This page gives information on the Background Render Element.
Overview
The Background Render Element includes just the background as set in the scene, with the rest of the image rendered as black. It stores an image of the texture used in the background behind geometry in a scene as seen from the camera. Geometry that blocks the background image renders as black.
This render element interprets a background texture, such as the texture set in the 3ds Max Environment dialog, as the background; other types of manually created backgrounds, such as a plane mapped with a texture set outside a window, is not interpreted to be the "background" for this render element.
Parameters
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 VRay Frame Buffer.
Color mapping – Applies the color mapping options specified in the Color mapping rollout (Render Setup window > V-Ray tab) to this render element. This option is enabled by default.
Multiplier – Sets the overall intensity of the render element, where 1.0 is the standard multiplier.
Denoise – Specifies whether to denoise this render element.
Common Uses
The Background Render Element is primarily used for layering the Beauty element (or combined render elements) on top of the background image. The Alpha Render Element can be used to create a matte for such a composite. See the scene before and after adding the Background Render Element.
Notes
When the background is behind a transparent or semi-transparent material such as glass or clear plastic, make sure the Alpha channel is enabled for the material for all render elements; otherwise, the background is not visible in the render element. For example, when using VRayMtl for a glass material, set the Affect channels parameter for both Reflection and Refraction to All channels to cause the background to appear in the Background Render Element behind the glass.