Selected Bibliography Architectural Graphics | 页面 151

SHADE & SHADOWS Multiview Drawings The casting of shade and shadows is especially useful to overcome the flatness of multi view drawings and enh ance the illusion of depth.lt generally requires two related views-either aplan and elevationor two related elevations-and the transferring of information back and forth from one view to the other. ::l...h. :,··.:'.'.·. ' .. ' • In multiview drawings, we assume the conventional direction of sunlight to be parallel to the diagonal of a cube from the upper left front corner to the lower right rear corner. TOr • While the true altitude of this diagonal is 35° 16', in plan and elevationviews, this direction is seen as the 45° diagonal of asquare. This convention produces shadows of widt hor depthequal to the width or depth of the projections that cast t he shadows. FI\ONI 51 DE ------------------~--~ The process of determining the shape of a cast shadow begins with drawing a 45° light ray through a point along the casting edge in both views. In the view showingthe edge view of the receiving surface, the ray is extended until it intersects the receiving surface. f'!..AN VIEW ~---r- . A We project this intersection to the related view. The intersection of this transferred line withthe ray in the adjacent view marks the shadow of the point. RENOERING TONAL VALUES /145