Sky

This page provides information about the Sky rollout of Vantage's Environment tab.

Overview

The Sky rollout offers properties for the environment setup. It is located under the Environment tab in the right-hand side panel.

The Sky settings are grouped into basic and advanced settings tabs.

	Settings tab – Contains general settings for configuring the environment mode and parameters.
	Include/Exclude tab – .Contains include/exclude lists of objects that are affected by the environment.

Settings

Texture Mode

The following parameters are available for Texture Mode.

Load environment – Loads an image for Environment.

RGB color space – Specifies the RGB color space of the environment texture.

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.

Flip horizontally – Flips the environment image horizontally.

Clamp to 1 – Clamps the colors of the Environment texture to a value of 1.

Rotation – Specifies a rotation angle in degrees for the Environment texture.

Intensity – Specifies the intensity of the Environment lighting.

Solid Color Mode

Physical Sky Mode

The following parameters are available for Physical Sky Mode.

Intensity – Specifies the intensity of the Environment lighting.

Sky model – Specifies the use of location coordinates, date and time of day to control the sun position. See the Sky Model examples below.

Preetham et al. – The sky procedural texture is generated based on the Preetham et al. model.
CIE Clear – The sky procedural texture is generated based on the CIE method for a clear sky.
CIE Overcast – The sky procedural texture is generated based on the CIE method for a cloudy sky.
Hosek et al. – The sky procedural texture is generated based on the Hosek et al. model.
PRG Clear Sky (old) – The sky procedural texture is generated based on the PRG Clear Sky model (prior to V-Ray 7) which has enhanced sunrise and sunset sky.
PRG Clear Sky – The sky procedural texture is generated using the updated PRG Clear Sky method. The updated PRG Clear Sky allows for rendering the sky at various observer altitudes, up to several kilometers controlled by the Altitude parameter. It also supports rendering of nautical twilight effects with sun positions up to 12 degrees below the horizon. Additionally, it features enhanced turbidity control, enabling the rendering of sky conditions with turbidity values ranging from 1.81 to 4.89. See the PRG Clear Sky examples below.

Ground albedo – Sets the color of the ground.

Indirect hor illum – Specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky. This parameter is enabled when one of the CIE Sky Models(CIE Clear, CIE Overcast) are selected.

Blend angle – Specifies the angle in degrees where blending will occur between the horizon line and sky. Values close to 0.0 produce a sharper horizon line, while larger values produce a softer horizon line. See the PRG Clear Sky - Blend Angle examples below.

Horizon offset – Allows you to manually lower the horizon line. See the PRG Clear Sky - Horizon Offset examples below.

Turbidity – Determines the amount of dust in the air, which in turn affects the color of the sun and sky. Smaller values produce a clear, blue sky and sun similar to what is seen in rural areas, while larger values make the sun and sky more yellow and orange. See the PRG Clear Sky - Turbidity examples below.

Altitude – Controls the observer's altitude in meters. As the altitude increases, sky clarity improves, and the horizon line becomes less defined. See the PRG Clear Sky - Altitude examples below.

Ozone – Affects the color of the sun light. Available in the range between 0.0 and 1.0. Smaller values make the sunlight more yellow, while larger values make it bluer.

Include/Exclude

Light include/exclude – Specifies a list of objects to be included in or excluded from illumination. Objects are added to the list using the Pick scene object(s) tool.

Shadow include/exclude – Specifies a list of objects to be included in or excluded from shadow-casting. Objects are added to the list using the Pick scene object(s) tool.

Pick scene object(s) () – Selects objects and adds them to the include/exclude list.

Delete selected object(s) from the list () – Removes the selected objects from the include/exclude list.

Examples

The following examples demonstrate the effect that individual Sky parameters have on the scene. Click on any image to view it at a higher resolution.

Sky Models

The images below show the different sky model types. Default values for VRaySky have been used.

Preetham et al.

CIE Clear

CIE Overcast

Hosek et al.

PRG Clear Sky Old

PRG Clear Sky

PRG Clear Sky - Turbidity

In this example, you can see how the amount of dust in the air affects the color of the sun and sky. Smaller values produce a clear image, while higher values dim the sun and sky.

01_PRGNew_Turbidity-2

Turbidity = 2

02_PRGNew_Turbidity-2x6

Turbidity = 2.6

03_PRGNew_Turbidity-3

Turbidity = 3

04_PRGNew_Turbidity-4

Turbidity = 4

05_PRGNew_Turbidity-5

Turbidity = 5

PRG Clear Sky - Altitude

This example shows how the Altitude values affect the visualization of the sky. Higher Altitude values result in better sky clarity and a less defined horizon line.

01_PRGNew_Altitude-0

Altitude = 0

02_PRGNew_Altitude-1000

Altitude = 1000

03_PRGNew_Altitude-2000

Altitude = 2000

04_PRGNew_Altitude-10000

Altitude = 10000

05_PRGNew_Altitude-15000

Altitude = 15000

PRG Clear Sky - Nautical twilight effect

This example shows how the sun's position affects the sky, creating a twilight effect. Changing the sun's position could require adjusting the Exposure Value as well.

01_PRGNew_EV10_0deg