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 incompositing 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
To use render elements, select from the Available render elements column and click the Add button to add the passes you wish to generate at render time. When you render the scene, the added render elements listed in the column on the right, will also render, which can be viewed from the VFB window's channel drop-down menu.
For more information on the parameters on this dialog, see the Render Elements tab page.
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).
Denoise – Enables the render element's denoising, provided the Denoiser render element is present.
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