Shadow Geometry for Solids of Revolution
In this chapter, we explore the analysis of shadows of Right Circular SHGCs (solids of revolution). We have already seen that, when the viewing angle σ is known, the tangency contours themselves can be analyzed. Thus, the problem addressed here is the use of shadows to determine the viewing angle. Ideally, we would like to perform some simple analysis, such as analysis of the position of the terminator in the image. This turns out to be very complicated, so we turn instead to the results of chapter 7 for curved surfaces in general. We will apply these to determine the surface normals along the terminator, and present an algorithm for determining the viewing angle from these surface normals.
KeywordsSurface Normal Surface Gradient Single Surface Texture Gradient Illumination Direction
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