This page provides information on the Normals Render Element which creates a normals image from surface normals in the scene.
Overview
vrayRE_Normals is a render element that stores the camera space normal map using the geometry's surface normals. The Normals Render Element is useful for adjusting lighting in the composite. For example, the red, green and blue channels can be adjusted in compositing software.
Bump maps are not represented in this render element; to include bump maps, use the Bump Normals Render Element.
When Normals Render Element is saved as a separate render channel, its output value is kept between [0;1] range; if saved as a multichannel .exr, its output value is in the range from -1 to 1.
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.
Attributes
The parameters for this render element appear in the Attribute Editor under Extra V-Ray Attributes.
Enabled – 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.
Filename suffix – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.normals.vrimg).
Filtering – Applies the image filter to this channel. Image filter settings are in the Image Sampler rollout in the VRay tab of the Render Settings.
When using the Progressive image sampler, even if disabled, Filtering will affect the render channel.
Normals Color Generation
The Normals Render Element uses screen space to determine the colors in the render element. With screen space in the camera view:
The X axis runs left-right perpendicular to the camera viewing angle. This is represented in the Red channel of vrayRE_Normals with 1 being left-facing geometry and 0 being right-facing geometry.
The Y runs up-down perpendicular to the viewing angle. This is represented in the Green channel of vrayRE_Normals with 1 being up-facing geometry and 0 being down-facing geometry.
The Z runs forward-back to the viewing angle. This is represented in the Blue channel of vrayRE_Normals with 1 being forward-facing geometry and 0 being back-facing geometry.
Screen space XYZ coordinate system
relationship to camera and RGB colors
(Some geometry has been hidden in this screenshot for the sake of clarity)
Full vrayRE_Normals Render Element
World Normals Render
World Normals renders can be produced with a SamplerInfo render element with its type set to Normal vector and Coordinate system set to World. This renders all visible objects in the scene with colors based on the world space X, Y, and Z coordinates of their polygonal normal, and represents the actual 3D coordinate in space. These can be both positive and negative, so a floating point image format should always be used when saving this output.
Common Uses - Relighting
The 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 below a relighting workflow is used at a composite level to change the lighting in the scene. Note that it does not create any extra shadowing. This example is exactly the same under the hood as that shown in the Bump Normals Render Element page with the only change being that the Normals render element was used here instead of the Bump Normals render element.
Bump Normals Render Element
The World Positions pass
Original Beauty Composite
The resulting relit composite
(2 point lights of varying intensities and colors were used along with 2 directional lights)