Sky

The V-Ray Sky texture map is typically used as an environment map to help simulate outdoor lighting. The texture changes its appearance based on the position of the V-Ray Sun, which it is normally used in conjunction with the V-Ray Sun and Sky System. The example below on the left is a swatch of the sky map with a visible horizon line and ground. The renders to the right show a chrome shader ball and a diffuse shader ball with the VRaySky texture map as an environment along with sun lighting.

Transform – Specifies the transformation of the Sun.

Target Transform – Specifies the transformation of the Sun pivot

Sun – If specified, all parameters are taken from the sun.

Up Vector – Specifies an up vector different from the one for the scene.

Find Sun Automatically – When enabled, attaches the sun automatically and takes settings from it.

Sun Dir Only – When enabled, uses only the direction of the specified sun. No other parameters will be inherited.

Sun Invisible – Controls whether the shape of the Dome Light source is visible in the resulting render. When disabled, the source light is rendered in the current light color, otherwise the light source itself is not visible in the scene.

Sky Model – Determines the procedural model that will be used to generate the VRaySky texture:

Preetham et al. – When selected, the  VRaySky procedural texture will be generated based on the Preetham et al. method. 
CIE Clear – When selected, the VRaySky procedural texture will be generated based on the CIE method for clear sky.
CIE Overcast – When selected, the VRaySky procedural texture will be generated based on the CIE method for cloudy sky.
Hosek et al – When selected, the VRaySky procedural texture will be generated based on the Hosek et al. method and uses a different ground and sky gradient.

Turbidity – 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. 

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

Intensity Multiplier – Determines the intensity value when overwriting the sun settings.

Size Multiplier – 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. 

Horiz Illum. – Specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky. Note: Only available when CIE Overcast or CIE Clear are selected as the Sky model.

Horizon Offset – Allows the user to manually lower the horizon line.

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.

Water Vapour – Controls the amount of water vapor in the atmosphere which affects the sky color.

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