Ray tracing

Summary

Ray tracing computes the paths of waves through a system by following rays of geometrical optics. In a medium of varying refractive index the rays solve the ray equation, and at interfaces they obey Snell's law and the law of reflection. Along each ray one can also carry the optical path length, the amplitude and the polarization. It is used to design lenses, to study the propagation of radio and seismic waves, and to compute images in computer graphics.