New option to change perimeter order. #534

README.markdown

@@ -197,6 +197,7 @@ The author of the Silk icon set is Mark James.
         --extra-perimeters  Add more perimeters when needed (default: yes)
         --randomize-start   Randomize starting point across layers (default: yes)
         --avoid-crossing-perimeters Optimize travel moves so that no perimeters are crossed (default: no)
+        --external-perimeters-first Reverse perimeter order. (default: no)
         --only-retract-when-crossing-perimeters
                             Disable retraction when travelling between infill paths inside the same island.
                             (default: yes)

lib/Slic3r/Config.pm

@@ -562,6 +562,13 @@ our $Options = {
         type    => 'bool',
         default => 0,
     },
+    'external_perimeters_first' => {
+        label   => 'External perimeters first',
+        tooltip => 'Print contour perimeters from the outermost one to the innermost one instead of the default inverse order.',
+        cli     => 'external-perimeters-first!',
+        type    => 'bool',
+        default => 0,
+    },
     'only_retract_when_crossing_perimeters' => {
         label   => 'Only retract when crossing perimeters',
         tooltip => 'Disables retraction when travelling between infill paths inside the same island.',

lib/Slic3r/GUI/Tab.pm

@@ -407,7 +407,7 @@ sub build {
         },
         {
             title => 'Advanced',
-            options => [qw(avoid_crossing_perimeters)],
+            options => [qw(avoid_crossing_perimeters external_perimeters_first)],
         },
     ]);
     

lib/Slic3r/Layer/Region.pm

@@ -404,10 +404,14 @@ sub make_perimeters {
             }
         }
         
-        # do holes, then contours starting from innermost one
+        # first do holes
         $self->_add_perimeter($holes[$_], $is_external{$_} ? EXTR_ROLE_EXTERNAL_PERIMETER : undef)
             for reverse 0 .. $#holes;
-        for my $depth (reverse 0 .. $#$island) {
+        
+        # then do contours according to the user settings
+        my @contour_order = 0 .. $#$island;
+        @contour_order = reverse @contour_order if !$Slic3r::Config->external_perimeters_first;
+        for my $depth (@contour_order) {
             my $role = $depth == $#$island ? EXTR_ROLE_CONTOUR_INTERNAL_PERIMETER
                 : $depth == 0 ? EXTR_ROLE_EXTERNAL_PERIMETER
                 : EXTR_ROLE_PERIMETER;

slic3r.pl

@@ -250,6 +250,7 @@ $j
     --extra-perimeters  Add more perimeters when needed (default: yes)
     --randomize-start   Randomize starting point across layers (default: yes)
     --avoid-crossing-perimeters Optimize travel moves so that no perimeters are crossed (default: no)
+    --external-perimeters-first Reverse perimeter order. (default: no)
     --only-retract-when-crossing-perimeters
                         Disable retraction when travelling between infill paths inside the same island.
                         (default: no)