diff --git a/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm b/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm
index 7b5752cd2..0cc8b2dec 100644
--- a/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm
+++ b/lib/Slic3r/GUI/Plater/ObjectCutDialog.pm
@@ -227,12 +227,14 @@ sub _update {
                 push @objects, $self->{model_object};
             }
         
+            my $z_cut = $z + $self->{model_object}->bounding_box->z_min;        
+        
             # get section contour
             my @expolygons = ();
             foreach my $volume (@{$self->{model_object}->volumes}) {
                 next if !$volume->mesh;
                 next if $volume->modifier;
-                my $expp = $volume->mesh->slice([ $z + $volume->mesh->bounding_box->z_min ])->[0];
+                my $expp = $volume->mesh->slice([ $z_cut ])->[0];
                 push @expolygons, @$expp;
             }
             foreach my $expolygon (@expolygons) {