diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index c1d50a5f9c..dbe5e6f4bd 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -413,7 +413,7 @@ sub load_model_objects {
         }
     
         $self->{print}->auto_assign_extruders($o);
-        $self->{print}->add_model_object($self->{model}, $o);
+        $self->{print}->add_model_object($o);
     }
     
     # if user turned autocentering off, automatic arranging would disappoint them
@@ -547,7 +547,7 @@ sub rotate {
         
         # update print
         $self->{print}->delete_object($obj_idx);
-        $self->{print}->add_model_object($self->{model}, $model_object, $obj_idx);
+        $self->{print}->add_model_object($model_object, $obj_idx);
         
         $object->transform_thumbnail($self->{model}, $obj_idx);
     }
@@ -583,8 +583,7 @@ sub changescale {
         
         # update print
         $self->{print}->delete_object($obj_idx);
-        $self->{print}->add_model_object($self->{model},
-            $model_object, $obj_idx);
+        $self->{print}->add_model_object($model_object, $obj_idx);
         
         $object->transform_thumbnail($self->{model}, $obj_idx);
     }
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 8bd1bf4fc9..331d89abae 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -104,9 +104,8 @@ sub apply_config {
     if ($rearrange_regions) {
         # the current subdivision of regions does not make sense anymore.
         # we need to remove all objects and re-add them
-        my @models_objects = map [$_->model, $_->model_object], @{$self->objects};
         $self->clear_objects;
-        $self->add_model_object(@$_) for @models_objects;
+        $self->add_model_object($_->model_object) for @{$self->objects};
     }
 }
 
@@ -121,7 +120,7 @@ sub has_support_material {
 # and have explicit instance positions
 sub add_model_object {
     my $self = shift;
-    my ($model, $object, $obj_idx) = @_;
+    my ($object, $obj_idx) = @_;
     
     my $object_config = $object->config->clone;
     $object_config->normalize;
@@ -170,7 +169,6 @@ sub add_model_object {
     # initialize print object
     my $o = Slic3r::Print::Object->new(
         print               => $self,
-        model               => $model,  # for strong ref
         model_object        => $object,
         region_volumes      => [ map $volumes{$_}, 0..$#{$self->regions} ],
         copies              => [ map Slic3r::Point->new_scale(@{ $_->offset }), @{ $object->instances } ],
@@ -221,9 +219,9 @@ sub reload_object {
     # For now we just re-add all objects since we haven't implemented this incremental logic yet.
     # This should also check whether object volumes (parts) have changed.
     
-    my @models_objects = map [$_->model, $_->model_object], @{$self->objects};
+    my @models_objects = map $_->model_object, @{$self->objects};
     $self->clear_objects;
-    $self->add_model_object(@$_) for @models_objects;
+    $self->add_model_object($_) for @models_objects;
 }
 
 sub validate {
diff --git a/lib/Slic3r/Print/Object.pm b/lib/Slic3r/Print/Object.pm
index 0fe61cb5df..a43123a880 100644
--- a/lib/Slic3r/Print/Object.pm
+++ b/lib/Slic3r/Print/Object.pm
@@ -10,8 +10,7 @@ use Slic3r::Print::State ':steps';
 use Slic3r::Surface ':types';
 
 has 'print'             => (is => 'ro', weak_ref => 1, required => 1);
-has 'model'             => (is => 'ro', required => 1);  # for strong ref so model subobjects are kept in memory
-has 'model_object'      => (is => 'ro', required => 1);
+has 'model_object'      => (is => 'ro', required => 1);  # caller is responsible for holding the Model object
 has 'region_volumes'    => (is => 'rw', default => sub { [] });  # by region_id
 has 'copies'            => (is => 'ro');  # Slic3r::Point objects in scaled G-code coordinates
 has 'config'            => (is => 'ro', default => sub { Slic3r::Config::PrintObject->new });
diff --git a/lib/Slic3r/Print/Simple.pm b/lib/Slic3r/Print/Simple.pm
index c3230149b3..6e64cab5f6 100644
--- a/lib/Slic3r/Print/Simple.pm
+++ b/lib/Slic3r/Print/Simple.pm
@@ -67,7 +67,7 @@ sub set_model {
     
     foreach my $model_object (@{$model->objects}) {
         $self->_print->auto_assign_extruders($model_object);
-        $self->_print->add_model_object($model, $model_object);
+        $self->_print->add_model_object($model_object);
     }
 }
 
diff --git a/lib/Slic3r/Test.pm b/lib/Slic3r/Test.pm
index 034379c7a5..7d8ce66391 100644
--- a/lib/Slic3r/Test.pm
+++ b/lib/Slic3r/Test.pm
@@ -151,7 +151,7 @@ sub init_print {
         $model->center_instances_around_point($print->config->print_center);
         foreach my $model_object (@{$model->objects}) {
             $print->auto_assign_extruders($model_object);
-            $print->add_model_object($model, $model_object);
+            $print->add_model_object($model_object);
         }
     }
     $print->validate;
diff --git a/slic3r.pl b/slic3r.pl
index d2c08073c0..ed25c6b8dc 100755
--- a/slic3r.pl
+++ b/slic3r.pl
@@ -172,7 +172,6 @@ if (@ARGV) {  # slicing from command line
         
         $sprint->apply_config($config);
         $sprint->set_model($model);
-        undef $model;  # free memory
         
         if ($opt{export_svg}) {
             $sprint->export_svg;