Skin is in fact slightly translucent this subtle but crucial effect gives skin its soft appearance and is absolutely vital for realistic rendering, as shown in Figure 14-2b.įor most materials, the reflectance of light is usually separated into two components that are handled independently: (1) surface reflectance, typically approximated with a simple specular calculation and (2) subsurface scattering, typically approximated with a simple diffuse calculation.
What's missing? The difficulties arise mainly due to subsurface scattering, the process whereby light goes beneath the skin surface, scatters and gets partially absorbed, and then exits somewhere else. However, naively rendering the resulting model gives an unrealistic, hard, dry-looking appearance, as you can see in Figure 14-2a. Fortunately, modern 3D scanning technology allows us to capture even this extreme level of detail. A realistic model of skin must include wrinkles, pores, freckles, hair follicles, scars, and so on. The sheer amount of detail in human skin presents one barrier. Skin has always been difficult to render: it has many subtle visual characteristics, and human viewers are acutely sensitive to the appearance of skin in general and faces in particular. Such physically based models provide flexibility by supporting realistic rendering across different lighting scenarios and requiring the least amount of tweaking to get great results.įigure 14-1 Real-Time Rendering of Realistic Human Skin 14.1 The Appearance of Skin Our goal throughout is to employ the most physically accurate models available that exhibit a tractable real-time implementation. In this chapter, we present advanced techniques for generating such images. The shading performance of modern GPUs, coupled with advances in 3D scanning technology, research in rendering of subsurface scattering effects, and a detailed understanding of the physical composition of skin, has made it possible to generate incredibly realistic real-time images of human skin and faces. Advanced Techniques for Realistic Real-Time Skin Rendering You can also subscribe to our Developer News Feed to get notifications of new material on the site.Ĭhapter 14. The CD content, including demos and content, is available on the web and for download. GPU Gems 3 GPU Gems 3 is now available for free online!
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