A rendered view is a photo realistic view that includes light and shadows. When you render a 3D scene, the program performs a series of lighting calculations to determine the lighting in a scene. These are also called radiosity calculations. Once a final result is met, the scene is ray traced, or rendered. Ray tracing works by tracing the path taken by a ray of light through the scene, and calculating the ray’s reflection, refraction, or absorption whenever it intersects an element in the scene.
Material properties define how light reflects off a surface. Direct light and ambient light levels define the light that is reflected. Direct light is light that is emitted from light fixtures. It has a specific color, intensity and direction. Ambient light can be thought of as a general level of light that is everywhere in the scene. Every light in a scene contributes to the overall ambient light in a scene.
The first part of the radiosity process involves finding those element surfaces that are visible to direct light and calculating how much light is transferred to each element. Some elements will receive more light than others depending on their surface properties, and different surfaces will reflect different amounts of light. Still, each element will absorb some of the light, so the total amount reflected back into the scene will be less than that emitted by the light fixtures.
The next part of the process involves finding the element that reflects the most light, and repeating the process. The element is considered a secondary light source, so we need to calculate how much of its light is transferred to other elements in the scene. The process is repeated, one step at a time, until the amount of light remaining in the scene is negligible in comparison to the light originally emitted by the light fixtures. We then say that the radiosity calculations have converged to a solution, and that’s when ray tracing can begin.