ABSTRACT
Ray tracing can accurately simulate the natural beauty of transparent objects. Transparent materials, or media, as they are called, allow light to pass through them. Common examples include glasses, clear plastics, and gases such as air. In physics, these are called dielectrics. This chapter discusses the concepts and physical processes of transparency and examines the practical issues involved in correctly ray tracing transparent objects. It explains how a simplified model of transparency is implemented in ray tracing. The chapter also discusses what happens when a ray hits the boundary between two dielectrics: refraction, the transmitted ray, and total internal reflection. Total internal reflection does not only occur when a ray hits the inside surface of an object. If we ray trace an object whose ior is less than the surrounding medium, total internal reflection can occur when a ray hits it from the outside.
