The Background rollout provides control over how the Sky sphere is rendered. The rollout is located under the Environment tab in the right-hand side panel.

Mode – Specifies the mode which will be used for the background. Note that the Background texture is not used for lighting and glossy reflections. See the Background Mode example below.

Same as environment – Uses the specified Environment source.

Solid color – Uses a solid color for the background.

Image – Uses an image as a background.

The following parameters are available for Solid Color mode:

Color – Specifies a color as a background.

Intensity – Specifies the intensity for the background image/color. See the Solid Color Intensity example below.

Use for refraction/mirror reflection – When enabled, the background override is used for both refraction and perfect (glossiness=1) reflection rays. See the Use for Refraction/Mirror Reflection example below.

The following parameters are available for Image mode:

Color – Specifies a color as a background when Background Image is empty. When a background image is loaded through the Load background option, the color has no effect.

Load background – Specifies an image to use as a background.

RGB color space – Specifies the RGB color space of the background image.

Auto – The color space is deduced by the file's name.
Raw – No transformation is applied to R|G|B colors.
sRGB – The loaded image is considered in sRGB color space.
ACEScg – The loaded image is considered in ACEScg color space.

Mapping – Specifies the mapping method for the image - spherical or screen. See the Mapping example below.

Rotation – Specifies a rotation angle in degrees for the background image. Available when Spherical is set for Mapping.

Flip horizontally – Reverses the image along the vertical axis, swapping the left and right sides. The vertical position remains unchanged. In short, the image is flipped horizontally.

Fit – Controls how the environment texture is mapped to the camera view. It offers three modes: 

Inside – Maps the environment texture to fit the camera view height while keeping the texture proportions.
Outside – Maps the environment texture to fit the camera view width while keeping the texture proportions.
Stretch – Stretches the environment texture to fit the camera view without keeping the texture proportions.

Intensity – Specifies the intensity for the background image/color.

Use for refraction/mirror reflection – When enabled, the background override is used for both refraction and perfect (glossiness=1) reflection rays. See the Use for Refraction/Mirror Reflection example below.

Background Mode

This example shows the difference between all three Background Modes.

Solid Color Intensity

This example shows the effect of the Intensity parameter when Background Mode is Solid color.

Use for Refraction/Mirror Reflection

This example shows the effect of the Use for refraction/mirror reflection parameter. The Background mode is set to Image. Note how the reflection changes to reflect the new overwritten background instead of the original physical sky and procedural clouds.

Mapping

This example shows the effect of the Mapping parameter. The Background mode is set to Image. Note that the image used as background is best suited for spherical map.