[VRaySun and VRaySky example]

 

General

VRaySun parameters

VRaySky parameters

Notes

References and links

 

Search keywords: sun, sky, VRaySun, VRaySky, environment, daylight, sunlight, exterior lighting 

General

The VRaySun and VRaySky are special features which are provided by the V-Ray renderer. Developed to work together, the VRaySun and VRaySky 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 VRaySun.

 

The V-Ray Sun and Sky are based largely on the model presented in [1]. For a more complete list of references, please see the References and links section.

VRaySun parameters

The VRaySun is located in the (Create - Lights - VRay) panel. V-Ray SunYou can also specify the VRaySun as the sun type inside a Rhino Daylight system.

 

Modify Sun Button - Clicking this button will open up the Rhino Sun Options where you are able to adjust Sun Position, Date and Time, and Location

Sun

Enabled - turns on and off the sun light.

 

Water Vapor - aqueous vapor, is the gas phase of water. Water vapor is one state of the water cycle within the hydrosphere.

 

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. For further information, please see the Examples section.

 

Horizon Illum. - specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky

 

Sky Model - Allows you to specify the procedural model that will be used to generate the VRaySky texture.

 

- Preetham et al. - when this mode is selected the VRaySky procedural texture will be generated based on the Preetham et al. method.

- CIE Clear - when this mode is selected the VRaySky procedural texture will be generated based on the CIE method for clear sky.

- CIE Overcast - when this mode is selected the VRaySky procedural texture will be generated based on the CIE method for cloudy sky

 

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.

 

Intensity multiplier - this is an intensity multiplier for the VRaySun. Since the sun is very bright by default, you can use this parameter to reduce its effect. See the Notes and Examples sections for more information.

 

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.

 

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.

Sampling

Photon Subdivs - this value is used by V-Ray when calculating the Global Photon Map. Lower values mean more noisy results, but will render faster. Higher values produce smoother results but take more time.

 

Photon Emit Distance - this parameter defines a radius arround the sun from where the photons will be shot.

 

Photon Radius - determines the radius of the area, in where photons would be shot. This area is represented by the green cylinder around the Sun's ray vector. This parameter has effect when photons are used in the GI solutions or caustics.

 

Caustic Subdivs - this value is used by V-Ray when calculating Caustics. Lower values mean more noisy results, but will render faster. Higher values produce smoother results but take more time.

 

Affect Diffuse - this determines whether the VRaySun is affecting the diffuse properties of the materials.

 

Affect Specular - this determines whether the VRaySun is affecting the specular of the materials.

 

Diffuse Mult - a multiplier for the illumination generated by the Global Photon Map.

 

Caustic Mult - a multiplier for the illumination created by Caustics.

Shadow

Shadows - turns the casting of shadows On and Off

 

Shadow Bias - moves the shadow toward or away from the shadow-casting object (or objects). If the bias value is too low, shadows can "leak" through places they shouldn't, produce moire patterns or making out-of-place dark areas on meshes. If bias is too high, shadows can "detach" from an object. If the bias value is too extreme in either direction, shadows might not be rendered at all. For further info, please see the Examples section.

 

Shadow Subdivs - this controls the number of samples for the area shadow of the sun. More subdivs produce area shadows with better quality but render slower. For further info, please see the Examples section.

 

Shadow Color - a tint for the shadows created by the V-Ray Sun

VRaySky parameters

VRaySky parametersThe VRaySky texture map is typically used as an environment map, either in the Rhino Environment dialog, or in one of the slots of the V-Ray Environment rollout and behaves very much like a HDRI environment map. The VRaySky changes its appearance based on the position of the VRaySun.

 

Sun - specifies how the VRaySky determines its parameters: 

Off - the VRaySky will automatically take its parameters from the first enabled VRaySun in the scene. In this case, none of the other parameters of VRaySky are accessible.

 

On - you can choose a different light source. It is recommended that you choose only direct lights, as the vector for the direction is taken into consideration when computing the appearance of the sky. In that case the VRaySun is no longer controlling the VRaySky and the parameters in the texture map rollout determine the final look of the sky.

 

Sky Brightness -

 

Turbidity - refer to VRaySun parameters

 

Ozone - refer to VRaySun parameters

 

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.

 

Sky Model - Allows you to specify the procedural model that will be used to generate the VRaySky texture.

 

- Preetham et al. - when this mode is selected the VRaySky procedural texture will be generated based on the Preetham et al. method.

- CIE Clear - when this mode is selected the VRaySky procedural texture will be generated based on the CIE method for clear sky.

- CIE Overcast - when this mode is selected the VRaySky procedural texture will be generated based on the CIE method for cloudy sky

 

Size Mult - refer to VRaySun parameters

 

Water Vapor- refer to VRaySun parameters

 

Horizon Illum. - refer to VRaySun parameters

Notes

References and links

Here is a list of links and references about the V-Ray Sun and Sky implementation, as well as general information about the illumination of the Sun.