Drape molds are made of plaster or MDF. You roll the clay with a rolling pin, place it over the mold and press it with a soft sponge and cut off the excess clay. The mold now absorbs the liquid from the clay, after a while the mold with clay is to be turned over and you take out the mold. There are also sprig molds that are used to press clay into the mold to create feet, figures, handles etc.