V-Ray Sky is a special feature provided by the V-Ray renderer to work with the V-Ray Sun. Together, V-Ray Sun and V-Ray Sky 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 V-Ray Sun.
When the V-Ray Sun and Sky systems are connected together, they will share a number of parameters. For example, changes made to the Sun section of the Sky Texture will directly affect the V-Ray Sun. See the V-Ray Sun and V-Ray Sky | SunLight page under Lights for additional information and examples.
Sun – Specifies the V-Ray Sun that will be connected with the Sky texture. The following parameters will affect this specific Sun light.
Color – Shifts the hue of the SunLight system towards the color specified in the field.
Color Mode – Determines the way the color in the Filter color parameter affects the color of the sun.
Filter – Shifts the V-Ray sun's hue according to the Filter Color parameter.
Direct – Sets the color of the V-Ray sun to the color in the Filter Color parameter. The intensity of the light no longer depends on the V-Ray Sun's position in the sky. Instead, intensity is controlled through the Intensity Multiplier.
Override – Sets the color of the V-Ray sun to the color in the Filter Color parameter. The intensity of the of the light still depends on the V-Ray Sun's position in the sky.
Intensity Multiplier – Determines the brightness of the sun and can be used to reduce the default brightness.
Size Multiplier – Determines the visible size of the sun. This includes the appearance of the sun disc as seen by the camera and reflections, as well as the blurriness of the sun shadows.
Sky Model – Specifies the procedural model that will be used to generate the V-Ray Sky texture.
Preetham et al. – The V-Ray Sky procedural texture will be generated based on the Preetham et al. method.
CIE Clear – The V-Ray Sky procedural texture will be generated based on the CIE method for clear sky.
CIE Overcast – The V-Ray Sky procedural texture will be generated based on the CIE method for cloudy sky
Hosek et al. – The V-Ray Sky procedural texture will be generated based on the Hosek et al. method.
Horizon Illum. – Specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky.
Turbidity – Determines the amount of dust in the air and affects the color of the sun and sky. Smaller values produce a clear, blue sky and sun as seen in rural areas, while larger values make them yellow and orange as seen in a big city's atmosphere.
Ozone – Affects the color of the light. Values closer to 0.0 make the sunlight yellow, and values closer to 1.0 make it blue.
Albedo Color – Sets the ground color of the V-Ray Sun and Sky system.
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.
Horizon Offset – Allows the user to manually lower the horizon line.
Invisible – When enabled, the sun becomes invisible to both the camera and reflections. This is useful to prevent bright speckles on glossy surfaces where a ray with low probability hits the extremely bright sun disk.
Affect Diffuse – When enabled, the V-Ray Sun affects the diffuse properties of the materials. The slider sets the multiplier that controls the V-Ray Sun's contribution to the diffuse illumination.
Affect Specular – When enabled, the V-Ray Sun affects the specular of the materials. The slider sets the multiplier that controls the V-Ray Sun's contribution to the specular reflection.
Shadow – When enabled, the Sun produces shadows.
Caustic Subdivisions – Used by V-Ray when calculating Caustics. Lower values produce noisy results, but will render faster. Higher values produce smoother results, but take more time.
Emit Radius – Defines the area around the V-Ray Sun from where the photons will be shot.