Selected Bibliography Architectural Graphics | Page 140

MODELING FORM "Modeling" refers to the technique of rendering the illusion of volume, solidity, and depth on at wo-dimensional surface by means of shading. Shading w tona l values extends a ith simple drawing of contours into the three-dimensional realm offorms arranged in space. \ Since the definition of edges gives rise to shape recognition, we look to edges t o discover the configuration of the surfaces of athree-dimensional form. We must therefore be careful how we define the nature of the edge or boundary wherever two shapes of contrasting values meet.The skillful manipulation of tona l edges is critical to defining the nature and solidity of a surface or object. '" Hard edges delineate sharp, angular breaks in form or describe contours that are sep arated fromthe background by some intervening space. We define hard edges w an abrupt and incisive shift in tonal value. ith Soft edges describe indistinct or vague background shapes, gently curving surfaces and rounded forms, and areas of low contrast. We create soft edges with a gradual change intonal valueor diffusetonal contrast. Digital Modeling It is relat ively easy to create three-dimensional digital models, and to ǒ6