This page gives information about the Bump Normals Render Element.
The Bump Normals Render Element creates a normal-style image from the camera view from bumps and normals in the scene. The normals are generated using screen space (the Screen coordinate system in 3ds Max) 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. For a diagram that illustrates how normal-style colors are generated, see the Normals (VRayNormals) page.
This render element is similar to the Normals (VRayNormals) Render Element that does not include bump maps. Also compare with Sampler Info (VRaySamplerInfo), which can render a normal map in object or world space in addition to camera (screen) space.
The Bump Normals Render Element is useful for adjusting lighting that comes from a particular direction. For example, faces of objects pointing toward the camera are predominantly blue in VRayBumpNormals, so the lighting on such objects can be adjusted by using the blue channel in compositing software.
This render element is enabled through the Render Elements tab of the Render Setup window in 3ds Max and displays its parameters in a rollout at the bottom of the window:
VRayVFB – When enabled, the render element appears in the V-Ray Virtual Frame Buffer.
Deep output – Specifies whether to include this render element in deep images.
Common Uses - Relighting
The Bump Normals Render Element is useful for changing the appearance of lighting in a scene in a composite without the need for re-rendering. In the example, 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 Normals Render Element provides information about how lights affect each surface; the Point Position element passes the spatial location of each pixel. When used together with the Bump Normals, it allows lights added in composite to react on the pixels as if they were the surface of the model.
The Point Position pass in this example is created using the VRaySamplerInfo Render Element in World space, with a Point multiplier of 0.001.
See the render before and after compositing:
The Point Position pass