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Orthographic projection (or orthogonal projection) is a means of representing a three-dimensional object in two dimensions. It is a form of parallel projection, where all the projection lines are orthogonal to the projection plane, resulting in every plane of the scene appearing in affine transformation on the viewing surface. When multiple views of an object are drawn, it is called multiview orthographic projection. A lens providing an orthographic projection is known as an (object-space) telecentric lens. The term ''orthographic'' is also sometimes reserved specifically for depictions of objects where the axis or plane of the object is also parallel with the projection plane,〔 as in ''multiview orthographic projections''. == Origin == The orthographic projection has been known since antiquity, with its cartographic uses being well documented. Hipparchus used the projection in the 2nd century BC to determine the places of star-rise and star-set. In about 14 BC, Roman engineer Marcus Vitruvius Pollio used the projection to construct sundials and to compute sun positions.〔Snyder, John P. (1993). ''Flattening the Earth: Two Thousand Years of Map Projections'' pp. 16–18. Chicago and London: The University of Chicago Press. ISBN 0-226-76746-9.〕 Vitruvius also seems to have devised the term orthographic (from the Greek ''orthos'' (= “straight”) and graphē (= “drawing”) for the projection. However, the name ''analemma'', which also meant a sundial showing latitude and longitude, was the common name until François d'Aguilon of Antwerp promoted its present name in 1613.〔 The earliest surviving maps on the projection appear as woodcut drawings of terrestrial globes of 1509 (anonymous), 1533 and 1551 (Johannes Schöner), and 1524 and 1551 (Apian).〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「orthographic projection」の詳細全文を読む スポンサード リンク
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