In this tutorial, we will learn about the GI bounces rendering algorithms Photon mapping and Light Cache. Also, we’ll study in detail the working principle and each function of Light cache, as well as learn about the optimal values of its settings. This tutorial answers the following questions. What a photon map is and how it works? What are the disadvantages of using the photon map? How does a modified photon map algorithm Light cache work? What is a cell of Light cache? How can Light cache store direct light and calculate the diffuse reflections? How and why do the Light cache filters work? What is the difference between Pre-filtering and Filtering? What are the values in the Light cache settings that provide the most acceptable result?
Read cg tutorial Best V-Ray Settings - Light Cache at RenderStuff