6 modules - PI-VR GmbH

6 MODULES6.1.5 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 pixel accordingly.It has nothing to do with light, it is purely a rendering trick that looks nice andincreases a geometry’s realism. That is because in real life surfaces that are closetogether (like small cracks) are darker due to dirt, shadows or the like than surfacesthat are not occluded by other things. The Ambient Occlusion processthough is approximating this result, it does not simulate light bouncing around orgoes through things. This is why Ambient Occlusion still works without lights in112