When one speaks of sculpture today, works in a variety of materials come to mind because the parameters of "sculpture" have been vastly expanded. Mobiles, stabiles, installations and assemblages are all included as forms of sculpture and each may be made out of a variety of materials, but basically, regardless of material or size, traditional sculpture occurs in two forms: sculpture in the round and relief sculpture.
Sculpture in the round is freestanding or three-dimensional. It has height, width, and depth. We can walk around it and look at it from all sides. Relief sculpture is two-dimensional. A relief is meant to be seen from the front only. Relief is often classified by the degree of the images projection from the background into low or bas-relief, high relief, and sometimes an intermediate mid-relief. Relief is the usual sculptural medium for large figure groups and narrative subjects, which are difficult to accomplish in the round, and is the typical technique used both for architectural sculpture, which is attached to buildings, and for small-scale sculpture decorating other objects, as in much pottery, metalwork and jewellery. Reliefs may also decorate steles, upright slabs, usually of stone, which contain sculpture or sometimes just inscriptions.
The techniques used in sculpture include assemblage which is joining two or more odds and ends to form a composition, modelling which is the manipulation of malleable or soft material to
References: * http://en.wikipedia.org/wiki/Sculpture# * http://creativeparis.info/en/offer-details/p_sculpture-modelling-and-casting-for-all-media-types/offre-336/categorie-3/ * http://www.getty.edu/education/teachers/classroom_resources/curricula/sculpture/background2.html