Arch: Fixed regression in compound walls

src/Mod/Arch/ArchWall.py

@@ -928,8 +928,10 @@ class _Wall(ArchComponent.Component):
                             FreeCAD.Console.PrintWarning(translate("Arch","This mesh is an invalid solid")+"\n")
                             obj.Base.ViewObject.show()
         if not base:
-            FreeCAD.Console.PrintError(translate("Arch","Error: Invalid base object")+"\n")
-            return
+            #FreeCAD.Console.PrintError(translate("Arch","Error: Invalid base object")+"\n")
+            #return
+            # walls can be made of only a series of additions and have no base shape
+            base = Part.Shape()
 
         base = self.processSubShapes(obj,base,pl)