Sculptural Techniques, from Conception to the Finished Work Artists conceive their work in several stages, calling on various techniques and materials. The first stage often consists of a preliminary design, a simple sketch or detailed study, which is then modelled in reduced format in a malleable material (wax or clay) enabling the artist to give expression to the slightest modulation in his thoughts. It might be a fragmentary outline of great spontaneity, or a model already possessing all the characteristics of the finished work, like Renaud's Vigilance. These models are presented to the patrons who have commissioned the work for their agreement before it is produced to the required dimensions. The artist can then cast this model in plaster, obtaining an original plaster cast which he/she often reworks after receiving it back from the caster. Other casts can then be made from this first plaster cast: plaster or bronze casts (such as the Duc de Luynes by Rude) or marbles, where the model is mechanically enlarged to the desired size (two original terracottas, Socrate and Ossian by François Lucas, show traces of having been produced in this way). However, terracotta is also traditionally used in Toulouse for very large ornamental sculptures, especially for gardens. From the 17th Century onwards, free-standing terracottas multiplied in response to the growing demands of less wealthy collectors.