itemData: data relative to an item. If the item is a point item, 3 values are required (x;y;z). If the item is a line item, 6 values are required, and if the item is a triangle item, 9 values are required. Additional values (auxiliary values) might be required depending on the drawing object attributes. See the
drawing object types and attributes for more information. If NULL the drawing object is emptied of all its items