diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index aa0448dda..d826b1df5 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -76,11 +76,18 @@ has 'fills' => (
     default => sub { [] },
 );
 
-sub z {
+# Z used for slicing
+sub slice_z {
     my $self = shift;
     return ($self->id * $Slic3r::layer_height + $Slic3r::layer_height/2) / $Slic3r::resolution;
 }
 
+# Z used for printing
+sub print_z {
+    my $self = shift;
+    return ($self->id + 1) * $Slic3r::layer_height / $Slic3r::resolution;
+}
+
 sub add_surface {
     my $self = shift;
     my (@vertices) = @_;
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index f05e5eef2..dd8ded327 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -431,7 +431,7 @@ sub export_gcode {
     # write gcode commands layer by layer
     foreach my $layer (@{ $self->layers }) {
         # go to layer
-        printf $fh $extruder->move_z($Slic3r::z_offset + $layer->z * $Slic3r::resolution);
+        printf $fh $extruder->move_z($Slic3r::z_offset + $layer->print_z * $Slic3r::resolution);
         
         # extrude skirts
         printf $fh $extruder->extrude_loop($_, 'skirt') for @{ $layer->skirts };
diff --git a/lib/Slic3r/STL.pm b/lib/Slic3r/STL.pm
index cc1d692ad..d0fd9e0e4 100644
--- a/lib/Slic3r/STL.pm
+++ b/lib/Slic3r/STL.pm
@@ -127,7 +127,7 @@ sub _facet {
     
     for (my $layer_id = $min_layer; $layer_id <= $max_layer; $layer_id++) {
         my $layer = $print->layer($layer_id);
-        $layer->add_line($_) for $self->intersect_facet(\@vertices, $layer->z);
+        $layer->add_line($_) for $self->intersect_facet(\@vertices, $layer->slice_z);
     }
 }