Aside from foam, there are a number of materials that are used as filling for the sofa. Two other examples of filling materials are the fiber and the feather. The fiber or the foam with the fiber wrap will give that softer look to the sofa and a softer feel to the sofa as well. To maintain the one made from fiber, what you can do is to simply plump it and to turn the cushion from time to time to even the wear.