diff --git a/src/Mod/Draft/draftmake/make_dimension.py b/src/Mod/Draft/draftmake/make_dimension.py
index 95823151ac..e6830bcc1f 100644
--- a/src/Mod/Draft/draftmake/make_dimension.py
+++ b/src/Mod/Draft/draftmake/make_dimension.py
@@ -602,7 +602,7 @@ def make_angular_dimension(center=App.Vector(0, 0, 0),
             _err(translate("draft","Wrong input: must be a vector."))
             return None
 
-    if normal is not None:
+    if not normal:
         normal = WorkingPlane.get_working_plane(update=False).axis
 
     new_obj = App.ActiveDocument.addObject("App::FeaturePython",