diff --git a/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm b/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
index f4d55cb68..4adf9366e 100644
--- a/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
+++ b/lib/Slic3r/GUI/Plater/ObjectPartsPanel.pm
@@ -344,12 +344,12 @@ sub on_btn_lambda {
     my $params = $dlg->ObjectParameter;
     my $type = "".$params->{"type"};
     my $name = "lambda-".$params->{"type"};
-    my $mesh = Slic3r::TriangleMesh->new();
+    my $mesh;
 
     if ($type eq "box") {
-        $mesh = $mesh->cube($params->{"dim"}[0], $params->{"dim"}[1], $params->{"dim"}[2]);
+        $mesh = Slic3r::TriangleMesh::cube($params->{"dim"}[0], $params->{"dim"}[1], $params->{"dim"}[2]);
     } elsif ($type eq "cylinder") {
-        $mesh = $mesh->cylinder($params->{"cyl_r"}, $params->{"cyl_h"});
+        $mesh = Slic3r::TriangleMesh::cylinder($params->{"cyl_r"}, $params->{"cyl_h"});
     } else {
         return;
     }
diff --git a/xs/xsp/TriangleMesh.xsp b/xs/xsp/TriangleMesh.xsp
index 32425d6d4..7f2e71bcb 100644
--- a/xs/xsp/TriangleMesh.xsp
+++ b/xs/xsp/TriangleMesh.xsp
@@ -37,10 +37,7 @@
         %code{% RETVAL = THIS->bounding_box().center(); %};
     int facets_count();
     void reset_repair_stats();
-    Clone<TriangleMesh> cube(double x, double y, double z) 
-        %code{% RETVAL = make_cube(x, y, z); %};
-    Clone<TriangleMesh> cylinder(double r, double h) 
-        %code{% RETVAL = make_cylinder(r, h); %};
+
 %{
 
 void
@@ -228,6 +225,21 @@ TriangleMesh::bb3()
     OUTPUT:
         RETVAL
 
+
+Clone<TriangleMesh>
+cube(double x, double y, double z) 
+    CODE:
+        RETVAL = make_cube(x,y,z);
+    OUTPUT:
+        RETVAL
+
+Clone<TriangleMesh> 
+cylinder(double r, double h) 
+    CODE:
+        RETVAL = make_cylinder(r, h);
+    OUTPUT:
+        RETVAL
+
 %}
 };