Sculpture is the term for a three-dimensional work of art made by carving, modelling or assembly. The word sculpture derives from Latin "sculptura" and ultimately the verb "sculpere", meaning "to cut". The artist working in sculpture is called a sculptor and he or she sculpts from solid materials such as stone or wood, arriving at the final form by taking material away so that sculpting is a subtractive process. Modelling, on the other hand, is the activity entailing making a sculpture in soft, ductile materials such as clay or plaster of Paris, some of which are then as desired cast in bronze, without removing material. Modelling is, therefore, an additive process entailing shaping, enlarging and building up. In modern art, in which those classic materials are not always used, it is often difficult to distinguish between sculpting and modelling. In English, however, they are increasingly being used as synonyms for a three-dimensional object made in the above mentioned ways.