Ray tracing works on the principle that a light source sends out straight rays which continue on its path until it collides with an object. If the object is reflective like metal or transparent like glass, refraction is caused and the new path of the ray is dependent on the objects properties. The ray continues until it hits a new object and the pattern is repeated. Refraction is the bending of the path of a light wave as it passes across the boundary separating two media.
Ray tracing follows the path of a ray backwards, from the eye to the image and then to the light source.
http://www.geocities.com/jamisbuck/raytracing.html#Shadows
The illustration below shows how ray tracing deals with shadows.
http://www.geocities.com/jamisbuck/raytracing.html#Shadows
Ray tracing doesn’t take account of diffuse interreflections.
This rendering technique needs a huge amount of processing power, as each time the camera moves, new calculations must be made about the lighting and the time required to produce an image is hugely affected by the number of light sources.
Filed under: Radiosity and Ray Tracing
