This page gives an overview of the Global Illumination render element and explains how it is used in compositing.
The Global Illumination Render Element is a color image that stores indirect lighting information coming from reflected diffuse light in a scene (without direct light and reflection contributions) when Global Illumination is enabled in Render Settings. This element may be used directly in Back to Beauty compositing and adjusted for brightness and color to control the final image easily.
For even more control of indirect illumination without re-rendering the scene, the Global Illumination render element may be re-assembled by multiplying the Raw Global Illumination Render Element by the Diffuse Render Element:
vrayRE_RawGlobalIllumination x vrayRE_Diffuse = vrayRE_GlobalIllumination
UI Path: ||Render Settings window|| > Render Elements tab > GI
The parameters for this render element appear in the Attribute Editor under Extra V-Ray Attributes.
Enabled – When checked, the render element appears in the V-Ray Virtual Frame Buffer.
Deep output – Specifies whether to include this render element in deep images.
Filename suffix – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.GI.vrimg).
The Global Illumination Render Element is useful for changing the appearance of Indirect lighting after rendering, using a compositing or image editing software. Below are a couple of examples of its use.
Global Illumination Render Element
Original Beauty Composite
Tinted and Brightened GI