Choose Infinite Light in Light Type option to use Sun Light Tab.

The Physical Sun and Physical Sky are developed to work together, they reproduce the real-life Sun and Sky environment of the Earth. Both are coded so that they change their appearance depending on the direction of the Physical Sun.

Physical Sun – turns on and off the sun light.

Sun Invisible – when on, this option makes the sun invisible, both to the camera and to reflections. This is useful to prevent bright speckles on glossy surfaces where a ray with low probability hits the extremely bright sun disk.

Atmosphere Shadows – lets you determine whether atmospheric effects, such as fog, can cast shadows.

Physical Sky – turns on and off the sky light and environment.

Sky Only – use only sky, sun will not be used in scene.

Sky model – allows you to specify the procedural model that will be used to generate the sky.

  • Preetham (default) – when this mode is selected the V-Ray Sky procedural texture will be generated based on the Preetham et al. method.
  • CIE Clear – when this mode is selected the V-Ray Sky procedural texture will be generated based on the CIE method for clear sky.
  • CIE Overcast – when this mode is selected the V-Ray Sky procedural texture will be generated based on the CIE method for cloudy sky.
  • Hosek et al. – when selected, the V-Ray Sky procedural texture will be generated based on the Hosek et al. method and uses a different ground and sky gradient.

Sky intensity multiplier – this is an intensity multiplier for the Physical Sky. The multiplier can be set to greater than 100%. Note that Physical Sky intensity increasing does not affect Physical Sun brightness intensity.

Override BG Env. – when this option is unchecked Physical Sky has no effect to Background and Background from Enviroment tab will be visible on render.

Override GI Env. – when this option is unchecked Physical Sky has no effect to GI Enviroment and GI Enviroment from Enviroment tab will be visible on render.

Override Refl. Env. – when this option is unchecked Physical Sky has no effect to Reflection and Reflection from Enviroment tab will be visible on render.

Override Refr. Env. – when this option is unchecked Physical Sky has no effect to Refraction and Refraction from Enviroment tab will be visible on render.

Turbidity – this parameter determines the amount of dust in the air and affects the color of the sun and sky. Smaller values produce a clear and blue sky and sun as you get in the country, while larger values make them yellow and orange as, for example, in a big city. For further info, please see the Examples section.

Ozone – this parameter affects the color of the sun light. Available in the range between 0.0 and 1.0. Smaller values make the sunlight more yellow, larger values make it blue. For further info, please see the Examples section.

Water vapour – aqueous vapor, is the gas phase of water. Water vapor is one state of the water cycle within the hydrosphere. Not used in current version.

Size Multiplier – this parameter controls the visible size of the sun. This affects the appearance of the sun disc as seen by the camera and reflections, as well as the blurriness of the sun shadows.

Filter Color – this option allows the user to shift the hue of the V-Ray Sun and Sky system towards the color specified in the field.

Photon Emit Radius – determines the radius of the area, in where photons would be shot.

Horizon Illumination for Phys Cam – specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky. This value affects only on V-Ray Physical Camera Tag.

Horizon Illumination for Std Cam – specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky. This value affects only on Cinema4D Camera render, even if it have V-Ray Physical Camera Tag on it.

Intensity multiplier for Phys Cam – this is an intensity multiplier for the Physical Sun. Since the sun is very bright by default, you can use this parameter to reduce its effect. This multiplier affects only on V-Ray Physical Camera Tag.

Intensity multiplier for Std Cam – this is an intensity multiplier for the Physical Sun. Since the sun is very bright by default, you can use this parameter to reduce its effect. This multiplier affects only on Cinema4D Camera render, even if it have V-Ray Physical Camera Tag on it.

Ground Albedo – Sets the color of the V-Ray Sun and Sky system’s ground.

Color Mapping

Convert to Grayscale – This will automatically convert sky to grayscale.

Gamma Correction – correct gamma value for Physical Sky.

Contrast Correction – correct contrast value for Physical Sky.

Hue Offset – correct hue value for Physical Sky.

Hue Gain – correct hue intensity for Physical Sky.

Saturation Offset – correct saturation value for Physical Sky.

Saturation Gain – correct saturation intensity for Physical Sky.

Lightness Offset – correct lightness value for Physical Sky.

Lightness Gain – correct lightness intensity  for Physical Sky.

Example: Direction of the V-Ray Sun Light

Note: All the images below are rendered with Color mapping: HSV exponentialDark multiplier: 1.0Bright multiplier: 1.0 unless otherwise noted.

This example demonstrates the effect of the sun direction. Note how in addition to the scene brightness, the sun position also changes the appearance of the sky and the sun light color.

Enabled: onTurbidity: 3.0Shadow subdivision: 8Intensity multiplier: 0.01Size multiplier: 1.0.

Sun Z height: 500

Sun Z height: 1600

Sun Z height: 6000 (almost straight above)

Example: The Turbidity Parameter

This example demonstrates the effect of the Turbidity parameter. Generally, this controls the amount of dust particles in the air. Notice how larger values cause the sun and the sky to become yellowish while smaller values make the sky clear.

Enabled: onIntensity multiplier: 0.01Shadow subdivision: 8Size multiplier: 1.0

Turbidity is 2.0

Turbidity is 4.0

Turbidity is 8.0

Example: Ozone Value

The Ozone parameter affects only the color of the light emitted by the sun. Higher values cause the color mapping mode to change. This example demonstrates the looks achieved with several different color mapping modes.

Enabled: onTurbidity: 2.0Shadow subdivision: 36, Intensity multiplier: 0.01Size multiplier: 10.0.

Ozone: 0.0

Ozone: 0.5

Ozone: 1.0

Example: The Intensity Multiplier Parameter

Enabled: onTurbidity: 3.0Shadow subdivision: 8Size multiplier: 1.0

Height: Z = 0, Intensity mult: 0.01

Height: Z = 0, Intensity mult: 0.03

Height: Z = 0, Intensity mult: 0.05

Height: Z = 500, Intensity mult: 0.01

Height: Z = 500, Intensity mult: 0.03

Height: Z = 500, Intensity mult: 0.05

Example: The Size Multiplier Parameter

This example demonstrates the effect of the Size multiplier parameter. Notice how changes in this parameter affect both the visible sun size and the shadow softness (however overall illumination strength remains the same).

Enabled: onTurbidity: 3.0Shadow subdivision: 8, Intensity multiplier: 0.01

Size multiplier is 4.0

Size multiplier is 10.0

Size multiplier is 40.0

Example: The Shadow Subdivs Parameter

This example demonstrates the effect of the Shadow subdivs parameter. Note how lower subdivs cause the shadows to be more noisy.

Enabled: onHeight Z1200, Turbidity is 2.0, Intensity multiplier is 0.01, Size multiplier: 10.0

Shadow subdivs is 8

Shadow subdivs is 16

Shadow subdivs is 48

Example: Shadow Bias

Enabled: onTurbidity: 2.0Shadow subdivision: 36, Intensity multiplier: 0.01Size multiplier: 10.0

Shadow bias: 0.0

Shadow bias: 7.0

Shadow bias: 13.0

Example: V-Ray Sun and Sky with Different Color Mapping Types

In addition to the parameters of the sun and sky, their appearance also depends on the selected color mapping mode. This example demonstrates the looks achieved with several different color mapping modes.

Enabled: onHeight Z800, Turbidity: 3.0Shadow subdivision: 8, Intensity multiplier: 0.01Size multiplier: 1.0

Color mapping: Exponential

Color mapping: HSV exponential

Color mapping: Intensity exponential

By default, the V-Ray Sun and V-Ray Sky are very bright. In the real world, the average solar irradiance is about 1000 W/m^2. Since the image output in V-Ray is in W/m^2/sr, you will typically find that the average RGB values produces by the sun and the sky are about 200.0-300.0 units. This is quite correct from a physical point of view, but is not enough for a nice image. You can either use Color mapping to bring these values to a smaller range (which is the preferred way) or you can use the Sun intensity multiplier to make the sun and sky less bright. Using the V-Ray Physical Camera with suitable values also produces a correct result without changing the sun and sky parameters.