6 modules - PI-VR GmbH

6.1 Scene6.1.5 Ambient OcclusionScene » AmbientOcclusion» Ambient Occlusion Ambient Occlusion simulates soft global illumination by computingshadows resulting from light coming from all directions. These shadowsare similar to shadows cast from an overcast sky. This has the effect of darkeningcracks, creases, corners and points of contact.Ambient Occlusion is a specific not-physically-accurate rendering trick. It basicallysamples a hemisphere around each point on the face, sees what proportionof a hemisphere is occluded by other geometry and shades the pixelaccordingly. It has nothing to do with light, it is purely a rendering trick thatlooks nice and increases a geometry’s realism. That is because in real life surfacesthat are close together (like small cracks) are darker due to dirt, shadowsor the like than surfaces that are not occluded by other things. The AmbientOcclusion process though is approximating this result, it does not simulate lightbouncing around or goes through things. This is why Ambient Occlusion still123