Learn how to have global illumination in a real-time engine using Iray renderer. With Iray Photoreal Renderer, allow your real-time engine to use the full global illumination computation from the most advanced path tracer. The technique uses the properties of the physically based material (MDL) assigned to the object and all the various sources of energy in the scene. Sources can be high-dynamic-range images, built-in sun and sky, implicit lights, such as point, spot, and area lights, and also emissive objects. The method also allows use of light path expression, which can create a light map for a specific group of lights, or excluding objects from the calculation.