since the purpose of figure drawing classes is to learn how to draw humans of all kinds, male and female models of all ages, shapes, and ethnicities are usually sought, rather than selecting only beautiful models or those with "ideal" figures. some instructors specifically seek to avoid the sort of models preferred by fashion photographers, seeking more "realistic" examples and to avoid any implication of sexual objectification. instructors may also favor models of particular body types based on the unique contours or surface textures they provide. the variety of models hired may be limited by the need for them to hold a pose for extended periods (eliminating restless children and frail older persons), and concerns of modesty and legality when models pose nude (restricting the use of minors).