diff --git a/xs/src/admesh/util.c b/xs/src/admesh/util.c
index 22aad0432..a1a90fb19 100644
--- a/xs/src/admesh/util.c
+++ b/xs/src/admesh/util.c
@@ -236,6 +236,8 @@ stl_rotate(float *x, float *y, float angle)
 extern void
 stl_get_size(stl_file *stl)
 {
+    if (stl->stats.number_of_facets == 0) return;
+    
   int i;
   int j;
 
diff --git a/xs/t/01_trianglemesh.t b/xs/t/01_trianglemesh.t
index 5c18de5a9..65e1f0441 100644
--- a/xs/t/01_trianglemesh.t
+++ b/xs/t/01_trianglemesh.t
@@ -107,7 +107,7 @@ my $cube = {
         my $upper = Slic3r::TriangleMesh->new;
         my $lower = Slic3r::TriangleMesh->new;
         $m->cut(0, $upper, $lower);
-        #$upper->repair; $lower->repair;
+        $upper->repair; $lower->repair;
         is $upper->facets_count, 12, 'upper mesh has all facets except those belonging to the slicing plane';
         is $lower->facets_count,  0, 'lower mesh has no facets';
     }
@@ -115,9 +115,13 @@ my $cube = {
         my $upper = Slic3r::TriangleMesh->new;
         my $lower = Slic3r::TriangleMesh->new;
         $m->cut(10, $upper, $lower);
-        #$upper->repair; $lower->repair;
-        is $upper->facets_count, 16, 'upper mesh has the right number of facets';
-        is $lower->facets_count, 16, 'lower mesh has the right number of facets';
+        $upper->repair; $lower->repair;
+        # we expect:
+        # 2 facets on external horizontal surfaces
+        # 3 facets on each side = 12 facets
+        # 6 facets on the triangulated side (8 vertices)
+        is $upper->facets_count, 2+12+6, 'upper mesh has the expected number of facets';
+        is $lower->facets_count, 2+12+6, 'lower mesh has the expected number of facets';
     }
 }