))
-          || !memcmp(&stl->facet_start[i].vertex[1],
-                     &stl->facet_start[i].vertex[2], sizeof(stl_vertex))
-          || !memcmp(&stl->facet_start[i].vertex[0],
-                     &stl->facet_start[i].vertex[2], sizeof(stl_vertex))) {
-      stl_remove_degenerate(stl, i);
-      i--;
-    }
-  }
-
-  if(stl->stats.connected_facets_1_edge < stl->stats.number_of_facets) {
-    /* remove completely unconnected facets */
-    for(i = 0; i < stl->stats.number_of_facets; i++) {
-      if(   (stl->neighbors_start[i].neighbor[0] == -1)
-            && (stl->neighbors_start[i].neighbor[1] == -1)
-            && (stl->neighbors_start[i].neighbor[2] == -1)) {
-        /* This facet is completely unconnected.  Remove it. */
-        stl_remove_facet(stl, i);
-        i--;
-      }
-    }
-  }
-}
-
-static void
-stl_remove_degenerate(stl_file *stl, int facet) {
-  int edge1;
-  int edge2;
-  int edge3;
-  int neighbor1;
-  int neighbor2;
-  int neighbor3;
-  int vnot1;
-  int vnot2;
-  int vnot3;
-
-  if (stl->error) return;
-
-  if(   !memcmp(&stl->facet_start[facet].vertex[0],
-                &stl->facet_start[facet].vertex[1], sizeof(stl_vertex))
-        && !memcmp(&stl->facet_start[facet].vertex[1],
-                   &stl->facet_start[facet].vertex[2], sizeof(stl_vertex))) {
-    /* all 3 vertices are equal.  Just remove the facet.  I don't think*/
-    /* this is really possible, but just in case... */
-    printf("removing a facet in stl_remove_degenerate\n");
-
-    stl_remove_facet(stl, facet);
-    return;
-  }
-
-  if(!memcmp(&stl->facet_start[facet].vertex[0],
-             &stl->facet_start[facet].vertex[1], sizeof(stl_vertex))) {
-    edge1 = 1;
-    edge2 = 2;
-    edge3 = 0;
-  } else if(!memcmp(&stl->facet_start[facet].vertex[1],
-                    &stl->facet_start[facet].vertex[2], sizeof(stl_vertex))) {
-    edge1 = 0;
-    edge2 = 2;
-    edge3 = 1;
-  } else if(!memcmp(&stl->facet_start[facet].vertex[2],
-                    &stl->facet_start[facet].vertex[0], sizeof(stl_vertex))) {
-    edge1 = 0;
-    edge2 = 1;
-    edge3 = 2;
-  } else {
-    /* No degenerate. Function shouldn't have been called. */
-    return;
-  }
-  neighbor1 = stl->neighbors_start[facet].neighbor[edge1];
-  neighbor2 = stl->neighbors_start[facet].neighbor[edge2];
-
-  if(neighbor1 == -1) {
-    stl_update_connects_remove_1(stl, neighbor2);
-  }
-  if(neighbor2 == -1) {
-    stl_update_connects_remove_1(stl, neighbor1);
-  }
-
-
-  neighbor3 = stl->neighbors_start[facet].neighbor[edge3];
-  vnot1 = stl->neighbors_start[facet].which_vertex_not[edge1];
-  vnot2 = stl->neighbors_start[facet].which_vertex_not[edge2];
-  vnot3 = stl->neighbors_start[facet].which_vertex_not[edge3];
-
-  if(neighbor1 >= 0){
-    stl->neighbors_start[neighbor1].neighbor[(vnot1 + 1) % 3] = neighbor2;
-    stl->neighbors_start[neighbor1].which_vertex_not[(vnot1 + 1) % 3] = vnot2;
-  }
-  if(neighbor2 >= 0){
-    stl->neighbors_start[neighbor2].neighbor[(vnot2 + 1) % 3] = neighbor1;
-    stl->neighbors_start[neighbor2].which_vertex_not[(vnot2 + 1) % 3] = vnot1;
-  }
-
-  stl_remove_facet(stl, facet);
-
-  if(neighbor3 >= 0) {
-    stl_update_connects_remove_1(stl, neighbor3);
-    stl->neighbors_start[neighbor3].neighbor[(vnot3 + 1) % 3] = -1;
-  }
-}
-
-void
-stl_update_connects_remove_1(stl_file *stl, int facet_num) {
-  int j;
-
-  if (stl->error) return;
-  /* Update list of connected edges */
-  j = ((stl->neighbors_start[facet_num].neighbor[0] == -1) +
-       (stl->neighbors_start[facet_num].neighbor[1] == -1) +
-       (stl->neighbors_start[facet_num].neighbor[2] == -1));
-  if(j == 0) {		       /* Facet has 3 neighbors */
-    stl->stats.connected_facets_3_edge -= 1;
-  } else if(j == 1) {	     /* Facet has 2 neighbors */
-    stl->stats.connected_facets_2_edge -= 1;
-  } else if(j == 2) {	     /* Facet has 1 neighbor  */
-    stl->stats.connected_facets_1_edge -= 1;
-  }
-}
-
-void
-stl_fill_holes(stl_file *stl) {
-  stl_facet facet;
-  stl_facet new_facet;
-  int neighbors_initial[3];
-  stl_hash_edge edge;
-  int first_facet;
-  int direction;
-  int facet_num;
-  int vnot;
-  int next_edge;
-  int pivot_vertex;
-  int next_facet;
-  int i;
-  int j;
-  int k;
-
-  if (stl->error) return;
-
-  /* Insert all unconnected edges into hash list */
-  stl_initialize_facet_check_nearby(stl);
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    facet = stl->facet_start[i];
-    for(j = 0; j < 3; j++) {
-      if(stl->neighbors_start[i].neighbor[j] != -1) continue;
-      edge.facet_number = i;
-      edge.which_edge = j;
-      stl_load_edge_exact(stl, &edge, &facet.vertex[j],
-                          &facet.vertex[(j + 1) % 3]);
-
-      insert_hash_edge(stl, edge, stl_match_neighbors_exact);
-    }
-  }
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    facet = stl->facet_start[i];
-    neighbors_initial[0] = stl->neighbors_start[i].neighbor[0];
-    neighbors_initial[1] = stl->neighbors_start[i].neighbor[1];
-    neighbors_initial[2] = stl->neighbors_start[i].neighbor[2];
-    first_facet = i;
-    for(j = 0; j < 3; j++) {
-      if(stl->neighbors_start[i].neighbor[j] != -1) continue;
-
-      new_facet.vertex[0] = facet.vertex[j];
-      new_facet.vertex[1] = facet.vertex[(j + 1) % 3];
-      if(neighbors_initial[(j + 2) % 3] == -1) {
-        direction = 1;
-      } else {
-        direction = 0;
-      }
-
-      facet_num = i;
-      vnot = (j + 2) % 3;
-
-      for(;;) {
-        if(vnot > 2) {
-          if(direction == 0) {
-            pivot_vertex = (vnot + 2) % 3;
-            next_edge = pivot_vertex;
-            direction = 1;
-          } else {
-            pivot_vertex = (vnot + 1) % 3;
-            next_edge = vnot % 3;
-            direction = 0;
-          }
-        } else {
-          if(direction == 0) {
-            pivot_vertex = (vnot + 1) % 3;
-            next_edge = vnot;
-          } else {
-            pivot_vertex = (vnot + 2) % 3;
-            next_edge = pivot_vertex;
-          }
-        }
-        next_facet = stl->neighbors_start[facet_num].neighbor[next_edge];
-
-        if(next_facet == -1) {
-          new_facet.vertex[2] = stl->facet_start[facet_num].
-                                vertex[vnot % 3];
-          stl_add_facet(stl, &new_facet);
-          for(k = 0; k < 3; k++) {
-            edge.facet_number = stl->stats.number_of_facets - 1;
-            edge.which_edge = k;
-            stl_load_edge_exact(stl, &edge, &new_facet.vertex[k],
-                                &new_facet.vertex[(k + 1) % 3]);
-
-            insert_hash_edge(stl, edge, stl_match_neighbors_exact);
-          }
-          break;
-        } else {
-          vnot = stl->neighbors_start[facet_num].
-                 which_vertex_not[next_edge];
-          facet_num = next_facet;
-        }
-
-        if(facet_num == first_facet) {
-          /* back to the beginning */
-          printf("\
-Back to the first facet filling holes: probably a mobius part.\n\
-Try using a smaller tolerance or don't do a nearby check\n");
-          return;
-        }
-      }
-    }
-  }
-}
-
-void
-stl_add_facet(stl_file *stl, stl_facet *new_facet) {
-  if (stl->error) return;
-
-  stl->stats.facets_added += 1;
-  if(stl->stats.facets_malloced < stl->stats.number_of_facets + 1) {
-    stl->facet_start = (stl_facet*)realloc(stl->facet_start,
-                                           (sizeof(stl_facet) * (stl->stats.facets_malloced + 256)));
-    if(stl->facet_start == NULL) perror("stl_add_facet");
-    stl->neighbors_start = (stl_neighbors*)realloc(stl->neighbors_start,
-                           (sizeof(stl_neighbors) * (stl->stats.facets_malloced + 256)));
-    if(stl->neighbors_start == NULL) perror("stl_add_facet");
-    stl->stats.facets_malloced += 256;
-  }
-  stl->facet_start[stl->stats.number_of_facets] = *new_facet;
-
-  /* note that the normal vector is not set here, just initialized to 0 */
-  stl->facet_start[stl->stats.number_of_facets].normal.x = 0.0;
-  stl->facet_start[stl->stats.number_of_facets].normal.y = 0.0;
-  stl->facet_start[stl->stats.number_of_facets].normal.z = 0.0;
-
-  stl->neighbors_start[stl->stats.number_of_facets].neighbor[0] = -1;
-  stl->neighbors_start[stl->stats.number_of_facets].neighbor[1] = -1;
-  stl->neighbors_start[stl->stats.number_of_facets].neighbor[2] = -1;
-  stl->stats.number_of_facets += 1;
-}
diff --git a/xs/src/admesh/connect.cpp b/xs/src/admesh/connect.cpp
new file mode 100644
index 000000000..e9129d007
--- /dev/null
+++ b/xs/src/admesh/connect.cpp
@@ -0,0 +1,988 @@
+/*  ADMesh -- process triangulated solid meshes
+ *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
+ *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Questions, comments, suggestions, etc to
+ *           https://github.com/admesh/admesh/issues
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include "stl.h"
+
+
+static void stl_match_neighbors_exact(stl_file *stl,
+                                      stl_hash_edge *edge_a, stl_hash_edge *edge_b);
+static void stl_match_neighbors_nearby(stl_file *stl,
+                                       stl_hash_edge *edge_a, stl_hash_edge *edge_b);
+static void stl_record_neighbors(stl_file *stl,
+                                 stl_hash_edge *edge_a, stl_hash_edge *edge_b);
+static void stl_initialize_facet_check_exact(stl_file *stl);
+static void stl_initialize_facet_check_nearby(stl_file *stl);
+static void stl_load_edge_exact(stl_file *stl, stl_hash_edge *edge,
+                                stl_vertex *a, stl_vertex *b);
+static int stl_load_edge_nearby(stl_file *stl, stl_hash_edge *edge,
+                                stl_vertex *a, stl_vertex *b, float tolerance);
+static void insert_hash_edge(stl_file *stl, stl_hash_edge edge,
+                             void (*match_neighbors)(stl_file *stl,
+                                 stl_hash_edge *edge_a, stl_hash_edge *edge_b));
+static int stl_get_hash_for_edge(int M, stl_hash_edge *edge);
+static int stl_compare_function(stl_hash_edge *edge_a, stl_hash_edge *edge_b);
+static void stl_free_edges(stl_file *stl);
+static void stl_remove_facet(stl_file *stl, int facet_number);
+static void stl_change_vertices(stl_file *stl, int facet_num, int vnot,
+                                stl_vertex new_vertex);
+static void stl_which_vertices_to_change(stl_file *stl, stl_hash_edge *edge_a,
+    stl_hash_edge *edge_b, int *facet1, int *vertex1,
+    int *facet2, int *vertex2,
+    stl_vertex *new_vertex1, stl_vertex *new_vertex2);
+static void stl_remove_degenerate(stl_file *stl, int facet);
+extern int stl_check_normal_vector(stl_file *stl,
+                                   int facet_num, int normal_fix_flag);
+static void stl_update_connects_remove_1(stl_file *stl, int facet_num);
+
+
+void
+stl_check_facets_exact(stl_file *stl) {
+  /* This function builds the neighbors list.  No modifications are made
+   *  to any of the facets.  The edges are said to match only if all six
+   *  floats of the first edge matches all six floats of the second edge.
+   */
+
+  stl_hash_edge  edge;
+  stl_facet      facet;
+  int            i;
+  int            j;
+
+  if (stl->error) return;
+
+  stl->stats.connected_edges = 0;
+  stl->stats.connected_facets_1_edge = 0;
+  stl->stats.connected_facets_2_edge = 0;
+  stl->stats.connected_facets_3_edge = 0;
+
+  stl_initialize_facet_check_exact(stl);
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    facet = stl->facet_start[i];
+    // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
+    // When using a memcmp on raw floats, those numbers report to be different.
+    // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
+    {
+      uint32_t *f = (uint32_t*)&facet;
+      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
+        if (*f == 0x80000000)
+            // Negative zero, switch to positive zero.
+            *f = 0;
+    }
+
+    /* If any two of the three vertices are found to be exactally the same, call them degenerate and remove the facet. */
+    if(   !memcmp(&facet.vertex[0], &facet.vertex[1],
+                  sizeof(stl_vertex))
+          || !memcmp(&facet.vertex[1], &facet.vertex[2],
+                     sizeof(stl_vertex))
+          || !memcmp(&facet.vertex[0], &facet.vertex[2],
+                     sizeof(stl_vertex))) {
+      stl->stats.degenerate_facets += 1;
+      stl_remove_facet(stl, i);
+      i--;
+      continue;
+
+    }
+    for(j = 0; j < 3; j++) {
+      edge.facet_number = i;
+      edge.which_edge = j;
+      stl_load_edge_exact(stl, &edge, &facet.vertex[j],
+                          &facet.vertex[(j + 1) % 3]);
+
+      insert_hash_edge(stl, edge, stl_match_neighbors_exact);
+    }
+  }
+  stl_free_edges(stl);
+
+#if 0
+  printf("Number of faces: %d, number of manifold edges: %d, number of connected edges: %d, number of unconnected edges: %d\r\n", 
+    stl->stats.number_of_facets, stl->stats.number_of_facets * 3, 
+    stl->stats.connected_edges, stl->stats.number_of_facets * 3 - stl->stats.connected_edges);
+#endif
+}
+
+static void
+stl_load_edge_exact(stl_file *stl, stl_hash_edge *edge,
+                    stl_vertex *a, stl_vertex *b) {
+
+  if (stl->error) return;
+
+  {
+    float diff_x = ABS(a->x - b->x);
+    float diff_y = ABS(a->y - b->y);
+    float diff_z = ABS(a->z - b->z);
+    float max_diff = STL_MAX(diff_x, diff_y);
+    max_diff = STL_MAX(diff_z, max_diff);
+    stl->stats.shortest_edge = STL_MIN(max_diff, stl->stats.shortest_edge);
+  }
+
+  // Ensure identical vertex ordering of equal edges.
+  // This method is numerically robust.
+  if ((a->x != b->x) ? 
+        (a->x < b->x) : 
+        ((a->y != b->y) ? 
+            (a->y < b->y) : 
+            (a->z < b->z))) {
+    memcpy(&edge->key[0], a, sizeof(stl_vertex));
+    memcpy(&edge->key[3], b, sizeof(stl_vertex));
+  } else {
+    memcpy(&edge->key[0], b, sizeof(stl_vertex));
+    memcpy(&edge->key[3], a, sizeof(stl_vertex));
+    edge->which_edge += 3; /* this edge is loaded backwards */
+  }
+}
+
+static void
+stl_initialize_facet_check_exact(stl_file *stl) {
+  int i;
+
+  if (stl->error) return;
+
+  stl->stats.malloced = 0;
+  stl->stats.freed = 0;
+  stl->stats.collisions = 0;
+
+
+  stl->M = 81397;
+
+  for(i = 0; i < stl->stats.number_of_facets ; i++) {
+    /* initialize neighbors list to -1 to mark unconnected edges */
+    stl->neighbors_start[i].neighbor[0] = -1;
+    stl->neighbors_start[i].neighbor[1] = -1;
+    stl->neighbors_start[i].neighbor[2] = -1;
+  }
+
+  stl->heads = (stl_hash_edge**)calloc(stl->M, sizeof(*stl->heads));
+  if(stl->heads == NULL) perror("stl_initialize_facet_check_exact");
+
+  stl->tail = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
+  if(stl->tail == NULL) perror("stl_initialize_facet_check_exact");
+
+  stl->tail->next = stl->tail;
+
+  for(i = 0; i < stl->M; i++) {
+    stl->heads[i] = stl->tail;
+  }
+}
+
+static void
+insert_hash_edge(stl_file *stl, stl_hash_edge edge,
+                 void (*match_neighbors)(stl_file *stl,
+                     stl_hash_edge *edge_a, stl_hash_edge *edge_b)) {
+  stl_hash_edge *link;
+  stl_hash_edge *new_edge;
+  stl_hash_edge *temp;
+  int            chain_number;
+
+  if (stl->error) return;
+
+  chain_number = stl_get_hash_for_edge(stl->M, &edge);
+
+  link = stl->heads[chain_number];
+
+  if(link == stl->tail) {
+    /* This list doesn't have any edges currently in it.  Add this one. */
+    new_edge = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
+    if(new_edge == NULL) perror("insert_hash_edge");
+    stl->stats.malloced++;
+    *new_edge = edge;
+    new_edge->next = stl->tail;
+    stl->heads[chain_number] = new_edge;
+    return;
+  } else  if(!stl_compare_function(&edge, link)) {
+    /* This is a match.  Record result in neighbors list. */
+    match_neighbors(stl, &edge, link);
+    /* Delete the matched edge from the list. */
+    stl->heads[chain_number] = link->next;
+    free(link);
+    stl->stats.freed++;
+    return;
+  } else {
+    /* Continue through the rest of the list */
+    for(;;) {
+      if(link->next == stl->tail) {
+        /* This is the last item in the list. Insert a new edge. */
+        new_edge = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
+        if(new_edge == NULL) perror("insert_hash_edge");
+        stl->stats.malloced++;
+        *new_edge = edge;
+        new_edge->next = stl->tail;
+        link->next = new_edge;
+        stl->stats.collisions++;
+        return;
+      } else  if(!stl_compare_function(&edge, link->next)) {
+        /* This is a match.  Record result in neighbors list. */
+        match_neighbors(stl, &edge, link->next);
+
+        /* Delete the matched edge from the list. */
+        temp = link->next;
+        link->next = link->next->next;
+        free(temp);
+        stl->stats.freed++;
+        return;
+      } else {
+        /* This is not a match.  Go to the next link */
+        link = link->next;
+        stl->stats.collisions++;
+      }
+    }
+  }
+}
+
+
+static int
+stl_get_hash_for_edge(int M, stl_hash_edge *edge) {
+  return ((edge->key[0] / 23 + edge->key[1] / 19 + edge->key[2] / 17
+           + edge->key[3] /13  + edge->key[4] / 11 + edge->key[5] / 7 ) % M);
+}
+
+static int
+stl_compare_function(stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
+  if(edge_a->facet_number == edge_b->facet_number) {
+    return 1;			/* Don't match edges of the same facet */
+  } else {
+    return memcmp(edge_a, edge_b, SIZEOF_EDGE_SORT);
+  }
+}
+
+void
+stl_check_facets_nearby(stl_file *stl, float tolerance) {
+  stl_hash_edge  edge[3];
+  stl_facet      facet;
+  int            i;
+  int            j;
+
+  if (stl->error) return;
+
+  if(   (stl->stats.connected_facets_1_edge == stl->stats.number_of_facets)
+        && (stl->stats.connected_facets_2_edge == stl->stats.number_of_facets)
+        && (stl->stats.connected_facets_3_edge == stl->stats.number_of_facets)) {
+    /* No need to check any further.  All facets are connected */
+    return;
+  }
+
+  stl_initialize_facet_check_nearby(stl);
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    facet = stl->facet_start[i];
+    // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
+    // When using a memcmp on raw floats, those numbers report to be different.
+    // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
+    {
+      uint32_t *f = (uint32_t*)&facet;
+      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
+        if (*f == 0x80000000)
+            // Negative zero, switch to positive zero.
+            *f = 0;
+    }
+    for(j = 0; j < 3; j++) {
+      if(stl->neighbors_start[i].neighbor[j] == -1) {
+        edge[j].facet_number = i;
+        edge[j].which_edge = j;
+        if(stl_load_edge_nearby(stl, &edge[j], &facet.vertex[j],
+                                &facet.vertex[(j + 1) % 3],
+                                tolerance)) {
+          /* only insert edges that have different keys */
+          insert_hash_edge(stl, edge[j], stl_match_neighbors_nearby);
+        }
+      }
+    }
+  }
+
+  stl_free_edges(stl);
+}
+
+static int
+stl_load_edge_nearby(stl_file *stl, stl_hash_edge *edge,
+                     stl_vertex *a, stl_vertex *b, float tolerance) {
+  // Index of a grid cell spaced by tolerance.
+  uint32_t vertex1[3] = {
+    (uint32_t)((a->x - stl->stats.min.x) / tolerance),
+    (uint32_t)((a->y - stl->stats.min.y) / tolerance),
+    (uint32_t)((a->z - stl->stats.min.z) / tolerance)
+  };
+  uint32_t vertex2[3] = {
+    (uint32_t)((b->x - stl->stats.min.x) / tolerance),
+    (uint32_t)((b->y - stl->stats.min.y) / tolerance),
+    (uint32_t)((b->z - stl->stats.min.z) / tolerance)
+  };
+
+  if(   (vertex1[0] == vertex2[0])
+        && (vertex1[1] == vertex2[1])
+        && (vertex1[2] == vertex2[2])) {
+    /* Both vertices hash to the same value */
+    return 0;
+  }
+
+  // Ensure identical vertex ordering of edges, which vertices land into equal grid cells.
+  // This method is numerically robust.
+  if ((vertex1[0] != vertex2[0]) ? 
+        (vertex1[0] < vertex2[0]) : 
+        ((vertex1[1] != vertex2[1]) ? 
+            (vertex1[1] < vertex2[1]) : 
+            (vertex1[2] < vertex2[2]))) {
+    memcpy(&edge->key[0], vertex1, sizeof(stl_vertex));
+    memcpy(&edge->key[3], vertex2, sizeof(stl_vertex));
+  } else {
+    memcpy(&edge->key[0], vertex2, sizeof(stl_vertex));
+    memcpy(&edge->key[3], vertex1, sizeof(stl_vertex));
+    edge->which_edge += 3; /* this edge is loaded backwards */
+  }
+  return 1;
+}
+
+static void
+stl_free_edges(stl_file *stl) {
+  int i;
+  stl_hash_edge *temp;
+
+  if (stl->error) return;
+
+  if(stl->stats.malloced != stl->stats.freed) {
+    for(i = 0; i < stl->M; i++) {
+      for(temp = stl->heads[i]; stl->heads[i] != stl->tail;
+          temp = stl->heads[i]) {
+        stl->heads[i] = stl->heads[i]->next;
+        free(temp);
+        stl->stats.freed++;
+      }
+    }
+  }
+  free(stl->heads);
+  free(stl->tail);
+}
+
+static void
+stl_initialize_facet_check_nearby(stl_file *stl) {
+  int i;
+
+  if (stl->error) return;
+
+  stl->stats.malloced = 0;
+  stl->stats.freed = 0;
+  stl->stats.collisions = 0;
+
+  /*  tolerance = STL_MAX(stl->stats.shortest_edge, tolerance);*/
+  /*  tolerance = STL_MAX((stl->stats.bounding_diameter / 500000.0), tolerance);*/
+  /*  tolerance *= 0.5;*/
+
+  stl->M = 81397;
+
+  stl->heads = (stl_hash_edge**)calloc(stl->M, sizeof(*stl->heads));
+  if(stl->heads == NULL) perror("stl_initialize_facet_check_nearby");
+
+  stl->tail = (stl_hash_edge*)malloc(sizeof(stl_hash_edge));
+  if(stl->tail == NULL) perror("stl_initialize_facet_check_nearby");
+
+  stl->tail->next = stl->tail;
+
+  for(i = 0; i < stl->M; i++) {
+    stl->heads[i] = stl->tail;
+  }
+}
+
+
+
+static void
+stl_record_neighbors(stl_file *stl,
+                     stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
+  int i;
+  int j;
+
+  if (stl->error) return;
+
+  /* Facet a's neighbor is facet b */
+  stl->neighbors_start[edge_a->facet_number].neighbor[edge_a->which_edge % 3] =
+    edge_b->facet_number;	/* sets the .neighbor part */
+
+  stl->neighbors_start[edge_a->facet_number].
+  which_vertex_not[edge_a->which_edge % 3] =
+    (edge_b->which_edge + 2) % 3; /* sets the .which_vertex_not part */
+
+  /* Facet b's neighbor is facet a */
+  stl->neighbors_start[edge_b->facet_number].neighbor[edge_b->which_edge % 3] =
+    edge_a->facet_number;	/* sets the .neighbor part */
+
+  stl->neighbors_start[edge_b->facet_number].
+  which_vertex_not[edge_b->which_edge % 3] =
+    (edge_a->which_edge + 2) % 3; /* sets the .which_vertex_not part */
+
+  if(   ((edge_a->which_edge < 3) && (edge_b->which_edge < 3))
+        || ((edge_a->which_edge > 2) && (edge_b->which_edge > 2))) {
+    /* these facets are oriented in opposite directions.  */
+    /*  their normals are probably messed up. */
+    stl->neighbors_start[edge_a->facet_number].
+    which_vertex_not[edge_a->which_edge % 3] += 3;
+    stl->neighbors_start[edge_b->facet_number].
+    which_vertex_not[edge_b->which_edge % 3] += 3;
+  }
+
+
+  /* Count successful connects */
+  /* Total connects */
+  stl->stats.connected_edges += 2;
+  /* Count individual connects */
+  i = ((stl->neighbors_start[edge_a->facet_number].neighbor[0] == -1) +
+       (stl->neighbors_start[edge_a->facet_number].neighbor[1] == -1) +
+       (stl->neighbors_start[edge_a->facet_number].neighbor[2] == -1));
+  j = ((stl->neighbors_start[edge_b->facet_number].neighbor[0] == -1) +
+       (stl->neighbors_start[edge_b->facet_number].neighbor[1] == -1) +
+       (stl->neighbors_start[edge_b->facet_number].neighbor[2] == -1));
+  if(i == 2) {
+    stl->stats.connected_facets_1_edge +=1;
+  } else if(i == 1) {
+    stl->stats.connected_facets_2_edge +=1;
+  } else {
+    stl->stats.connected_facets_3_edge +=1;
+  }
+  if(j == 2) {
+    stl->stats.connected_facets_1_edge +=1;
+  } else if(j == 1) {
+    stl->stats.connected_facets_2_edge +=1;
+  } else {
+    stl->stats.connected_facets_3_edge +=1;
+  }
+}
+
+static void
+stl_match_neighbors_exact(stl_file *stl,
+                          stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
+  if (stl->error) return;
+  stl_record_neighbors(stl, edge_a, edge_b);
+}
+
+static void
+stl_match_neighbors_nearby(stl_file *stl,
+                           stl_hash_edge *edge_a, stl_hash_edge *edge_b) {
+  int facet1;
+  int facet2;
+  int vertex1;
+  int vertex2;
+  int vnot1;
+  int vnot2;
+  stl_vertex new_vertex1;
+  stl_vertex new_vertex2;
+
+  if (stl->error) return;
+
+  stl_record_neighbors(stl, edge_a, edge_b);
+  stl_which_vertices_to_change(stl, edge_a, edge_b, &facet1, &vertex1,
+                               &facet2, &vertex2, &new_vertex1, &new_vertex2);
+  if(facet1 != -1) {
+    if(facet1 == edge_a->facet_number) {
+      vnot1 = (edge_a->which_edge + 2) % 3;
+    } else {
+      vnot1 = (edge_b->which_edge + 2) % 3;
+    }
+    if(((vnot1 + 2) % 3) == vertex1) {
+      vnot1 += 3;
+    }
+    stl_change_vertices(stl, facet1, vnot1, new_vertex1);
+  }
+  if(facet2 != -1) {
+    if(facet2 == edge_a->facet_number) {
+      vnot2 = (edge_a->which_edge + 2) % 3;
+    } else {
+      vnot2 = (edge_b->which_edge + 2) % 3;
+    }
+    if(((vnot2 + 2) % 3) == vertex2) {
+      vnot2 += 3;
+    }
+    stl_change_vertices(stl, facet2, vnot2, new_vertex2);
+  }
+  stl->stats.edges_fixed += 2;
+}
+
+
+static void
+stl_change_vertices(stl_file *stl, int facet_num, int vnot,
+                    stl_vertex new_vertex) {
+  int first_facet;
+  int direction;
+  int next_edge;
+  int pivot_vertex;
+
+  if (stl->error) return;
+
+  first_facet = facet_num;
+  direction = 0;
+
+  for(;;) {
+    if(vnot > 2) {
+      if(direction == 0) {
+        pivot_vertex = (vnot + 2) % 3;
+        next_edge = pivot_vertex;
+        direction = 1;
+      } else {
+        pivot_vertex = (vnot + 1) % 3;
+        next_edge = vnot % 3;
+        direction = 0;
+      }
+    } else {
+      if(direction == 0) {
+        pivot_vertex = (vnot + 1) % 3;
+        next_edge = vnot;
+      } else {
+        pivot_vertex = (vnot + 2) % 3;
+        next_edge = pivot_vertex;
+      }
+    }
+#if 0
+    if (stl->facet_start[facet_num].vertex[pivot_vertex].x == new_vertex.x &&
+        stl->facet_start[facet_num].vertex[pivot_vertex].y == new_vertex.y &&
+        stl->facet_start[facet_num].vertex[pivot_vertex].z == new_vertex.z)
+      printf("Changing vertex %f,%f,%f: Same !!!\r\n", 
+        new_vertex.x, new_vertex.y, new_vertex.z);
+    else {
+      if (stl->facet_start[facet_num].vertex[pivot_vertex].x != new_vertex.x)
+        printf("Changing coordinate x, vertex %e (0x%08x) to %e(0x%08x)\r\n", 
+          stl->facet_start[facet_num].vertex[pivot_vertex].x,
+          *reinterpret_cast<const int*>(&stl->facet_start[facet_num].vertex[pivot_vertex].x),
+          new_vertex.x,
+          *reinterpret_cast<const int*>(&new_vertex.x));
+      if (stl->facet_start[facet_num].vertex[pivot_vertex].y != new_vertex.y)
+        printf("Changing coordinate x, vertex %e (0x%08x) to %e(0x%08x)\r\n", 
+          stl->facet_start[facet_num].vertex[pivot_vertex].y,
+          *reinterpret_cast<const int*>(&stl->facet_start[facet_num].vertex[pivot_vertex].y),
+          new_vertex.y,
+          *reinterpret_cast<const int*>(&new_vertex.y));
+      if (stl->facet_start[facet_num].vertex[pivot_vertex].z != new_vertex.z)
+        printf("Changing coordinate x, vertex %e (0x%08x) to %e(0x%08x)\r\n", 
+          stl->facet_start[facet_num].vertex[pivot_vertex].z,
+          *reinterpret_cast<const int*>(&stl->facet_start[facet_num].vertex[pivot_vertex].z),
+          new_vertex.z,
+          *reinterpret_cast<const int*>(&new_vertex.z));
+    }
+#endif
+    stl->facet_start[facet_num].vertex[pivot_vertex] = new_vertex;
+    vnot = stl->neighbors_start[facet_num].which_vertex_not[next_edge];
+    facet_num = stl->neighbors_start[facet_num].neighbor[next_edge];
+
+    if(facet_num == -1) {
+      break;
+    }
+
+    if(facet_num == first_facet) {
+      /* back to the beginning */
+      printf("\
+Back to the first facet changing vertices: probably a mobius part.\n\
+Try using a smaller tolerance or don't do a nearby check\n");
+      return;
+    }
+  }
+}
+
+
+static void
+stl_which_vertices_to_change(stl_file *stl, stl_hash_edge *edge_a,
+                             stl_hash_edge *edge_b, int *facet1, int *vertex1,
+                             int *facet2, int *vertex2,
+                             stl_vertex *new_vertex1, stl_vertex *new_vertex2) {
+  int v1a;			/* pair 1, facet a */
+  int v1b;			/* pair 1, facet b */
+  int v2a;			/* pair 2, facet a */
+  int v2b;			/* pair 2, facet b */
+
+  /* Find first pair */
+  if(edge_a->which_edge < 3) {
+    v1a = edge_a->which_edge;
+    v2a = (edge_a->which_edge + 1) % 3;
+  } else {
+    v2a = edge_a->which_edge % 3;
+    v1a = (edge_a->which_edge + 1) % 3;
+  }
+  if(edge_b->which_edge < 3) {
+    v1b = edge_b->which_edge;
+    v2b = (edge_b->which_edge + 1) % 3;
+  } else {
+    v2b = edge_b->which_edge % 3;
+    v1b = (edge_b->which_edge + 1) % 3;
+  }
+
+  /* Of the first pair, which vertex, if any, should be changed */
+  if(!memcmp(&stl->facet_start[edge_a->facet_number].vertex[v1a],
+             &stl->facet_start[edge_b->facet_number].vertex[v1b],
+             sizeof(stl_vertex))) {
+    /* These facets are already equal.  No need to change. */
+    *facet1 = -1;
+  } else {
+    if(   (stl->neighbors_start[edge_a->facet_number].neighbor[v1a] == -1)
+          && (stl->neighbors_start[edge_a->facet_number].
+              neighbor[(v1a + 2) % 3] == -1)) {
+      /* This vertex has no neighbors.  This is a good one to change */
+      *facet1 = edge_a->facet_number;
+      *vertex1 = v1a;
+      *new_vertex1 = stl->facet_start[edge_b->facet_number].vertex[v1b];
+    } else {
+      *facet1 = edge_b->facet_number;
+      *vertex1 = v1b;
+      *new_vertex1 = stl->facet_start[edge_a->facet_number].vertex[v1a];
+    }
+  }
+
+  /* Of the second pair, which vertex, if any, should be changed */
+  if(!memcmp(&stl->facet_start[edge_a->facet_number].vertex[v2a],
+             &stl->facet_start[edge_b->facet_number].vertex[v2b],
+             sizeof(stl_vertex))) {
+    /* These facets are already equal.  No need to change. */
+    *facet2 = -1;
+  } else {
+    if(   (stl->neighbors_start[edge_a->facet_number].neighbor[v2a] == -1)
+          && (stl->neighbors_start[edge_a->facet_number].
+              neighbor[(v2a + 2) % 3] == -1)) {
+      /* This vertex has no neighbors.  This is a good one to change */
+      *facet2 = edge_a->facet_number;
+      *vertex2 = v2a;
+      *new_vertex2 = stl->facet_start[edge_b->facet_number].vertex[v2b];
+    } else {
+      *facet2 = edge_b->facet_number;
+      *vertex2 = v2b;
+      *new_vertex2 = stl->facet_start[edge_a->facet_number].vertex[v2a];
+    }
+  }
+}
+
+static void
+stl_remove_facet(stl_file *stl, int facet_number) {
+  int neighbor[3];
+  int vnot[3];
+  int i;
+  int j;
+
+  if (stl->error) return;
+
+  stl->stats.facets_removed += 1;
+  /* Update list of connected edges */
+  j = ((stl->neighbors_start[facet_number].neighbor[0] == -1) +
+       (stl->neighbors_start[facet_number].neighbor[1] == -1) +
+       (stl->neighbors_start[facet_number].neighbor[2] == -1));
+  if(j == 2) {
+    stl->stats.connected_facets_1_edge -= 1;
+  } else if(j == 1) {
+    stl->stats.connected_facets_2_edge -= 1;
+    stl->stats.connected_facets_1_edge -= 1;
+  } else if(j == 0) {
+    stl->stats.connected_facets_3_edge -= 1;
+    stl->stats.connected_facets_2_edge -= 1;
+    stl->stats.connected_facets_1_edge -= 1;
+  }
+
+  stl->facet_start[facet_number] =
+    stl->facet_start[stl->stats.number_of_facets - 1];
+  /* I could reallocate at this point, but it is not really necessary. */
+  stl->neighbors_start[facet_number] =
+    stl->neighbors_start[stl->stats.number_of_facets - 1];
+  stl->stats.number_of_facets -= 1;
+
+  for(i = 0; i < 3; i++) {
+    neighbor[i] = stl->neighbors_start[facet_number].neighbor[i];
+    vnot[i] = stl->neighbors_start[facet_number].which_vertex_not[i];
+  }
+
+  for(i = 0; i < 3; i++) {
+    if(neighbor[i] != -1) {
+      if(stl->neighbors_start[neighbor[i]].neighbor[(vnot[i] + 1)% 3] !=
+          stl->stats.number_of_facets) {
+        printf("\
+in stl_remove_facet: neighbor = %d numfacets = %d this is wrong\n",
+               stl->neighbors_start[neighbor[i]].neighbor[(vnot[i] + 1)% 3],
+               stl->stats.number_of_facets);
+        return;
+      }
+      stl->neighbors_start[neighbor[i]].neighbor[(vnot[i] + 1)% 3]
+        = facet_number;
+    }
+  }
+}
+
+void
+stl_remove_unconnected_facets(stl_file *stl) {
+  /* A couple of things need to be done here.  One is to remove any */
+  /* completely unconnected facets (0 edges connected) since these are */
+  /* useless and could be completely wrong.   The second thing that needs to */
+  /* be done is to remove any degenerate facets that were created during */
+  /* stl_check_facets_nearby(). */
+
+  int i;
+
+  if (stl->error) return;
+
+  /* remove degenerate facets */
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    if(   !memcmp(&stl->facet_start[i].vertex[0],
+                  &stl->facet_start[i].vertex[1], sizeof(stl_vertex))
+          || !memcmp(&stl->facet_start[i].vertex[1],
+                     &stl->facet_start[i].vertex[2], sizeof(stl_vertex))
+          || !memcmp(&stl->facet_start[i].vertex[0],
+                     &stl->facet_start[i].vertex[2], sizeof(stl_vertex))) {
+      stl_remove_degenerate(stl, i);
+      i--;
+    }
+  }
+
+  if(stl->stats.connected_facets_1_edge < stl->stats.number_of_facets) {
+    /* remove completely unconnected facets */
+    for(i = 0; i < stl->stats.number_of_facets; i++) {
+      if(   (stl->neighbors_start[i].neighbor[0] == -1)
+            && (stl->neighbors_start[i].neighbor[1] == -1)
+            && (stl->neighbors_start[i].neighbor[2] == -1)) {
+        /* This facet is completely unconnected.  Remove it. */
+        stl_remove_facet(stl, i);
+        i--;
+      }
+    }
+  }
+}
+
+static void
+stl_remove_degenerate(stl_file *stl, int facet) {
+  int edge1;
+  int edge2;
+  int edge3;
+  int neighbor1;
+  int neighbor2;
+  int neighbor3;
+  int vnot1;
+  int vnot2;
+  int vnot3;
+
+  if (stl->error) return;
+
+  if(   !memcmp(&stl->facet_start[facet].vertex[0],
+                &stl->facet_start[facet].vertex[1], sizeof(stl_vertex))
+        && !memcmp(&stl->facet_start[facet].vertex[1],
+                   &stl->facet_start[facet].vertex[2], sizeof(stl_vertex))) {
+    /* all 3 vertices are equal.  Just remove the facet.  I don't think*/
+    /* this is really possible, but just in case... */
+    printf("removing a facet in stl_remove_degenerate\n");
+
+    stl_remove_facet(stl, facet);
+    return;
+  }
+
+  if(!memcmp(&stl->facet_start[facet].vertex[0],
+             &stl->facet_start[facet].vertex[1], sizeof(stl_vertex))) {
+    edge1 = 1;
+    edge2 = 2;
+    edge3 = 0;
+  } else if(!memcmp(&stl->facet_start[facet].vertex[1],
+                    &stl->facet_start[facet].vertex[2], sizeof(stl_vertex))) {
+    edge1 = 0;
+    edge2 = 2;
+    edge3 = 1;
+  } else if(!memcmp(&stl->facet_start[facet].vertex[2],
+                    &stl->facet_start[facet].vertex[0], sizeof(stl_vertex))) {
+    edge1 = 0;
+    edge2 = 1;
+    edge3 = 2;
+  } else {
+    /* No degenerate. Function shouldn't have been called. */
+    return;
+  }
+  neighbor1 = stl->neighbors_start[facet].neighbor[edge1];
+  neighbor2 = stl->neighbors_start[facet].neighbor[edge2];
+
+  if(neighbor1 == -1) {
+    stl_update_connects_remove_1(stl, neighbor2);
+  }
+  if(neighbor2 == -1) {
+    stl_update_connects_remove_1(stl, neighbor1);
+  }
+
+
+  neighbor3 = stl->neighbors_start[facet].neighbor[edge3];
+  vnot1 = stl->neighbors_start[facet].which_vertex_not[edge1];
+  vnot2 = stl->neighbors_start[facet].which_vertex_not[edge2];
+  vnot3 = stl->neighbors_start[facet].which_vertex_not[edge3];
+
+  if(neighbor1 >= 0){
+    stl->neighbors_start[neighbor1].neighbor[(vnot1 + 1) % 3] = neighbor2;
+    stl->neighbors_start[neighbor1].which_vertex_not[(vnot1 + 1) % 3] = vnot2;
+  }
+  if(neighbor2 >= 0){
+    stl->neighbors_start[neighbor2].neighbor[(vnot2 + 1) % 3] = neighbor1;
+    stl->neighbors_start[neighbor2].which_vertex_not[(vnot2 + 1) % 3] = vnot1;
+  }
+
+  stl_remove_facet(stl, facet);
+
+  if(neighbor3 >= 0) {
+    stl_update_connects_remove_1(stl, neighbor3);
+    stl->neighbors_start[neighbor3].neighbor[(vnot3 + 1) % 3] = -1;
+  }
+}
+
+void
+stl_update_connects_remove_1(stl_file *stl, int facet_num) {
+  int j;
+
+  if (stl->error) return;
+  /* Update list of connected edges */
+  j = ((stl->neighbors_start[facet_num].neighbor[0] == -1) +
+       (stl->neighbors_start[facet_num].neighbor[1] == -1) +
+       (stl->neighbors_start[facet_num].neighbor[2] == -1));
+  if(j == 0) {		       /* Facet has 3 neighbors */
+    stl->stats.connected_facets_3_edge -= 1;
+  } else if(j == 1) {	     /* Facet has 2 neighbors */
+    stl->stats.connected_facets_2_edge -= 1;
+  } else if(j == 2) {	     /* Facet has 1 neighbor  */
+    stl->stats.connected_facets_1_edge -= 1;
+  }
+}
+
+void
+stl_fill_holes(stl_file *stl) {
+  stl_facet facet;
+  stl_facet new_facet;
+  int neighbors_initial[3];
+  stl_hash_edge edge;
+  int first_facet;
+  int direction;
+  int facet_num;
+  int vnot;
+  int next_edge;
+  int pivot_vertex;
+  int next_facet;
+  int i;
+  int j;
+  int k;
+
+  if (stl->error) return;
+
+  /* Insert all unconnected edges into hash list */
+  stl_initialize_facet_check_nearby(stl);
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    facet = stl->facet_start[i];
+    for(j = 0; j < 3; j++) {
+      if(stl->neighbors_start[i].neighbor[j] != -1) continue;
+      edge.facet_number = i;
+      edge.which_edge = j;
+      stl_load_edge_exact(stl, &edge, &facet.vertex[j],
+                          &facet.vertex[(j + 1) % 3]);
+
+      insert_hash_edge(stl, edge, stl_match_neighbors_exact);
+    }
+  }
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    facet = stl->facet_start[i];
+    neighbors_initial[0] = stl->neighbors_start[i].neighbor[0];
+    neighbors_initial[1] = stl->neighbors_start[i].neighbor[1];
+    neighbors_initial[2] = stl->neighbors_start[i].neighbor[2];
+    first_facet = i;
+    for(j = 0; j < 3; j++) {
+      if(stl->neighbors_start[i].neighbor[j] != -1) continue;
+
+      new_facet.vertex[0] = facet.vertex[j];
+      new_facet.vertex[1] = facet.vertex[(j + 1) % 3];
+      if(neighbors_initial[(j + 2) % 3] == -1) {
+        direction = 1;
+      } else {
+        direction = 0;
+      }
+
+      facet_num = i;
+      vnot = (j + 2) % 3;
+
+      for(;;) {
+        if(vnot > 2) {
+          if(direction == 0) {
+            pivot_vertex = (vnot + 2) % 3;
+            next_edge = pivot_vertex;
+            direction = 1;
+          } else {
+            pivot_vertex = (vnot + 1) % 3;
+            next_edge = vnot % 3;
+            direction = 0;
+          }
+        } else {
+          if(direction == 0) {
+            pivot_vertex = (vnot + 1) % 3;
+            next_edge = vnot;
+          } else {
+            pivot_vertex = (vnot + 2) % 3;
+            next_edge = pivot_vertex;
+          }
+        }
+        next_facet = stl->neighbors_start[facet_num].neighbor[next_edge];
+
+        if(next_facet == -1) {
+          new_facet.vertex[2] = stl->facet_start[facet_num].
+                                vertex[vnot % 3];
+          stl_add_facet(stl, &new_facet);
+          for(k = 0; k < 3; k++) {
+            edge.facet_number = stl->stats.number_of_facets - 1;
+            edge.which_edge = k;
+            stl_load_edge_exact(stl, &edge, &new_facet.vertex[k],
+                                &new_facet.vertex[(k + 1) % 3]);
+
+            insert_hash_edge(stl, edge, stl_match_neighbors_exact);
+          }
+          break;
+        } else {
+          vnot = stl->neighbors_start[facet_num].
+                 which_vertex_not[next_edge];
+          facet_num = next_facet;
+        }
+
+        if(facet_num == first_facet) {
+          /* back to the beginning */
+          printf("\
+Back to the first facet filling holes: probably a mobius part.\n\
+Try using a smaller tolerance or don't do a nearby check\n");
+          return;
+        }
+      }
+    }
+  }
+}
+
+void
+stl_add_facet(stl_file *stl, stl_facet *new_facet) {
+  if (stl->error) return;
+
+  stl->stats.facets_added += 1;
+  if(stl->stats.facets_malloced < stl->stats.number_of_facets + 1) {
+    stl->facet_start = (stl_facet*)realloc(stl->facet_start,
+                                           (sizeof(stl_facet) * (stl->stats.facets_malloced + 256)));
+    if(stl->facet_start == NULL) perror("stl_add_facet");
+    stl->neighbors_start = (stl_neighbors*)realloc(stl->neighbors_start,
+                           (sizeof(stl_neighbors) * (stl->stats.facets_malloced + 256)));
+    if(stl->neighbors_start == NULL) perror("stl_add_facet");
+    stl->stats.facets_malloced += 256;
+  }
+  stl->facet_start[stl->stats.number_of_facets] = *new_facet;
+
+  /* note that the normal vector is not set here, just initialized to 0 */
+  stl->facet_start[stl->stats.number_of_facets].normal.x = 0.0;
+  stl->facet_start[stl->stats.number_of_facets].normal.y = 0.0;
+  stl->facet_start[stl->stats.number_of_facets].normal.z = 0.0;
+
+  stl->neighbors_start[stl->stats.number_of_facets].neighbor[0] = -1;
+  stl->neighbors_start[stl->stats.number_of_facets].neighbor[1] = -1;
+  stl->neighbors_start[stl->stats.number_of_facets].neighbor[2] = -1;
+  stl->stats.number_of_facets += 1;
+}
diff --git a/xs/src/admesh/normals.c b/xs/src/admesh/normals.c
deleted file mode 100644
index 2832899fa..000000000
--- a/xs/src/admesh/normals.c
+++ /dev/null
@@ -1,333 +0,0 @@
-/*  ADMesh -- process triangulated solid meshes
- *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
- *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
-
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
-
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *  Questions, comments, suggestions, etc to
- *           https://github.com/admesh/admesh/issues
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <math.h>
-
-#include "stl.h"
-
-static void stl_reverse_facet(stl_file *stl, int facet_num);
-static void stl_reverse_vector(float v[]);
-int stl_check_normal_vector(stl_file *stl, int facet_num, int normal_fix_flag);
-
-static void
-stl_reverse_facet(stl_file *stl, int facet_num) {
-  stl_vertex tmp_vertex;
-  /*  int tmp_neighbor;*/
-  int neighbor[3];
-  int vnot[3];
-
-  stl->stats.facets_reversed += 1;
-
-  neighbor[0] = stl->neighbors_start[facet_num].neighbor[0];
-  neighbor[1] = stl->neighbors_start[facet_num].neighbor[1];
-  neighbor[2] = stl->neighbors_start[facet_num].neighbor[2];
-  vnot[0] = stl->neighbors_start[facet_num].which_vertex_not[0];
-  vnot[1] = stl->neighbors_start[facet_num].which_vertex_not[1];
-  vnot[2] = stl->neighbors_start[facet_num].which_vertex_not[2];
-
-  /* reverse the facet */
-  tmp_vertex = stl->facet_start[facet_num].vertex[0];
-  stl->facet_start[facet_num].vertex[0] =
-    stl->facet_start[facet_num].vertex[1];
-  stl->facet_start[facet_num].vertex[1] = tmp_vertex;
-
-  /* fix the vnots of the neighboring facets */
-  if(neighbor[0] != -1)
-    stl->neighbors_start[neighbor[0]].which_vertex_not[(vnot[0] + 1) % 3] =
-      (stl->neighbors_start[neighbor[0]].
-       which_vertex_not[(vnot[0] + 1) % 3] + 3) % 6;
-  if(neighbor[1] != -1)
-    stl->neighbors_start[neighbor[1]].which_vertex_not[(vnot[1] + 1) % 3] =
-      (stl->neighbors_start[neighbor[1]].
-       which_vertex_not[(vnot[1] + 1) % 3] + 4) % 6;
-  if(neighbor[2] != -1)
-    stl->neighbors_start[neighbor[2]].which_vertex_not[(vnot[2] + 1) % 3] =
-      (stl->neighbors_start[neighbor[2]].
-       which_vertex_not[(vnot[2] + 1) % 3] + 2) % 6;
-
-  /* swap the neighbors of the facet that is being reversed */
-  stl->neighbors_start[facet_num].neighbor[1] = neighbor[2];
-  stl->neighbors_start[facet_num].neighbor[2] = neighbor[1];
-
-  /* swap the vnots of the facet that is being reversed */
-  stl->neighbors_start[facet_num].which_vertex_not[1] = vnot[2];
-  stl->neighbors_start[facet_num].which_vertex_not[2] = vnot[1];
-
-  /* reverse the values of the vnots of the facet that is being reversed */
-  stl->neighbors_start[facet_num].which_vertex_not[0] =
-    (stl->neighbors_start[facet_num].which_vertex_not[0] + 3) % 6;
-  stl->neighbors_start[facet_num].which_vertex_not[1] =
-    (stl->neighbors_start[facet_num].which_vertex_not[1] + 3) % 6;
-  stl->neighbors_start[facet_num].which_vertex_not[2] =
-    (stl->neighbors_start[facet_num].which_vertex_not[2] + 3) % 6;
-}
-
-void
-stl_fix_normal_directions(stl_file *stl) {
-  char *norm_sw;
-  /*  int edge_num;*/
-  /*  int vnot;*/
-  int checked = 0;
-  int facet_num;
-  /*  int next_facet;*/
-  int i;
-  int j;
-  struct stl_normal {
-    int               facet_num;
-    struct stl_normal *next;
-  };
-  struct stl_normal *head;
-  struct stl_normal *tail;
-  struct stl_normal *newn;
-  struct stl_normal *temp;
-
-  if (stl->error) return;
-
-  /* Initialize linked list. */
-  head = (struct stl_normal*)malloc(sizeof(struct stl_normal));
-  if(head == NULL) perror("stl_fix_normal_directions");
-  tail = (struct stl_normal*)malloc(sizeof(struct stl_normal));
-  if(tail == NULL) perror("stl_fix_normal_directions");
-  head->next = tail;
-  tail->next = tail;
-
-  /* Initialize list that keeps track of already fixed facets. */
-  norm_sw = (char*)calloc(stl->stats.number_of_facets, sizeof(char));
-  if(norm_sw == NULL) perror("stl_fix_normal_directions");
-
-
-  facet_num = 0;
-  /* If normal vector is not within tolerance and backwards:
-     Arbitrarily starts at face 0.  If this one is wrong, we're screwed.  Thankfully, the chances
-     of it being wrong randomly are low if most of the triangles are right: */
-  if(stl_check_normal_vector(stl, 0, 0) == 2)
-    stl_reverse_facet(stl, 0);
-
-  /* Say that we've fixed this facet: */
-  norm_sw[facet_num] = 1;
-  checked++;
-
-  for(;;) {
-    /* Add neighbors_to_list.
-       Add unconnected neighbors to the list:a  */
-    for(j = 0; j < 3; j++) {
-      /* Reverse the neighboring facets if necessary. */
-      if(stl->neighbors_start[facet_num].which_vertex_not[j] > 2) {
-        /* If the facet has a neighbor that is -1, it means that edge isn't shared by another facet */
-        if(stl->neighbors_start[facet_num].neighbor[j] != -1) {
-          stl_reverse_facet
-          (stl, stl->neighbors_start[facet_num].neighbor[j]);
-        }
-      }
-      /* If this edge of the facet is connected: */
-      if(stl->neighbors_start[facet_num].neighbor[j] != -1) {
-        /* If we haven't fixed this facet yet, add it to the list: */
-        if(norm_sw[stl->neighbors_start[facet_num].neighbor[j]] != 1) {
-          /* Add node to beginning of list. */
-          newn = (struct stl_normal*)malloc(sizeof(struct stl_normal));
-          if(newn == NULL) perror("stl_fix_normal_directions");
-          newn->facet_num = stl->neighbors_start[facet_num].neighbor[j];
-          newn->next = head->next;
-          head->next = newn;
-        }
-      }
-    }
-    /* Get next facet to fix from top of list. */
-    if(head->next != tail) {
-      facet_num = head->next->facet_num;
-      if(norm_sw[facet_num] != 1) { /* If facet is in list mutiple times */
-        norm_sw[facet_num] = 1; /* Record this one as being fixed. */
-        checked++;
-      }
-      temp = head->next;	/* Delete this facet from the list. */
-      head->next = head->next->next;
-      free(temp);
-    } else { /* if we ran out of facets to fix: */
-      /* All of the facets in this part have been fixed. */
-      stl->stats.number_of_parts += 1;
-      if(checked >= stl->stats.number_of_facets) {
-        /* All of the facets have been checked.  Bail out. */
-        break;
-      } else {
-        /* There is another part here.  Find it and continue. */
-        for(i = 0; i < stl->stats.number_of_facets; i++) {
-          if(norm_sw[i] == 0) {
-            /* This is the first facet of the next part. */
-            facet_num = i;
-            if(stl_check_normal_vector(stl, i, 0) == 2) {
-              stl_reverse_facet(stl, i);
-            }
-
-            norm_sw[facet_num] = 1;
-            checked++;
-            break;
-          }
-        }
-      }
-    }
-  }
-  free(head);
-  free(tail);
-  free(norm_sw);
-}
-
-int
-stl_check_normal_vector(stl_file *stl, int facet_num, int normal_fix_flag) {
-  /* Returns 0 if the normal is within tolerance */
-  /* Returns 1 if the normal is not within tolerance, but direction is OK */
-  /* Returns 2 if the normal is not within tolerance and backwards */
-  /* Returns 4 if the status is unknown. */
-
-  float normal[3];
-  float test_norm[3];
-  stl_facet *facet;
-
-  facet = &stl->facet_start[facet_num];
-
-  stl_calculate_normal(normal, facet);
-  stl_normalize_vector(normal);
-
-  if(   (ABS(normal[0] - facet->normal.x) < 0.001)
-        && (ABS(normal[1] - facet->normal.y) < 0.001)
-        && (ABS(normal[2] - facet->normal.z) < 0.001)) {
-    /* It is not really necessary to change the values here */
-    /* but just for consistency, I will. */
-    facet->normal.x = normal[0];
-    facet->normal.y = normal[1];
-    facet->normal.z = normal[2];
-    return 0;
-  }
-
-  test_norm[0] = facet->normal.x;
-  test_norm[1] = facet->normal.y;
-  test_norm[2] = facet->normal.z;
-
-  stl_normalize_vector(test_norm);
-  if(   (ABS(normal[0] - test_norm[0]) < 0.001)
-        && (ABS(normal[1] - test_norm[1]) < 0.001)
-        && (ABS(normal[2] - test_norm[2]) < 0.001)) {
-    if(normal_fix_flag) {
-      facet->normal.x = normal[0];
-      facet->normal.y = normal[1];
-      facet->normal.z = normal[2];
-      stl->stats.normals_fixed += 1;
-    }
-    return 1;
-  }
-
-  stl_reverse_vector(test_norm);
-  if(   (ABS(normal[0] - test_norm[0]) < 0.001)
-        && (ABS(normal[1] - test_norm[1]) < 0.001)
-        && (ABS(normal[2] - test_norm[2]) < 0.001)) {
-    /* Facet is backwards. */
-    if(normal_fix_flag) {
-      facet->normal.x = normal[0];
-      facet->normal.y = normal[1];
-      facet->normal.z = normal[2];
-      stl->stats.normals_fixed += 1;
-    }
-    return 2;
-  }
-  if(normal_fix_flag) {
-    facet->normal.x = normal[0];
-    facet->normal.y = normal[1];
-    facet->normal.z = normal[2];
-    stl->stats.normals_fixed += 1;
-  }
-  return 4;
-}
-
-static void
-stl_reverse_vector(float v[]) {
-  v[0] *= -1;
-  v[1] *= -1;
-  v[2] *= -1;
-}
-
-
-void
-stl_calculate_normal(float normal[], stl_facet *facet) {
-  float v1[3];
-  float v2[3];
-
-  v1[0] = facet->vertex[1].x - facet->vertex[0].x;
-  v1[1] = facet->vertex[1].y - facet->vertex[0].y;
-  v1[2] = facet->vertex[1].z - facet->vertex[0].z;
-  v2[0] = facet->vertex[2].x - facet->vertex[0].x;
-  v2[1] = facet->vertex[2].y - facet->vertex[0].y;
-  v2[2] = facet->vertex[2].z - facet->vertex[0].z;
-
-  normal[0] = (float)((double)v1[1] * (double)v2[2]) - ((double)v1[2] * (double)v2[1]);
-  normal[1] = (float)((double)v1[2] * (double)v2[0]) - ((double)v1[0] * (double)v2[2]);
-  normal[2] = (float)((double)v1[0] * (double)v2[1]) - ((double)v1[1] * (double)v2[0]);
-}
-
-void stl_normalize_vector(float v[]) {
-  double length;
-  double factor;
-  float min_normal_length;
-
-  length = sqrt((double)v[0] * (double)v[0] + (double)v[1] * (double)v[1] + (double)v[2] * (double)v[2]);
-  min_normal_length = 0.000000000001;
-  if(length < min_normal_length) {
-    v[0] = 0.0;
-    v[1] = 0.0;
-    v[2] = 0.0;
-    return;
-  }
-  factor = 1.0 / length;
-  v[0] *= factor;
-  v[1] *= factor;
-  v[2] *= factor;
-}
-
-void
-stl_fix_normal_values(stl_file *stl) {
-  int i;
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    stl_check_normal_vector(stl, i, 1);
-  }
-}
-
-void
-stl_reverse_all_facets(stl_file *stl) {
-  int i;
-  float normal[3];
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    stl_reverse_facet(stl, i);
-    stl_calculate_normal(normal, &stl->facet_start[i]);
-    stl_normalize_vector(normal);
-    stl->facet_start[i].normal.x = normal[0];
-    stl->facet_start[i].normal.y = normal[1];
-    stl->facet_start[i].normal.z = normal[2];
-  }
-}
-
diff --git a/xs/src/admesh/normals.cpp b/xs/src/admesh/normals.cpp
new file mode 100644
index 000000000..28b1c47b0
--- /dev/null
+++ b/xs/src/admesh/normals.cpp
@@ -0,0 +1,325 @@
+/*  ADMesh -- process triangulated solid meshes
+ *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
+ *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Questions, comments, suggestions, etc to
+ *           https://github.com/admesh/admesh/issues
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include "stl.h"
+
+static void stl_reverse_vector(float v[]) {
+  v[0] *= -1;
+  v[1] *= -1;
+  v[2] *= -1;
+}
+
+static int stl_check_normal_vector(stl_file *stl, int facet_num, int normal_fix_flag);
+
+static void
+stl_reverse_facet(stl_file *stl, int facet_num) {
+  stl_vertex tmp_vertex;
+  /*  int tmp_neighbor;*/
+  int neighbor[3];
+  int vnot[3];
+
+  stl->stats.facets_reversed += 1;
+
+  neighbor[0] = stl->neighbors_start[facet_num].neighbor[0];
+  neighbor[1] = stl->neighbors_start[facet_num].neighbor[1];
+  neighbor[2] = stl->neighbors_start[facet_num].neighbor[2];
+  vnot[0] = stl->neighbors_start[facet_num].which_vertex_not[0];
+  vnot[1] = stl->neighbors_start[facet_num].which_vertex_not[1];
+  vnot[2] = stl->neighbors_start[facet_num].which_vertex_not[2];
+
+  /* reverse the facet */
+  tmp_vertex = stl->facet_start[facet_num].vertex[0];
+  stl->facet_start[facet_num].vertex[0] =
+    stl->facet_start[facet_num].vertex[1];
+  stl->facet_start[facet_num].vertex[1] = tmp_vertex;
+
+  /* fix the vnots of the neighboring facets */
+  if(neighbor[0] != -1)
+    stl->neighbors_start[neighbor[0]].which_vertex_not[(vnot[0] + 1) % 3] =
+      (stl->neighbors_start[neighbor[0]].
+       which_vertex_not[(vnot[0] + 1) % 3] + 3) % 6;
+  if(neighbor[1] != -1)
+    stl->neighbors_start[neighbor[1]].which_vertex_not[(vnot[1] + 1) % 3] =
+      (stl->neighbors_start[neighbor[1]].
+       which_vertex_not[(vnot[1] + 1) % 3] + 4) % 6;
+  if(neighbor[2] != -1)
+    stl->neighbors_start[neighbor[2]].which_vertex_not[(vnot[2] + 1) % 3] =
+      (stl->neighbors_start[neighbor[2]].
+       which_vertex_not[(vnot[2] + 1) % 3] + 2) % 6;
+
+  /* swap the neighbors of the facet that is being reversed */
+  stl->neighbors_start[facet_num].neighbor[1] = neighbor[2];
+  stl->neighbors_start[facet_num].neighbor[2] = neighbor[1];
+
+  /* swap the vnots of the facet that is being reversed */
+  stl->neighbors_start[facet_num].which_vertex_not[1] = vnot[2];
+  stl->neighbors_start[facet_num].which_vertex_not[2] = vnot[1];
+
+  /* reverse the values of the vnots of the facet that is being reversed */
+  stl->neighbors_start[facet_num].which_vertex_not[0] =
+    (stl->neighbors_start[facet_num].which_vertex_not[0] + 3) % 6;
+  stl->neighbors_start[facet_num].which_vertex_not[1] =
+    (stl->neighbors_start[facet_num].which_vertex_not[1] + 3) % 6;
+  stl->neighbors_start[facet_num].which_vertex_not[2] =
+    (stl->neighbors_start[facet_num].which_vertex_not[2] + 3) % 6;
+}
+
+void
+stl_fix_normal_directions(stl_file *stl) {
+  char *norm_sw;
+  /*  int edge_num;*/
+  /*  int vnot;*/
+  int checked = 0;
+  int facet_num;
+  /*  int next_facet;*/
+  int i;
+  int j;
+  struct stl_normal {
+    int               facet_num;
+    struct stl_normal *next;
+  };
+  struct stl_normal *head;
+  struct stl_normal *tail;
+  struct stl_normal *newn;
+  struct stl_normal *temp;
+
+  if (stl->error) return;
+
+  /* Initialize linked list. */
+  head = (struct stl_normal*)malloc(sizeof(struct stl_normal));
+  if(head == NULL) perror("stl_fix_normal_directions");
+  tail = (struct stl_normal*)malloc(sizeof(struct stl_normal));
+  if(tail == NULL) perror("stl_fix_normal_directions");
+  head->next = tail;
+  tail->next = tail;
+
+  /* Initialize list that keeps track of already fixed facets. */
+  norm_sw = (char*)calloc(stl->stats.number_of_facets, sizeof(char));
+  if(norm_sw == NULL) perror("stl_fix_normal_directions");
+
+
+  facet_num = 0;
+  /* If normal vector is not within tolerance and backwards:
+     Arbitrarily starts at face 0.  If this one is wrong, we're screwed.  Thankfully, the chances
+     of it being wrong randomly are low if most of the triangles are right: */
+  if(stl_check_normal_vector(stl, 0, 0) == 2)
+    stl_reverse_facet(stl, 0);
+
+  /* Say that we've fixed this facet: */
+  norm_sw[facet_num] = 1;
+  checked++;
+
+  for(;;) {
+    /* Add neighbors_to_list.
+       Add unconnected neighbors to the list:a  */
+    for(j = 0; j < 3; j++) {
+      /* Reverse the neighboring facets if necessary. */
+      if(stl->neighbors_start[facet_num].which_vertex_not[j] > 2) {
+        /* If the facet has a neighbor that is -1, it means that edge isn't shared by another facet */
+        if(stl->neighbors_start[facet_num].neighbor[j] != -1)
+          stl_reverse_facet(stl, stl->neighbors_start[facet_num].neighbor[j]);
+      }
+      /* If this edge of the facet is connected: */
+      if(stl->neighbors_start[facet_num].neighbor[j] != -1) {
+        /* If we haven't fixed this facet yet, add it to the list: */
+        if(norm_sw[stl->neighbors_start[facet_num].neighbor[j]] != 1) {
+          /* Add node to beginning of list. */
+          newn = (struct stl_normal*)malloc(sizeof(struct stl_normal));
+          if(newn == NULL) perror("stl_fix_normal_directions");
+          newn->facet_num = stl->neighbors_start[facet_num].neighbor[j];
+          newn->next = head->next;
+          head->next = newn;
+        }
+      }
+    }
+    /* Get next facet to fix from top of list. */
+    if(head->next != tail) {
+      facet_num = head->next->facet_num;
+      if(norm_sw[facet_num] != 1) { /* If facet is in list mutiple times */
+        norm_sw[facet_num] = 1; /* Record this one as being fixed. */
+        checked++;
+      }
+      temp = head->next;	/* Delete this facet from the list. */
+      head->next = head->next->next;
+      free(temp);
+    } else { /* if we ran out of facets to fix: */
+      /* All of the facets in this part have been fixed. */
+      stl->stats.number_of_parts += 1;
+      if(checked >= stl->stats.number_of_facets) {
+        /* All of the facets have been checked.  Bail out. */
+        break;
+      } else {
+        /* There is another part here.  Find it and continue. */
+        for(i = 0; i < stl->stats.number_of_facets; i++) {
+          if(norm_sw[i] == 0) {
+            /* This is the first facet of the next part. */
+            facet_num = i;
+            if(stl_check_normal_vector(stl, i, 0) == 2) {
+              stl_reverse_facet(stl, i);
+            }
+
+            norm_sw[facet_num] = 1;
+            checked++;
+            break;
+          }
+        }
+      }
+    }
+  }
+  free(head);
+  free(tail);
+  free(norm_sw);
+}
+
+static int stl_check_normal_vector(stl_file *stl, int facet_num, int normal_fix_flag) {
+  /* Returns 0 if the normal is within tolerance */
+  /* Returns 1 if the normal is not within tolerance, but direction is OK */
+  /* Returns 2 if the normal is not within tolerance and backwards */
+  /* Returns 4 if the status is unknown. */
+
+  float normal[3];
+  float test_norm[3];
+  stl_facet *facet;
+
+  facet = &stl->facet_start[facet_num];
+
+  stl_calculate_normal(normal, facet);
+  stl_normalize_vector(normal);
+
+  if(   (ABS(normal[0] - facet->normal.x) < 0.001)
+        && (ABS(normal[1] - facet->normal.y) < 0.001)
+        && (ABS(normal[2] - facet->normal.z) < 0.001)) {
+    /* It is not really necessary to change the values here */
+    /* but just for consistency, I will. */
+    facet->normal.x = normal[0];
+    facet->normal.y = normal[1];
+    facet->normal.z = normal[2];
+    return 0;
+  }
+
+  test_norm[0] = facet->normal.x;
+  test_norm[1] = facet->normal.y;
+  test_norm[2] = facet->normal.z;
+
+  stl_normalize_vector(test_norm);
+  if(   (ABS(normal[0] - test_norm[0]) < 0.001)
+        && (ABS(normal[1] - test_norm[1]) < 0.001)
+        && (ABS(normal[2] - test_norm[2]) < 0.001)) {
+    if(normal_fix_flag) {
+      facet->normal.x = normal[0];
+      facet->normal.y = normal[1];
+      facet->normal.z = normal[2];
+      stl->stats.normals_fixed += 1;
+    }
+    return 1;
+  }
+
+  stl_reverse_vector(test_norm);
+  if(   (ABS(normal[0] - test_norm[0]) < 0.001)
+        && (ABS(normal[1] - test_norm[1]) < 0.001)
+        && (ABS(normal[2] - test_norm[2]) < 0.001)) {
+    /* Facet is backwards. */
+    if(normal_fix_flag) {
+      facet->normal.x = normal[0];
+      facet->normal.y = normal[1];
+      facet->normal.z = normal[2];
+      stl->stats.normals_fixed += 1;
+    }
+    return 2;
+  }
+  if(normal_fix_flag) {
+    facet->normal.x = normal[0];
+    facet->normal.y = normal[1];
+    facet->normal.z = normal[2];
+    stl->stats.normals_fixed += 1;
+  }
+  return 4;
+}
+
+void stl_calculate_normal(float normal[], stl_facet *facet) {
+  float v1[3] = {
+    facet->vertex[1].x - facet->vertex[0].x,
+    facet->vertex[1].y - facet->vertex[0].y,
+    facet->vertex[1].z - facet->vertex[0].z
+  };
+  float v2[3] = {
+    facet->vertex[2].x - facet->vertex[0].x,
+    facet->vertex[2].y - facet->vertex[0].y,
+    facet->vertex[2].z - facet->vertex[0].z
+  };
+  normal[0] = (float)((double)v1[1] * (double)v2[2]) - ((double)v1[2] * (double)v2[1]);
+  normal[1] = (float)((double)v1[2] * (double)v2[0]) - ((double)v1[0] * (double)v2[2]);
+  normal[2] = (float)((double)v1[0] * (double)v2[1]) - ((double)v1[1] * (double)v2[0]);
+}
+
+void stl_normalize_vector(float v[]) {
+  double length;
+  double factor;
+  float min_normal_length;
+
+  length = sqrt((double)v[0] * (double)v[0] + (double)v[1] * (double)v[1] + (double)v[2] * (double)v[2]);
+  min_normal_length = 0.000000000001;
+  if(length < min_normal_length) {
+    v[0] = 0.0;
+    v[1] = 0.0;
+    v[2] = 0.0;
+    return;
+  }
+  factor = 1.0 / length;
+  v[0] *= factor;
+  v[1] *= factor;
+  v[2] *= factor;
+}
+
+void
+stl_fix_normal_values(stl_file *stl) {
+  int i;
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    stl_check_normal_vector(stl, i, 1);
+  }
+}
+
+void
+stl_reverse_all_facets(stl_file *stl) {
+  int i;
+  float normal[3];
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    stl_reverse_facet(stl, i);
+    stl_calculate_normal(normal, &stl->facet_start[i]);
+    stl_normalize_vector(normal);
+    stl->facet_start[i].normal.x = normal[0];
+    stl->facet_start[i].normal.y = normal[1];
+    stl->facet_start[i].normal.z = normal[2];
+  }
+}
+
diff --git a/xs/src/admesh/shared.c b/xs/src/admesh/shared.c
deleted file mode 100644
index 56164e25f..000000000
--- a/xs/src/admesh/shared.c
+++ /dev/null
@@ -1,262 +0,0 @@
-/*  ADMesh -- process triangulated solid meshes
- *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
- *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
-
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
-
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *  Questions, comments, suggestions, etc to
- *           https://github.com/admesh/admesh/issues
- */
-
-#include <stdlib.h>
-#include <string.h>
-
-#include "stl.h"
-
-void
-stl_invalidate_shared_vertices(stl_file *stl) {
-  if (stl->error) return;
-
-  if (stl->v_indices != NULL) {
-    free(stl->v_indices);
-    stl->v_indices = NULL;
-  }
-  if (stl->v_shared != NULL) {
-    free(stl->v_shared);
-    stl->v_shared = NULL;
-  }
-}
-
-void
-stl_generate_shared_vertices(stl_file *stl) {
-  int i;
-  int j;
-  int first_facet;
-  int direction;
-  int facet_num;
-  int vnot;
-  int next_edge;
-  int pivot_vertex;
-  int next_facet;
-  int reversed;
-
-  if (stl->error) return;
-
-  /* make sure this function is idempotent and does not leak memory */
-  stl_invalidate_shared_vertices(stl);
-
-  stl->v_indices = (v_indices_struct*)
-                   calloc(stl->stats.number_of_facets, sizeof(v_indices_struct));
-  if(stl->v_indices == NULL) perror("stl_generate_shared_vertices");
-  stl->v_shared = (stl_vertex*)
-                  calloc((stl->stats.number_of_facets / 2), sizeof(stl_vertex));
-  if(stl->v_shared == NULL) perror("stl_generate_shared_vertices");
-  stl->stats.shared_malloced = stl->stats.number_of_facets / 2;
-  stl->stats.shared_vertices = 0;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    stl->v_indices[i].vertex[0] = -1;
-    stl->v_indices[i].vertex[1] = -1;
-    stl->v_indices[i].vertex[2] = -1;
-  }
-
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    first_facet = i;
-    for(j = 0; j < 3; j++) {
-      if(stl->v_indices[i].vertex[j] != -1) {
-        continue;
-      }
-      if(stl->stats.shared_vertices == stl->stats.shared_malloced) {
-        stl->stats.shared_malloced += 1024;
-        stl->v_shared = (stl_vertex*)realloc(stl->v_shared,
-                                             stl->stats.shared_malloced * sizeof(stl_vertex));
-        if(stl->v_shared == NULL) perror("stl_generate_shared_vertices");
-      }
-
-      stl->v_shared[stl->stats.shared_vertices] =
-        stl->facet_start[i].vertex[j];
-
-      direction = 0;
-      reversed = 0;
-      facet_num = i;
-      vnot = (j + 2) % 3;
-
-      for(;;) {
-        if(vnot > 2) {
-          if(direction == 0) {
-            pivot_vertex = (vnot + 2) % 3;
-            next_edge = pivot_vertex;
-            direction = 1;
-          } else {
-            pivot_vertex = (vnot + 1) % 3;
-            next_edge = vnot % 3;
-            direction = 0;
-          }
-        } else {
-          if(direction == 0) {
-            pivot_vertex = (vnot + 1) % 3;
-            next_edge = vnot;
-          } else {
-            pivot_vertex = (vnot + 2) % 3;
-            next_edge = pivot_vertex;
-          }
-        }
-        stl->v_indices[facet_num].vertex[pivot_vertex] =
-          stl->stats.shared_vertices;
-
-        next_facet = stl->neighbors_start[facet_num].neighbor[next_edge];
-        if(next_facet == -1) {
-          if(reversed) {
-            break;
-          } else {
-            direction = 1;
-            vnot = (j + 1) % 3;
-            reversed = 1;
-            facet_num = first_facet;
-          }
-        } else if(next_facet != first_facet) {
-          vnot = stl->neighbors_start[facet_num].
-                 which_vertex_not[next_edge];
-          facet_num = next_facet;
-        } else {
-          break;
-        }
-      }
-      stl->stats.shared_vertices += 1;
-    }
-  }
-}
-
-void
-stl_write_off(stl_file *stl, char *file) {
-  int i;
-  FILE      *fp;
-  char      *error_msg;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "w");
-  if(fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  fprintf(fp, "OFF\n");
-  fprintf(fp, "%d %d 0\n",
-          stl->stats.shared_vertices, stl->stats.number_of_facets);
-
-  for(i = 0; i < stl->stats.shared_vertices; i++) {
-    fprintf(fp, "\t%f %f %f\n",
-            stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
-  }
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    fprintf(fp, "\t3 %d %d %d\n", stl->v_indices[i].vertex[0],
-            stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
-  }
-  fclose(fp);
-}
-
-void
-stl_write_vrml(stl_file *stl, char *file) {
-  int i;
-  FILE      *fp;
-  char      *error_msg;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "w");
-  if(fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  fprintf(fp, "#VRML V1.0 ascii\n\n");
-  fprintf(fp, "Separator {\n");
-  fprintf(fp, "\tDEF STLShape ShapeHints {\n");
-  fprintf(fp, "\t\tvertexOrdering COUNTERCLOCKWISE\n");
-  fprintf(fp, "\t\tfaceType CONVEX\n");
-  fprintf(fp, "\t\tshapeType SOLID\n");
-  fprintf(fp, "\t\tcreaseAngle 0.0\n");
-  fprintf(fp, "\t}\n");
-  fprintf(fp, "\tDEF STLModel Separator {\n");
-  fprintf(fp, "\t\tDEF STLColor Material {\n");
-  fprintf(fp, "\t\t\temissiveColor 0.700000 0.700000 0.000000\n");
-  fprintf(fp, "\t\t}\n");
-  fprintf(fp, "\t\tDEF STLVertices Coordinate3 {\n");
-  fprintf(fp, "\t\t\tpoint [\n");
-
-  for(i = 0; i < (stl->stats.shared_vertices - 1); i++) {
-    fprintf(fp, "\t\t\t\t%f %f %f,\n",
-            stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
-  }
-  fprintf(fp, "\t\t\t\t%f %f %f]\n",
-          stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
-  fprintf(fp, "\t\t}\n");
-  fprintf(fp, "\t\tDEF STLTriangles IndexedFaceSet {\n");
-  fprintf(fp, "\t\t\tcoordIndex [\n");
-
-  for(i = 0; i < (stl->stats.number_of_facets - 1); i++) {
-    fprintf(fp, "\t\t\t\t%d, %d, %d, -1,\n", stl->v_indices[i].vertex[0],
-            stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
-  }
-  fprintf(fp, "\t\t\t\t%d, %d, %d, -1]\n", stl->v_indices[i].vertex[0],
-          stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
-  fprintf(fp, "\t\t}\n");
-  fprintf(fp, "\t}\n");
-  fprintf(fp, "}\n");
-  fclose(fp);
-}
-
-void stl_write_obj (stl_file *stl, char *file) {
-  int i;
-  FILE* fp;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "w");
-  if (fp == NULL) {
-    char* error_msg = (char*)malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing", file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  for (i = 0; i < stl->stats.shared_vertices; i++) {
-    fprintf(fp, "v %f %f %f\n", stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
-  }
-  for (i = 0; i < stl->stats.number_of_facets; i++) {
-    fprintf(fp, "f %d %d %d\n", stl->v_indices[i].vertex[0]+1, stl->v_indices[i].vertex[1]+1, stl->v_indices[i].vertex[2]+1);
-  }
-
-  fclose(fp);
-}
diff --git a/xs/src/admesh/shared.cpp b/xs/src/admesh/shared.cpp
new file mode 100644
index 000000000..8080f3574
--- /dev/null
+++ b/xs/src/admesh/shared.cpp
@@ -0,0 +1,264 @@
+/*  ADMesh -- process triangulated solid meshes
+ *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
+ *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Questions, comments, suggestions, etc to
+ *           https://github.com/admesh/admesh/issues
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <boost/nowide/cstdio.hpp>
+
+#include "stl.h"
+
+void
+stl_invalidate_shared_vertices(stl_file *stl) {
+  if (stl->error) return;
+
+  if (stl->v_indices != NULL) {
+    free(stl->v_indices);
+    stl->v_indices = NULL;
+  }
+  if (stl->v_shared != NULL) {
+    free(stl->v_shared);
+    stl->v_shared = NULL;
+  }
+}
+
+void
+stl_generate_shared_vertices(stl_file *stl) {
+  int i;
+  int j;
+  int first_facet;
+  int direction;
+  int facet_num;
+  int vnot;
+  int next_edge;
+  int pivot_vertex;
+  int next_facet;
+  int reversed;
+
+  if (stl->error) return;
+
+  /* make sure this function is idempotent and does not leak memory */
+  stl_invalidate_shared_vertices(stl);
+
+  stl->v_indices = (v_indices_struct*)
+                   calloc(stl->stats.number_of_facets, sizeof(v_indices_struct));
+  if(stl->v_indices == NULL) perror("stl_generate_shared_vertices");
+  stl->v_shared = (stl_vertex*)
+                  calloc((stl->stats.number_of_facets / 2), sizeof(stl_vertex));
+  if(stl->v_shared == NULL) perror("stl_generate_shared_vertices");
+  stl->stats.shared_malloced = stl->stats.number_of_facets / 2;
+  stl->stats.shared_vertices = 0;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    stl->v_indices[i].vertex[0] = -1;
+    stl->v_indices[i].vertex[1] = -1;
+    stl->v_indices[i].vertex[2] = -1;
+  }
+
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    first_facet = i;
+    for(j = 0; j < 3; j++) {
+      if(stl->v_indices[i].vertex[j] != -1) {
+        continue;
+      }
+      if(stl->stats.shared_vertices == stl->stats.shared_malloced) {
+        stl->stats.shared_malloced += 1024;
+        stl->v_shared = (stl_vertex*)realloc(stl->v_shared,
+                                             stl->stats.shared_malloced * sizeof(stl_vertex));
+        if(stl->v_shared == NULL) perror("stl_generate_shared_vertices");
+      }
+
+      stl->v_shared[stl->stats.shared_vertices] =
+        stl->facet_start[i].vertex[j];
+
+      direction = 0;
+      reversed = 0;
+      facet_num = i;
+      vnot = (j + 2) % 3;
+
+      for(;;) {
+        if(vnot > 2) {
+          if(direction == 0) {
+            pivot_vertex = (vnot + 2) % 3;
+            next_edge = pivot_vertex;
+            direction = 1;
+          } else {
+            pivot_vertex = (vnot + 1) % 3;
+            next_edge = vnot % 3;
+            direction = 0;
+          }
+        } else {
+          if(direction == 0) {
+            pivot_vertex = (vnot + 1) % 3;
+            next_edge = vnot;
+          } else {
+            pivot_vertex = (vnot + 2) % 3;
+            next_edge = pivot_vertex;
+          }
+        }
+        stl->v_indices[facet_num].vertex[pivot_vertex] =
+          stl->stats.shared_vertices;
+
+        next_facet = stl->neighbors_start[facet_num].neighbor[next_edge];
+        if(next_facet == -1) {
+          if(reversed) {
+            break;
+          } else {
+            direction = 1;
+            vnot = (j + 1) % 3;
+            reversed = 1;
+            facet_num = first_facet;
+          }
+        } else if(next_facet != first_facet) {
+          vnot = stl->neighbors_start[facet_num].
+                 which_vertex_not[next_edge];
+          facet_num = next_facet;
+        } else {
+          break;
+        }
+      }
+      stl->stats.shared_vertices += 1;
+    }
+  }
+}
+
+void
+stl_write_off(stl_file *stl, char *file) {
+  int i;
+  FILE      *fp;
+  char      *error_msg;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  fp = boost::nowide::fopen(file, "w");
+  if(fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  fprintf(fp, "OFF\n");
+  fprintf(fp, "%d %d 0\n",
+          stl->stats.shared_vertices, stl->stats.number_of_facets);
+
+  for(i = 0; i < stl->stats.shared_vertices; i++) {
+    fprintf(fp, "\t%f %f %f\n",
+            stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
+  }
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    fprintf(fp, "\t3 %d %d %d\n", stl->v_indices[i].vertex[0],
+            stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
+  }
+  fclose(fp);
+}
+
+void
+stl_write_vrml(stl_file *stl, char *file) {
+  int i;
+  FILE      *fp;
+  char      *error_msg;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  fp = boost::nowide::fopen(file, "w");
+  if(fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  fprintf(fp, "#VRML V1.0 ascii\n\n");
+  fprintf(fp, "Separator {\n");
+  fprintf(fp, "\tDEF STLShape ShapeHints {\n");
+  fprintf(fp, "\t\tvertexOrdering COUNTERCLOCKWISE\n");
+  fprintf(fp, "\t\tfaceType CONVEX\n");
+  fprintf(fp, "\t\tshapeType SOLID\n");
+  fprintf(fp, "\t\tcreaseAngle 0.0\n");
+  fprintf(fp, "\t}\n");
+  fprintf(fp, "\tDEF STLModel Separator {\n");
+  fprintf(fp, "\t\tDEF STLColor Material {\n");
+  fprintf(fp, "\t\t\temissiveColor 0.700000 0.700000 0.000000\n");
+  fprintf(fp, "\t\t}\n");
+  fprintf(fp, "\t\tDEF STLVertices Coordinate3 {\n");
+  fprintf(fp, "\t\t\tpoint [\n");
+
+  for(i = 0; i < (stl->stats.shared_vertices - 1); i++) {
+    fprintf(fp, "\t\t\t\t%f %f %f,\n",
+            stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
+  }
+  fprintf(fp, "\t\t\t\t%f %f %f]\n",
+          stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
+  fprintf(fp, "\t\t}\n");
+  fprintf(fp, "\t\tDEF STLTriangles IndexedFaceSet {\n");
+  fprintf(fp, "\t\t\tcoordIndex [\n");
+
+  for(i = 0; i < (stl->stats.number_of_facets - 1); i++) {
+    fprintf(fp, "\t\t\t\t%d, %d, %d, -1,\n", stl->v_indices[i].vertex[0],
+            stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
+  }
+  fprintf(fp, "\t\t\t\t%d, %d, %d, -1]\n", stl->v_indices[i].vertex[0],
+          stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
+  fprintf(fp, "\t\t}\n");
+  fprintf(fp, "\t}\n");
+  fprintf(fp, "}\n");
+  fclose(fp);
+}
+
+void stl_write_obj (stl_file *stl, char *file) {
+  int i;
+  FILE* fp;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  fp = boost::nowide::fopen(file, "w");
+  if (fp == NULL) {
+    char* error_msg = (char*)malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing", file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  for (i = 0; i < stl->stats.shared_vertices; i++) {
+    fprintf(fp, "v %f %f %f\n", stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
+  }
+  for (i = 0; i < stl->stats.number_of_facets; i++) {
+    fprintf(fp, "f %d %d %d\n", stl->v_indices[i].vertex[0]+1, stl->v_indices[i].vertex[1]+1, stl->v_indices[i].vertex[2]+1);
+  }
+
+  fclose(fp);
+}
diff --git a/xs/src/admesh/stl.h b/xs/src/admesh/stl.h
index 139983632..82c860636 100644
--- a/xs/src/admesh/stl.h
+++ b/xs/src/admesh/stl.h
@@ -32,10 +32,6 @@
 #error "admesh works correctly on little endian machines only!"
 #endif
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #define STL_MAX(A,B) ((A)>(B)? (A):(B))
 #define STL_MIN(A,B) ((A)<(B)? (A):(B))
 #define ABS(X)  ((X) < 0 ? -(X) : (X))
@@ -223,8 +219,4 @@ extern void stl_clear_error(stl_file *stl);
 extern int stl_get_error(stl_file *stl);
 extern void stl_exit_on_error(stl_file *stl);
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif
diff --git a/xs/src/admesh/stl_io.c b/xs/src/admesh/stl_io.c
deleted file mode 100644
index 7d8e4eab8..000000000
--- a/xs/src/admesh/stl_io.c
+++ /dev/null
@@ -1,420 +0,0 @@
-/*  ADMesh -- process triangulated solid meshes
- *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
- *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
-
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
-
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *  Questions, comments, suggestions, etc to
- *           https://github.com/admesh/admesh/issues
- */
-
-#include <stdlib.h>
-#include <string.h>
-#include "stl.h"
-#include "config.h"
-
-#if !defined(SEEK_SET)
-#define SEEK_SET 0
-#define SEEK_CUR 1
-#define SEEK_END 2
-#endif
-
-void
-stl_print_edges(stl_file *stl, FILE *file) {
-  int i;
-  int edges_allocated;
-
-  if (stl->error) return;
-
-  edges_allocated = stl->stats.number_of_facets * 3;
-  for(i = 0; i < edges_allocated; i++) {
-    fprintf(file, "%d, %f, %f, %f, %f, %f, %f\n",
-            stl->edge_start[i].facet_number,
-            stl->edge_start[i].p1.x, stl->edge_start[i].p1.y,
-            stl->edge_start[i].p1.z, stl->edge_start[i].p2.x,
-            stl->edge_start[i].p2.y, stl->edge_start[i].p2.z);
-  }
-}
-
-
-void
-stl_stats_out(stl_file *stl, FILE *file, char *input_file) {
-  if (stl->error) return;
-
-  /* this is here for Slic3r, without our config.h
-     it won't use this part of the code anyway */
-#ifndef VERSION
-#define VERSION "unknown"
-#endif
-  fprintf(file, "\n\
-================= Results produced by ADMesh version " VERSION " ================\n");
-  fprintf(file, "\
-Input file         : %s\n", input_file);
-  if(stl->stats.type == binary) {
-    fprintf(file, "\
-File type          : Binary STL file\n");
-  } else {
-    fprintf(file, "\
-File type          : ASCII STL file\n");
-  }
-  fprintf(file, "\
-Header             : %s\n", stl->stats.header);
-  fprintf(file, "============== Size ==============\n");
-  fprintf(file, "Min X = % f, Max X = % f\n",
-          stl->stats.min.x, stl->stats.max.x);
-  fprintf(file, "Min Y = % f, Max Y = % f\n",
-          stl->stats.min.y, stl->stats.max.y);
-  fprintf(file, "Min Z = % f, Max Z = % f\n",
-          stl->stats.min.z, stl->stats.max.z);
-
-  fprintf(file, "\
-========= Facet Status ========== Original ============ Final ====\n");
-  fprintf(file, "\
-Number of facets                 : %5d               %5d\n",
-          stl->stats.original_num_facets, stl->stats.number_of_facets);
-  fprintf(file, "\
-Facets with 1 disconnected edge  : %5d               %5d\n",
-          stl->stats.facets_w_1_bad_edge, stl->stats.connected_facets_2_edge -
-          stl->stats.connected_facets_3_edge);
-  fprintf(file, "\
-Facets with 2 disconnected edges : %5d               %5d\n",
-          stl->stats.facets_w_2_bad_edge, stl->stats.connected_facets_1_edge -
-          stl->stats.connected_facets_2_edge);
-  fprintf(file, "\
-Facets with 3 disconnected edges : %5d               %5d\n",
-          stl->stats.facets_w_3_bad_edge, stl->stats.number_of_facets -
-          stl->stats.connected_facets_1_edge);
-  fprintf(file, "\
-Total disconnected facets        : %5d               %5d\n",
-          stl->stats.facets_w_1_bad_edge + stl->stats.facets_w_2_bad_edge +
-          stl->stats.facets_w_3_bad_edge, stl->stats.number_of_facets -
-          stl->stats.connected_facets_3_edge);
-
-  fprintf(file,
-          "=== Processing Statistics ===     ===== Other Statistics =====\n");
-  fprintf(file, "\
-Number of parts       : %5d        Volume   : % f\n",
-          stl->stats.number_of_parts, stl->stats.volume);
-  fprintf(file, "\
-Degenerate facets     : %5d\n", stl->stats.degenerate_facets);
-  fprintf(file, "\
-Edges fixed           : %5d\n", stl->stats.edges_fixed);
-  fprintf(file, "\
-Facets removed        : %5d\n", stl->stats.facets_removed);
-  fprintf(file, "\
-Facets added          : %5d\n", stl->stats.facets_added);
-  fprintf(file, "\
-Facets reversed       : %5d\n", stl->stats.facets_reversed);
-  fprintf(file, "\
-Backwards edges       : %5d\n", stl->stats.backwards_edges);
-  fprintf(file, "\
-Normals fixed         : %5d\n", stl->stats.normals_fixed);
-}
-
-void
-stl_write_ascii(stl_file *stl, const char *file, const char *label) {
-  int       i;
-  FILE      *fp;
-  char      *error_msg;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "w");
-  if(fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  fprintf(fp, "solid  %s\n", label);
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    fprintf(fp, "  facet normal % .8E % .8E % .8E\n",
-            stl->facet_start[i].normal.x, stl->facet_start[i].normal.y,
-            stl->facet_start[i].normal.z);
-    fprintf(fp, "    outer loop\n");
-    fprintf(fp, "      vertex % .8E % .8E % .8E\n",
-            stl->facet_start[i].vertex[0].x, stl->facet_start[i].vertex[0].y,
-            stl->facet_start[i].vertex[0].z);
-    fprintf(fp, "      vertex % .8E % .8E % .8E\n",
-            stl->facet_start[i].vertex[1].x, stl->facet_start[i].vertex[1].y,
-            stl->facet_start[i].vertex[1].z);
-    fprintf(fp, "      vertex % .8E % .8E % .8E\n",
-            stl->facet_start[i].vertex[2].x, stl->facet_start[i].vertex[2].y,
-            stl->facet_start[i].vertex[2].z);
-    fprintf(fp, "    endloop\n");
-    fprintf(fp, "  endfacet\n");
-  }
-
-  fprintf(fp, "endsolid  %s\n", label);
-
-  fclose(fp);
-}
-
-void
-stl_print_neighbors(stl_file *stl, char *file) {
-  int i;
-  FILE *fp;
-  char *error_msg;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "w");
-  if(fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_print_neighbors: Couldn't open %s for writing",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    fprintf(fp, "%d, %d,%d, %d,%d, %d,%d\n",
-            i,
-            stl->neighbors_start[i].neighbor[0],
-            (int)stl->neighbors_start[i].which_vertex_not[0],
-            stl->neighbors_start[i].neighbor[1],
-            (int)stl->neighbors_start[i].which_vertex_not[1],
-            stl->neighbors_start[i].neighbor[2],
-            (int)stl->neighbors_start[i].which_vertex_not[2]);
-  }
-  fclose(fp);
-}
-
-void
-stl_write_binary(stl_file *stl, const char *file, const char *label) {
-  FILE      *fp;
-  int       i;
-  char      *error_msg;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "wb");
-  if(fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_write_binary: Couldn't open %s for writing",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  fprintf(fp, "%s", label);
-  for(i = strlen(label); i < LABEL_SIZE; i++) putc(0, fp);
-
-  fseek(fp, LABEL_SIZE, SEEK_SET);
-  fwrite(&stl->stats.number_of_facets, 4, 1, fp);
-  for(i = 0; i < stl->stats.number_of_facets; i++)
-    fwrite(stl->facet_start + i, SIZEOF_STL_FACET, 1, fp);
-  fclose(fp);
-}
-
-void
-stl_write_vertex(stl_file *stl, int facet, int vertex) {
-  if (stl->error) return;
-  printf("  vertex %d/%d % .8E % .8E % .8E\n", vertex, facet,
-         stl->facet_start[facet].vertex[vertex].x,
-         stl->facet_start[facet].vertex[vertex].y,
-         stl->facet_start[facet].vertex[vertex].z);
-}
-
-void
-stl_write_facet(stl_file *stl, char *label, int facet) {
-  if (stl->error) return;
-  printf("facet (%d)/ %s\n", facet, label);
-  stl_write_vertex(stl, facet, 0);
-  stl_write_vertex(stl, facet, 1);
-  stl_write_vertex(stl, facet, 2);
-}
-
-void
-stl_write_edge(stl_file *stl, char *label, stl_hash_edge edge) {
-  if (stl->error) return;
-  printf("edge (%d)/(%d) %s\n", edge.facet_number, edge.which_edge, label);
-  if(edge.which_edge < 3) {
-    stl_write_vertex(stl, edge.facet_number, edge.which_edge % 3);
-    stl_write_vertex(stl, edge.facet_number, (edge.which_edge + 1) % 3);
-  } else {
-    stl_write_vertex(stl, edge.facet_number, (edge.which_edge + 1) % 3);
-    stl_write_vertex(stl, edge.facet_number, edge.which_edge % 3);
-  }
-}
-
-void
-stl_write_neighbor(stl_file *stl, int facet) {
-  if (stl->error) return;
-  printf("Neighbors %d: %d, %d, %d ;  %d, %d, %d\n", facet,
-         stl->neighbors_start[facet].neighbor[0],
-         stl->neighbors_start[facet].neighbor[1],
-         stl->neighbors_start[facet].neighbor[2],
-         stl->neighbors_start[facet].which_vertex_not[0],
-         stl->neighbors_start[facet].which_vertex_not[1],
-         stl->neighbors_start[facet].which_vertex_not[2]);
-}
-
-void
-stl_write_quad_object(stl_file *stl, char *file) {
-  FILE      *fp;
-  int       i;
-  int       j;
-  char      *error_msg;
-  stl_vertex connect_color;
-  stl_vertex uncon_1_color;
-  stl_vertex uncon_2_color;
-  stl_vertex uncon_3_color;
-  stl_vertex color;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "w");
-  if(fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_write_quad_object: Couldn't open %s for writing",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  connect_color.x = 0.0;
-  connect_color.y = 0.0;
-  connect_color.z = 1.0;
-  uncon_1_color.x = 0.0;
-  uncon_1_color.y = 1.0;
-  uncon_1_color.z = 0.0;
-  uncon_2_color.x = 1.0;
-  uncon_2_color.y = 1.0;
-  uncon_2_color.z = 1.0;
-  uncon_3_color.x = 1.0;
-  uncon_3_color.y = 0.0;
-  uncon_3_color.z = 0.0;
-
-  fprintf(fp, "CQUAD\n");
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    j = ((stl->neighbors_start[i].neighbor[0] == -1) +
-         (stl->neighbors_start[i].neighbor[1] == -1) +
-         (stl->neighbors_start[i].neighbor[2] == -1));
-    if(j == 0) {
-      color = connect_color;
-    } else if(j == 1) {
-      color = uncon_1_color;
-    } else if(j == 2) {
-      color = uncon_2_color;
-    } else {
-      color = uncon_3_color;
-    }
-    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
-            stl->facet_start[i].vertex[0].x,
-            stl->facet_start[i].vertex[0].y,
-            stl->facet_start[i].vertex[0].z, color.x, color.y, color.z);
-    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
-            stl->facet_start[i].vertex[1].x,
-            stl->facet_start[i].vertex[1].y,
-            stl->facet_start[i].vertex[1].z, color.x, color.y, color.z);
-    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
-            stl->facet_start[i].vertex[2].x,
-            stl->facet_start[i].vertex[2].y,
-            stl->facet_start[i].vertex[2].z, color.x, color.y, color.z);
-    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
-            stl->facet_start[i].vertex[2].x,
-            stl->facet_start[i].vertex[2].y,
-            stl->facet_start[i].vertex[2].z, color.x, color.y, color.z);
-  }
-  fclose(fp);
-}
-
-void
-stl_write_dxf(stl_file *stl, char *file, char *label) {
-  int       i;
-  FILE      *fp;
-  char      *error_msg;
-
-  if (stl->error) return;
-
-  /* Open the file */
-  fp = fopen(file, "w");
-  if(fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-
-  fprintf(fp, "999\n%s\n", label);
-  fprintf(fp, "0\nSECTION\n2\nHEADER\n0\nENDSEC\n");
-  fprintf(fp, "0\nSECTION\n2\nTABLES\n0\nTABLE\n2\nLAYER\n70\n1\n\
-0\nLAYER\n2\n0\n70\n0\n62\n7\n6\nCONTINUOUS\n0\nENDTAB\n0\nENDSEC\n");
-  fprintf(fp, "0\nSECTION\n2\nBLOCKS\n0\nENDSEC\n");
-
-  fprintf(fp, "0\nSECTION\n2\nENTITIES\n");
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    fprintf(fp, "0\n3DFACE\n8\n0\n");
-    fprintf(fp, "10\n%f\n20\n%f\n30\n%f\n",
-            stl->facet_start[i].vertex[0].x, stl->facet_start[i].vertex[0].y,
-            stl->facet_start[i].vertex[0].z);
-    fprintf(fp, "11\n%f\n21\n%f\n31\n%f\n",
-            stl->facet_start[i].vertex[1].x, stl->facet_start[i].vertex[1].y,
-            stl->facet_start[i].vertex[1].z);
-    fprintf(fp, "12\n%f\n22\n%f\n32\n%f\n",
-            stl->facet_start[i].vertex[2].x, stl->facet_start[i].vertex[2].y,
-            stl->facet_start[i].vertex[2].z);
-    fprintf(fp, "13\n%f\n23\n%f\n33\n%f\n",
-            stl->facet_start[i].vertex[2].x, stl->facet_start[i].vertex[2].y,
-            stl->facet_start[i].vertex[2].z);
-  }
-
-  fprintf(fp, "0\nENDSEC\n0\nEOF\n");
-
-  fclose(fp);
-}
-
-void
-stl_clear_error(stl_file *stl) {
-  stl->error = 0;
-}
-
-void
-stl_exit_on_error(stl_file *stl) {
-  if (!stl->error) return;
-  stl->error = 0;
-  stl_close(stl);
-  exit(1);
-}
-
-int
-stl_get_error(stl_file *stl) {
-  return stl->error;
-}
diff --git a/xs/src/admesh/stl_io.cpp b/xs/src/admesh/stl_io.cpp
new file mode 100644
index 000000000..f58d6b4f6
--- /dev/null
+++ b/xs/src/admesh/stl_io.cpp
@@ -0,0 +1,421 @@
+/*  ADMesh -- process triangulated solid meshes
+ *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
+ *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Questions, comments, suggestions, etc to
+ *           https://github.com/admesh/admesh/issues
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "stl.h"
+#include "config.h"
+
+#include <boost/nowide/cstdio.hpp>
+
+#if !defined(SEEK_SET)
+#define SEEK_SET 0
+#define SEEK_CUR 1
+#define SEEK_END 2
+#endif
+
+void
+stl_print_edges(stl_file *stl, FILE *file) {
+  int i;
+  int edges_allocated;
+
+  if (stl->error) return;
+
+  edges_allocated = stl->stats.number_of_facets * 3;
+  for(i = 0; i < edges_allocated; i++) {
+    fprintf(file, "%d, %f, %f, %f, %f, %f, %f\n",
+            stl->edge_start[i].facet_number,
+            stl->edge_start[i].p1.x, stl->edge_start[i].p1.y,
+            stl->edge_start[i].p1.z, stl->edge_start[i].p2.x,
+            stl->edge_start[i].p2.y, stl->edge_start[i].p2.z);
+  }
+}
+
+
+void
+stl_stats_out(stl_file *stl, FILE *file, char *input_file) {
+  if (stl->error) return;
+
+  /* this is here for Slic3r, without our config.h
+     it won't use this part of the code anyway */
+#ifndef VERSION
+#define VERSION "unknown"
+#endif
+  fprintf(file, "\n\
+================= Results produced by ADMesh version " VERSION " ================\n");
+  fprintf(file, "\
+Input file         : %s\n", input_file);
+  if(stl->stats.type == binary) {
+    fprintf(file, "\
+File type          : Binary STL file\n");
+  } else {
+    fprintf(file, "\
+File type          : ASCII STL file\n");
+  }
+  fprintf(file, "\
+Header             : %s\n", stl->stats.header);
+  fprintf(file, "============== Size ==============\n");
+  fprintf(file, "Min X = % f, Max X = % f\n",
+          stl->stats.min.x, stl->stats.max.x);
+  fprintf(file, "Min Y = % f, Max Y = % f\n",
+          stl->stats.min.y, stl->stats.max.y);
+  fprintf(file, "Min Z = % f, Max Z = % f\n",
+          stl->stats.min.z, stl->stats.max.z);
+
+  fprintf(file, "\
+========= Facet Status ========== Original ============ Final ====\n");
+  fprintf(file, "\
+Number of facets                 : %5d               %5d\n",
+          stl->stats.original_num_facets, stl->stats.number_of_facets);
+  fprintf(file, "\
+Facets with 1 disconnected edge  : %5d               %5d\n",
+          stl->stats.facets_w_1_bad_edge, stl->stats.connected_facets_2_edge -
+          stl->stats.connected_facets_3_edge);
+  fprintf(file, "\
+Facets with 2 disconnected edges : %5d               %5d\n",
+          stl->stats.facets_w_2_bad_edge, stl->stats.connected_facets_1_edge -
+          stl->stats.connected_facets_2_edge);
+  fprintf(file, "\
+Facets with 3 disconnected edges : %5d               %5d\n",
+          stl->stats.facets_w_3_bad_edge, stl->stats.number_of_facets -
+          stl->stats.connected_facets_1_edge);
+  fprintf(file, "\
+Total disconnected facets        : %5d               %5d\n",
+          stl->stats.facets_w_1_bad_edge + stl->stats.facets_w_2_bad_edge +
+          stl->stats.facets_w_3_bad_edge, stl->stats.number_of_facets -
+          stl->stats.connected_facets_3_edge);
+
+  fprintf(file,
+          "=== Processing Statistics ===     ===== Other Statistics =====\n");
+  fprintf(file, "\
+Number of parts       : %5d        Volume   : % f\n",
+          stl->stats.number_of_parts, stl->stats.volume);
+  fprintf(file, "\
+Degenerate facets     : %5d\n", stl->stats.degenerate_facets);
+  fprintf(file, "\
+Edges fixed           : %5d\n", stl->stats.edges_fixed);
+  fprintf(file, "\
+Facets removed        : %5d\n", stl->stats.facets_removed);
+  fprintf(file, "\
+Facets added          : %5d\n", stl->stats.facets_added);
+  fprintf(file, "\
+Facets reversed       : %5d\n", stl->stats.facets_reversed);
+  fprintf(file, "\
+Backwards edges       : %5d\n", stl->stats.backwards_edges);
+  fprintf(file, "\
+Normals fixed         : %5d\n", stl->stats.normals_fixed);
+}
+
+void
+stl_write_ascii(stl_file *stl, const char *file, const char *label) {
+  int       i;
+  char      *error_msg;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  FILE *fp = boost::nowide::fopen(file, "w");
+  if(fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  fprintf(fp, "solid  %s\n", label);
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    fprintf(fp, "  facet normal % .8E % .8E % .8E\n",
+            stl->facet_start[i].normal.x, stl->facet_start[i].normal.y,
+            stl->facet_start[i].normal.z);
+    fprintf(fp, "    outer loop\n");
+    fprintf(fp, "      vertex % .8E % .8E % .8E\n",
+            stl->facet_start[i].vertex[0].x, stl->facet_start[i].vertex[0].y,
+            stl->facet_start[i].vertex[0].z);
+    fprintf(fp, "      vertex % .8E % .8E % .8E\n",
+            stl->facet_start[i].vertex[1].x, stl->facet_start[i].vertex[1].y,
+            stl->facet_start[i].vertex[1].z);
+    fprintf(fp, "      vertex % .8E % .8E % .8E\n",
+            stl->facet_start[i].vertex[2].x, stl->facet_start[i].vertex[2].y,
+            stl->facet_start[i].vertex[2].z);
+    fprintf(fp, "    endloop\n");
+    fprintf(fp, "  endfacet\n");
+  }
+
+  fprintf(fp, "endsolid  %s\n", label);
+
+  fclose(fp);
+}
+
+void
+stl_print_neighbors(stl_file *stl, char *file) {
+  int i;
+  FILE *fp;
+  char *error_msg;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  fp = boost::nowide::fopen(file, "w");
+  if(fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_print_neighbors: Couldn't open %s for writing",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    fprintf(fp, "%d, %d,%d, %d,%d, %d,%d\n",
+            i,
+            stl->neighbors_start[i].neighbor[0],
+            (int)stl->neighbors_start[i].which_vertex_not[0],
+            stl->neighbors_start[i].neighbor[1],
+            (int)stl->neighbors_start[i].which_vertex_not[1],
+            stl->neighbors_start[i].neighbor[2],
+            (int)stl->neighbors_start[i].which_vertex_not[2]);
+  }
+  fclose(fp);
+}
+
+void
+stl_write_binary(stl_file *stl, const char *file, const char *label) {
+  FILE      *fp;
+  int       i;
+  char      *error_msg;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  fp = boost::nowide::fopen(file, "wb");
+  if(fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_write_binary: Couldn't open %s for writing",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  fprintf(fp, "%s", label);
+  for(i = strlen(label); i < LABEL_SIZE; i++) putc(0, fp);
+
+  fseek(fp, LABEL_SIZE, SEEK_SET);
+  fwrite(&stl->stats.number_of_facets, 4, 1, fp);
+  for(i = 0; i < stl->stats.number_of_facets; i++)
+    fwrite(stl->facet_start + i, SIZEOF_STL_FACET, 1, fp);
+  fclose(fp);
+}
+
+void
+stl_write_vertex(stl_file *stl, int facet, int vertex) {
+  if (stl->error) return;
+  printf("  vertex %d/%d % .8E % .8E % .8E\n", vertex, facet,
+         stl->facet_start[facet].vertex[vertex].x,
+         stl->facet_start[facet].vertex[vertex].y,
+         stl->facet_start[facet].vertex[vertex].z);
+}
+
+void
+stl_write_facet(stl_file *stl, char *label, int facet) {
+  if (stl->error) return;
+  printf("facet (%d)/ %s\n", facet, label);
+  stl_write_vertex(stl, facet, 0);
+  stl_write_vertex(stl, facet, 1);
+  stl_write_vertex(stl, facet, 2);
+}
+
+void
+stl_write_edge(stl_file *stl, char *label, stl_hash_edge edge) {
+  if (stl->error) return;
+  printf("edge (%d)/(%d) %s\n", edge.facet_number, edge.which_edge, label);
+  if(edge.which_edge < 3) {
+    stl_write_vertex(stl, edge.facet_number, edge.which_edge % 3);
+    stl_write_vertex(stl, edge.facet_number, (edge.which_edge + 1) % 3);
+  } else {
+    stl_write_vertex(stl, edge.facet_number, (edge.which_edge + 1) % 3);
+    stl_write_vertex(stl, edge.facet_number, edge.which_edge % 3);
+  }
+}
+
+void
+stl_write_neighbor(stl_file *stl, int facet) {
+  if (stl->error) return;
+  printf("Neighbors %d: %d, %d, %d ;  %d, %d, %d\n", facet,
+         stl->neighbors_start[facet].neighbor[0],
+         stl->neighbors_start[facet].neighbor[1],
+         stl->neighbors_start[facet].neighbor[2],
+         stl->neighbors_start[facet].which_vertex_not[0],
+         stl->neighbors_start[facet].which_vertex_not[1],
+         stl->neighbors_start[facet].which_vertex_not[2]);
+}
+
+void
+stl_write_quad_object(stl_file *stl, char *file) {
+  FILE      *fp;
+  int       i;
+  int       j;
+  char      *error_msg;
+  stl_vertex connect_color;
+  stl_vertex uncon_1_color;
+  stl_vertex uncon_2_color;
+  stl_vertex uncon_3_color;
+  stl_vertex color;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  fp = boost::nowide::fopen(file, "w");
+  if(fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_write_quad_object: Couldn't open %s for writing",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  connect_color.x = 0.0;
+  connect_color.y = 0.0;
+  connect_color.z = 1.0;
+  uncon_1_color.x = 0.0;
+  uncon_1_color.y = 1.0;
+  uncon_1_color.z = 0.0;
+  uncon_2_color.x = 1.0;
+  uncon_2_color.y = 1.0;
+  uncon_2_color.z = 1.0;
+  uncon_3_color.x = 1.0;
+  uncon_3_color.y = 0.0;
+  uncon_3_color.z = 0.0;
+
+  fprintf(fp, "CQUAD\n");
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    j = ((stl->neighbors_start[i].neighbor[0] == -1) +
+         (stl->neighbors_start[i].neighbor[1] == -1) +
+         (stl->neighbors_start[i].neighbor[2] == -1));
+    if(j == 0) {
+      color = connect_color;
+    } else if(j == 1) {
+      color = uncon_1_color;
+    } else if(j == 2) {
+      color = uncon_2_color;
+    } else {
+      color = uncon_3_color;
+    }
+    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
+            stl->facet_start[i].vertex[0].x,
+            stl->facet_start[i].vertex[0].y,
+            stl->facet_start[i].vertex[0].z, color.x, color.y, color.z);
+    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
+            stl->facet_start[i].vertex[1].x,
+            stl->facet_start[i].vertex[1].y,
+            stl->facet_start[i].vertex[1].z, color.x, color.y, color.z);
+    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
+            stl->facet_start[i].vertex[2].x,
+            stl->facet_start[i].vertex[2].y,
+            stl->facet_start[i].vertex[2].z, color.x, color.y, color.z);
+    fprintf(fp, "%f %f %f    %1.1f %1.1f %1.1f 1\n",
+            stl->facet_start[i].vertex[2].x,
+            stl->facet_start[i].vertex[2].y,
+            stl->facet_start[i].vertex[2].z, color.x, color.y, color.z);
+  }
+  fclose(fp);
+}
+
+void
+stl_write_dxf(stl_file *stl, char *file, char *label) {
+  int       i;
+  FILE      *fp;
+  char      *error_msg;
+
+  if (stl->error) return;
+
+  /* Open the file */
+  fp = boost::nowide::fopen(file, "w");
+  if(fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+
+  fprintf(fp, "999\n%s\n", label);
+  fprintf(fp, "0\nSECTION\n2\nHEADER\n0\nENDSEC\n");
+  fprintf(fp, "0\nSECTION\n2\nTABLES\n0\nTABLE\n2\nLAYER\n70\n1\n\
+0\nLAYER\n2\n0\n70\n0\n62\n7\n6\nCONTINUOUS\n0\nENDTAB\n0\nENDSEC\n");
+  fprintf(fp, "0\nSECTION\n2\nBLOCKS\n0\nENDSEC\n");
+
+  fprintf(fp, "0\nSECTION\n2\nENTITIES\n");
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    fprintf(fp, "0\n3DFACE\n8\n0\n");
+    fprintf(fp, "10\n%f\n20\n%f\n30\n%f\n",
+            stl->facet_start[i].vertex[0].x, stl->facet_start[i].vertex[0].y,
+            stl->facet_start[i].vertex[0].z);
+    fprintf(fp, "11\n%f\n21\n%f\n31\n%f\n",
+            stl->facet_start[i].vertex[1].x, stl->facet_start[i].vertex[1].y,
+            stl->facet_start[i].vertex[1].z);
+    fprintf(fp, "12\n%f\n22\n%f\n32\n%f\n",
+            stl->facet_start[i].vertex[2].x, stl->facet_start[i].vertex[2].y,
+            stl->facet_start[i].vertex[2].z);
+    fprintf(fp, "13\n%f\n23\n%f\n33\n%f\n",
+            stl->facet_start[i].vertex[2].x, stl->facet_start[i].vertex[2].y,
+            stl->facet_start[i].vertex[2].z);
+  }
+
+  fprintf(fp, "0\nENDSEC\n0\nEOF\n");
+
+  fclose(fp);
+}
+
+void
+stl_clear_error(stl_file *stl) {
+  stl->error = 0;
+}
+
+void
+stl_exit_on_error(stl_file *stl) {
+  if (!stl->error) return;
+  stl->error = 0;
+  stl_close(stl);
+  exit(1);
+}
+
+int
+stl_get_error(stl_file *stl) {
+  return stl->error;
+}
diff --git a/xs/src/admesh/stlinit.c b/xs/src/admesh/stlinit.c
deleted file mode 100644
index 13f1f43af..000000000
--- a/xs/src/admesh/stlinit.c
+++ /dev/null
@@ -1,426 +0,0 @@
-/*  ADMesh -- process triangulated solid meshes
- *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
- *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
-
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
-
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *  Questions, comments, suggestions, etc to
- *           https://github.com/admesh/admesh/issues
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <math.h>
-#include <assert.h>
-
-#include "stl.h"
-
-#ifndef SEEK_SET
-#error "SEEK_SET not defined"
-#endif
-
-void
-stl_open(stl_file *stl, const char *file) {
-  stl_initialize(stl);
-  stl_count_facets(stl, file);
-  stl_allocate(stl);
-  stl_read(stl, 0, 1);
-  if (!stl->error) fclose(stl->fp);
-}
-
-
-void
-stl_initialize(stl_file *stl) {
-  memset(stl, 0, sizeof(stl_file));
-  stl->stats.volume = -1.0;
-}
-
-void
-stl_count_facets(stl_file *stl, const char *file) {
-  long           file_size;
-  int            header_num_facets;
-  int            num_facets;
-  int            i;
-  size_t         s;
-  unsigned char  chtest[128];
-  int            num_lines = 1;
-  char           *error_msg;
-
-  if (stl->error) return;
-
-  /* Open the file in binary mode first */
-  stl->fp = fopen(file, "rb");
-  if(stl->fp == NULL) {
-    error_msg = (char*)
-                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-    sprintf(error_msg, "stl_initialize: Couldn't open %s for reading",
-            file);
-    perror(error_msg);
-    free(error_msg);
-    stl->error = 1;
-    return;
-  }
-  /* Find size of file */
-  fseek(stl->fp, 0, SEEK_END);
-  file_size = ftell(stl->fp);
-
-  /* Check for binary or ASCII file */
-  fseek(stl->fp, HEADER_SIZE, SEEK_SET);
-  if (!fread(chtest, sizeof(chtest), 1, stl->fp)) {
-    perror("The input is an empty file");
-    stl->error = 1;
-    return;
-  }
-  stl->stats.type = ascii;
-  for(s = 0; s < sizeof(chtest); s++) {
-    if(chtest[s] > 127) {
-      stl->stats.type = binary;
-      break;
-    }
-  }
-  rewind(stl->fp);
-
-  /* Get the header and the number of facets in the .STL file */
-  /* If the .STL file is binary, then do the following */
-  if(stl->stats.type == binary) {
-    /* Test if the STL file has the right size  */
-    if(((file_size - HEADER_SIZE) % SIZEOF_STL_FACET != 0)
-        || (file_size < STL_MIN_FILE_SIZE)) {
-      fprintf(stderr, "The file %s has the wrong size.\n", file);
-      stl->error = 1;
-      return;
-    }
-    num_facets = (file_size - HEADER_SIZE) / SIZEOF_STL_FACET;
-
-    /* Read the header */
-    if (fread(stl->stats.header, LABEL_SIZE, 1, stl->fp) > 79) {
-      stl->stats.header[80] = '\0';
-    }
-
-    /* Read the int following the header.  This should contain # of facets */
-    if((!fread(&header_num_facets, sizeof(int), 1, stl->fp)) || (num_facets != header_num_facets)) {
-      fprintf(stderr,
-              "Warning: File size doesn't match number of facets in the header\n");
-    }
-  }
-  /* Otherwise, if the .STL file is ASCII, then do the following */
-  else {
-    /* Reopen the file in text mode (for getting correct newlines on Windows) */
-    // fix to silence a warning about unused return value.
-    // obviously if it fails we have problems....
-    stl->fp = freopen(file, "r", stl->fp);
-
-    // do another null check to be safe
-    if(stl->fp == NULL) {
-      error_msg = (char*)
-        malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
-      sprintf(error_msg, "stl_initialize: Couldn't open %s for reading",
-          file);
-      perror(error_msg);
-      free(error_msg);
-      stl->error = 1;
-      return;
-    }
-    
-    /* Find the number of facets */
-    char linebuf[100];
-    while (fgets(linebuf, 100, stl->fp) != NULL) {
-        /* don't count short lines */
-        if (strlen(linebuf) <= 4) continue;
-        
-        /* skip solid/endsolid lines as broken STL file generators may put several of them */
-        if (strncmp(linebuf, "solid", 5) == 0 || strncmp(linebuf, "endsolid", 8) == 0) continue;
-        
-        ++num_lines;
-    }
-    
-    rewind(stl->fp);
-    
-    /* Get the header */
-    for(i = 0;
-        (i < 80) && (stl->stats.header[i] = getc(stl->fp)) != '\n'; i++);
-    stl->stats.header[i] = '\0'; /* Lose the '\n' */
-    stl->stats.header[80] = '\0';
-
-    num_facets = num_lines / ASCII_LINES_PER_FACET;
-  }
-  stl->stats.number_of_facets += num_facets;
-  stl->stats.original_num_facets = stl->stats.number_of_facets;
-}
-
-void
-stl_allocate(stl_file *stl) {
-  if (stl->error) return;
-
-  /*  Allocate memory for the entire .STL file */
-  stl->facet_start = (stl_facet*)calloc(stl->stats.number_of_facets,
-                                        sizeof(stl_facet));
-  if(stl->facet_start == NULL) perror("stl_initialize");
-  stl->stats.facets_malloced = stl->stats.number_of_facets;
-
-  /* Allocate memory for the neighbors list */
-  stl->neighbors_start = (stl_neighbors*)
-                         calloc(stl->stats.number_of_facets, sizeof(stl_neighbors));
-  if(stl->facet_start == NULL) perror("stl_initialize");
-}
-
-void
-stl_open_merge(stl_file *stl, char *file_to_merge) {
-  int num_facets_so_far;
-  stl_type origStlType;
-  FILE *origFp;
-  stl_file stl_to_merge;
-
-  if (stl->error) return;
-
-  /* Record how many facets we have so far from the first file.  We will start putting
-     facets in the next position.  Since we're 0-indexed, it'l be the same position. */
-  num_facets_so_far = stl->stats.number_of_facets;
-
-  /* Record the file type we started with: */
-  origStlType=stl->stats.type;
-  /* Record the file pointer too: */
-  origFp=stl->fp;
-
-  /* Initialize the sturucture with zero stats, header info and sizes: */
-  stl_initialize(&stl_to_merge);
-  stl_count_facets(&stl_to_merge, file_to_merge);
-
-  /* Copy what we need to into stl so that we can read the file_to_merge directly into it
-     using stl_read:  Save the rest of the valuable info: */
-  stl->stats.type=stl_to_merge.stats.type;
-  stl->fp=stl_to_merge.fp;
-
-  /* Add the number of facets we already have in stl with what we we found in stl_to_merge but
-     haven't read yet. */
-  stl->stats.number_of_facets=num_facets_so_far+stl_to_merge.stats.number_of_facets;
-
-  /* Allocate enough room for stl->stats.number_of_facets facets and neighbors: */
-  stl_reallocate(stl);
-
-  /* Read the file to merge directly into stl, adding it to what we have already.
-     Start at num_facets_so_far, the index to the first unused facet.  Also say
-     that this isn't our first time so we should augment stats like min and max
-     instead of erasing them. */
-  stl_read(stl, num_facets_so_far, 0);
-
-  /* Restore the stl information we overwrote (for stl_read) so that it still accurately
-     reflects the subject part: */
-  stl->stats.type=origStlType;
-  stl->fp=origFp;
-}
-
-extern void
-stl_reallocate(stl_file *stl) {
-  if (stl->error) return;
-  /*  Reallocate more memory for the .STL file(s) */
-  stl->facet_start = (stl_facet*)realloc(stl->facet_start, stl->stats.number_of_facets *
-                                         sizeof(stl_facet));
-  if(stl->facet_start == NULL) perror("stl_initialize");
-  stl->stats.facets_malloced = stl->stats.number_of_facets;
-
-  /* Reallocate more memory for the neighbors list */
-  stl->neighbors_start = (stl_neighbors*)
-                         realloc(stl->neighbors_start, stl->stats.number_of_facets *
-                                 sizeof(stl_neighbors));
-  if(stl->facet_start == NULL) perror("stl_initialize");
-}
-
-
-/* Reads the contents of the file pointed to by stl->fp into the stl structure,
-   starting at facet first_facet.  The second argument says if it's our first
-   time running this for the stl and therefore we should reset our max and min stats. */
-void
-stl_read(stl_file *stl, int first_facet, int first) {
-  stl_facet facet;
-  int   i;
-
-  if (stl->error) return;
-
-  if(stl->stats.type == binary) {
-    fseek(stl->fp, HEADER_SIZE, SEEK_SET);
-  } else {
-    rewind(stl->fp);
-  }
-
-  char normal_buf[3][32];
-  for(i = first_facet; i < stl->stats.number_of_facets; i++) {
-    if(stl->stats.type == binary)
-      /* Read a single facet from a binary .STL file */
-    {
-      /* we assume little-endian architecture! */
-      if (fread(&facet, 1, SIZEOF_STL_FACET, stl->fp) != SIZEOF_STL_FACET) {
-        stl->error = 1;
-        return;
-      }
-    } else
-      /* Read a single facet from an ASCII .STL file */
-    {
-      // skip solid/endsolid
-      // (in this order, otherwise it won't work when they are paired in the middle of a file)
-      fscanf(stl->fp, "endsolid\n");
-      fscanf(stl->fp, "solid%*[^\n]\n");  // name might contain spaces so %*s doesn't work and it also can be empty (just "solid")
-      // Leading space in the fscanf format skips all leading white spaces including numerous new lines and tabs.
-      int res_normal     = fscanf(stl->fp, " facet normal %31s %31s %31s", normal_buf[0], normal_buf[1], normal_buf[2]);
-      assert(res_normal == 3);
-      int res_outer_loop = fscanf(stl->fp, " outer loop");
-      assert(res_outer_loop == 0);
-      int res_vertex1    = fscanf(stl->fp, " vertex %f %f %f", &facet.vertex[0].x, &facet.vertex[0].y, &facet.vertex[0].z);
-      assert(res_vertex1 == 3);
-      int res_vertex2    = fscanf(stl->fp, " vertex %f %f %f", &facet.vertex[1].x, &facet.vertex[1].y, &facet.vertex[1].z);
-      assert(res_vertex2 == 3);
-      int res_vertex3    = fscanf(stl->fp, " vertex %f %f %f", &facet.vertex[2].x, &facet.vertex[2].y, &facet.vertex[2].z);
-      assert(res_vertex3 == 3);
-      int res_endloop    = fscanf(stl->fp, " endloop");
-      assert(res_endloop == 0);
-      // There is a leading and trailing white space around endfacet to eat up all leading and trailing white spaces including numerous tabs and new lines.
-      int res_endfacet   = fscanf(stl->fp, " endfacet ");
-      if (res_normal != 3 || res_outer_loop != 0 || res_vertex1 != 3 || res_vertex2 != 3 || res_vertex3 != 3 || res_endloop != 0 || res_endfacet != 0) {
-        perror("Something is syntactically very wrong with this ASCII STL!");
-        stl->error = 1;
-        return;
-      }
-
-      // The facet normal has been parsed as a single string as to workaround for not a numbers in the normal definition.
-	  if (sscanf(normal_buf[0], "%f", &facet.normal.x) != 1 ||
-		  sscanf(normal_buf[1], "%f", &facet.normal.y) != 1 ||
-		  sscanf(normal_buf[2], "%f", &facet.normal.z) != 1) {
-		  // Normal was mangled. Maybe denormals or "not a number" were stored?
-		  // Just reset the normal and silently ignore it.
-		  memset(&facet.normal, 0, sizeof(facet.normal));
-	  }
-    }
-
-#if 0
-      // Report close to zero vertex coordinates. Due to the nature of the floating point numbers,
-      // close to zero values may be represented with singificantly higher precision than the rest of the vertices.
-      // It may be worth to round these numbers to zero during loading to reduce the number of errors reported
-      // during the STL import.
-      for (size_t j = 0; j < 3; ++ j) {
-        if (facet.vertex[j].x > -1e-12f && facet.vertex[j].x < 1e-12f)
-            printf("stl_read: facet %d.x = %e\r\n", j, facet.vertex[j].x);
-        if (facet.vertex[j].y > -1e-12f && facet.vertex[j].y < 1e-12f)
-            printf("stl_read: facet %d.y = %e\r\n", j, facet.vertex[j].y);
-        if (facet.vertex[j].z > -1e-12f && facet.vertex[j].z < 1e-12f)
-            printf("stl_read: facet %d.z = %e\r\n", j, facet.vertex[j].z);
-      }
-#endif
-
-#if 1
-    {
-      // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
-      // When using a memcmp on raw floats, those numbers report to be different.
-      // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
-      uint32_t *f = (uint32_t*)&facet;
-      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
-        if (*f == 0x80000000)
-          // Negative zero, switch to positive zero.
-          *f = 0;
-    }
-#else
-    {
-      // Due to the nature of the floating point numbers, close to zero values may be represented with singificantly higher precision 
-      // than the rest of the vertices. Round them to zero.
-      float *f = (float*)&facet;
-      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
-        if (*f > -1e-12f && *f < 1e-12f)
-          // Negative zero, switch to positive zero.
-          *f = 0;
-    }
-#endif
-    /* Write the facet into memory. */
-    memcpy(stl->facet_start+i, &facet, SIZEOF_STL_FACET);
-    stl_facet_stats(stl, facet, first);
-    first = 0;
-  }
-  stl->stats.size.x = stl->stats.max.x - stl->stats.min.x;
-  stl->stats.size.y = stl->stats.max.y - stl->stats.min.y;
-  stl->stats.size.z = stl->stats.max.z - stl->stats.min.z;
-  stl->stats.bounding_diameter = sqrt(
-                                   stl->stats.size.x * stl->stats.size.x +
-                                   stl->stats.size.y * stl->stats.size.y +
-                                   stl->stats.size.z * stl->stats.size.z
-                                 );
-}
-
-void
-stl_facet_stats(stl_file *stl, stl_facet facet, int first) {
-  float diff_x;
-  float diff_y;
-  float diff_z;
-  float max_diff;
-
-  if (stl->error) return;
-
-  /* while we are going through all of the facets, let's find the  */
-  /* maximum and minimum values for x, y, and z  */
-
-  /* Initialize the max and min values the first time through*/
-  if (first) {
-    stl->stats.max.x = facet.vertex[0].x;
-    stl->stats.min.x = facet.vertex[0].x;
-    stl->stats.max.y = facet.vertex[0].y;
-    stl->stats.min.y = facet.vertex[0].y;
-    stl->stats.max.z = facet.vertex[0].z;
-    stl->stats.min.z = facet.vertex[0].z;
-
-    diff_x = ABS(facet.vertex[0].x - facet.vertex[1].x);
-    diff_y = ABS(facet.vertex[0].y - facet.vertex[1].y);
-    diff_z = ABS(facet.vertex[0].z - facet.vertex[1].z);
-    max_diff = STL_MAX(diff_x, diff_y);
-    max_diff = STL_MAX(diff_z, max_diff);
-    stl->stats.shortest_edge = max_diff;
-
-    first = 0;
-  }
-
-  /* now find the max and min values */
-  stl->stats.max.x = STL_MAX(stl->stats.max.x, facet.vertex[0].x);
-  stl->stats.min.x = STL_MIN(stl->stats.min.x, facet.vertex[0].x);
-  stl->stats.max.y = STL_MAX(stl->stats.max.y, facet.vertex[0].y);
-  stl->stats.min.y = STL_MIN(stl->stats.min.y, facet.vertex[0].y);
-  stl->stats.max.z = STL_MAX(stl->stats.max.z, facet.vertex[0].z);
-  stl->stats.min.z = STL_MIN(stl->stats.min.z, facet.vertex[0].z);
-
-  stl->stats.max.x = STL_MAX(stl->stats.max.x, facet.vertex[1].x);
-  stl->stats.min.x = STL_MIN(stl->stats.min.x, facet.vertex[1].x);
-  stl->stats.max.y = STL_MAX(stl->stats.max.y, facet.vertex[1].y);
-  stl->stats.min.y = STL_MIN(stl->stats.min.y, facet.vertex[1].y);
-  stl->stats.max.z = STL_MAX(stl->stats.max.z, facet.vertex[1].z);
-  stl->stats.min.z = STL_MIN(stl->stats.min.z, facet.vertex[1].z);
-
-  stl->stats.max.x = STL_MAX(stl->stats.max.x, facet.vertex[2].x);
-  stl->stats.min.x = STL_MIN(stl->stats.min.x, facet.vertex[2].x);
-  stl->stats.max.y = STL_MAX(stl->stats.max.y, facet.vertex[2].y);
-  stl->stats.min.y = STL_MIN(stl->stats.min.y, facet.vertex[2].y);
-  stl->stats.max.z = STL_MAX(stl->stats.max.z, facet.vertex[2].z);
-  stl->stats.min.z = STL_MIN(stl->stats.min.z, facet.vertex[2].z);
-}
-
-void
-stl_close(stl_file *stl) {
-  if (stl->error) return;
-
-  if(stl->neighbors_start != NULL)
-    free(stl->neighbors_start);
-  if(stl->facet_start != NULL)
-    free(stl->facet_start);
-  if(stl->v_indices != NULL)
-    free(stl->v_indices);
-  if(stl->v_shared != NULL)
-    free(stl->v_shared);
-}
-
diff --git a/xs/src/admesh/stlinit.cpp b/xs/src/admesh/stlinit.cpp
new file mode 100644
index 000000000..f5110d394
--- /dev/null
+++ b/xs/src/admesh/stlinit.cpp
@@ -0,0 +1,428 @@
+/*  ADMesh -- process triangulated solid meshes
+ *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
+ *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Questions, comments, suggestions, etc to
+ *           https://github.com/admesh/admesh/issues
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <assert.h>
+
+#include <boost/nowide/cstdio.hpp>
+
+#include "stl.h"
+
+#ifndef SEEK_SET
+#error "SEEK_SET not defined"
+#endif
+
+void
+stl_open(stl_file *stl, const char *file) {
+  stl_initialize(stl);
+  stl_count_facets(stl, file);
+  stl_allocate(stl);
+  stl_read(stl, 0, 1);
+  if (!stl->error) fclose(stl->fp);
+}
+
+
+void
+stl_initialize(stl_file *stl) {
+  memset(stl, 0, sizeof(stl_file));
+  stl->stats.volume = -1.0;
+}
+
+void
+stl_count_facets(stl_file *stl, const char *file) {
+  long           file_size;
+  int            header_num_facets;
+  int            num_facets;
+  int            i;
+  size_t         s;
+  unsigned char  chtest[128];
+  int            num_lines = 1;
+  char           *error_msg;
+
+  if (stl->error) return;
+
+  /* Open the file in binary mode first */
+  stl->fp = boost::nowide::fopen(file, "rb");
+  if(stl->fp == NULL) {
+    error_msg = (char*)
+                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+    sprintf(error_msg, "stl_initialize: Couldn't open %s for reading",
+            file);
+    perror(error_msg);
+    free(error_msg);
+    stl->error = 1;
+    return;
+  }
+  /* Find size of file */
+  fseek(stl->fp, 0, SEEK_END);
+  file_size = ftell(stl->fp);
+
+  /* Check for binary or ASCII file */
+  fseek(stl->fp, HEADER_SIZE, SEEK_SET);
+  if (!fread(chtest, sizeof(chtest), 1, stl->fp)) {
+    perror("The input is an empty file");
+    stl->error = 1;
+    return;
+  }
+  stl->stats.type = ascii;
+  for(s = 0; s < sizeof(chtest); s++) {
+    if(chtest[s] > 127) {
+      stl->stats.type = binary;
+      break;
+    }
+  }
+  rewind(stl->fp);
+
+  /* Get the header and the number of facets in the .STL file */
+  /* If the .STL file is binary, then do the following */
+  if(stl->stats.type == binary) {
+    /* Test if the STL file has the right size  */
+    if(((file_size - HEADER_SIZE) % SIZEOF_STL_FACET != 0)
+        || (file_size < STL_MIN_FILE_SIZE)) {
+      fprintf(stderr, "The file %s has the wrong size.\n", file);
+      stl->error = 1;
+      return;
+    }
+    num_facets = (file_size - HEADER_SIZE) / SIZEOF_STL_FACET;
+
+    /* Read the header */
+    if (fread(stl->stats.header, LABEL_SIZE, 1, stl->fp) > 79) {
+      stl->stats.header[80] = '\0';
+    }
+
+    /* Read the int following the header.  This should contain # of facets */
+    if((!fread(&header_num_facets, sizeof(int), 1, stl->fp)) || (num_facets != header_num_facets)) {
+      fprintf(stderr,
+              "Warning: File size doesn't match number of facets in the header\n");
+    }
+  }
+  /* Otherwise, if the .STL file is ASCII, then do the following */
+  else {
+    /* Reopen the file in text mode (for getting correct newlines on Windows) */
+    // fix to silence a warning about unused return value.
+    // obviously if it fails we have problems....
+    stl->fp = boost::nowide::freopen(file, "r", stl->fp);
+
+    // do another null check to be safe
+    if(stl->fp == NULL) {
+      error_msg = (char*)
+        malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
+      sprintf(error_msg, "stl_initialize: Couldn't open %s for reading",
+          file);
+      perror(error_msg);
+      free(error_msg);
+      stl->error = 1;
+      return;
+    }
+    
+    /* Find the number of facets */
+    char linebuf[100];
+    while (fgets(linebuf, 100, stl->fp) != NULL) {
+        /* don't count short lines */
+        if (strlen(linebuf) <= 4) continue;
+        
+        /* skip solid/endsolid lines as broken STL file generators may put several of them */
+        if (strncmp(linebuf, "solid", 5) == 0 || strncmp(linebuf, "endsolid", 8) == 0) continue;
+        
+        ++num_lines;
+    }
+    
+    rewind(stl->fp);
+    
+    /* Get the header */
+    for(i = 0;
+        (i < 80) && (stl->stats.header[i] = getc(stl->fp)) != '\n'; i++);
+    stl->stats.header[i] = '\0'; /* Lose the '\n' */
+    stl->stats.header[80] = '\0';
+
+    num_facets = num_lines / ASCII_LINES_PER_FACET;
+  }
+  stl->stats.number_of_facets += num_facets;
+  stl->stats.original_num_facets = stl->stats.number_of_facets;
+}
+
+void
+stl_allocate(stl_file *stl) {
+  if (stl->error) return;
+
+  /*  Allocate memory for the entire .STL file */
+  stl->facet_start = (stl_facet*)calloc(stl->stats.number_of_facets,
+                                        sizeof(stl_facet));
+  if(stl->facet_start == NULL) perror("stl_initialize");
+  stl->stats.facets_malloced = stl->stats.number_of_facets;
+
+  /* Allocate memory for the neighbors list */
+  stl->neighbors_start = (stl_neighbors*)
+                         calloc(stl->stats.number_of_facets, sizeof(stl_neighbors));
+  if(stl->facet_start == NULL) perror("stl_initialize");
+}
+
+void
+stl_open_merge(stl_file *stl, char *file_to_merge) {
+  int num_facets_so_far;
+  stl_type origStlType;
+  FILE *origFp;
+  stl_file stl_to_merge;
+
+  if (stl->error) return;
+
+  /* Record how many facets we have so far from the first file.  We will start putting
+     facets in the next position.  Since we're 0-indexed, it'l be the same position. */
+  num_facets_so_far = stl->stats.number_of_facets;
+
+  /* Record the file type we started with: */
+  origStlType=stl->stats.type;
+  /* Record the file pointer too: */
+  origFp=stl->fp;
+
+  /* Initialize the sturucture with zero stats, header info and sizes: */
+  stl_initialize(&stl_to_merge);
+  stl_count_facets(&stl_to_merge, file_to_merge);
+
+  /* Copy what we need to into stl so that we can read the file_to_merge directly into it
+     using stl_read:  Save the rest of the valuable info: */
+  stl->stats.type=stl_to_merge.stats.type;
+  stl->fp=stl_to_merge.fp;
+
+  /* Add the number of facets we already have in stl with what we we found in stl_to_merge but
+     haven't read yet. */
+  stl->stats.number_of_facets=num_facets_so_far+stl_to_merge.stats.number_of_facets;
+
+  /* Allocate enough room for stl->stats.number_of_facets facets and neighbors: */
+  stl_reallocate(stl);
+
+  /* Read the file to merge directly into stl, adding it to what we have already.
+     Start at num_facets_so_far, the index to the first unused facet.  Also say
+     that this isn't our first time so we should augment stats like min and max
+     instead of erasing them. */
+  stl_read(stl, num_facets_so_far, 0);
+
+  /* Restore the stl information we overwrote (for stl_read) so that it still accurately
+     reflects the subject part: */
+  stl->stats.type=origStlType;
+  stl->fp=origFp;
+}
+
+extern void
+stl_reallocate(stl_file *stl) {
+  if (stl->error) return;
+  /*  Reallocate more memory for the .STL file(s) */
+  stl->facet_start = (stl_facet*)realloc(stl->facet_start, stl->stats.number_of_facets *
+                                         sizeof(stl_facet));
+  if(stl->facet_start == NULL) perror("stl_initialize");
+  stl->stats.facets_malloced = stl->stats.number_of_facets;
+
+  /* Reallocate more memory for the neighbors list */
+  stl->neighbors_start = (stl_neighbors*)
+                         realloc(stl->neighbors_start, stl->stats.number_of_facets *
+                                 sizeof(stl_neighbors));
+  if(stl->facet_start == NULL) perror("stl_initialize");
+}
+
+
+/* Reads the contents of the file pointed to by stl->fp into the stl structure,
+   starting at facet first_facet.  The second argument says if it's our first
+   time running this for the stl and therefore we should reset our max and min stats. */
+void
+stl_read(stl_file *stl, int first_facet, int first) {
+  stl_facet facet;
+  int   i;
+
+  if (stl->error) return;
+
+  if(stl->stats.type == binary) {
+    fseek(stl->fp, HEADER_SIZE, SEEK_SET);
+  } else {
+    rewind(stl->fp);
+  }
+
+  char normal_buf[3][32];
+  for(i = first_facet; i < stl->stats.number_of_facets; i++) {
+    if(stl->stats.type == binary)
+      /* Read a single facet from a binary .STL file */
+    {
+      /* we assume little-endian architecture! */
+      if (fread(&facet, 1, SIZEOF_STL_FACET, stl->fp) != SIZEOF_STL_FACET) {
+        stl->error = 1;
+        return;
+      }
+    } else
+      /* Read a single facet from an ASCII .STL file */
+    {
+      // skip solid/endsolid
+      // (in this order, otherwise it won't work when they are paired in the middle of a file)
+      fscanf(stl->fp, "endsolid\n");
+      fscanf(stl->fp, "solid%*[^\n]\n");  // name might contain spaces so %*s doesn't work and it also can be empty (just "solid")
+      // Leading space in the fscanf format skips all leading white spaces including numerous new lines and tabs.
+      int res_normal     = fscanf(stl->fp, " facet normal %31s %31s %31s", normal_buf[0], normal_buf[1], normal_buf[2]);
+      assert(res_normal == 3);
+      int res_outer_loop = fscanf(stl->fp, " outer loop");
+      assert(res_outer_loop == 0);
+      int res_vertex1    = fscanf(stl->fp, " vertex %f %f %f", &facet.vertex[0].x, &facet.vertex[0].y, &facet.vertex[0].z);
+      assert(res_vertex1 == 3);
+      int res_vertex2    = fscanf(stl->fp, " vertex %f %f %f", &facet.vertex[1].x, &facet.vertex[1].y, &facet.vertex[1].z);
+      assert(res_vertex2 == 3);
+      int res_vertex3    = fscanf(stl->fp, " vertex %f %f %f", &facet.vertex[2].x, &facet.vertex[2].y, &facet.vertex[2].z);
+      assert(res_vertex3 == 3);
+      int res_endloop    = fscanf(stl->fp, " endloop");
+      assert(res_endloop == 0);
+      // There is a leading and trailing white space around endfacet to eat up all leading and trailing white spaces including numerous tabs and new lines.
+      int res_endfacet   = fscanf(stl->fp, " endfacet ");
+      if (res_normal != 3 || res_outer_loop != 0 || res_vertex1 != 3 || res_vertex2 != 3 || res_vertex3 != 3 || res_endloop != 0 || res_endfacet != 0) {
+        perror("Something is syntactically very wrong with this ASCII STL!");
+        stl->error = 1;
+        return;
+      }
+
+      // The facet normal has been parsed as a single string as to workaround for not a numbers in the normal definition.
+	  if (sscanf(normal_buf[0], "%f", &facet.normal.x) != 1 ||
+		  sscanf(normal_buf[1], "%f", &facet.normal.y) != 1 ||
+		  sscanf(normal_buf[2], "%f", &facet.normal.z) != 1) {
+		  // Normal was mangled. Maybe denormals or "not a number" were stored?
+		  // Just reset the normal and silently ignore it.
+		  memset(&facet.normal, 0, sizeof(facet.normal));
+	  }
+    }
+
+#if 0
+      // Report close to zero vertex coordinates. Due to the nature of the floating point numbers,
+      // close to zero values may be represented with singificantly higher precision than the rest of the vertices.
+      // It may be worth to round these numbers to zero during loading to reduce the number of errors reported
+      // during the STL import.
+      for (size_t j = 0; j < 3; ++ j) {
+        if (facet.vertex[j].x > -1e-12f && facet.vertex[j].x < 1e-12f)
+            printf("stl_read: facet %d.x = %e\r\n", j, facet.vertex[j].x);
+        if (facet.vertex[j].y > -1e-12f && facet.vertex[j].y < 1e-12f)
+            printf("stl_read: facet %d.y = %e\r\n", j, facet.vertex[j].y);
+        if (facet.vertex[j].z > -1e-12f && facet.vertex[j].z < 1e-12f)
+            printf("stl_read: facet %d.z = %e\r\n", j, facet.vertex[j].z);
+      }
+#endif
+
+#if 1
+    {
+      // Positive and negative zeros are possible in the floats, which are considered equal by the FP unit.
+      // When using a memcmp on raw floats, those numbers report to be different.
+      // Unify all +0 and -0 to +0 to make the floats equal under memcmp.
+      uint32_t *f = (uint32_t*)&facet;
+      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
+        if (*f == 0x80000000)
+          // Negative zero, switch to positive zero.
+          *f = 0;
+    }
+#else
+    {
+      // Due to the nature of the floating point numbers, close to zero values may be represented with singificantly higher precision 
+      // than the rest of the vertices. Round them to zero.
+      float *f = (float*)&facet;
+      for (int j = 0; j < 12; ++ j, ++ f) // 3x vertex + normal: 4x3 = 12 floats
+        if (*f > -1e-12f && *f < 1e-12f)
+          // Negative zero, switch to positive zero.
+          *f = 0;
+    }
+#endif
+    /* Write the facet into memory. */
+    memcpy(stl->facet_start+i, &facet, SIZEOF_STL_FACET);
+    stl_facet_stats(stl, facet, first);
+    first = 0;
+  }
+  stl->stats.size.x = stl->stats.max.x - stl->stats.min.x;
+  stl->stats.size.y = stl->stats.max.y - stl->stats.min.y;
+  stl->stats.size.z = stl->stats.max.z - stl->stats.min.z;
+  stl->stats.bounding_diameter = sqrt(
+                                   stl->stats.size.x * stl->stats.size.x +
+                                   stl->stats.size.y * stl->stats.size.y +
+                                   stl->stats.size.z * stl->stats.size.z
+                                 );
+}
+
+void
+stl_facet_stats(stl_file *stl, stl_facet facet, int first) {
+  float diff_x;
+  float diff_y;
+  float diff_z;
+  float max_diff;
+
+  if (stl->error) return;
+
+  /* while we are going through all of the facets, let's find the  */
+  /* maximum and minimum values for x, y, and z  */
+
+  /* Initialize the max and min values the first time through*/
+  if (first) {
+    stl->stats.max.x = facet.vertex[0].x;
+    stl->stats.min.x = facet.vertex[0].x;
+    stl->stats.max.y = facet.vertex[0].y;
+    stl->stats.min.y = facet.vertex[0].y;
+    stl->stats.max.z = facet.vertex[0].z;
+    stl->stats.min.z = facet.vertex[0].z;
+
+    diff_x = ABS(facet.vertex[0].x - facet.vertex[1].x);
+    diff_y = ABS(facet.vertex[0].y - facet.vertex[1].y);
+    diff_z = ABS(facet.vertex[0].z - facet.vertex[1].z);
+    max_diff = STL_MAX(diff_x, diff_y);
+    max_diff = STL_MAX(diff_z, max_diff);
+    stl->stats.shortest_edge = max_diff;
+
+    first = 0;
+  }
+
+  /* now find the max and min values */
+  stl->stats.max.x = STL_MAX(stl->stats.max.x, facet.vertex[0].x);
+  stl->stats.min.x = STL_MIN(stl->stats.min.x, facet.vertex[0].x);
+  stl->stats.max.y = STL_MAX(stl->stats.max.y, facet.vertex[0].y);
+  stl->stats.min.y = STL_MIN(stl->stats.min.y, facet.vertex[0].y);
+  stl->stats.max.z = STL_MAX(stl->stats.max.z, facet.vertex[0].z);
+  stl->stats.min.z = STL_MIN(stl->stats.min.z, facet.vertex[0].z);
+
+  stl->stats.max.x = STL_MAX(stl->stats.max.x, facet.vertex[1].x);
+  stl->stats.min.x = STL_MIN(stl->stats.min.x, facet.vertex[1].x);
+  stl->stats.max.y = STL_MAX(stl->stats.max.y, facet.vertex[1].y);
+  stl->stats.min.y = STL_MIN(stl->stats.min.y, facet.vertex[1].y);
+  stl->stats.max.z = STL_MAX(stl->stats.max.z, facet.vertex[1].z);
+  stl->stats.min.z = STL_MIN(stl->stats.min.z, facet.vertex[1].z);
+
+  stl->stats.max.x = STL_MAX(stl->stats.max.x, facet.vertex[2].x);
+  stl->stats.min.x = STL_MIN(stl->stats.min.x, facet.vertex[2].x);
+  stl->stats.max.y = STL_MAX(stl->stats.max.y, facet.vertex[2].y);
+  stl->stats.min.y = STL_MIN(stl->stats.min.y, facet.vertex[2].y);
+  stl->stats.max.z = STL_MAX(stl->stats.max.z, facet.vertex[2].z);
+  stl->stats.min.z = STL_MIN(stl->stats.min.z, facet.vertex[2].z);
+}
+
+void
+stl_close(stl_file *stl) {
+  if (stl->error) return;
+
+  if(stl->neighbors_start != NULL)
+    free(stl->neighbors_start);
+  if(stl->facet_start != NULL)
+    free(stl->facet_start);
+  if(stl->v_indices != NULL)
+    free(stl->v_indices);
+  if(stl->v_shared != NULL)
+    free(stl->v_shared);
+}
+
diff --git a/xs/src/admesh/util.c b/xs/src/admesh/util.c
deleted file mode 100644
index cabb8a778..000000000
--- a/xs/src/admesh/util.c
+++ /dev/null
@@ -1,573 +0,0 @@
-/*  ADMesh -- process triangulated solid meshes
- *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
- *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
-
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
-
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *  Questions, comments, suggestions, etc to
- *           https://github.com/admesh/admesh/issues
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <math.h>
-
-#include "stl.h"
-
-static void stl_rotate(float *x, float *y, const double c, const double s);
-static float get_area(stl_facet *facet);
-static float get_volume(stl_file *stl);
-
-
-void
-stl_verify_neighbors(stl_file *stl) {
-  int i;
-  int j;
-  stl_edge edge_a;
-  stl_edge edge_b;
-  int neighbor;
-  int vnot;
-
-  if (stl->error) return;
-
-  stl->stats.backwards_edges = 0;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      edge_a.p1 = stl->facet_start[i].vertex[j];
-      edge_a.p2 = stl->facet_start[i].vertex[(j + 1) % 3];
-      neighbor = stl->neighbors_start[i].neighbor[j];
-      vnot = stl->neighbors_start[i].which_vertex_not[j];
-
-      if(neighbor == -1)
-        continue;		/* this edge has no neighbor... Continue. */
-      if(vnot < 3) {
-        edge_b.p1 = stl->facet_start[neighbor].vertex[(vnot + 2) % 3];
-        edge_b.p2 = stl->facet_start[neighbor].vertex[(vnot + 1) % 3];
-      } else {
-        stl->stats.backwards_edges += 1;
-        edge_b.p1 = stl->facet_start[neighbor].vertex[(vnot + 1) % 3];
-        edge_b.p2 = stl->facet_start[neighbor].vertex[(vnot + 2) % 3];
-      }
-      if(memcmp(&edge_a, &edge_b, SIZEOF_EDGE_SORT) != 0) {
-        /* These edges should match but they don't.  Print results. */
-        printf("edge %d of facet %d doesn't match edge %d of facet %d\n",
-               j, i, vnot + 1, neighbor);
-        stl_write_facet(stl, (char*)"first facet", i);
-        stl_write_facet(stl, (char*)"second facet", neighbor);
-      }
-    }
-  }
-}
-
-void
-stl_translate(stl_file *stl, float x, float y, float z) {
-  int i;
-  int j;
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl->facet_start[i].vertex[j].x -= (stl->stats.min.x - x);
-      stl->facet_start[i].vertex[j].y -= (stl->stats.min.y - y);
-      stl->facet_start[i].vertex[j].z -= (stl->stats.min.z - z);
-    }
-  }
-  stl->stats.max.x -= (stl->stats.min.x - x);
-  stl->stats.max.y -= (stl->stats.min.y - y);
-  stl->stats.max.z -= (stl->stats.min.z - z);
-  stl->stats.min.x = x;
-  stl->stats.min.y = y;
-  stl->stats.min.z = z;
-
-  stl_invalidate_shared_vertices(stl);
-}
-
-/* Translates the stl by x,y,z, relatively from wherever it is currently */
-void
-stl_translate_relative(stl_file *stl, float x, float y, float z) {
-  int i;
-  int j;
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl->facet_start[i].vertex[j].x += x;
-      stl->facet_start[i].vertex[j].y += y;
-      stl->facet_start[i].vertex[j].z += z;
-    }
-  }
-  stl->stats.min.x += x;
-  stl->stats.min.y += y;
-  stl->stats.min.z += z;
-  stl->stats.max.x += x;
-  stl->stats.max.y += y;
-  stl->stats.max.z += z;
-
-  stl_invalidate_shared_vertices(stl);
-}
-
-void
-stl_scale_versor(stl_file *stl, float versor[3]) {
-  int i;
-  int j;
-
-  if (stl->error) return;
-
-  /* scale extents */
-  stl->stats.min.x *= versor[0];
-  stl->stats.min.y *= versor[1];
-  stl->stats.min.z *= versor[2];
-  stl->stats.max.x *= versor[0];
-  stl->stats.max.y *= versor[1];
-  stl->stats.max.z *= versor[2];
-
-  /* scale size */
-  stl->stats.size.x *= versor[0];
-  stl->stats.size.y *= versor[1];
-  stl->stats.size.z *= versor[2];
-
-  /* scale volume */
-  if (stl->stats.volume > 0.0) {
-    stl->stats.volume *= (versor[0] * versor[1] * versor[2]);
-  }
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl->facet_start[i].vertex[j].x *= versor[0];
-      stl->facet_start[i].vertex[j].y *= versor[1];
-      stl->facet_start[i].vertex[j].z *= versor[2];
-    }
-  }
-
-  stl_invalidate_shared_vertices(stl);
-}
-
-void
-stl_scale(stl_file *stl, float factor) {
-  float versor[3];
-
-  if (stl->error) return;
-
-  versor[0] = factor;
-  versor[1] = factor;
-  versor[2] = factor;
-  stl_scale_versor(stl, versor);
-}
-
-static void calculate_normals(stl_file *stl) {
-  long i;
-  float normal[3];
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    stl_calculate_normal(normal, &stl->facet_start[i]);
-    stl_normalize_vector(normal);
-    stl->facet_start[i].normal.x = normal[0];
-    stl->facet_start[i].normal.y = normal[1];
-    stl->facet_start[i].normal.z = normal[2];
-  }
-}
-
-void stl_transform(stl_file *stl, float *trafo3x4) {
-  int i_face, i_vertex, i, j;
-  if (stl->error)
-    return;
-  for (i_face = 0; i_face < stl->stats.number_of_facets; ++ i_face) {
-    stl_vertex *vertices = stl->facet_start[i_face].vertex;
-    for (i_vertex = 0; i_vertex < 3; ++ i_vertex) {
-      stl_vertex &v_dst = vertices[i_vertex];
-      stl_vertex  v_src = v_dst;
-      v_dst.x = trafo3x4[0] * v_src.x + trafo3x4[1] * v_src.y + trafo3x4[2]  * v_src.z + trafo3x4[3];
-      v_dst.y = trafo3x4[4] * v_src.x + trafo3x4[5] * v_src.y + trafo3x4[6]  * v_src.z + trafo3x4[7];
-      v_dst.z = trafo3x4[8] * v_src.x + trafo3x4[9] * v_src.y + trafo3x4[10] * v_src.z + trafo3x4[11];
-    }
-  }
-  stl_get_size(stl);
-  calculate_normals(stl);
-}
-
-void
-stl_rotate_x(stl_file *stl, float angle) {
-  int i;
-  int j;
-  double radian_angle = (angle / 180.0) * M_PI;
-  double c = cos(radian_angle);
-  double s = sin(radian_angle);
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl_rotate(&stl->facet_start[i].vertex[j].y,
-                 &stl->facet_start[i].vertex[j].z, c, s);
-    }
-  }
-  stl_get_size(stl);
-  calculate_normals(stl);
-}
-
-void
-stl_rotate_y(stl_file *stl, float angle) {
-  int i;
-  int j;
-  double radian_angle = (angle / 180.0) * M_PI;
-  double c = cos(radian_angle);
-  double s = sin(radian_angle);
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl_rotate(&stl->facet_start[i].vertex[j].z,
-                 &stl->facet_start[i].vertex[j].x, c, s);
-    }
-  }
-  stl_get_size(stl);
-  calculate_normals(stl);
-}
-
-void
-stl_rotate_z(stl_file *stl, float angle) {
-  int i;
-  int j;
-  double radian_angle = (angle / 180.0) * M_PI;
-  double c = cos(radian_angle);
-  double s = sin(radian_angle);
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl_rotate(&stl->facet_start[i].vertex[j].x,
-                 &stl->facet_start[i].vertex[j].y, c, s);
-    }
-  }
-  stl_get_size(stl);
-  calculate_normals(stl);
-}
-
-
-
-static void
-stl_rotate(float *x, float *y, const double c, const double s) {
-  double xold = *x;
-  double yold = *y;
-  *x = float(c * xold - s * yold);
-  *y = float(s * xold + c * yold);
-}
-
-extern void
-stl_get_size(stl_file *stl) {
-  int i;
-  int j;
-
-  if (stl->error) return;
-  if (stl->stats.number_of_facets == 0) return;
-
-  stl->stats.min.x = stl->facet_start[0].vertex[0].x;
-  stl->stats.min.y = stl->facet_start[0].vertex[0].y;
-  stl->stats.min.z = stl->facet_start[0].vertex[0].z;
-  stl->stats.max.x = stl->facet_start[0].vertex[0].x;
-  stl->stats.max.y = stl->facet_start[0].vertex[0].y;
-  stl->stats.max.z = stl->facet_start[0].vertex[0].z;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl->stats.min.x = STL_MIN(stl->stats.min.x,
-                                 stl->facet_start[i].vertex[j].x);
-      stl->stats.min.y = STL_MIN(stl->stats.min.y,
-                                 stl->facet_start[i].vertex[j].y);
-      stl->stats.min.z = STL_MIN(stl->stats.min.z,
-                                 stl->facet_start[i].vertex[j].z);
-      stl->stats.max.x = STL_MAX(stl->stats.max.x,
-                                 stl->facet_start[i].vertex[j].x);
-      stl->stats.max.y = STL_MAX(stl->stats.max.y,
-                                 stl->facet_start[i].vertex[j].y);
-      stl->stats.max.z = STL_MAX(stl->stats.max.z,
-                                 stl->facet_start[i].vertex[j].z);
-    }
-  }
-  stl->stats.size.x = stl->stats.max.x - stl->stats.min.x;
-  stl->stats.size.y = stl->stats.max.y - stl->stats.min.y;
-  stl->stats.size.z = stl->stats.max.z - stl->stats.min.z;
-  stl->stats.bounding_diameter = sqrt(
-                                   stl->stats.size.x * stl->stats.size.x +
-                                   stl->stats.size.y * stl->stats.size.y +
-                                   stl->stats.size.z * stl->stats.size.z
-                                 );
-}
-
-void
-stl_mirror_xy(stl_file *stl) {
-  int i;
-  int j;
-  float temp_size;
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl->facet_start[i].vertex[j].z *= -1.0;
-    }
-  }
-  temp_size = stl->stats.min.z;
-  stl->stats.min.z = stl->stats.max.z;
-  stl->stats.max.z = temp_size;
-  stl->stats.min.z *= -1.0;
-  stl->stats.max.z *= -1.0;
-  stl_reverse_all_facets(stl);
-  stl->stats.facets_reversed -= stl->stats.number_of_facets;  /* for not altering stats */
-}
-
-void
-stl_mirror_yz(stl_file *stl) {
-  int i;
-  int j;
-  float temp_size;
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl->facet_start[i].vertex[j].x *= -1.0;
-    }
-  }
-  temp_size = stl->stats.min.x;
-  stl->stats.min.x = stl->stats.max.x;
-  stl->stats.max.x = temp_size;
-  stl->stats.min.x *= -1.0;
-  stl->stats.max.x *= -1.0;
-  stl_reverse_all_facets(stl);
-  stl->stats.facets_reversed -= stl->stats.number_of_facets;  /* for not altering stats */
-}
-
-void
-stl_mirror_xz(stl_file *stl) {
-  int i;
-  int j;
-  float temp_size;
-
-  if (stl->error) return;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    for(j = 0; j < 3; j++) {
-      stl->facet_start[i].vertex[j].y *= -1.0;
-    }
-  }
-  temp_size = stl->stats.min.y;
-  stl->stats.min.y = stl->stats.max.y;
-  stl->stats.max.y = temp_size;
-  stl->stats.min.y *= -1.0;
-  stl->stats.max.y *= -1.0;
-  stl_reverse_all_facets(stl);
-  stl->stats.facets_reversed -= stl->stats.number_of_facets;  /* for not altering stats */
-}
-
-static float get_volume(stl_file *stl) {
-  long i;
-  stl_vertex p0;
-  stl_vertex p;
-  stl_normal n;
-  float height;
-  float area;
-  float volume = 0.0;
-
-  if (stl->error) return 0;
-
-  /* Choose a point, any point as the reference */
-  p0.x = stl->facet_start[0].vertex[0].x;
-  p0.y = stl->facet_start[0].vertex[0].y;
-  p0.z = stl->facet_start[0].vertex[0].z;
-
-  for(i = 0; i < stl->stats.number_of_facets; i++) {
-    p.x = stl->facet_start[i].vertex[0].x - p0.x;
-    p.y = stl->facet_start[i].vertex[0].y - p0.y;
-    p.z = stl->facet_start[i].vertex[0].z - p0.z;
-    /* Do dot product to get distance from point to plane */
-    n = stl->facet_start[i].normal;
-    height = (n.x * p.x) + (n.y * p.y) + (n.z * p.z);
-    area = get_area(&stl->facet_start[i]);
-    volume += (area * height) / 3.0;
-  }
-  return volume;
-}
-
-void stl_calculate_volume(stl_file *stl) {
-  if (stl->error) return;
-  stl->stats.volume = get_volume(stl);
-  if(stl->stats.volume < 0.0) {
-    stl_reverse_all_facets(stl);
-    stl->stats.volume = -stl->stats.volume;
-  }
-}
-
-static float get_area(stl_facet *facet) {
-  double cross[3][3];
-  float sum[3];
-  float n[3];
-  float area;
-  int i;
-
-  /* cast to double before calculating cross product because large coordinates
-     can result in overflowing product
-    (bad area is responsible for bad volume and bad facets reversal) */
-  for(i = 0; i < 3; i++) {
-    cross[i][0]=(((double)facet->vertex[i].y * (double)facet->vertex[(i + 1) % 3].z) -
-                 ((double)facet->vertex[i].z * (double)facet->vertex[(i + 1) % 3].y));
-    cross[i][1]=(((double)facet->vertex[i].z * (double)facet->vertex[(i + 1) % 3].x) -
-                 ((double)facet->vertex[i].x * (double)facet->vertex[(i + 1) % 3].z));
-    cross[i][2]=(((double)facet->vertex[i].x * (double)facet->vertex[(i + 1) % 3].y) -
-                 ((double)facet->vertex[i].y * (double)facet->vertex[(i + 1) % 3].x));
-  }
-
-  sum[0] = cross[0][0] + cross[1][0] + cross[2][0];
-  sum[1] = cross[0][1] + cross[1][1] + cross[2][1];
-  sum[2] = cross[0][2] + cross[1][2] + cross[2][2];
-
-  /* This should already be done.  But just in case, let's do it again */
-  stl_calculate_normal(n, facet);
-  stl_normalize_vector(n);
-
-  area = 0.5 * (n[0] * sum[0] + n[1] * sum[1] + n[2] * sum[2]);
-  return area;
-}
-
-void stl_repair(stl_file *stl,
-                int fixall_flag,
-                int exact_flag,
-                int tolerance_flag,
-                float tolerance,
-                int increment_flag,
-                float increment,
-                int nearby_flag,
-                int iterations,
-                int remove_unconnected_flag,
-                int fill_holes_flag,
-                int normal_directions_flag,
-                int normal_values_flag,
-                int reverse_all_flag,
-                int verbose_flag) {
-  
-  int i;
-  int last_edges_fixed = 0;
-
-  if (stl->error) return;
-
-  if(exact_flag || fixall_flag || nearby_flag || remove_unconnected_flag
-      || fill_holes_flag || normal_directions_flag) {
-    if (verbose_flag)
-      printf("Checking exact...\n");
-    exact_flag = 1;
-    stl_check_facets_exact(stl);
-    stl->stats.facets_w_1_bad_edge =
-      (stl->stats.connected_facets_2_edge -
-       stl->stats.connected_facets_3_edge);
-    stl->stats.facets_w_2_bad_edge =
-      (stl->stats.connected_facets_1_edge -
-       stl->stats.connected_facets_2_edge);
-    stl->stats.facets_w_3_bad_edge =
-      (stl->stats.number_of_facets -
-       stl->stats.connected_facets_1_edge);
-  }
-
-  if(nearby_flag || fixall_flag) {
-    if(!tolerance_flag) {
-      tolerance = stl->stats.shortest_edge;
-    }
-    if(!increment_flag) {
-      increment = stl->stats.bounding_diameter / 10000.0;
-    }
-
-    if(stl->stats.connected_facets_3_edge < stl->stats.number_of_facets) {
-      for(i = 0; i < iterations; i++) {
-        if(stl->stats.connected_facets_3_edge <
-            stl->stats.number_of_facets) {
-          if (verbose_flag)
-            printf("\
-Checking nearby. Tolerance= %f Iteration=%d of %d...",
-                 tolerance, i + 1, iterations);
-          stl_check_facets_nearby(stl, tolerance);
-          if (verbose_flag)
-            printf("  Fixed %d edges.\n",
-                 stl->stats.edges_fixed - last_edges_fixed);
-          last_edges_fixed = stl->stats.edges_fixed;
-          tolerance += increment;
-        } else {
-          if (verbose_flag)
-            printf("\
-All facets connected.  No further nearby check necessary.\n");
-          break;
-        }
-      }
-    } else {
-      if (verbose_flag)
-        printf("All facets connected.  No nearby check necessary.\n");
-    }
-  }
-
-  if(remove_unconnected_flag || fixall_flag || fill_holes_flag) {
-    if(stl->stats.connected_facets_3_edge <  stl->stats.number_of_facets) {
-      if (verbose_flag)
-        printf("Removing unconnected facets...\n");
-      stl_remove_unconnected_facets(stl);
-    } else
-      if (verbose_flag)
-        printf("No unconnected need to be removed.\n");
-  }
-
-  if(fill_holes_flag || fixall_flag) {
-    if(stl->stats.connected_facets_3_edge <  stl->stats.number_of_facets) {
-      if (verbose_flag)
-        printf("Filling holes...\n");
-      stl_fill_holes(stl);
-    } else
-      if (verbose_flag)
-        printf("No holes need to be filled.\n");
-  }
-
-  if(reverse_all_flag) {
-    if (verbose_flag)
-      printf("Reversing all facets...\n");
-    stl_reverse_all_facets(stl);
-  }
-
-  if(normal_directions_flag || fixall_flag) {
-    if (verbose_flag)
-      printf("Checking normal directions...\n");
-    stl_fix_normal_directions(stl);
-  }
-
-  if(normal_values_flag || fixall_flag) {
-    if (verbose_flag)
-      printf("Checking normal values...\n");
-    stl_fix_normal_values(stl);
-  }
-
-  /* Always calculate the volume.  It shouldn't take too long */
-  if (verbose_flag)
-    printf("Calculating volume...\n");
-  stl_calculate_volume(stl);
-
-  if(exact_flag) {
-    if (verbose_flag)
-      printf("Verifying neighbors...\n");
-    stl_verify_neighbors(stl);
-  }
-}
diff --git a/xs/src/admesh/util.cpp b/xs/src/admesh/util.cpp
new file mode 100644
index 000000000..b0c31469d
--- /dev/null
+++ b/xs/src/admesh/util.cpp
@@ -0,0 +1,573 @@
+/*  ADMesh -- process triangulated solid meshes
+ *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
+ *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Questions, comments, suggestions, etc to
+ *           https://github.com/admesh/admesh/issues
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include "stl.h"
+
+static void stl_rotate(float *x, float *y, const double c, const double s);
+static float get_area(stl_facet *facet);
+static float get_volume(stl_file *stl);
+
+
+void
+stl_verify_neighbors(stl_file *stl) {
+  int i;
+  int j;
+  stl_edge edge_a;
+  stl_edge edge_b;
+  int neighbor;
+  int vnot;
+
+  if (stl->error) return;
+
+  stl->stats.backwards_edges = 0;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      edge_a.p1 = stl->facet_start[i].vertex[j];
+      edge_a.p2 = stl->facet_start[i].vertex[(j + 1) % 3];
+      neighbor = stl->neighbors_start[i].neighbor[j];
+      vnot = stl->neighbors_start[i].which_vertex_not[j];
+
+      if(neighbor == -1)
+        continue;		/* this edge has no neighbor... Continue. */
+      if(vnot < 3) {
+        edge_b.p1 = stl->facet_start[neighbor].vertex[(vnot + 2) % 3];
+        edge_b.p2 = stl->facet_start[neighbor].vertex[(vnot + 1) % 3];
+      } else {
+        stl->stats.backwards_edges += 1;
+        edge_b.p1 = stl->facet_start[neighbor].vertex[(vnot + 1) % 3];
+        edge_b.p2 = stl->facet_start[neighbor].vertex[(vnot + 2) % 3];
+      }
+      if(memcmp(&edge_a, &edge_b, SIZEOF_EDGE_SORT) != 0) {
+        /* These edges should match but they don't.  Print results. */
+        printf("edge %d of facet %d doesn't match edge %d of facet %d\n",
+               j, i, vnot + 1, neighbor);
+        stl_write_facet(stl, (char*)"first facet", i);
+        stl_write_facet(stl, (char*)"second facet", neighbor);
+      }
+    }
+  }
+}
+
+void
+stl_translate(stl_file *stl, float x, float y, float z) {
+  int i;
+  int j;
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl->facet_start[i].vertex[j].x -= (stl->stats.min.x - x);
+      stl->facet_start[i].vertex[j].y -= (stl->stats.min.y - y);
+      stl->facet_start[i].vertex[j].z -= (stl->stats.min.z - z);
+    }
+  }
+  stl->stats.max.x -= (stl->stats.min.x - x);
+  stl->stats.max.y -= (stl->stats.min.y - y);
+  stl->stats.max.z -= (stl->stats.min.z - z);
+  stl->stats.min.x = x;
+  stl->stats.min.y = y;
+  stl->stats.min.z = z;
+
+  stl_invalidate_shared_vertices(stl);
+}
+
+/* Translates the stl by x,y,z, relatively from wherever it is currently */
+void
+stl_translate_relative(stl_file *stl, float x, float y, float z) {
+  int i;
+  int j;
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl->facet_start[i].vertex[j].x += x;
+      stl->facet_start[i].vertex[j].y += y;
+      stl->facet_start[i].vertex[j].z += z;
+    }
+  }
+  stl->stats.min.x += x;
+  stl->stats.min.y += y;
+  stl->stats.min.z += z;
+  stl->stats.max.x += x;
+  stl->stats.max.y += y;
+  stl->stats.max.z += z;
+
+  stl_invalidate_shared_vertices(stl);
+}
+
+void
+stl_scale_versor(stl_file *stl, float versor[3]) {
+  int i;
+  int j;
+
+  if (stl->error) return;
+
+  /* scale extents */
+  stl->stats.min.x *= versor[0];
+  stl->stats.min.y *= versor[1];
+  stl->stats.min.z *= versor[2];
+  stl->stats.max.x *= versor[0];
+  stl->stats.max.y *= versor[1];
+  stl->stats.max.z *= versor[2];
+
+  /* scale size */
+  stl->stats.size.x *= versor[0];
+  stl->stats.size.y *= versor[1];
+  stl->stats.size.z *= versor[2];
+
+  /* scale volume */
+  if (stl->stats.volume > 0.0) {
+    stl->stats.volume *= (versor[0] * versor[1] * versor[2]);
+  }
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl->facet_start[i].vertex[j].x *= versor[0];
+      stl->facet_start[i].vertex[j].y *= versor[1];
+      stl->facet_start[i].vertex[j].z *= versor[2];
+    }
+  }
+
+  stl_invalidate_shared_vertices(stl);
+}
+
+void
+stl_scale(stl_file *stl, float factor) {
+  float versor[3];
+
+  if (stl->error) return;
+
+  versor[0] = factor;
+  versor[1] = factor;
+  versor[2] = factor;
+  stl_scale_versor(stl, versor);
+}
+
+static void calculate_normals(stl_file *stl) {
+  long i;
+  float normal[3];
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    stl_calculate_normal(normal, &stl->facet_start[i]);
+    stl_normalize_vector(normal);
+    stl->facet_start[i].normal.x = normal[0];
+    stl->facet_start[i].normal.y = normal[1];
+    stl->facet_start[i].normal.z = normal[2];
+  }
+}
+
+void stl_transform(stl_file *stl, float *trafo3x4) {
+  int i_face, i_vertex;
+  if (stl->error)
+    return;
+  for (i_face = 0; i_face < stl->stats.number_of_facets; ++ i_face) {
+    stl_vertex *vertices = stl->facet_start[i_face].vertex;
+    for (i_vertex = 0; i_vertex < 3; ++ i_vertex) {
+      stl_vertex &v_dst = vertices[i_vertex];
+      stl_vertex  v_src = v_dst;
+      v_dst.x = trafo3x4[0] * v_src.x + trafo3x4[1] * v_src.y + trafo3x4[2]  * v_src.z + trafo3x4[3];
+      v_dst.y = trafo3x4[4] * v_src.x + trafo3x4[5] * v_src.y + trafo3x4[6]  * v_src.z + trafo3x4[7];
+      v_dst.z = trafo3x4[8] * v_src.x + trafo3x4[9] * v_src.y + trafo3x4[10] * v_src.z + trafo3x4[11];
+    }
+  }
+  stl_get_size(stl);
+  calculate_normals(stl);
+}
+
+void
+stl_rotate_x(stl_file *stl, float angle) {
+  int i;
+  int j;
+  double radian_angle = (angle / 180.0) * M_PI;
+  double c = cos(radian_angle);
+  double s = sin(radian_angle);
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl_rotate(&stl->facet_start[i].vertex[j].y,
+                 &stl->facet_start[i].vertex[j].z, c, s);
+    }
+  }
+  stl_get_size(stl);
+  calculate_normals(stl);
+}
+
+void
+stl_rotate_y(stl_file *stl, float angle) {
+  int i;
+  int j;
+  double radian_angle = (angle / 180.0) * M_PI;
+  double c = cos(radian_angle);
+  double s = sin(radian_angle);
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl_rotate(&stl->facet_start[i].vertex[j].z,
+                 &stl->facet_start[i].vertex[j].x, c, s);
+    }
+  }
+  stl_get_size(stl);
+  calculate_normals(stl);
+}
+
+void
+stl_rotate_z(stl_file *stl, float angle) {
+  int i;
+  int j;
+  double radian_angle = (angle / 180.0) * M_PI;
+  double c = cos(radian_angle);
+  double s = sin(radian_angle);
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl_rotate(&stl->facet_start[i].vertex[j].x,
+                 &stl->facet_start[i].vertex[j].y, c, s);
+    }
+  }
+  stl_get_size(stl);
+  calculate_normals(stl);
+}
+
+
+
+static void
+stl_rotate(float *x, float *y, const double c, const double s) {
+  double xold = *x;
+  double yold = *y;
+  *x = float(c * xold - s * yold);
+  *y = float(s * xold + c * yold);
+}
+
+extern void
+stl_get_size(stl_file *stl) {
+  int i;
+  int j;
+
+  if (stl->error) return;
+  if (stl->stats.number_of_facets == 0) return;
+
+  stl->stats.min.x = stl->facet_start[0].vertex[0].x;
+  stl->stats.min.y = stl->facet_start[0].vertex[0].y;
+  stl->stats.min.z = stl->facet_start[0].vertex[0].z;
+  stl->stats.max.x = stl->facet_start[0].vertex[0].x;
+  stl->stats.max.y = stl->facet_start[0].vertex[0].y;
+  stl->stats.max.z = stl->facet_start[0].vertex[0].z;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl->stats.min.x = STL_MIN(stl->stats.min.x,
+                                 stl->facet_start[i].vertex[j].x);
+      stl->stats.min.y = STL_MIN(stl->stats.min.y,
+                                 stl->facet_start[i].vertex[j].y);
+      stl->stats.min.z = STL_MIN(stl->stats.min.z,
+                                 stl->facet_start[i].vertex[j].z);
+      stl->stats.max.x = STL_MAX(stl->stats.max.x,
+                                 stl->facet_start[i].vertex[j].x);
+      stl->stats.max.y = STL_MAX(stl->stats.max.y,
+                                 stl->facet_start[i].vertex[j].y);
+      stl->stats.max.z = STL_MAX(stl->stats.max.z,
+                                 stl->facet_start[i].vertex[j].z);
+    }
+  }
+  stl->stats.size.x = stl->stats.max.x - stl->stats.min.x;
+  stl->stats.size.y = stl->stats.max.y - stl->stats.min.y;
+  stl->stats.size.z = stl->stats.max.z - stl->stats.min.z;
+  stl->stats.bounding_diameter = sqrt(
+                                   stl->stats.size.x * stl->stats.size.x +
+                                   stl->stats.size.y * stl->stats.size.y +
+                                   stl->stats.size.z * stl->stats.size.z
+                                 );
+}
+
+void
+stl_mirror_xy(stl_file *stl) {
+  int i;
+  int j;
+  float temp_size;
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl->facet_start[i].vertex[j].z *= -1.0;
+    }
+  }
+  temp_size = stl->stats.min.z;
+  stl->stats.min.z = stl->stats.max.z;
+  stl->stats.max.z = temp_size;
+  stl->stats.min.z *= -1.0;
+  stl->stats.max.z *= -1.0;
+  stl_reverse_all_facets(stl);
+  stl->stats.facets_reversed -= stl->stats.number_of_facets;  /* for not altering stats */
+}
+
+void
+stl_mirror_yz(stl_file *stl) {
+  int i;
+  int j;
+  float temp_size;
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl->facet_start[i].vertex[j].x *= -1.0;
+    }
+  }
+  temp_size = stl->stats.min.x;
+  stl->stats.min.x = stl->stats.max.x;
+  stl->stats.max.x = temp_size;
+  stl->stats.min.x *= -1.0;
+  stl->stats.max.x *= -1.0;
+  stl_reverse_all_facets(stl);
+  stl->stats.facets_reversed -= stl->stats.number_of_facets;  /* for not altering stats */
+}
+
+void
+stl_mirror_xz(stl_file *stl) {
+  int i;
+  int j;
+  float temp_size;
+
+  if (stl->error) return;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    for(j = 0; j < 3; j++) {
+      stl->facet_start[i].vertex[j].y *= -1.0;
+    }
+  }
+  temp_size = stl->stats.min.y;
+  stl->stats.min.y = stl->stats.max.y;
+  stl->stats.max.y = temp_size;
+  stl->stats.min.y *= -1.0;
+  stl->stats.max.y *= -1.0;
+  stl_reverse_all_facets(stl);
+  stl->stats.facets_reversed -= stl->stats.number_of_facets;  /* for not altering stats */
+}
+
+static float get_volume(stl_file *stl) {
+  long i;
+  stl_vertex p0;
+  stl_vertex p;
+  stl_normal n;
+  float height;
+  float area;
+  float volume = 0.0;
+
+  if (stl->error) return 0;
+
+  /* Choose a point, any point as the reference */
+  p0.x = stl->facet_start[0].vertex[0].x;
+  p0.y = stl->facet_start[0].vertex[0].y;
+  p0.z = stl->facet_start[0].vertex[0].z;
+
+  for(i = 0; i < stl->stats.number_of_facets; i++) {
+    p.x = stl->facet_start[i].vertex[0].x - p0.x;
+    p.y = stl->facet_start[i].vertex[0].y - p0.y;
+    p.z = stl->facet_start[i].vertex[0].z - p0.z;
+    /* Do dot product to get distance from point to plane */
+    n = stl->facet_start[i].normal;
+    height = (n.x * p.x) + (n.y * p.y) + (n.z * p.z);
+    area = get_area(&stl->facet_start[i]);
+    volume += (area * height) / 3.0f;
+  }
+  return volume;
+}
+
+void stl_calculate_volume(stl_file *stl) {
+  if (stl->error) return;
+  stl->stats.volume = get_volume(stl);
+  if(stl->stats.volume < 0.0) {
+    stl_reverse_all_facets(stl);
+    stl->stats.volume = -stl->stats.volume;
+  }
+}
+
+static float get_area(stl_facet *facet) {
+  double cross[3][3];
+  float sum[3];
+  float n[3];
+  float area;
+  int i;
+
+  /* cast to double before calculating cross product because large coordinates
+     can result in overflowing product
+    (bad area is responsible for bad volume and bad facets reversal) */
+  for(i = 0; i < 3; i++) {
+    cross[i][0]=(((double)facet->vertex[i].y * (double)facet->vertex[(i + 1) % 3].z) -
+                 ((double)facet->vertex[i].z * (double)facet->vertex[(i + 1) % 3].y));
+    cross[i][1]=(((double)facet->vertex[i].z * (double)facet->vertex[(i + 1) % 3].x) -
+                 ((double)facet->vertex[i].x * (double)facet->vertex[(i + 1) % 3].z));
+    cross[i][2]=(((double)facet->vertex[i].x * (double)facet->vertex[(i + 1) % 3].y) -
+                 ((double)facet->vertex[i].y * (double)facet->vertex[(i + 1) % 3].x));
+  }
+
+  sum[0] = cross[0][0] + cross[1][0] + cross[2][0];
+  sum[1] = cross[0][1] + cross[1][1] + cross[2][1];
+  sum[2] = cross[0][2] + cross[1][2] + cross[2][2];
+
+  /* This should already be done.  But just in case, let's do it again */
+  stl_calculate_normal(n, facet);
+  stl_normalize_vector(n);
+
+  area = 0.5 * (n[0] * sum[0] + n[1] * sum[1] + n[2] * sum[2]);
+  return area;
+}
+
+void stl_repair(stl_file *stl,
+                int fixall_flag,
+                int exact_flag,
+                int tolerance_flag,
+                float tolerance,
+                int increment_flag,
+                float increment,
+                int nearby_flag,
+                int iterations,
+                int remove_unconnected_flag,
+                int fill_holes_flag,
+                int normal_directions_flag,
+                int normal_values_flag,
+                int reverse_all_flag,
+                int verbose_flag) {
+  
+  int i;
+  int last_edges_fixed = 0;
+
+  if (stl->error) return;
+
+  if(exact_flag || fixall_flag || nearby_flag || remove_unconnected_flag
+      || fill_holes_flag || normal_directions_flag) {
+    if (verbose_flag)
+      printf("Checking exact...\n");
+    exact_flag = 1;
+    stl_check_facets_exact(stl);
+    stl->stats.facets_w_1_bad_edge =
+      (stl->stats.connected_facets_2_edge -
+       stl->stats.connected_facets_3_edge);
+    stl->stats.facets_w_2_bad_edge =
+      (stl->stats.connected_facets_1_edge -
+       stl->stats.connected_facets_2_edge);
+    stl->stats.facets_w_3_bad_edge =
+      (stl->stats.number_of_facets -
+       stl->stats.connected_facets_1_edge);
+  }
+
+  if(nearby_flag || fixall_flag) {
+    if(!tolerance_flag) {
+      tolerance = stl->stats.shortest_edge;
+    }
+    if(!increment_flag) {
+      increment = stl->stats.bounding_diameter / 10000.0;
+    }
+
+    if(stl->stats.connected_facets_3_edge < stl->stats.number_of_facets) {
+      for(i = 0; i < iterations; i++) {
+        if(stl->stats.connected_facets_3_edge <
+            stl->stats.number_of_facets) {
+          if (verbose_flag)
+            printf("\
+Checking nearby. Tolerance= %f Iteration=%d of %d...",
+                 tolerance, i + 1, iterations);
+          stl_check_facets_nearby(stl, tolerance);
+          if (verbose_flag)
+            printf("  Fixed %d edges.\n",
+                 stl->stats.edges_fixed - last_edges_fixed);
+          last_edges_fixed = stl->stats.edges_fixed;
+          tolerance += increment;
+        } else {
+          if (verbose_flag)
+            printf("\
+All facets connected.  No further nearby check necessary.\n");
+          break;
+        }
+      }
+    } else {
+      if (verbose_flag)
+        printf("All facets connected.  No nearby check necessary.\n");
+    }
+  }
+
+  if(remove_unconnected_flag || fixall_flag || fill_holes_flag) {
+    if(stl->stats.connected_facets_3_edge <  stl->stats.number_of_facets) {
+      if (verbose_flag)
+        printf("Removing unconnected facets...\n");
+      stl_remove_unconnected_facets(stl);
+    } else
+      if (verbose_flag)
+        printf("No unconnected need to be removed.\n");
+  }
+
+  if(fill_holes_flag || fixall_flag) {
+    if(stl->stats.connected_facets_3_edge <  stl->stats.number_of_facets) {
+      if (verbose_flag)
+        printf("Filling holes...\n");
+      stl_fill_holes(stl);
+    } else
+      if (verbose_flag)
+        printf("No holes need to be filled.\n");
+  }
+
+  if(reverse_all_flag) {
+    if (verbose_flag)
+      printf("Reversing all facets...\n");
+    stl_reverse_all_facets(stl);
+  }
+
+  if(normal_directions_flag || fixall_flag) {
+    if (verbose_flag)
+      printf("Checking normal directions...\n");
+    stl_fix_normal_directions(stl);
+  }
+
+  if(normal_values_flag || fixall_flag) {
+    if (verbose_flag)
+      printf("Checking normal values...\n");
+    stl_fix_normal_values(stl);
+  }
+
+  /* Always calculate the volume.  It shouldn't take too long */
+  if (verbose_flag)
+    printf("Calculating volume...\n");
+  stl_calculate_volume(stl);
+
+  if(exact_flag) {
+    if (verbose_flag)
+      printf("Verifying neighbors...\n");
+    stl_verify_neighbors(stl);
+  }
+}
diff --git a/xs/src/libslic3r/Format/AMF.cpp b/xs/src/libslic3r/Format/AMF.cpp
index 9a9047eac..b8abf038b 100644
--- a/xs/src/libslic3r/Format/AMF.cpp
+++ b/xs/src/libslic3r/Format/AMF.cpp
@@ -3,6 +3,8 @@
 #include <string>
 #include <expat/expat.h>
 
+#include <boost/nowide/cstdio.hpp>
+
 #include "../libslic3r.h"
 #include "../Model.hpp"
 #include "AMF.hpp"
@@ -480,7 +482,7 @@ bool load_amf(const char *path, Model *model)
         return false;
     }
 
-    FILE *pFile = ::fopen(path, "rt");
+    FILE *pFile = boost::nowide::fopen(path, "rt");
     if (pFile == nullptr) {
         printf("Cannot open file %s\n", path);
         return false;
@@ -522,7 +524,7 @@ bool load_amf(const char *path, Model *model)
 
 bool store_amf(const char *path, Model *model)
 {
-    FILE *file = ::fopen(path, "wb");
+    FILE *file = boost::nowide::fopen(path, "wb");
     if (file == nullptr)
         return false;
 
diff --git a/xs/src/libslic3r/Format/PRUS.cpp b/xs/src/libslic3r/Format/PRUS.cpp
index 6b686d6ea..b7ef33774 100644
--- a/xs/src/libslic3r/Format/PRUS.cpp
+++ b/xs/src/libslic3r/Format/PRUS.cpp
@@ -2,6 +2,8 @@
 
 #include <string.h>
 
+#include <boost/nowide/convert.hpp>
+
 #include <wx/string.h>
 #include <wx/wfstream.h>
 #include <wx/zipstrm.h>
@@ -119,7 +121,14 @@ bool load_prus(const char *path, Model *model)
 {
     // To receive the content of the zipped 'scene.xml' file.
     std::vector<char>           scene_xml_data;
-    wxFFileInputStream          in(path);
+    wxFFileInputStream          in(
+#ifdef WIN32
+        // On Windows, convert to a 16bit unicode string.
+        boost::nowide::widen(path).c_str()
+#else
+        path
+#endif
+        );
     wxZipInputStream            zip(in);
     std::unique_ptr<wxZipEntry> entry;
     size_t                      num_models = 0;
diff --git a/xs/src/libslic3r/Format/objparser.cpp b/xs/src/libslic3r/Format/objparser.cpp
index d8b86b703..88dfae695 100644
--- a/xs/src/libslic3r/Format/objparser.cpp
+++ b/xs/src/libslic3r/Format/objparser.cpp
@@ -1,6 +1,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <boost/nowide/cstdio.hpp>
+
 #include "objparser.hpp"
 
 namespace ObjParser {
@@ -318,7 +320,7 @@ static bool obj_parseline(const char *line, ObjData &data)
 
 bool objparse(const char *path, ObjData &data)
 {
-	FILE *pFile = ::fopen(path, "rt");
+	FILE *pFile = boost::nowide::fopen(path, "rt");
 	if (pFile == 0)
 		return false;
 
@@ -446,7 +448,7 @@ bool loadvectornameidx(FILE *pFile, std::vector<T> &v)
 
 bool objbinsave(const char *path, const ObjData &data)
 {
-	FILE *pFile = ::fopen(path, "wb");
+	FILE *pFile = boost::nowide::fopen(path, "wb");
 	if (pFile == 0)
 		return false;
 
@@ -471,7 +473,7 @@ bool objbinsave(const char *path, const ObjData &data)
 
 bool objbinload(const char *path, ObjData &data)
 {
-	FILE *pFile = ::fopen(path, "rb");
+	FILE *pFile = boost::nowide::fopen(path, "rb");
 	if (pFile == 0)
 		return false;
 
diff --git a/xs/src/libslic3r/GCode.cpp b/xs/src/libslic3r/GCode.cpp
index 5acda3a98..699621974 100644
--- a/xs/src/libslic3r/GCode.cpp
+++ b/xs/src/libslic3r/GCode.cpp
@@ -13,6 +13,10 @@
 #include <boost/date_time/local_time/local_time.hpp>
 #include <boost/foreach.hpp>
 
+#include <boost/nowide/iostream.hpp>
+#include <boost/nowide/cstdio.hpp>
+#include <boost/nowide/cstdlib.hpp>
+
 #include "SVG.hpp"
 
 #if 0
@@ -306,7 +310,33 @@ std::vector<std::pair<coordf_t, std::vector<GCode::LayerToPrint>>> GCode::collec
     return layers_to_print;
 }
 
-bool GCode::do_export(FILE *file, Print &print)
+bool GCode::do_export(Print *print, const char *path)
+{
+    // Remove the old g-code if it exists.
+    boost::nowide::remove(path);
+
+    std::string path_tmp(path);
+    path_tmp += ".tmp";
+
+    FILE *file = boost::nowide::fopen(path_tmp.c_str(), "wb");
+    if (file == nullptr)
+        return false;
+
+    bool result = this->_do_export(*print, file);
+    fclose(file);
+
+    if (result && boost::nowide::rename(path_tmp.c_str(), path) != 0) {
+        boost::nowide::cerr << "Failed to remove the output G-code file from " << path_tmp << " to " << path
+            << ". Is " << path_tmp << " locked?" << std::endl;
+        result = false;
+    }
+
+    if (! result)
+        boost::nowide::remove(path_tmp.c_str());
+    return result;
+}
+
+bool GCode::_do_export(Print &print, FILE *file)
 {
     // How many times will be change_layer() called?
     // change_layer() in turn increments the progress bar status.
diff --git a/xs/src/libslic3r/GCode.hpp b/xs/src/libslic3r/GCode.hpp
index 51ab5eb84..ac0af3f2c 100644
--- a/xs/src/libslic3r/GCode.hpp
+++ b/xs/src/libslic3r/GCode.hpp
@@ -126,7 +126,7 @@ public:
         {}
     ~GCode() {}
 
-    bool            do_export(FILE *file, Print &print);
+    bool            do_export(Print *print, const char *path);
 
     // Exported for the helper classes (OozePrevention, Wipe) and for the Perl binding for unit tests.
     const Pointf&   origin() const { return m_origin; }
@@ -146,6 +146,8 @@ public:
     void            apply_print_config(const PrintConfig &print_config);
 
 protected:
+    bool            _do_export(Print &print, FILE *file);
+
     // Object and support extrusions of the same PrintObject at the same print_z.
     struct LayerToPrint
     {
diff --git a/xs/src/libslic3r/Model.cpp b/xs/src/libslic3r/Model.cpp
index 5d0de1576..455469f8a 100644
--- a/xs/src/libslic3r/Model.cpp
+++ b/xs/src/libslic3r/Model.cpp
@@ -10,6 +10,7 @@
 
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/filesystem.hpp>
+#include <boost/nowide/iostream.hpp>
 
 namespace Slic3r {
 
@@ -739,7 +740,7 @@ void ModelObject::print_info() const
 {
     using namespace std;
     cout << fixed;
-    cout << "[" << boost::filesystem::path(this->input_file).filename().string() << "]" << endl;
+    boost::nowide::cout << "[" << boost::filesystem::path(this->input_file).filename().string() << "]" << endl;
     
     TriangleMesh mesh = this->raw_mesh();
     mesh.check_topology();
diff --git a/xs/src/libslic3r/SVG.cpp b/xs/src/libslic3r/SVG.cpp
index b8580fd5e..c94db8e74 100644
--- a/xs/src/libslic3r/SVG.cpp
+++ b/xs/src/libslic3r/SVG.cpp
@@ -1,6 +1,8 @@
 #include "SVG.hpp"
 #include <iostream>
 
+#include <boost/nowide/cstdio.hpp>
+
 #define COORD(x) ((float)unscale((x))*10)
 
 namespace Slic3r {
@@ -8,7 +10,7 @@ namespace Slic3r {
 bool SVG::open(const char* afilename)
 {
     this->filename = afilename;
-    this->f = fopen(afilename, "w");
+    this->f = boost::nowide::fopen(afilename, "w");
     if (this->f == NULL)
         return false;
     fprintf(this->f,
@@ -27,7 +29,7 @@ bool SVG::open(const char* afilename, const BoundingBox &bbox, const coord_t bbo
     this->filename = afilename;
     this->origin   = bbox.min - Point(bbox_offset, bbox_offset);
     this->flipY    = aflipY;
-    this->f        = ::fopen(afilename, "w");
+    this->f        = boost::nowide::fopen(afilename, "w");
     if (f == NULL)
         return false;
     float w = COORD(bbox.max.x - bbox.min.x + 2 * bbox_offset);
diff --git a/xs/src/libslic3r/Utils.hpp b/xs/src/libslic3r/Utils.hpp
index 0b6b87d28..45d1f2c51 100644
--- a/xs/src/libslic3r/Utils.hpp
+++ b/xs/src/libslic3r/Utils.hpp
@@ -6,6 +6,10 @@ namespace Slic3r {
 extern void set_logging_level(unsigned int level);
 extern void trace(unsigned int level, const char *message);
 
+extern std::string encode_path(const char *src);
+extern std::string decode_path(const char *src);
+extern std::string normalize_utf8_nfc(const char *src);
+
 // Compute the next highest power of 2 of 32-bit v
 // http://graphics.stanford.edu/~seander/bithacks.html
 template<typename T>
diff --git a/xs/src/libslic3r/utils.cpp b/xs/src/libslic3r/utils.cpp
index 50db6f300..ea34fb18c 100644
--- a/xs/src/libslic3r/utils.cpp
+++ b/xs/src/libslic3r/utils.cpp
@@ -1,7 +1,21 @@
+#include <locale>
+
 #include <boost/log/core.hpp>
 #include <boost/log/trivial.hpp>
 #include <boost/log/expressions.hpp>
 
+#include <boost/locale.hpp>
+
+#include <boost/nowide/integration/filesystem.hpp>
+#include <boost/nowide/convert.hpp>
+
+#ifdef WIN32
+extern "C" {
+__declspec(dllimport) int WideCharToMultiByte(unsigned int, unsigned long, wchar_t const *, int, char *, int, char const *, int *);
+__declspec(dllimport) int MultiByteToWideChar(unsigned int, unsigned long, char const *, int, wchar_t *, int);
+}
+#endif /* WIN32 */
+
 namespace Slic3r {
 
 static boost::log::trivial::severity_level logSeverity = boost::log::trivial::error;
@@ -30,9 +44,13 @@ void set_logging_level(unsigned int level)
 }
 
 // Force set_logging_level(<=error) after loading of the DLL.
-static struct SetLoggingLevelOnInit {
-    SetLoggingLevelOnInit() { set_logging_level(1); }
-} g_SetLoggingLevelOnInit;
+// Switch boost::filesystem to utf8.
+static struct RunOnInit {
+    RunOnInit() { 
+        boost::nowide::nowide_filesystem();
+        set_logging_level(1);
+    }
+} g_RunOnInit;
 
 void trace(unsigned int level, const char *message)
 {
@@ -56,6 +74,46 @@ void trace(unsigned int level, const char *message)
         (::boost::log::keywords::severity = severity)) << message;
 }
 
+std::string encode_path(const char *src)
+{    
+#ifdef WIN32
+    // Convert the source utf8 encoded string to a wide string.
+    std::wstring wstr_src = boost::nowide::widen(src);
+    if (wstr_src.length() == 0)
+        return std::string();
+    // Convert a wide string to a local code page.
+    int size_needed = ::WideCharToMultiByte(0, 0, wstr_src.data(), (int)wstr_src.size(), nullptr, 0, nullptr, nullptr);
+    std::string str_dst(size_needed, 0);
+    ::WideCharToMultiByte(0, 0, wstr_src.data(), (int)wstr_src.size(), const_cast<char*>(str_dst.data()), size_needed, nullptr, nullptr);
+    return str_dst;
+#else /* WIN32 */
+    return src;
+#endif /* WIN32 */
+}
+
+std::string decode_path(const char *src)
+{  
+#ifdef WIN32
+    int len = strlen(src);
+    if (len == 0)
+        return std::string();
+    // Convert the string encoded using the local code page to a wide string.
+    int size_needed = ::MultiByteToWideChar(0, 0, src, len, nullptr, 0);
+    std::wstring wstr_dst(size_needed, 0);
+    ::MultiByteToWideChar(0, 0, src, len, const_cast<wchar_t*>(wstr_dst.data()), size_needed);
+    // Convert a wide string to utf8.
+    return boost::nowide::narrow(wstr_dst.c_str());
+#else /* WIN32 */
+    return src;
+#endif /* WIN32 */
+}
+
+std::string normalize_utf8_nfc(const char *src)
+{
+    static std::locale locale_utf8("en_US.UTF-8");
+    return boost::locale::normalize(src, boost::locale::norm_nfc, locale_utf8);
+}
+
 } // namespace Slic3r
 
 #ifdef SLIC3R_HAS_BROKEN_CROAK
diff --git a/xs/xsp/GCode.xsp b/xs/xsp/GCode.xsp
index 9104e481a..ea54fd3a7 100644
--- a/xs/xsp/GCode.xsp
+++ b/xs/xsp/GCode.xsp
@@ -17,17 +17,7 @@
 %name{Slic3r::GCode} class GCode {
     GCode();
     ~GCode();
-    std::string do_export(Print *print, const char *path)
-        %code{%
-            FILE *file = fopen(path, "wb");
-            if (file == nullptr) {
-                RETVAL = std::string("Failed to open ") + path + " for writing.";
-            } else {
-                THIS->do_export(file, *print);
-                fclose(file);
-                RETVAL = std::string();
-            }
-        %};
+    std::string do_export(Print *print, const char *path);
 
     Ref<Pointf> origin()
         %code{% RETVAL = &(THIS->origin()); %};
diff --git a/xs/xsp/XS.xsp b/xs/xsp/XS.xsp
index 8389e2d99..6ba6817c1 100644
--- a/xs/xsp/XS.xsp
+++ b/xs/xsp/XS.xsp
@@ -48,6 +48,24 @@ trace(level, message)
     CODE:
         Slic3r::trace(level, message);
 
+std::string
+encode_path(src)
+    const char *src;
+    CODE:
+        Slic3r::encode_path(src);
+
+std::string
+decode_path(src)
+    const char *src;
+    CODE:
+        Slic3r::decode_path(src);
+
+std::string
+normalize_utf8_nfc(src)
+    const char *src;
+    CODE:
+        Slic3r::normalize_utf8_nfc(src);
+
 void
 xspp_test_croak_hangs_on_strawberry()
     CODE:
-- 
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