Background Object - Arnold for Cinema4d
C4DtoA supports the native Cinema 4D Background object. You can use it with the shadow_matte shader for compositing scene geometry onto a photographic backplate.
Arnold specific settings can be edited via an Arnold tag added to the Background object.
Offscreen Color
Returns the specified color when the background is sampled outside of the screen. For example, in specular or transmission rays through a shadow_matte shader.
Render As Object
When enabled, the background is rendered as a plane surface facing the camera at a given distance. That means refraction index (IOR) is taken into account when the background is visible in transmission (for example, through glass).
Distance
Controls the distance of the background plate from the camera when rendered as an object. The plane can be moved to the camera far clip pane or a user-specified distance.
Visible in Transmission
When enabled, the background image becomes visible for transmission rays. IOR is ignored unless Render As Object is enabled.
Since the background plate is not available outside of the screen, transmission rays at the edge may return black, depending on the IOR. Consider using an Arnold Sky with HDRI in this case instead.