Planar Geometric Projections and Viewing Transformations
Ingrid Carlbom, Joseph Paciorek · ACM Computing Surveys · 1978
In computer graphics one is often concerned with representing three-dimensional objects on a two-dimensional display surface. The choice of such a representation depends on several factors, including the purpose for which the representation is intended, the visual effects that are desired, and the shape of the object. This paper describes how two-dimensional views can be obtained using planar geometric projections such as perspective and parallel projections. It discusses how these projections can be generated from a three-dimensional representation f an object in a manner suitable for computer graphics ystems. In particular, it shows how these projections can be generated using the viewing transfor-mations of the Core Graphics System. The factors that affect the choice of projection are also discussed, and some guidelines for making such a choice are given.