diff --git a/doc/assy.rst b/doc/assy.rst
index d488980ef..0d730a5f0 100644
--- a/doc/assy.rst
+++ b/doc/assy.rst
@@ -59,7 +59,7 @@ Next we want to define functions generating the assembly components based on the
             .workplane()
             .cboreHole(6, 15, 18)
             .faces("<Z")
-            .workplane()
+            .workplane(centerOption="CenterOfMass")
             .cboreHole(6, 15, 18)
         )
     
@@ -238,7 +238,7 @@ Below is the complete code including the final solve step.
             .workplane()
             .cboreHole(6, 15, 18)
             .faces("<Z")
-            .workplane()
+            .workplane(centerOption="CenterOfMass")
             .cboreHole(6, 15, 18)
         )
     
@@ -375,4 +375,4 @@ STEP can be loaded in all CAD tool, e.g. in FreeCAD and the XML be used in other
     
 In the case of STEP colors are preserved but not transparency.
 
-..  image:: _static/door_assy_freecad.png
\ No newline at end of file
+..  image:: _static/door_assy_freecad.png