diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index 9b10d321ea..3b0d037a20 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -469,7 +469,7 @@ sub load_model_objects {
             $need_arrange = 1;
         
             # add a default instance and center object around origin
-            $o->center_around_origin;
+            $o->center_around_origin;  # also aligns object to Z = 0
             $o->add_instance(offset => $bed_centerf);
         }
     
@@ -1074,15 +1074,7 @@ sub export_stl {
     return if !@{$self->{objects}};
         
     my $output_file = $self->_get_export_file('STL') or return;
-    
-    # In order to allow for consistent positioning in the parts editor,
-    # we never alter the original Z position. Meshes are aligned to zero 
-    # at slice time. So we do the same before exporting.
-    my $model = $self->{model}->clone;
-    foreach my $model_object (@{$model->objects}) {
-        $model_object->translate(0,0,-$model_object->bounding_box->z_min);
-    }
-    Slic3r::Format::STL->write_file($output_file, $model, binary => 1);
+    Slic3r::Format::STL->write_file($output_file, $self->{model}, binary => 1);
     $self->statusbar->SetStatusText("STL file exported to $output_file");
     
     # this method gets executed in a separate thread by wxWidgets since it's a button handler
@@ -1282,10 +1274,12 @@ sub object_settings_dialog {
 	$self->pause_background_process;
 	$dlg->ShowModal;
 	
-	# update thumbnail since parts may have changed
-	if ($dlg->PartsChanged) {
-    	$self->make_thumbnail($obj_idx);
-	}
+    # update thumbnail since parts may have changed
+    if ($dlg->PartsChanged) {
+	    # recenter and re-align to Z = 0
+	    $model_object->center_around_origin;
+        $self->make_thumbnail($obj_idx);
+    }
 	
 	# update print
 	if ($dlg->PartsChanged || $dlg->PartSettingsChanged) {
diff --git a/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm b/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
index d24aa8932c..bacc119d7d 100644
--- a/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
+++ b/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
@@ -214,7 +214,7 @@ sub on_btn_load {
                 $new_volume->set_name(basename($input_file));
                 
                 # apply the same translation we applied to the object
-                $new_volume->mesh->translate(@{$self->{model_object}->origin_translation}, 0);
+                $new_volume->mesh->translate(@{$self->{model_object}->origin_translation});
                 
                 # set a default extruder value, since user can't add it manually
                 $new_volume->config->set_ifndef('extruder', 0);
@@ -226,7 +226,9 @@ sub on_btn_load {
     
     $self->reload_tree;
     if ($self->{canvas}) {
+        $self->{canvas}->reset_objects;
         $self->{canvas}->load_object($self->{model_object});
+        $self->{canvas}->set_bounding_box($self->{model_object}->bounding_box);
         $self->{canvas}->Render;
     }
 }
diff --git a/lib/Slic3r/Print/Object.pm b/lib/Slic3r/Print/Object.pm
index 677cae1942..4a5ec01feb 100644
--- a/lib/Slic3r/Print/Object.pm
+++ b/lib/Slic3r/Print/Object.pm
@@ -332,7 +332,7 @@ sub _slice_region {
     # consider the first one
     $self->model_object->instances->[0]->transform_mesh($mesh, 1);
 
-    # align mesh to Z = 0 and apply XY shift
+    # align mesh to Z = 0 (it should be already aligned actually) and apply XY shift
     $mesh->translate((map unscale(-$_), @{$self->_copies_shift}), -$self->model_object->bounding_box->z_min);
     
     # perform actual slicing
diff --git a/lib/Slic3r/Print/Simple.pm b/lib/Slic3r/Print/Simple.pm
index 7647bbfc42..5618484fa1 100644
--- a/lib/Slic3r/Print/Simple.pm
+++ b/lib/Slic3r/Print/Simple.pm
@@ -68,6 +68,7 @@ sub set_model {
         # if all input objects have defined position(s) apply duplication to the whole model
         $model->duplicate($self->duplicate, $self->_print->config->min_object_distance);
     }
+    $_->translate(0,0,-$_->bounding_box->z_min) for @{$model->objects};
     $model->center_instances_around_point($self->print_center);
     
     foreach my $model_object (@{$model->objects}) {
diff --git a/xs/src/libslic3r/Model.cpp b/xs/src/libslic3r/Model.cpp
index d5e9aa6ee1..06919cedd3 100644
--- a/xs/src/libslic3r/Model.cpp
+++ b/xs/src/libslic3r/Model.cpp
@@ -480,26 +480,31 @@ ModelObject::center_around_origin()
         mesh.bounding_box(&bb);
     }
     
-    // first align to origin on XY
-    double shift_x = -bb.min.x;
-    double shift_y = -bb.min.y;
+    // first align to origin on XYZ
+    Vectorf3 vector(-bb.min.x, -bb.min.y, -bb.min.z);
     
     // then center it on XY
     Sizef3 size = bb.size();
-    shift_x -= size.x/2;
-    shift_y -= size.y/2;
+    vector.x -= size.x/2;
+    vector.y -= size.y/2;
     
-    this->translate(shift_x, shift_y, 0);
-    this->origin_translation.translate(shift_x, shift_y);
+    this->translate(vector);
+    this->origin_translation.translate(vector);
     
     if (!this->instances.empty()) {
         for (ModelInstancePtrs::const_iterator i = this->instances.begin(); i != this->instances.end(); ++i) {
-            (*i)->offset.translate(-shift_x, -shift_y);
+            (*i)->offset.translate(-vector.x, -vector.y);
         }
         this->update_bounding_box();
     }
 }
 
+void
+ModelObject::translate(const Vectorf3 &vector)
+{
+    this->translate(vector.x, vector.y, vector.z);
+}
+
 void
 ModelObject::translate(coordf_t x, coordf_t y, coordf_t z)
 {
diff --git a/xs/src/libslic3r/Model.hpp b/xs/src/libslic3r/Model.hpp
index 9cbe6be40b..62bb38bfc5 100644
--- a/xs/src/libslic3r/Model.hpp
+++ b/xs/src/libslic3r/Model.hpp
@@ -99,7 +99,7 @@ class ModelObject
         center_around_origin() method. Callers might want to apply the same translation
         to new volumes before adding them to this object in order to preset alignment
         when user expects that. */
-    Pointf origin_translation;
+    Pointf3 origin_translation;
     
     // these should be private but we need to expose them via XS until all methods are ported
     BoundingBoxf3 _bounding_box;
@@ -126,6 +126,7 @@ class ModelObject
     void raw_bounding_box(BoundingBoxf3* bb) const;
     void instance_bounding_box(size_t instance_idx, BoundingBoxf3* bb) const;
     void center_around_origin();
+    void translate(const Vectorf3 &vector);
     void translate(coordf_t x, coordf_t y, coordf_t z);
     void scale(const Pointf3 &versor);
     size_t materials_count() const;
diff --git a/xs/src/libslic3r/Point.cpp b/xs/src/libslic3r/Point.cpp
index 76da85334f..5f3f1da01a 100644
--- a/xs/src/libslic3r/Point.cpp
+++ b/xs/src/libslic3r/Point.cpp
@@ -41,7 +41,7 @@ Point::translate(double x, double y)
 }
 
 void
-Point::translate(const Point &vector)
+Point::translate(const Vector &vector)
 {
     this->translate(vector.x, vector.y);
 }
@@ -340,6 +340,12 @@ Pointf3::scale(double factor)
     this->z *= factor;
 }
 
+void
+Pointf3::translate(const Vectorf3 &vector)
+{
+    this->translate(vector.x, vector.y, vector.z);
+}
+
 void
 Pointf3::translate(double x, double y, double z)
 {
diff --git a/xs/src/libslic3r/Point.hpp b/xs/src/libslic3r/Point.hpp
index 60127b1b7a..271c9584ef 100644
--- a/xs/src/libslic3r/Point.hpp
+++ b/xs/src/libslic3r/Point.hpp
@@ -14,6 +14,7 @@ class Point;
 class Pointf;
 class Pointf3;
 typedef Point Vector;
+typedef Pointf3 Vectorf3;
 typedef std::vector<Point> Points;
 typedef std::vector<Point*> PointPtrs;
 typedef std::vector<const Point*> PointConstPtrs;
@@ -36,7 +37,7 @@ class Point
     std::string wkt() const;
     void scale(double factor);
     void translate(double x, double y);
-    void translate(const Point &vector);
+    void translate(const Vector &vector);
     void rotate(double angle, const Point &center);
     bool coincides_with(const Point &point) const;
     bool coincides_with_epsilon(const Point &point) const;
@@ -93,6 +94,7 @@ class Pointf3 : public Pointf
     coordf_t z;
     explicit Pointf3(coordf_t _x = 0, coordf_t _y = 0, coordf_t _z = 0): Pointf(_x, _y), z(_z) {};
     void scale(double factor);
+    void translate(const Vectorf3 &vector);
     void translate(double x, double y, double z);
 };
 
diff --git a/xs/t/19_model.t b/xs/t/19_model.t
index 56b3631af3..d6f6d97a18 100644
--- a/xs/t/19_model.t
+++ b/xs/t/19_model.t
@@ -10,9 +10,9 @@ use Test::More tests => 4;
     my $model = Slic3r::Model->new;
     my $object = $model->_add_object;
     isa_ok $object, 'Slic3r::Model::Object::Ref';
-    isa_ok $object->origin_translation, 'Slic3r::Pointf::Ref';
-    $object->origin_translation->translate(10,0);
-    is_deeply \@{$object->origin_translation}, [10,0], 'origin_translation is modified by ref';
+    isa_ok $object->origin_translation, 'Slic3r::Pointf3::Ref';
+    $object->origin_translation->translate(10,0,0);
+    is_deeply \@{$object->origin_translation}, [10,0,0], 'origin_translation is modified by ref';
     
     my $lhr = [ [ 5, 10, 0.1 ] ];
     $object->set_layer_height_ranges($lhr);
diff --git a/xs/xsp/Model.xsp b/xs/xsp/Model.xsp
index fd31a93d47..8d795f7d66 100644
--- a/xs/xsp/Model.xsp
+++ b/xs/xsp/Model.xsp
@@ -188,9 +188,9 @@ ModelMaterial::attributes()
     void set_layer_height_ranges(t_layer_height_ranges ranges)
         %code%{ THIS->layer_height_ranges = ranges; %};
 
-    Ref<Pointf> origin_translation()
+    Ref<Pointf3> origin_translation()
         %code%{ RETVAL = &THIS->origin_translation; %};
-    void set_origin_translation(Pointf* point)
+    void set_origin_translation(Pointf3* point)
         %code%{ THIS->origin_translation = *point; %};
     
     bool needed_repair() const;