A device capable of three-dimensional measurement, used for making an exact copy of a statue. In its most elementary form, as used by Greek and Roman sculptors, it consisted of a cage constructed round the model corresponding in its dimensions to the stone block from which the new sculpture was to be carved. Measurements were then taken from the top and sides to various key points on the original and the block was cut down in accordance to the data thus obtained. The use of pointing machines was revived in Renaissance Italy, stimulated by its renewed interest in the art of antiquity and its own vigorous sculptural production. More sophisticated pointing machines were developed in the 18th and 19th centuries which were capable of taking measurements from a small sculptural model and scaling up, providing the measurements for the full-scale final sculpture. Perhaps the most celebrated of all sculptors to make extensive use of the pointing machine was the great Neoclassical sculptor Antonio Canova (1757–1822).