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By S. Joseph (Joe) DeMarco
Overview – The GEOMETRIC PROJECTOR (GP) is a drawing board method for converting points on a 3-view drawing into a pictorial image on a two-dimensional picture plane--in plain words, a method for making a "perspective" drawing. It's a highly effective tool for making accurate perspectives. Most treatments of perspective assume a vertical picture plane and a horizontal line of sight at eyelevel above the ground that foreshorten only the horizontal lines that recede to one or two vanishing points. They ignore the more natural three vanishing- point view. GP provides the correct number of vanishing points for whatever view is taken.
The system described here was conceived by the author in 1943. It is quite unambiguous and straightforward. It is adaptable to any art genre that requires accurate perspective drawings. It is particularly well suited to the needs of aviation artists whose paintings more often than not embrace all three dimensions and cover vast regions of not only airspace, but land and sea as well. Although vanishing points are inherent in the system, GP does not rely on their use because they are frequently inaccessible on the average-size drawing board.
With GP, the range of viewing aspects is global. GP is a "hands-on" drawing system that uses the fundamentals of geometry. (The mathematical equations for ARTISTS' PERSPECTIVE MODELER, described elsewhere in this Website, are derived from GP.)
The GEOMETRIC PROJECTOR METHOD and its operation are described in the following pages. The object used to illustrate the system is a simplified version of the Ryan NYP airplane, Spirit of St. Louis, shown in Fig. 1.