+ /**
+ * Returns the z-level for object presentation, -1 if no z-level.
+ */
+ HYDRODATA_EXPORT virtual Standard_Boolean GetZLevel( Standard_Integer& theLevel ) const;
+
+ /**
+ * Set the z-level for object presentation.
+ */
+ HYDRODATA_EXPORT virtual void SetZLevel( const Standard_Integer& theLevel );
+
+ /**
+ * Remove the z-level of object presentation.
+ */
+ HYDRODATA_EXPORT virtual void RemoveZLevel();
+
+