+
+ /// Returns true if object must be displayed in the viewer: flag is stored in the
+ /// data model, so on undo/redo, open/save or recreation of object by history-playing it keeps
+ /// the original state i nthe current transaction.
+ MODEL_EXPORT virtual bool isDisplayed();
+
+ /// Sets the displayed/hidden state of the object. If it is changed, sends the "redisplay"
+ /// signal.
+ MODEL_EXPORT virtual void setDisplayed(const bool theDisplay);