Rendering a CG Scene - An Introduction to Computer Graphics for Artists - page 222

Fig. 12.6 The two crystalline objects in this render are randomly deformed cubes not intended to
resemble anything. By assigning physically accurate shaders to them and rendering with a path
tracer, a “photorealistic” render is made

cameras, and renderers all exist independently of an object's absolute dimensions
and other visible characteristics.
Any object, no matter how fanciful or how badly made, can be rendered so that
it looks real. This is because realism is not a function of models or textures, but of
lighting and rendering. If a wildly inaccurate model is lit well, it will be a credible
3D object, even if it does not credibly represent the object it is supposed to be. The
reason is that, within your scene, as far as the renderer is concerned, it is a real
object (Fig. 12.6 ). Photorealism then, is the quality of your lighting in a fi nished
render, and the credibility of your scene rests on the accuracy of the objects within
it, in combination with the lighting.

12.5.4 Physical Light Types

12.5.4.1 Key Light

A key light is the primary light source in an environment, and the strongest. Outdoors
during daylight hours this would normally be the sun. Indoors, it might still be the
sun, depending on window locations and whether the strength of interior lighting is
greater than light entering through windows.

12.5.4.2 Bounce Light

Bounce light can be used to refl ect somewhat dim light into the shadow side of an
object, partly illuminating it to make its structure clear. If it has color to it, that color