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title: "GI tab"
canonical: "https://documentation.chaos.com/space/VBLD/117638973/GI%20tab"
format: markdown
---
This page provides information on the GI tab of V-Ray's Render Settings. Overview Global Illumination (or GI) is the illumination in a scene that effectively comes from reflected (or bounced) light as opposed to coming directly from a light source. This enables more naturalistic and accurate lighting solutions. The indirect illumination controls in V-Ray are divided into two large sections:  primary diffuse bounces  and  secondary diffuse bounces . A primary diffuse bounce occurs when a shaded point is directly visible by the camera, or through specular reflective or refractive surfaces. A secondary bounce occurs when a shaded point is used in GI calculations. UI Path : ||Properties Editor|| >  Render  >  GI  tab Global Illumination On   –  Enables/disables indirect illumination. Engine  – Specifies the method to be used for the secondary diffuse bounces.  This option determines the contents of the next rollout . Follow the link for each GI Engine, to see its options. None  – No secondary bounces will be computed. Use this option to produce skylit images without indirect color bleeding. Brute force   – Selects the brute force method (direct computation) for secondary diffuse bounces. See the    Brute Force Engine   section for more information. Light cache  – Selects the  light cache method as the secondary GI engine. See the  Light Cache Engine  section for more information. Use Light Cache for Interactive Rendering  – When enabled, the Light Cache method is used for calculating global illumination in Interactive Rendering. Production rendering is done using the method specified in the  Engine  parameter. Caustics Caustics is an effect that is produced when light rays are reflected or refracted by materials, producing visible light patterns.  See its options on the  Caustics Rollout  page .