This page provides information on the Bump Normals Color Channel.
Overview
V-Ray Bump Normal is a render channel that stores the camera view as a normal map. The normals are generated using screen space which uses the XYZ orientation of the camera view. With Screen space, the X axis runs left-right across the view, Y runs up-down, and Z points out of the screen. Bump maps are also represented in this render element.
This render element is similar to the Normal Color Channel that does not include bump maps.
The Bump Normal is useful for adjusting lighting that comes from a particular direction. For example, faces of objects pointing toward the camera will be predominantly blue in Bump Normal, so the lighting on such objects can be adjusted by using the blue channel in compositing software.
UI Path
||Node Editor|| > Add > Render Channels > Color Channel > Type > Bump Normal
Common Uses - Relighting
The Bump Normal channel is useful for changing the appearance of lighting in a scene in a composite without the need for re-rendering. In the example below, a lighting workflow is used at a composite level to change the lighting in the scene. Note that it does not create any extra shadowing. While the Bump Normal Render Channel provides information about how lights will affect each surface, the Point Position element passes the spatial location of each pixel. When used together, it allows lights added in compositing to react to the pixels as if they were on the surface of the model.
Bump Normals Render Element
The World Positions pass
Original Beauty Composite
The resulting relit composite