The surface of
rendered objects in computer games often looks unrealistic. A new method
creates much more realistic images, imitating the complex scattering processes
under the surface. Overturning cars, flying missiles and airplanes speeding
across the screen on modern computers, 3D objects can be calculated in a flash.
However, many surfaces still look unnatural. Whether it is skin, stone or wax on
the computer screen, all materials look alike, as if the objects had all been
cut out of the same kind of opaque material. TU Wien (Vienna), the University
of Zaragoza and the video game company Activision-Blizzard have developed a new
mathematical method which makes surfaces appear much more realistic by taking
into account light scattering which occurs below the surface.
When we hold our
hand against the sun, it looks red along the edges, because light enters our
skin. The appearance of an object is strongly influenced by scattering of light
inside the material. It is called subsurface scattering. This scattering inside
the object is the main reason why different surfaces can look so different.
Skin does not look like wax and a plant does not look like a stone surface. Skin
is particularly tricky. A face can be rendered in high resolution, with
ultra-realistic details, down to single pores and tiny impurities; but this
does not mean that it looks realistic. When subsurface scattering is not taken
into account, even a perfectly modelled face looks as if it has been chiselled
out of a dull, opaque, skin-coloured stone.
More
information: